Characteristics and formation of rain forest soils from Quaternary basalt in Leyte, Philippines

The classical view about soils of tropical rain forest ecosystems is that these soils are old, acidic, and infertile. It is now widely acknowledged that this view which has greatly influenced research and management of the fragile rain forest ecosystem during the last several decades is largely a misconception. Although highly weathered soils (Oxisols or Ferralsols) are the most dominant soils in the humid tropics, tropical soils range from relatively young fertile soils (e.g. Inceptisols) to the highly weathered infertile soils (e..g. Oxisols). The extent of highly weathered soils is less in geologically young areas like in much of SE Asia.

More detailed investigations of rain forest soils are vital for the sustainable management of this threatened ecosystems. These could also lead to a better understanding of the response of rain forests to climate change.

Navarrete et al. (2009) recently conducted a study to evaluate the physical, chemical and mineralogical characterisitics of rain forest soils in Leyte, Philippines. Some of the important findings of that study include:

1) Soils along the catena studied showed minimal variations in their morphological, physical and chemical properties. This has important ecological implications as it tends to not support the idea that high soil spatial variability at short distances in rain forest ecosystems is a major factor for its high biodiversity.

2) The dominant soil-forming processes that produced the soils in the study area are weathering, loss of bases and acidification, desilification, ferrugination, clay formation and translocation, and structure formation. The loss of bases and acidification due to rapid leaching are shown by the low base saturation, very low exchangeable bases, acidic pH, and the low contents of total Ca, Na, Mg, and K. The degree of desilification is almost unifrom in all soils and may have reached 12-19% of that found in the parent material. Ferrugination is shown by the increased loss of bases, halloysitic and kaolinitic mineralogy, high contents of iron oxides and low base saturation. Clay formation and translocation are reflected by the high clay contents particularly in the middle part of the soil profile. Soil structure formation is exhibited by the good soil physical condition.

3) The nature of the basalt parent rock and the climatic condition prevailing in the area as well as its relief appear to be the dominant factors affecting the development of the soils.

Reference

Navarrete IA, K Tsutsuki, VB Asio, R Kondo. 2009. Characteristics and formation of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines. Environmental Geology 58: 1257-1268.

Lead pollution due to vehicular emissions in urban areas in the Philippines

Lead (Pb) has been known to be toxic since ancient times. It is a widespread contaminant in soils and Pb poisoning is one of the most prevalent public health problems in many parts of the world. It was the first metal to be linked with failures in reproduction. It can cross the placenta easily. It also affects the brain, causing hyperactivity and deficiency in the fine motor functions, thus, it results in damage to the brain. The nervous systems of children are especially sensitive to Pb leading to retardation. Pb is cardiotoxic and contributes to cardiomyopathy (disease of the heart muscle leading to the enlargement of the heart).

Pb is released into the environment from the weathering of Pb-containing rocks, the industry, and the combustion of fossil fuels. Emissions from vehicles are thus a major source of environmental contamination by Pb especially in cities. Ona et al. (2006) conducted a study that looked into Pb pollution in selected urban areas in the Philippines with the following objectives: (1) to determine the levels of Pb in soil from selected urbanized cities in central region of the Philippines; (2) to identify areas with soil Pb concentration values that exceed estimated natural concentrations and allow- able limits; and (3) to determine the possible sources that contribute to elevated soil Pb concentration (if any) in the study area.

The study focused on the determination of Pb levels in soils of selected cities in Luzon, Philippines. The sites included: Site 1 – Tarlac City in Tarlac; Site 2 – Cabanatuan City in Nueva Ecija; Site 3 – Malolos City in Bulacan; Site 4 – San Fernando City in Pampanga; Site 5 – Balanga City in Bataan; and Site 6 – Olongapo City in Zambales. Soil samples were collected from areas along major thoroughfares regularly tra- versed by tricycles, passenger jeepneys, cars, vans, trucks, buses, and other motor vehicles. Soil samples were collected from five sampling sites in each of the study areas. Samples from the selected sampling sites were obtained approximately 2 to 3 meters from the road. Analysis of the soil samples for Pb content was conducted using an atomic absorption spectrophotometer.

Findings revealed Pb levels ranging from 1.5 to 251 mg kg–1 in all the soil samples collected from the 30 sampling sites in the six cities. Elevated soil Pb levels i.e.greater than 25 mg kg–1 Pb) were observed in five out of the six cities sampled. Site 4 showed the highest Pb concentration (73.9 ± 94.4 mg kg–1), followed by Site 6 (56.3 ± 17.1 mg kg–1), Site 3 (52.0 ± 33.1 mg kg–1), Site 5 (39.3 ± 19.0 mg kg–1), and Site 2 (38.4 ± 33.2 mg kg–1). Soil Pb level in Site 1 (16.8 ± 12.2 mg kg–1) was within the estimated natural Pb concentration range of 5 to 25 mg kg–1. The study found that the average soil Pb concentration from the six cities studied were below the maximum tolerable limit according to World Health Organization (WHO) standards. The high Pb concentration in Site 4 was attributed by the authors mainly to vehicular emission.

The researchers concluded that "only one (San Juan in Site 4) of the thirty sampling sites showed a Pb concentration above the WHO permissible limit of 100 mg kg–1. San Juan in Site 4 had a Pb concentration of >250 mg kg–1. On the average, elevated Pb concentration was evident in the soil samples from San Fernando, Olongapo, Malolos, Balanga, and Cabanatuan. The average soil Pb concentrations in these cities exceeded the maximum estimated natural soil Pb concentration of 25 mg kg–1. Average soil Pb concentration in Site 1 (16.8 mg kg–1) was well within the estimated natural concentration range of 5 to 25 mg kg–1. Data gathered from the study areas showed that elevated levels of Pb in soil were due primarily to vehicular emissions and partly to igneous activity."

Reference
Ona LF, Alberto AMP, Prudente JA and Sigua GC. 2006. Levels of lead in urban soils from selected cities in a Central Region of the Philippines. Environ Sci & Pollut Res 13 (3) 177 – 183

The causes of the Guinsaugon landslide

On 17 February 2006, a catastrophic landslide buried the village of Guinsaugon, the second largest village of St. Bernard town (Southern Leyte, Philippines) killing more than a thousand residents and displacing approximately 19,000 people. The landslide originated on an approximately 800 m high escarpment produced by the Philippine Fault that bisects Leyte and the major islands of the Philippines. In a recent article which synthesized the papers presented during an international conference in Leyte 2008 and published in the international journal Bulletin of Engineering Geology and the Environment, Guthrie and co-workers (2009) arrived at the following conclusions:

"The approximately 15 million m3 landslide was a result of progressive failures and tectonic weakening in a region made especially vulnerable by the inter-reaction of geological/tectonic, climatic, and cultural factors. In Southern Leyte, geology and tectonics (including historical seismicity, the progressive disintegration of the rock mass, the development of smectite layers and the continuous development and movement of shears within the Philippine Fault Zone) combine in steep rugged terrain to produce a series of massive landslides ([10 million m3) of which the Guinsaugon event is the latest."

"The presence of rice paddies in the valley bottom had a major effect on the mobility of the rock avalanche, which increased the vulnerability of communities established to tend these fields. Having considered the available evidence, it is concluded that the landslide was not triggered by a seismic event that occurred several minutes afterward and that the recorded seismic signature was not a trace of the landslide itself. Rather, it is considered that the earthquake could be a result of tectonic unloading after the landslide occurred, or completely independent of the landslide event."

"The role of climate is, in some respects, similar to that of the seismic event. In terms of the trigger, the storm rainfall that occurred several days prior to the landslide undoubtedly raised pore water pressures in the source rock mass. However, progressive failure relies less and less on pore water pressure as failure becomes imminent. The danger of relying on triggers to ascertain the probability of failure is exemplified by the Guinsaugon event; in the lag time between the end of the period of heavy rainfall and the occurrence of the rockslide-debris avalanche, evacuated residents had returned to their homes. Possible trigger mechanisms can be incidental to the landslide itself; however, the progressive development of a large failure often produces telltale signs that are observable by a community of non-experts."


Our own field investigations have shown two important aspects of the landslide not very well taken up in the report. The first is about the role of the thin layers of mudstone in between thick layers of sandstone/siltstones which could have served as lubricant for the landsliding process. The other is the great possibility that the Guinsaugon village developed on old landslide debris. This was clearly shown by the fact that the lower hills not affected by the recent landslide showed comparable materials as the landslide area. Also, the behavior of the stream tells us a piece of very important information.

It is very likely that the stream was covered by landslide debris in the past which is the reason why it changed its course and appeared to go around the community. Early settlers may have found the sligthtly elevated part of the area convenient to build their houses since it was elevated (and thus not prone to flooding) but without any idea that it was landslide debris. The tragic landslide was waiting to happen. It was just a matter of time. Unfortunately, people were not aware of this.

The role of the paddy fields as claimed by the paper needs more scientific investigation. I am not convinced that it played a major role considering the fact that the debris itself was already saturated with water. The clayey soil material from the hillside probably had more influence on the movement of the debris than the paddy soil.

Reference

R. H. Guthrie, S. G. Evans, S. G. Catane, M. A. H. Zarco, and R. M. Saturay Jr. 2009. The 17 February 2006 rock slide-debris avalanche at Guinsaugon Philippines: a synthesis. Bulletin of Engineering Geology and the Environment 68:201–213

The problem of high levels of nickel in soils and plants in the ultramafic area in Samar, Philippines

Contributed by Janice P. Susaya, Sejong University, Seoul, Korea


One of the heavy metals that commonly occur in elevated amounts in natural ecosystems is nickel (Ni). Ni is considered an essential micronutrient for plants, humans, and animals. It can exist in trace amounts in air, food, drinking water, and soils. Although Ni plays an important role in the metabolism of humans and animals, its intake in excesssive amounts or over a prolonged period could pose health ricsks. Studies have shown that children living in polluted areas have hypertrophy of tonsils, enlarged lymphatic nodes, and enlarged livers. There is also evidence that soluble Ni particulate is linked to acute lung injury.

High Ni levels in natural ecosystems commonly come from ultramafic rocks (also called ultrabasic rocks). These are intrusive igneous rocks containing less than 45% silica (SiO2) with high concentrations of Ni, Mg, Fe, Cr, and Co. They are found in many places around the world and are common in many places in the Philippine like in Salcedo in the island of Samar.The watershed has a highly weathered soil (Oxisol) derived from the weathering of ultramafic rock. Previous studies conducted in the watershed revealed excessive levels of Ni, Cu, and Cr in the soil. Many farmers also complain of unexplained health problems which may be related to heavy metal toxicity.

In a study conducted in the Salcedo watershed and recently published in the international scientific journal Environmental Monitoring and Assessment, Susaya and co-workers (Susaya et al., 2009) evaluated the degree of Ni contamination in soils and plants in the watershed. The plants sampled included native species (non-food) such as Phyllanthus amarus, Melastoma affine, and Stachytarpeta jamaicensis as well as cultivated food crops like Calocasia esculenta, Citrullus vulgaris, Artocarpus heterophylla, Moringa oleifera, Psidium guajava, Lycopersicon esculentum, and Solanum melongena.

Results of the study showed that the quantity of total Ni in the soil was significantly high with a mean of 1,409 mg kg-1 while the available Ni was low with a mean of 8.66 mg kg-1. As the levels of total Ni greatly exceeded the maximum allowable concentration for agricultural soils, the site is not suitable for agricultural purposes. Available Ni levels were low due to the tight binding between Ni and the soil components. This explains why all plants investigated did not met the criterion for a Ni hyperaccumulator plant. Comparison of Ni levels between the food plants sampled and its recommended daily intake (RDI) suggests that consumption of a particular food plant grown in the study area is unlikely to pose health problems. However, prolonged consumption of a given food plant with high Ni level or combined consumption of different food plants with high Ni levels can induce accumulation of Ni above the RDI and thus could cause health problems.

Reference

Susaya JP, KH Kim, VB Asio, ZS Chen, and IA Navarrete. 2009. Quantifying nickel in soils and plants in the ultramafic area in Philippines. Environmental Monitoring and Assessment (now available online at http://www.springer.com/environment/environmental+toxicology/journal/10661)

A superheavy new element is named "copernicium"

Source: Website of GSI Helmholtz Center for Heavy Ion Research, Darmstadt

Element 112 in the periodic table is named in honor of the great astronomer Nicolaus Copernicus (1473-1543). Copernicus discovered that the Earth orbits the Sun ("heliocentric theory"), thus paving the way for our modern view of the world.

The discovering team of scientists at the GSI Helmholtzzentrum für Schwerionenforschung (Center for Heavy Ion Research) in Darmstadt, Germany, led by Professor Sigurd Hofmann (photo) suggested the name „copernicium“ with the element symbol “Cp” for the new element 112. A few weeks ago, the International Union of Pure and Applied Chemistry, IUPAC, officially confirmed the discovery. In around six months, IUPAC will officially endorse the new element's name. This period is set to allow the scientific community to discuss the suggested name "copernicium" before it is finally accepted by IUPAC.

Copernicus was born 1473 in Torun and died 1543 in Frombork, Poland. His discovery that the planets circle the Sun refuted the then accepted belief that the Earth was the center of the universe (or the "geocentric theory"). This finding was pivotal for the discovery of the gravitational force, which is responsible for the motion of the planets. It also led to the conclusion that the stars are incredibly far away and the universe inconceivably large, as the size and position of the stars does not change even though the Earth is moving. Furthermore, the new world view inspired by Copernicus had an impact on the human self-concept in theology and philosophy: humankind could no longer be seen as the center of the world.

With its planets revolving around the Sun on different orbits, the solar system is also a model for other physical systems. The structure of an atom is like a microcosm: its electrons orbit the atomic nucleus like the planets orbit the Sun. Exactly 112 electrons circle the atomic nucleus in an atom of the new element “copernicium”.

Element 112 is the heaviest element in the periodic table, 277 times heavier than hydrogen. It is produced by a nuclear fusion, when bombarding zinc ions onto a lead target. As the element already decays after a split second, its existence can only be proved with the help of extremely fast and sensitive analysis methods. Twenty-one scientists from Germany, Finland, Russia and Slovakia have been involved in the experiments at GSI that led to the discovery of element 112.

Since 1981, GSI accelerator experiments have yielded the discovery of six chemical elements, which carry the atomic numbers 107 to 112. The discovering teams at GSI already named five of them: element 107 is called bohrium, element 108 hassium, element 109 meitnerium, element 110 darmstadtium, and element 111 is named roentgenium.

The goal of the scientific research conducted at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt (founded in 1969) is to understand the structure and behavior of the world that surrounds us. In addition to broadening our understanding of the world, this knowledge also serves as a basis for technological progress in all areas of our lives.

GSI operates a large, in many aspects worldwide unique accelerator facility for heavy-ion beams. Researchers from around the world use the facility for experiments that help point the way to new and fascinating discoveries in basic research. In addition, the scientists use their findings to continually develop new and impressive applications.

The research program at GSI covers a broad range of activities extending from nuclear and atomic physics to plasma and materials research to biophysics and cancer therapy. Probably the best-known results are the discovery of six new chemical elements and the development of a new type of tumor therapy using ion beams.

Heavy metals in the environment and their health effects

Heavy metals have a density of 6.0 g/cm3 or more (much higher than the average particle density of soils which is 2.65 g/cm3) and occur naturally in rocks but concentrations are frequently elevated as a result of contamination. The most important heavy metals with regard to potential hazards and occurrence in contaminated soils are arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), lead (Pb) and zinc (Zn).

The sources of heavy metal pollutants are metal mining, metal smelting, metallurgical industries, and other metal-using industries, waste disposal, corrosions of metals in use, agriculture and forestry, forestry, fossil fuel combustion, and sports and leisure activities. Heavy metal contamination affects large areas worldwide. Hot spots of heavy metal pollution are located close to industrial sites, around large cities, and in the vicinity of mining and smelting plants. Agriculture in these areas faces major problems due to heavy metal transfer into crops and subsequently into the food chain.

Health effects of selected heavy metals

Arsenic (As). Arsenic is well-known as a poison and a carcinogen. It has an average concentration in the soil of 5 to 6 mg/kg. Its amount in the soil is related to rock type and industrial activity.

Cadmium (Cd). Its toxicity is linked with the reproduction problem because it affects sperm and reduces birth weight. It is a potential carcinogen and seems to be a causal factor in cardiovascular diseases and hypertension. Large concentrations of Cd in the soil are associated with parent material (black slates) and most are manmade (burning of fossil fuels, application of fertilizers, sewage sludge, plastic waste).

Chromium (Cr). It is required for carbohydrate and lipid metabolism and the utilization of amino acids. Its biological function is also closely associated with that of insulin and most Cr-stimulated reactions depend on insulin. However, excessive amounts can cause toxicity. Toxic levels are common in soils applied with sewage sludge.

Lead (Pb). This has been known to be toxic since the 2nd century BC in Greece. It is a widespread contaminant in soils. Lead poisoning is one of the most prevalent public health problems in many parts of the world. It was the first metal to be linked with failures in reproduction. It can cross the placenta easily. It also affects the brain, causing hyperactivity and deficiency in the fine motor functions, thus, it results in damage to the brain. The nervous systems of children are especially sensitive to Pb leading to retardation. It is also cardiotoxic and contributes to cardiomyopathy (disease of the heart muscle leading to the enlargement of the heart).

Mercury (Hg). This heavy metal is toxic even at low concentrations to a wide range of organisms including humans. The organic form of mercury can be particularly toxic, and the methyl-and ethyl-forms have been the cause of several major epidemics of poisoning in humans resulting from the ingestion of contaminated food, e.g. fish. Two major epidemics in Japan were caused by the release of methyl and other mercury compounds from an industrial site followed by the accumulation of the chemicals in edible fish. The poisoning became well-known as Minamata disease.

Nickel (Ni). Nickel occurs in the environment only at very low levels. Humans use nickel for many applications like the use of nickel as an ingredient of steel and other metal products. Foodstuffs have a low natural content of nickel but high amounts can occur in food crops grown in polluted soils. Humans may also be exposed to nickel by inhalation, drinking water, smoking, and eating contaminated food. Uptake of high quantities of nickel can cause cancer, respiratory failure, birth defects, allergies, and heart failure (www. Lenntech.com/periodic-chart-elements/Ni-en.htm)

References

Oliver, M.A. 1997. Soil and human health: a review. European Journal of Soil Science 48: 573-592.
Puschenreiter M., O Horak, W. Friesel, and W. Hartl. 2005. Low-cost agricultural measures to reduce heavy metal transfer into the food chain- a review. Plant Soil Environ 51: 1-11.
Susaya JP. 2007. MSc thesis. Institute of Tropical Ecology, Visayas State University, Baybay, Leyte, Philippines.

Environmental pollution and the safety of herbal and alternative medicinal products

There is scientific evidence that many over-the-counter health foods, neutraceuticals, and alternative medicinal products may not be safe. This was revealed in a paper written by Dr. K. Chan of Hongkong Baptist University and published in the international scientific journal Chemosphere.

The paper concluded that “the increase in popularity of such products has brought concerns and fears over the professionalism of practitioners and the quality, efficacy, and safety of their treatment methods and products from herbal and natural sources. These products maybe contaminated with excessive or banned pesticides, microbial contaminants, heavy metals, chemical toxins or adulterated with orthodox drugs."

"The excessive pesticides, microbial contaminants and heavy metals maybe related to the source of these herbal materials if they are grown under contaminated environment or during the collection of these plant materials. Chemical toxins may come from unfavorable or wrong storage conditions or chemical treatment due to storage. The presence of orthodox drugs maybe related to unprofessional practice of manufacturers."

Just a little explanation for the above. Plants growing in polluted soils may absorb the pollutants like heavy metals, pesticides and other harmful substances and store them in their tissues. Studies have shown (e.g. Susaya, 2007) that succulent plant species generally absorb high amounts of heavy metals from the soil. The pesticides may also come from excessive pesticide application to control pests during the production of the herbal plants.

The article is just a reminder to all of us. It may not be true to the products that you are now using. But it may turn out that the fresh herbal plants that we can get from our own backyard maybe safer than the beautifully packed but expensive ones produced somewhere else.

(Photo shows part of the medicinal plant garden of a 12th century castle along Rhein River in Germany.)

Reference

Chan K. 2003. Some aspects of toxic contaminants in herbal medicines. Chemosphere 52: 1361-1371

F.A. Fallou: The Father of Soil Science

History is one of the most complicated and subjective academic fields since it is greatly influenced by the knowledge, experience, interest, and personal taste of the authors who reconstruct the history of a given event or human endeavour. It also depends on the availability and accuracy of historical records as well as on the degree of detail of the historical account. The renowned historian Norman Davies author of the book "Europe: A History" (Pimlico, London, 1365pp) wrote that "history can be written at any magnification. One can write the history of the universe on a single page, or the life-cycle of a mayfly in forty volumes." Thus, it is not unusual to read many different versions or revisions of the historical account of a past event.

The history of soil science is no exception. Some aspects of it are still controversial such as the one about its founder. Although the Russian geographer Vasilii Vasilevich Dokuchaev (1846-1903) is widely considered as the founder of soil science on the basis of his book “Russian Chernozem” of 1883 which discussed soil formation as a function of the factors climate, parent material, organism, relief and time, a close examination of historical records would reveal that another scientist had made a major contribution two decades before him. He was Friedrich Albert Fallou.

F.A. Fallou (1794-1877) from Zörbig, a small town in Sachsen, Germany is considered by several important authors as the founder of soil science (Blanck, 1949; Joffe, 1949; Strzemski, 1975; Schroeder, 1983; Feger and Makeschin, 2007). In his seminal book Pedologie oder allgemeine und besondere Bodenkunde (Pedology or General and Special Soil Science) of 1862, Fallou justified why soil is a natural body that needs to be studied and argued for the recognition of soil science as an independent natural science. He also introduced the concept of soil profile, discussed the physical and chemical properties of soils and established a soil classification based on parent rock (Asio, 2005).

Contrary to popular notion, it was Fallou in his book of 1862 who first recognized the soil as a natural body and not Dokuchaev who only published his important work two decades later. This was in fact acknowledged by K.D. Glinka (1867-1927) in his lecture during the first international congress of soil science in 1927 although he appeared to downplay Fallou’s contribution and gave the credit to his teacher and countryman Dokuchaev (Glinka, 1927). Dokuchaev’s fame was further enhanced by the fact that Glinka was widely read in North America especially since he was the first president of the International Society of Soil Science. That Dokuchaev who was only about 16 years old and still a young student when Fallou’s influential book of 1862 (Fallou’s sixth book) was published, reinforces the notion that he was influenced by Fallou although according to Johnson et al. (2005) Dokuchaev cited Fallou only once in his important work on chernozem. Whether or not this omission was intentional is unknown. Interestingly, the American landscape pedologist David J. Brown noted that Dokuchaev’s “geologic-geographic investigations” and soil maps were apparently based on the geographic maps (e.g. climate-vegetation maps) of Russia developed by the great natural scientist and founder of geography Alexander von Humboldt (1769-1859) but this was not acknowledged by Dokuchaev in his book (Brown, 2006).

Until now very little is known about Fallou’s book. This can be seen from the fact that most books and papers that discuss soil science history only make brief mention of Fallou’s soil classification which is only part of Fallou’s trailblazing book. The book is divided into two parts. Part I (p. 1–198) is about the general knowledge of soils and Part II (p. 199–487) presents a detailed description of his soil types based on parent rock and is relatively known.

In the preface of Part I, Fallou wrote that "the current books on soil science are just compilation of mixed materials (an aggregate of unorganized materials) from geology, geography, agricultural chemistry and plant physiology." In contrast, he stated that his book "presents for the first time the existing soil knowledge as an interconnected, concise and organized body of knowledge" and thus, as a science. He wrote: "This is the first attempt of this nature; I have blazed a trail that others may follow and improve, it does not matter if it will lead to an entirely new building of knowledge based on other principles and in another style, so that the poor and unrecognized soil science will once and for all be accorded the honor and that it will likewise be recognized as a science."

In the 22-page introduction, Fallou discussed the nature and aims of soil science, justified why soil science should be an independent natural science, and why soil is a natural body that deserves to be studied. In Chapter 1 on Entstehung des Bodens (p. 23–52), Fallou discussed the origin of soils, particularly the role of weathering and related processes like transformation and leaching, although he did not yet use the term leaching.

Chapter 2 on Wesen des Bodens (p. 54–82) is a comprehensive discussion about the nature, origin, and characteristics of the inorganic and organic soil components.

Chapter 3 on Beschaffenheit des Bodens (p. 83–107) is about soil properties such as color, structure, weight, and density, porosity, penetrability, solubility (now erodibility), and moisture content.

Chapter 4 on Räumlichkeit (p. 108–130) is actually about the dimension of the soil body. It focuses on the horizontal dimension in terms of soil distribution in the landscape as well as the vertical dimension in terms of soil depth or thickness. Fallou also discussed the distribution and thickness of the soil in the landscape in relation to elevation and slope and thus, was a recognition of the effect of relief on soil characteristics.

Chapter 5 (p.131–144) is about the inner part of the soil body in terms of the nature of soil layering. Other chapters are about differences between soils (Chapter 6), classification of soils (Chapter 7), and the role of soil in the hydrologic cycle and in plant and animal growth as well as the changes of soil with time (Chapter 8).

In Chapter 8, he wrote that "everything changes itself in form and substance with time... the soil will, like all other things in this world, get not younger but older and in the end will lose its productivity." On his discussion about the chemical processes of soil change with time, Fallou wrote that "weathering in the soil body involves transformation and rearrangement... the most important is the dissolution of the unweathered rock material to release its nutrients for plants use thereby transforming it completely to soil."

Because of the great impacts of their contributions to the development of soil science, Fallou, Dokuchaev, and Liebig are considered by some authors as co-founders of soil science. Some others notably Joffe made a slightly different distinction: Fallou as the father of soil science; Dokuchaev as the founder of modern soil science.

(Note to readers: details of all references can be requested from me)

Selection of plants for phytoremediation of sites contaminated with several metals

Phytoremediation refers to the use of higher plants to rehabilitate contaminated sites without the need to excavate the contaminant material and dispose of it elsewhere. The use of plants capable of taking up high amounts of metals has been proven effective in the rehabilitation of metal-contaminated soils. Plants are grown for a certain period of time and are then harvested and subjected to composting, compaction, incineration, ashing, pyrolysis, direct disposal or liquid extraction. In principle, the best plants for the purpose are those that can tolerate the polluted soil condition, can absorb high amounts of the contaminants, and have economic value (e.g. flowering plants) so that they can also be a source of income. Thus, selection of the suitable plant species is crucial to the success of any phytoremediation program.

In a recent study by HY Lai of MingDao University and and ZS Chen of National Taiwan University published in the International Journal of Phytoremediation, 33 flowering plant species were tested on a 1.3-ha field in central Taiwan. The site is contaminated with multiple metals (As, Cr, Ni, Cu and Zn) due to the continuous irrigation of wastewater from surrounding chemical plants in the last decade. The study used three models for the selection of suitable species: 1) a relative percentage weighting of the growth condition and the metal accumulation capacity of 80% and 20%, respectively; 2) a relative percentage weighting of the growth condition and the metal accumulation capacity of 50% and 50%, respectively; and 3) a relative percentage weighting of the growth condition and the metal accumulation capacity of 0% and 100%, respectively.

The 33 plants included bougainvillea (Bougainvillea spp.), rainbow pink (Dianthus chinensis), serissa (Serissa japonica), French marigold (Tagetes patula), rose of Sharon (Hibiscus syriacus), water willow (Salix warburgu), Chinese ixora (Ixora chinensis), sunflower (Helianthus annuus), Chinese hibiscus (Hibiscus rosasinensis), gold dewdrop (Duranta repens), kalanchoe (Kalanchoe blossfeldiana), creeping trilobata (Wedelia trilobata), garden canna (Canna generalis), garden verbena (Verbena hybrida), Malabar chestnut (Pachira macrocarpa), purslane (Portulaca oloraua), common lantana (Lantana camara), fancy leaf caladium (Caladium xhortulanun), coleus (Coleus blumei), golden trumpet (Allamanda cathartica), common melastoma (Melastoma candidum), Carland flower (Hedychium coronarium), Manaca raintree (Brunfelsia uniflora), yellow cosmos (Cosmos sulphureus), silver apricot (Ginkgo biloba), temple tree (Plumeria acutifolia), orchid tree (Aglaia odorata), star cluster (Pentas lanceolata), blue daza (Evolvulus nuttallianus), cockscomb (Celosia cristata), scandent scheffera umbrella tree (Schefflera arboricola), Bojers spurge (Euphorbia splendens), and croton (Codialum variegatum).

Some of the highlights of the study: Twelve (12) plants out of the 33 tested were selected based on two key factors: 1) ability to tolerate the toxicity of metals (i.e. good growth of the plant) and 2) ability to accumulate high concentrations of metals in the shoot. Using equal weighting (meaning 50% to 50%) of good growth condition (factor No. 1) and of accumulated metal concentrations (factor No. 2), six (6) woody and six (6) herbaceous plant species showed the best potential for phytoremediation of the contaminated site and thus were selected for further testing. These included the following plant species: purslane, garden canna, Bojers spurge, Chinese ixora, croton, kalanchoe, serissa, garden verbena, rainbow pink, French marigold, scandent scheffera umbrella tree, Chinese hibiscus, and sunflower.

The study also revealed that the herbaceous species accumulated higher concentrations of metals and thus have higher “bioconcentration factor” (ratio of metal concentration in shoots to that of the soils) compared to the woody species. The increase of metal concentrations for the herbaceous species were 9.4-fold for Cu, 5.1-fold for Cr, and 8.9-fold for Zn while for the woody species they were 3.1-fold for Cu, 2.5-fold for Cr, and 4.3-fold for Zn.

Reference

Lai HY and ZS Chen. 2009. In-situ selection of suitable plants for the phytoremediation of multi-metals contaminated sites in central Taiwan. International Journal of Phytoremediation 11: 235-250.

Brief history and current state of soil science in the Philippines

First published June 2009. Revised November 2016.

Philippine soil science owes its early development to the Americans. The first soil survey was conducted by C. W. Dorsey an American soil surveyor in 1903. In 1921 a Division of Soil and Fertilizer was created under the Bureau of Science which in 1934 was renamed as Division of Soil Survey. In 1951, the Philippine Congress enacted Republic Act No. 622 organizing the Bureau of Soil Conservation with Dr. M. M. Alicante as its first director (BSWM, 2008). Teaching of soil science to students of agricultural science started as early as the 1920s at the University of the Philippines College of Agriculture (UPCA). R. L. Pendleton an American from California was one of the pioneer soil science instructors who taught from 1923 to 1935. Dr. Pendleton was also an outstanding researcher as reflected by the about 50 scientific papers he published (Pendleton, 1942; Carter, 1958).

Until about the 1960s, much of the work of soil scientists in the Bureau of Soil Conservation (which became Bureau of Soils in 1957) was on soil survey and mapping of soil series in the entire archipelago as well as in promoting soil conservation practices. Because of the major role that soil science played in the green revolution, Philippine soil science enjoyed rapid development in the 1970s and 1980s ("golden age") primarily due to the massive faculty development at the University of the Philippines at Los Banos (UPLB) wherein young faculty members were sent abroad primarily to the U.S.A. for graduate studies, and to the world class soil research that was at the time brewing at the nearby International Rice Research Institute (IRRI) thanks largely to Nyle C. Brady.

N.C. Brady (Source: Facebook.com)

NC Brady of Cornell University who taught at UPCA (now UPLB) as Cornell visiting professor after the war returned to Los Banos in 1973 as the third director general of IRRI and remained there until 1981. During Brady's time (and until now), many leading soil scientists from around the world visited or conducted research at IRRI. Some of the internationally well-known soil scientists who worked at IRRI included P.A. Roger (France), H.U. Neue and H.W. Scharpenseel (Germany), F.N. Ponnamperuma (Sri Lanka), T. Yoshida and I. Watanabe (Japan), N. van Breemen and F. Moormann (Netherlands), D.J. Greenland and G.J.D. Kirk (U.K.), R. Bloom and P.A. Sanchez (USA), and S. Sombatpanit (Thailand). By establishing a world class soil research at IRRI and through his soil science textbook (Nature and Properties of Soils), NC Brady has undoubtedly had a major impact on the development of Philippine soil science.

At UPLB, some of the soil scientists who represented, or were product of, the "golden age" and who became influential teachers included: R.B. Badayos (genesis, survey and classification); I.J. Manguiat  and E.S. Paterno (soil microbiology); G.O. San Valentin (soil mineralogy and soil chemistry); A. A. Briones (soil physics) and E.P. Paningbatan (soil physics and soil conservation); A.M. Briones, D.A. Carandang (soil chemistry); and C. P. Mamaril, H.P. Samonte, W.C. Cosico (soil fertility). Two foreigners also spent a few years teaching soil science at UPLB: Dr. S. Srinilta (soil physics) and Dr. U. Jones (soil fertility).

A special mention must be made of Nicolas L. Galvez, a highly trained and outstanding soil scientist who took charge of developing the Soils Department and of training future Filipino soil scientists at UPCA after the war. N.L. Galvez was the head of the Soils Department from 1948 to 1961 and served UPCA for 42 years. Without doubt, Dr. Galvez had the greatest contribution to Philippine soil science. For this reason, he is widely considered as the "Dean of Filipino Soil Scientists". (A museum has recently been established in his honor at UPLB).

Outside UPLB, examples of soil scientists who also stood out during the 1980s and 1990s were J.B. Dacayo of Central Luzon State University (CLSU), S.S. Magat of Philippine Coconut Authority, R.G. Escalada of VSU who advised more than a hundred undergraduate thesis students in agronomy and soil science (including this writer), and N.B. Inciong of BSWM.

At present, there is a new generation of well-trained soil scientists, many of whom have obtained advanced degrees from prestigious universities in Australia, Japan, Europe, and North America, who are working at various universities, research centers, government agencies, and private organizations throughout the country. Undergraduate/graduate degree programs in soil science are now offered by several universities throughout the country the most important of which are UPLB, CLSU, Benguet State University, Tarlac Agricultural University, and Central Bicol State University of Agriculture in Luzon; Visayas State University or VSU (formerly called ViSCA and LSU) in central Philippines; and University of Southern Mindanao and Central Mindanao University in the southern part of the country. Survey, mapping, and soil fertility evaluation of soils throughout the country are carried out by the Bureau of Soil and Water Management based in Quezon City.

The soil science program at VSU in Baybay, Leyte, deserves a brief mention. Started in the late 1970s, the program has produced graduates who are now successful academics and scientists not only in the Philippines but also in the USA, Europe and Japan. VSU soil scientists have also produced high quality papers which have been published in various international journals. On November 5, 2014, the VSU administration under President Jose L. Bacusmo created the Department of Soil Science from the existing Department of Agronomy and Soil Science. In terms of faculty strength, facilities, and scientific publication, VSU's Department of Soil Science is widely considered as the country's leading soil science department at the moment.*

Finally, Philippine soil science has clearly made major strides in the last three decades but it lags very much behind those in other countries in terms of scientific outputs and professional activities. This is even true for the ASEAN region alone. Regarding scientific outputs, very few papers have been published by Filipino soil scientists in peer-reviewed international journals. In terms of professional activities, the Philippine Society of Soil Science and Technology (PSSST) has not yet been fully recognized by the International Union of Soil Sciences, the global organization of soil scientists. So it cannot be seen in the global map of soil science. There is an increasingly popular view among young soil scientists that basing the PSSST at the BSWM, a non-academic entity, has stifled the development of the organization and of soil science in the country.
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* The two soil scientists (V.B. Asio & I.A. Navarrete) included in the top 450 scientists in the Philippines in 2016 based on scientific citations & h index by Webometrics (http://www.webometrics.info/en/node/148) are from the Department of Soil Science of VSU.


(Note: The article is based on the available historical materials that I have gathered so far. I will revise it when new information becomes available.)

Heavy metal pollution and nutrient deficiency problems in the abandoned Bagacay mine in Samar island

The National Policy Agenda on the Revitalization of Mining in the Philippines in 2004 gives top priority to the remediation and rehabilitation of abandoned mining sites all over the country. Consequently, the Department of Environment and Natural Resources (DENR) has identified remediation and rehabilitation of several abandoned mining sites as one of its top priorities (MGB-MESD 2006). Among all abandoned mining sites throughout the country needing urgent rehabilitation, the Bagacay Mine ranks first (MGB-MESD 2006).

Bagacay Mine, located at the border of a nature reserve in the western part of Samar Island, was formerly worked for the recovery of pyrite (FeS2) and copper (Cu) for nearly 50 years until its abandonment in 1992. It exhibits many environmental problems such as heavy metal pollution of soil and water and the formation of Acid Mine Drainage. Recent efforts to rehabilitate the area by re-vegetating it with introduced trees species such as mahogany (Swietenia macrophylla), mangium (Acacia mangium) and ipil-ipil (Leucaena leucocephala) as well as some grass species like tiger grass (Thysanolaena maxima) were a total failure.

An environmental assessment by the Mines and Geosciences Bureau (MGB-MESD, 2006) revealed very high levels of heavy metals in sediments (and soils) collected from various parts of the abandoned mining site. For the upstream sediments (soil and sediments deposited by various tributaries unaffected by mining activities), the levels of heavy metals (in mg/kg) were: Fe (5,900 to 96,000), Cu (9 to 2,216), Zn (<1 to 516) and Pb (22 to 694). The midstream materials which included rock and soil materials from the main pit and waste dumps, silt and sediments in the pit, and tailings from the tailing dams were more polluted and showed the following concentrations (mg/kg): Fe (36,400 to 487,500), Cu (220 to 50,100), Zn (100 to 187,700), Pb (8 to 2,341), As (6 to 5,969) and Hg (1 to 13). For the downstream sediments (from the Taft River), the heavy metals concentrations in mg/kg were: Fe (104,300 to 373,500), Cu (466 to 5,279), Zn (2,314 to 7,138), Pb (44 to 354), As (352 to 693) and Hg (2 to 5).

Some native plant species are starting to grow in clumps even in the most polluted portions of the abandoned site. Edralin (2008) collected soil samples around each clump of the native plants as well as plant tissues for chemical analysis. Findings revealed that the soil in the spots where the plants are starting to grow still have very low fertility status and are extremely acidic aside from containing excessive levels of the heavy metals. The study showed that the native plants that start to grow in the area have low nutrient (N and P) requirement and are able to tolerate the polluted condition either by not absorbing (avoiding) the heavy metals or by absorbing high levels of the metals (the study considered only Cu and Pb). The concentration of Cu in the plants such as Saccharum spontaneum L. and Neonauclea formicaria (Elm.) Merr. was positively correlated with the soil OM content. Two fern species Pityrogramma calomelanos (L.) Link and Lycopodium cernuum L. showed the highest concentrations of Cu in their tissues with values that fall within the toxic range for plants. Also, the highest concentration of Pb was shown by Lycopodium cernuun L. and Dicranopteris linearis (Burm.) Underw. with some of their Pb values also falling within the plant toxicity range.

References

Doyle C, Wicks C, Frank N 2007. Mining in the Philippines Concerns and Conflicts. Fact Finding Mission to the Philippines Report. Society of St. Columban, Widney Manor Rd., Knowle, Solihull B93 9AM, West Midlands, UK

Edralin Don Immanuel A. 2008. Copper, lead, nitrogen and phosphorus levels in soils and plants in the abandoned Bagacay mine in Western Samar. MSc thesis in tropical ecology, Visayas State University, Baybay, Leyte, Philippines.

Kabata-Pendias A 2004. Soil-plant transfers of trace element- an environmental issue.
Geoderma 122: 143-149

Mines and Geosciences Bureau - Mining Environment and Safety Division (MGB-MESD) 2006). Environmental Assessment of Abandoned Bagacay Mine Relative to the Proposed Interim Remediation Measures of the World Bank Supported Project. North Avenue, Diliman, Quezon City.

Is soil science in an upswing?

In many countries, soil science has been traditionally associated with agriculture because of the major function of soil as a medium for plant growth. So it was no surprise that the decline in funding for agricultural research worldwide in the last two decades had taken its toll on student enrolment in agricultural sciences including soil science. But there are good signs that soil science is now experiencing an upswing particularly because of its strong link to environmental management and global warming (soil is a major source and sink of carbon) and to recent increased focus on agriculture.

In a recent paper published in Geoderma, Dr. Alfred E. Hartemink of ISRIC in Wageningen, Netherlands, and Prof. Alex McBratney (University of Sydney) think that soil science renaissance (from French word meaning "rebirth") is currentyl taking place "where novel approaches to thought are combined with a revival of ideas from the past." They noted that renewed interest in food, feed, and fuel production and the publication of numerous reports have brought soils back onto the global research agenda.

Recent reports by the United Nations and other international organizations have highlighted the need for up-to-date and fine resolution soil information and the revival of soil research. They cited as examples of key issues that have been discussed in recent publications soil erosion, nutrient depletion, and pollution particularly in relation to environmental degradation, climate change, and world food production. They estimated that about 3.2 billion euro is spent yearly on soil research worldwide. They urge the soil science community to benefit from the current upsurge in soil science.

Reference

Hartemink AE and A McBratney. 2008. A soil science renaissance. Geoderma 148: 123-129.

Effects of biosolids application on N mineralization

Sewage sludge is the solid, semi-solid or liquid residue generated during the treatment of domestic sewage. Biosolids are the treated form of sewage sludge. The use of biosolids as soil amendments is widely seen as a way to reduce the accumulation of wastes and at the same time to enhance soil fertility for crop production. Studies have shown that the use of biosolids as soil amendment is an effective means of recovering plant nutrients and improving the physical and microbiological properties of soils.

However, there are problems associated with the use of biosolids such as heavy metal contamination and nitrate pollution. Biosolids containing excessive levels of heavy metals should not be used as soil amendments. As for nitrate pollution due to excessive mineralization, Hseu and Huang (2005) proposed that this maybe avoided by regulating the annual rate of application of biosolids to soil based on crop N requirement and the anticipated net amount of organic N mineralized in the soil treated with biosolids.

In an interesting study aimed to characterize the influence of the application of biosolids on the soil potential for N mineralization (N0) and also to elucidate the kinetics of N mineralization in tropical soils treated with different biosolids, Hseu and Huang (2005) used anaerobic biosolids and aerobic biosolids obtained from the wastewater treatment plants in Kaohsiung and Taipei, Taiwan. The biosolids were applied at rates of 10, 50 and 100 Mg ha−1 to three tropical soils and incubated for 48 weeks.

Findings of the study revealed that addition of both kinds of biosolids to the soil increased N mineralization potential to an extent related directly to the application rate and the N content of the biosolids. However, the cumulative amounts of N mineralized for soil treated with aerobic biosolids greatly exceeded those for the soil treated with anaerobic biosolids. Sandy soil treated with biosolids exhibited a relatively low potential for mineralizing N.

The contamination of the biosolids with relatively high levels of heavy metals such as Cu and Zn did not prevent an increase in N mineralization resulting from the application of biosolids to the soils. Approximately 3–34% of the total N content in the biosolids-treated soils was mineralized for 48-week incubation. Based on a demand of 150 kg N ha−1 for vegetable production in Taiwanese soils, the rate of biosolids application in the three soils are safe and will not cause nitrate accumulation.

Reference

Hseu ZY and CC Huang. 2005. Nitrogen mineralization potentials in three tropical soils treated with biosolids. Chemosphere 59: 447-454.

Could the alkaline soils of the world be the missing carbon sink?

The missing carbon sink is the large amount of unidentified carbon sink in the global carbon budget. According to the Woods Hole Research Center (2007) the average annual carbon emissions amount to 8.5 Pg (1 Pg or petagram is equal to 1 billion metric tonnes) comprising of 6.3 Pg from combustion of fossil fuels and 2.2 Pg from changes in land use. This is greater than the sum of the annual accumulation of carbon in the atmosphere (3.2 Pg) plus the annual uptake by the oceans (2.4 Pg) which is only 5.6 Pg. The difference of 2.9 Pg (i.e. 8.5-5.6=2.9) is unknown carbon sink required to balance the carbon budget.

Scientists have been searching for this big amount of unknown carbon sink during the last two decades. It was first thought to be located in the ocean considering that it occupies 70% of the earth’s surface. However, most scientists consider that the ocean sink is not big enough to account for the missing carbon (Xie et al., 2009). The next possible location is the world’s forest. In fact, many scientists believe that this large amount of missing carbon is absorbed by land-based carbon sinks particularly forests but estimates indicate that terrestrial ecosystems are a net sink of only 0.7 billion (Woods Hole Research Center, 2007). Some studies have revealed that carbon accumulation is largely counterbalanced by carbon loss from deforestation.

In a study published in Science, an international team of scientists led by Stephens (Stephens et al., 2007) revealed that the missing link may indeed be located in tropical ecosystems. They reported that northern terrestrial uptake of industrial carbon dioxide emissions is smaller than previously thought and that, after subtracting land-use emissions, tropical ecosystems may currently be strong sinks for carbon dioxide. But whether or not this is enough to account for the missing carbon is not yet clear.

The third possible location of the missing carbon sink is the soil which is one of the largest dynamic carbon pools on earth. In a recent paper published in the journal Environmental Geology, researchers from China revealed a carbon sink which has been largely overlooked in the past. Xie et al. (2009) reported that alkaline soils (i.e. soils with pH > 7.0) on land are absorbing CO2 at a rate of 0.3-3.0 μmol m-2 s-1 with an inorganic, non-biological process. The intensity of this CO2 absorption is determined by the salinity, alkalinity, temperature and water content of the saline/alkaline soils. They estimated the range at 62-622 g C m-2 year-1. Considering that there are about 700 million hectares of alkaline soils around the world, the amount of CO2 absorption could be very significant on a global scale and could be a major part of the missing carbon sink.

References

Woods Hole Research Center. 2007. The missing carbon sink. http://www.whrc(carbon/missingc.htm

Stephens B.B. et al. 2007. Weak northern and strong tropical land carbon uptake from vertical profile of atmospheric CO2. Science 316: 1732-1735.

Xie J, Y Li, C Zhai, C Li and Z Lan. 2009. CO2 absorption by alkaline soils and its implication to the global carbon cycle. Environmental Geology 56: 953-961.

Native tree species affect changes in chemical properties of a highly weathered soil

Contributed by Juvia P. Sueta, University of Göttingen, Germany

There is growing interest in the use of indigenous tree species in reforestation programs at present. Thought to be well adapted to their native areas, indigenous tree species are able to survive well and strongly influence the soil. However, the lack of published data on their performance often limits their full use and casts uncertainties on whether they have beneficial or negative impacts on the soil. To better understand the role of trees in improving soil quality, an understanding of how nutrient availability changes with time is important (Kelly and Mays, 1999).

In this study which we conducted at the VSU-GTZ reforestation project site (see photo) in Mt. Pangasugan, Leyte, Philippines, we looked at the influence of two native tree species- Parashorea plicata and Dipterocarpus warburgii- on the nature and rate of changes on the chemical properties of a highly weathered soil following a change in land use from Imperata grassland to plantation of indigenous tree species. Monthly sampling of carefully selected plots in two sites (dominated by native or indigenous species) was carried out to evaluate temporal as well as spatial variations in important soil chemical properties. In addition, rates of litter decomposition of the two species were also investigated on the sites.

We found significant monthly variations of soil pH, organic matter content, total N and available P. Significant differences between sites were also observed for organic matter, total N as well as Ca and Mg contents suggesting individual tree species effects. For most of the soil properties evaluated, irregular fluctuations at certain times of the year characterized by periods of high and low availability. This suggests a highly dynamic nutrient cycling within the system.

The influence of these native tree species could be attributed to its litter contribution to the soil. In both sites, some centimeters thick of organic layer could be observed on the soil surface throughout the year. An evaluation of decomposition revealed high rates for both species. This result suggests that aside from being dynamic, the cycling of nutrients also tends to be efficient. This efficient cycling of nutrient may also help explain why these native tree species appeared to grow well despite the inherently low levels of nutrients in this old, highly weathered soil.

References

Kelly JM and PA Mays. 1999. Nutrient supply changes within a growing season in two deciduous forest soils. Soil Sci Soc Am J 63: 226-232.

Sueta JP, VB Asio and AB Tulin. 2007. Chemical dynamics of a highly weathered soil under indigenous tree species in Mt. Pangasugan. Annals of Tropical Research 29: 73-89.

Does Sago palm respond to nitrogen application?

Sago palm (Metroxylon sagu Rottb.) is widely found in the tropical lowland forest and freshwater swamps across Southeast Asia and New Guinea. Sago, the starch extracted from the pith of sago palm stems, is a staple food for the lowland peoples of Papua New Guinea and the Moluccas (http://en.wikipedia.org/wiki/Sago).

In recent years, the plant has received increased scientific interest as new uses for sago starch like in the manufacture of alcohol, citric acid, bio-ethanol and biodegradable plastics are being explored. One important research issue is on how to increase sago production since, like most wild plants, the mineral nutrition of sago palm is still poorly understood. Little scientific information is also available about its response to fertilizer application.

In a new study published in the international journal Soil Science and Plant Nutrition, Lina and co-workers (Lina et al. 2009) found that N uptake of sago palm increased significantly but inconsistently with increasing N application. The few significant increases in N uptake that were observed did not translate into significant improvements in the growth parameters of sago plant, except for the number of leaflets in the pot experiment. No significant difference was likewise observed between the fertilizer use efficiency at the two fertilization rates (50 and 100 N kg ha-1) for either sago seedling or 2-year-old sago plants.

The study demonstrated that sago palm did take up N from the added fertilizer at low rates. Moreover, it showed that the growth parameters of sago plant are not sensitive to N application suggesting that the form of N and the timing of N fertilization are important factors for sago production.

Reference
Lina Suzette B., Okazaki M, Kimura DS, Yonebayachi K, Igura M, Quevedo MA, and Loreto AB. 2009. Nitrogen uptake by sago palm (Metroxylon sagu Rottb.) in the early growth stages. Soil Science and Plant Nutrition 55: 114-123.

Sofja Kovalevskaja Award for Top Level Junior Scientists and Scholars

The Alexander von Humboldt Foundation based in Bonn, Germany, announces that it now accepts application for the prestigious Sofja Kovalevskaja Award for Top Level Junior Scientists and Scholars. Below is the official announcement from Dr. Georg Schütte, Secretary General of the Foundation:

Dear Sir or Madam,

Political debate on higher education is currently focused on enhancing the internationalisation of Germany as a research location. Endeavours are underway to improve the showcasing of German research and to create offers designed to promote collaboration between German and foreign researchers. The Alexander von Humboldt Foundation is delighted to be able to contribute to this by announcing once again the Sofja Kovalevskaja Award for Top Level Junior Scientists and Scholars. This attractively endowed research award is an outstanding career opportunity for junior research talents of all disciplines from abroad to establish their own junior research groups at German research institutions.

The award recognises outstanding talent, above average initiative and a creative approach to research and grants exceptional research conditions: The award amount totalling up to 1.65 million EUR provides award winners with valuable risk capital, enabling them to put innovative research ideas into practice. They may spend five years working on research projects at an institute of their own choice, untroubled by administrative constraints. Furthermore, building up their own working groups allows the award winners to lay important foundations for a promising research career at a very early stage. The programme is funded by the Federal Ministry of Education and Research.

Scientists and scholars of all disciplines from abroad with outstanding qualifications, who have completed their doctorates within the last six years, are eligible to apply. The programme is also open to German academics working abroad. Applications must be submitted by 15 October 2009.

We should be very grateful if you would help us to search for international research talents. For example by disseminating the announcement at your institution or asking researchers you know to draw the attention of junior researchers who might be potential candidates to the award. Details of the application procedure for the Sofja Kovalevskaja Award can be found on our website at http://www.humboldt-foundation.de/SKP_en

Please do not hesitate to contact Dr. Oliver Lange (0228-833-274, oliver.lange@avh.de) or Monika Appmann (0228-833-186, monika.appmann@avh.de) if you have any further questions regarding the Sofja Kovalevskaja award.

With many thanks for your support and kind regards,

Dr. Georg Schütte

Secretary General

Alexander von Humboldt Foundation

Report on the 12th PSSST Conference held on May 21-22, 2009 in Davao City

Contributed by Judith Carla P. dela Torre (PhilRice)

The 12^th Annual Meeting and Scientific Conference of the Philippine Society of Soil Science and Technology, Inc. (PSSST) was held at Eden Nature Park, Toril, Davao City last May 21-22, 2009. About 140 members from the different international and local institutions, agencies, and state colleges and universities participated in the said event. With this year’s theme titled “Enhancing Soil Productivity and Environmental Quality”, scientists, researchers, extension workers, and students presented their paper and posters to help in finding solutions to issues like soil erosion, decreasing soil fertility and climate change; and to achieve better soil productivity for our country’s sustainable food production program.

The keynote address on “Rice Science for Food Self-sufficiency” was given by Atty. Ronilo A. Beronio, Executive Director of PhilRice. He discussed the rice self-sufficiency program to be achieved by 2013 and challenged soil scientists to educate farmers on how to make soil productive, to lead and preach the science of managing available farm and soil resources, and to effectively explain the synergistic effects of various fertilizers on plant growth.

The three plenary papers were: (1) Integrated Soil and Crop Nutrient Management for Vegetables in the Southern Philippines by Dr. Christopher Dorahy of ACIAR, Australia; (2) Facts and Myths of Organic and Inorganic Fertilizers by Dr. Cezar P. Mamaril of PhilRice; and (3) Enriched Potting Preparations (EPP) for Various Crops by Dr. Eduardo P. Paningbatan of UPLB.

The technical session was divided into three categories: junior, senior-competing, and senior-non-competing. For the junior category, three PSSST scholarship grantees presented their undergraduate thesis and competed for the best paper. At the same time, ten papers /presentations competed for the senior category while five others presented for the non-competing (senior) category. Moreover, 19 posters were presented and judged for the best poster award.

The following recognitions were awarded by Dr. Danilo M. Mendoza, PSSST President and Dr. Cezar P. Mamaril, Advisory Board Member:

Paper/Oral Presentation

Junior Category

Best Paper- Effects of Varying Soil Moisture Levels on the Growth and Development of Lakatan (Musa acuminate Colla.) (Kathy Tafere)

Senior Category

Best Paper – Studying the Effects of Drought on Rice Production in Nueva Ecija Using Remote Sensing Technology (Judith Carla P. dela Torre)

Second Place – Banana Fertilization at the FPO Plantation: Evaluation of Soil and Leaf Analysis Results (Ma. Asuncion L. Salibay)

Third Place – Performance of Bio-fertilizers in Irrigated Lowland Rice presented (Michelle B. Castillo)

Poster Paper

Best Poster – Can we use commercially available fertilizers for Soil NPK test? (Julie D. Elijay, Constancio A. Asis, Jr., and Jesiree Elena Ann P. dela Torre)

Second Place – Fate of Soil Nutrient after Rice Straw Incorporation (Corazon A. Santin, Jesusa M. Rivera and Evelyn F. Javier)

Third Place – PALAYAMANAN Model in Rainfed Rice Ecosystem in Nueva Ecija (Jesusa M. Rivera, Rizal G. Corales, Leylani M. Juliano, Sandro D. Cañete, Ailon Oliver V. Capistrano, Jeny V. Ravis, Jehru C. Magahud, and Madonna C. Casimero)

Continuous cultivation does not always decrease soil organic carbon content

It is generally known that continuous cultivation causes a decline in soil organic carbon and nutrient contents. This has been shown by many years of research on upland soils starting with the classic study by Nye and Greenland (1960). Our studies in the volcanic mountain of Leyte, Philippines, have also confirmed this (e.g. Asio et al., 1998; Navarrete and Tsutsuki, 2008).

But a recent paper by Benbi and Brar (2009) published in the international journal Agronomy for Sustainable Development does not support this widely held view. In fact, they showed that intensive cultivation increased soil organic carbon by 38 % after 25 years. These researchers evaluated the impact of intensive cultivation of an irrigated and optimally fertilized rice-wheat system in Punjab, India, and found that intensive cultivation enhanced carbon sequestration due to improved crop productivity, greater belowground C transport to the soil and reduced organic matter decomposition during the wetland rice season.

Results of the study also revealed that the rice-wheat cropping in alkaline soils creates a favourable pH environment by lowering soil pH towards neutrality. During the 25-year period, the soil pH declined from 8.8. to 7.7 which resulted in the improvement in nutrient availability. Continuous application of phosphoric fertilizer led to build-up of soil P and the magnitude of accumulation was proportional to the amount of fertilizer applied.

References

Asio V.B., R Jahn, K. Stahr, and J. Margraf. 1998. In: Soils of Tropical Forest Ecosystems (A. Schulte and D. Ruhiyat, eds.). Springer Verlag, Berlin, pp: 29-36.

Benbi D.K. and J.S. Brar. 2009. A 25-year record of carbon sequestration and soil properties in intensive agriculture. Agron. Sustain. Dev. 29: 257-265.

Navarrete IA and K Tsutsuki. 2008. Land-use impact on soil carbon, nitrogen, neutral sugar composition and related properties in a degraded Ultisol in Leyte, Philippines. Soil Science and Plant Nutrition 54: 321-331.

Nye P.H. and D.J. Greenland. 1960. The soil under shifting cultivation. Commonwealth Agricultural Bureau, England.

Organic fertilization improves soil fungi population

While organic fertilization is now widely known to improve the general soil quality, more data from field experiments are still needed to support this notion. Cwalina-Ambroziak and Bowszys (2009) carried out a 3-year field experiment to determine the influence of organic fertilization on the community of soil fungi as compared to no fertilization and NPK fertilization only. Findings of the study revealed a significantly higher total number of fungal colony-forming units in soil applied with organic fertilizer than in soil without fertilizer application and the one applied with NPK mineral fertilizers. Moreover, pathogen population was highest in soil without fertilization and lowest in the soil added with organic fertilizer.

The study demonstrated that organic fertilization has a positive influence on the structure of soil fungi communities. This was particularly more observable in the qualitative changes in fungi composition than in the changes in fungi numbers. Results of the study support the findings of other researchers that organic fertilization stimulates the growth of soil microorganisms and that it protects the plants against pathogens of the genus Pythium and Phytophthora.

According to Terekhova (2007) fungal communities represent one of the most important functional and structural components of biological systems. Fungi affect the properties of the soil via the regulation of pedogenic processes; the composition of soil organic matter; the soil structure status; the soil acidity; the soil temperature characteristics; and certainly via the regulation of the functioning of soil microbiota.

References

Cwalina-Ambroziak B. and T. Bowszys. 2009. Changes in fungi communities in organically fertilized soil. Plant Soil Environ 55: 25-32.

Terekhova V.A. 2007. The importance of mycological studies for soil quality control. Eurasian Soil Science 40: 583-587.

Leaf decomposition of exotic and native tree species: rates and effect on soil

Decomposition of organic materials on the forest floor is a vital link between the various components of the forest ecosystem. Through this process, mineral nutrients bound to the biomass are released into the soil and then subject to uptake by plants, fixation by soil components, and losses through leaching and erosion. Decomposition can have considerable influence on the biological and chemical properties of the forest soil depending on the kind of organic material, soil properties, climate, and the availability of decomposers (e.g. Gartner and Cardon, 2004).

Exotic tree species are introduced species from other regions. They are widespread in tropical and subtropical countries since they are popular as reforestation species even in harsh environments (Nyland, 1996) due to their ability to adapt easily to variable site conditions (Weidelt, 1976). Many are considered economically viable because of their fast growth characteristic. Farmers value exotic species more than the native ones because of forestry extension recommendations and desirable cultural attributes (Cromwell and Bradie, 1996). In the Philippines, the most well-known exotic tree species belonging to this group are Mahogany (Sweitenia macrophylla King), Gmelina (Gmelina arborea Roxb.) and Teak (Tectona grandis Linn.).

Native tree species are species which originated from the region where they are growing. Among the more commonly known Philippine native tree species are Bagtikan (Parashorea plicata Brandis), Hagakhak (Dipterocarpus validus Blume) and Narra (Pterocarpus indicus Willd.). The first two species belong to Dipterocarpaceae family, the latter to the Fabaceae.

Presently, there is widespread notion that the use of exotic tree species for reforestation causes negative ecological effects such as soil degradation (Sawyer, 1993). Lindsay and French (2005) cited early studies showing that there are strong positive feedbacks between plant species composition and soil properties such that introduction of a new species can change nutrient cycling and soil properties. It is also believed that native tree species have positive effects on the site. However, very little data exist to support these claims.

We evaluated the effects of incorporation and subsequent decomposition of leaves of exotic tree species (Gmelina arborea, Sweitenia macrophylla and Tectona grandis) and native tree species (Pterocarpus indicus, Dipterocarpus validus and Parashorea plicata) on the quality of forest soil. Forty-two pots filled with an acidic and clayey forest soil and added with fresh leaves of the different tree species were set-up in an open area in Mt. Pangasugan. Retrieval of the first three pots for each treatment was done after two months and the remaining three pots, five months later. Soil samples were collected from each pot and analyzed for pH, OM, total N, available P, and respiration rates.

Our main findings were:

1. Decomposition of the leaves of exotic tree species generally did not change soil pH except that of S. macrophylla which increased soil pH after 5 months. In contrast, the leaves of the native species tended to decrease soil pH particularly in the first two months of decomposition.

2. There was no considerable difference between the effects of the leaves of exotic and those of native tree species on the organic matter and total nitrogen contents of the soil.

3. Available phosphorus content of the soil was significantly increased by the decomposition of leaves of both exotic and native species.

4. The leaves of exotic tree species decompose faster than those of the native species. This finding agrees with that of a separate litter decomposition study by litterbag method conducted at the same site by Aragon (2004).

Source:

Batistel CC and VB Asio. 2009. Effects of leaf decomposition of selected exotic and native tree species on forest soil quality. Annals of Tropical Research (in press)

References

Aragon JA. 2004. Leaf litter decomposition of Dipterocarpus validus Brandis (Dipterocarpaceae) and Gmelina arborea (Verbenaceae) in two forest sites of Mt. Pangasugan. Undergrad Thesis, Leyte State University, Baybay, Leyte. 50 pp.

Cromwell E and A Bradie. 1996. Germplasm for Multipurpose Trees: Access and Utility in Small-farm Communities. ODI London.

Gartner TB and ZG Cardon. 2004. Decomposition dynamics in mixed species leaf litter. Oikos 104: 230-246.

Lindsay EA and K French. 2005. Litterfall and nitrogen cycling following invasion by Chrysanthemoides monilifera ssp. Rotundata in coastal Australia. Journal of Applied Ecology 42: 556-566.

Nyland R 1996. Silviculture (Concepts and Application). McGraw-Hill Co. Inc. Singapore.

Sawyer J 1993. Plantations in the Tropics: Environmental Concerns. IUCN/UNEP/WWWF, Gland, Switzerland.

Weidelt H A 1976. Manual of Reforestation and Erosion Control for the Philippines. German Agency for Technical Corporation LTD (GTZ) Germany.