Friday, August 3, 2018

Cebu Highlands: some notes on the agricultural practices and beautiful landscape

By Dr. Luz Geneston Asio
Department of Agronomy, Visayas State University

The highlands in the middle of Cebu which extends from the city in the east to Balamban/Asturias in the west, presents a beautiful mixture of protected landscapes with good secondary forest cover, and crop production systems consisting of orchard particularly mango, annual crops, vegetables and cut flowers. 

Beautiful views of the Cebu Highlands

The very beautiful scenery reminds visitors of Baguio City or some foreign places like Indonesia or Taiwan. Clearly observable even on distant undulating slopes are the mango trees which are adapted to the agroclimatic conditions of Cebu. 

Mango trees are abundant in certain parts of the landscape
Cebuanos are widely known to be corn eaters. This explains why corn is the most widely grown grain crop in the highlands. On red acidic soils from igneous rocks as well as on dark calcareous soils from limestone, nutrient deficiency symptoms (N, P) are clearly observable. But the crop is still able to produce a relatively good yield.

Large and small corn plantations are common in the highlands

On degraded limestone slopes on the western side close to Balamban, coconut plantations can be seen which are also showing nutrient deficiency symptoms most probably nitrogen and iron as indicated by the yellowing of leaves (plant analysis data from comparable lands in southern Leyte indeed revealed both nitrogen and iron deficiencies). 
Coconut plantations in the western side
But the most impressive crop production venture by the people in the highlands is the one which consists of cut flowers (e.g. Chrysanthemum) and vegetables (lettuce, cabbage, chayote, etc). The cut flowers are delivered to the city while the vegetables are sold in the city and in local stores along the highway. 

Stores selling the farm products are found along the highway

It must, however, be mentioned that although contour farming can be seen on some steep slopes, unsustainable cultivation practices can be clearly observed. The most obvious is the plowing or planting of crops along the slope (top to bottom orientation). This practice promotes soil erosion and loss of nutrients from the soil. This should be taken seriously as this could lead to severe soil erosion on the slopes accompanied by siltation of the streams below. It could have long-term impact on the water quality and quantity in the streams.

(Report was based on the field work we conducted from July 31 to August 2, 2018. I thank Dr. Vic Asio for his ideas and Julian Cumad (MSc Soil Science student) for organizing our visit. All photos are owned by the author.  

Tuesday, July 31, 2018

Rice production in Eastern Samar: is there a bright future?

By Luz Geneston Asio, PhD
Department of Agronomy, VSU, Baybay City, Leyte

Eastern Samar has been consistently ranked as one of the poorest provinces in the country ( A major reason for this is the low agricultural productivity due to several reasons: frequent typhoons, lack of government support, lack of political will, old farming methods, and many others.

During our one-week field work in the province this July, we travelled to interior barangays, observed crop production practices and technologies, interviewed farmers and technicians to get a picture of the real reasons for the low rice productivity of the province.
A poor rice farmer in San Jose village in Borongan City

Very striking across most of Eastern Samar is the widespread occurrence of uncultivated or only partly cultivated alluvial lands particularly near river systems. Such lands generally have great potential for intensive and highly productive rice production due to their generally flat topography. But most areas are idle and covered with Cyperus sedge and other grasses due to the lack of any irrigation system to supply the fields with sufficient water. Our field observations indicate that enough water lies beneath the land surface but nothing is done to tap it (e.g. deep wells) to support rice production.

An idle former rice land in Dolores, Eastern Samar

Only partly cultivated alluvial plain in San Julian, Eastern Samar

In many areas, we observed that farmers are planting modern rice varieties but are managed in the traditional way. For example, the modern rice varieties need proper spacing to grow well but most farmers are still practicing the random planting without proper spacing. Farmers also complained that they received seeds and small amount of fertilizers from the Department of Agriculture only once. It did not help them improve their production.

Modern rice variety planted at random (without proper spacing)

Shortly after planting, the soil dries up due to the absence of an irrigation system

Modern rice varieties are high yielding. Meaning, they are capable of producing high grain yields but they need high amounts of nutrients from the soil for them to attain their yield potential. Unfortunately, most farmers do not apply fertilizers or apply only insufficient amounts of fertilizers. The explanation by some agricultural technicians that the modern varieties need less fertilizers than the traditional varieties is simply not correct.

A farmer in Sulat harvesting his rice (he uses coconut leaves to protect him from the sun)

Quinapundan in the south is the only municipality where rice production appears to be very productive. The municipality possesses a large alluvial plain which is used for intensive rice production. The major reason is the availability of a functional irrigation system which allows farmers to plant two or more croppings of rice a year. We wonder why the local government in this municipality has been very successful in its rice production program but not Borongan, San Julian, Sulat, Taft, Can-avid, Dolores and the other municipalities which have wide areas of alluvial plains which are generally suitable for lowland rice production.

Intensive rice cultivation in Quinapundan, Eastern Samar

The prediction of one high ranking government official who was interviewed on local TV that Eastern Samar will attain rice self sufficiency in the next five years is not attainable. Not unless of course the politicians will do something drastic to solve the real causes of low rice productivity in the province. 

Just imagine how many tons of rice will be produced once these large idle lands throughout the province will be made productive through functional irrigation system, proper fertilization, high yielding varieties and other modern farming methods. Unfortunately, for Eastehanons this is not the priority of the politicians. Thus, we can safely assume that Eastern Samar will continue to be one of the poorest provinces. The future of rice production in the province may not be bright at all.
All photos were taken and are owned by the author.

Sunday, February 18, 2018

Nutrient addition as a forest restoration management strategy for Yakal yamban seedling establishment in ophiolitic soils

by Johannes R. G. Asio
Institute of Tropical Ecology and Environmental Management (ITEEM),VSU, Baybay City, Leyte, Philippines
Dipterocarp trees (Dipterocarpaceae) have crucial ecological roles such as in the prevention of landslides, sequestration of atmospheric carbon, and biodiversity. They are also economically important in terms of timber production. These native trees are also adapted to a variety of climatic conditions and geographic locations (e.g. areas prone to heavy typhoons, marginal lands). However, the sustainable management of dipterocarp forests is still poorly understood due to the limited studies conducted on the subjet. This is particularly so in terms of the ability of these forest trees to thrive in marginal lands like those naturally contaminated with heavy metals and those soils with very low nutrient status such as ophiolitic and serpentinite areas (Corlett&Primack, 2006; DENR, 2012; Appanah, 1998; Walpole, 2010).
Ophiolite rocks are widespread in Leyte, Samar, Cebu and Palawan.These rocks generally underlain marginal lands. A typical ophiolite complex is a stratified igneous rock complex that consists of different rock layers: an upper basalt member, a middle gabbro member, and a lower peridotite member (Ishiwatari, 2016). The fertility of Ophiolite rocks in the Philippines has not yet been studied in detail, however, according to some literatures, it is generally moderately acidic to neutral, low soil organic matter, low nitrogen (N), phosphorus (P), and potassium (K), which are the major nutrients needed for plant growth, and it contains high amounts of heavy metals, such as chromium, nickel, iron, and cobalt among others (Dimalanta et al., 2006; Ocba, 2016).
Mineral fertilizers have been used in agriculture and forestry to improve crop yield, enhance the soil fertility, and soil health. Thus, this study hypothesized that the addition of N, P, and K to an ophiolite soil could enhance the growth of Yakalyamban (Shorea falciferoides Foxw.) in problematic areas. This dipterocarp species was chosen for this research as it has been known to thrive in the ophiolitic and serpentinite areas of Samar and it is critically endangered, thus the need to preserve this dipterocarp to prevent it from becoming extinct (Fernando et al., 2009, 2008).

This study aimed to test whether the addition of nutrients enhanced the seedling growth of yakal yamban grown in an ophiolitic soils, determine the optimum nutrient combination level for yakalyamban seedling quality; and assess and evaluate whether fertilization could very well be adopted as a nutrient management practice in using yakal yamban as a rainforestation species for forest restoration in problematic soils.
The potting medium was selected based on the soil data obtained by the VSU-OXFAM Project (2015). Detailed soil analysis done by the project showed that the soils in Barangay Padang, Hernani, Eastern Samar developed from ophiolitic rocks and have low levels of N,P,K, and Mg, but high levels of Ca. Twenty sacks of topsoil (0-30cm depth) were collected and transported to the Terrestrial Ecosystems Division of the Institute of Tropical Ecology and Environmental Management for this screenhouse experiment. The bulk soil samples were mixed, air-dried thoroughly, pulverized and sieved using a 4-mm mesh sieve. About 1.5 kg of the air-dried soil was weighed; 0.75 kg sieved soil (from the 4-mm sieve) and 0.75 kg unsieved soil to avoid soil compaction.

This one-year study was conducted using a 5 x 3 Randomized Complete Block Design (RCBD) with five treatments and three replicates, wherein each treatment per replication consisted of 10 seedlings. The treatment are as follows: T1- No fertilizer application, T2- Application of 3.65 g of Urea, 9.33 g of Solophos, & 2.8 g of Muriate of Potash, T3- Application of 3.65 g of Urea, 9.33 g of Solophos, T4- Application 9.33 g of Solophos& 2.8 g of Muriate of Potash, T5- Application of 3.65 g of Urea & 2.8 g of Muriate of Potash. Placement application was done wherein the exact amount of fertilizer for each seedling was applied a few centimeters below the soil surface. Tap water was used. About 400 mL was added as required.
Three (3) randomly selected seedlings in each replication were harvested after 3 months and 6 months from fertilizer application. The selected seedlings were photographed before and after harvest, documenting each plant part and making notable observations. Thereafter, each individual seedling was cut; each leaf was photographed in preparation for leaf area analysis. Then, each plant part (roots, stem, and leaves) was separated and placed into the corresponding paper bags ready for oven drying. The soil samples in each replication were mixed and placed into labelled plastic bags ready for air-drying and analysis.
Major Findings
Results revealed highly significant differences in leaf area, percent biomass allocation, and root-shoot ratio between treatments 6 months after sampling. In terms of leaf area, treatment 4 showed the highest leaf area value. All treatments added with phosphorus (treatments 2,3 and 4) had leaf area values that were statistically the same. This indicates that P is the most critical nutrient in the soil and that this tree species is sensitive to the P levels in the soil.

There were also significant differences in terms of the percent biomass allocation between treatments in the root, stem, and leaves, with treatment 5 showing the highest allocation in the roots; plants in P-deficient environments enhance root growth as it is their adaptive mechanism that enables them to thrive in these conditions. The result also coincides with the root-shoot ratio as study plants in treatment 5 had the highest root-shoot value.

Soil nutrient analysis was done to determine the nutrient status of each treatment. The analyses concur with the fact that ophiolitic soils are deficient with N, P, & K, thus the high values of the nutrients were due to the fertilizers added prior to destructive harvesting. It was also observed that the fertilizer treatments have not yet fully dissolved even after 6 months of application.
Plant nutrient concentration was also done to determine the nutrient content of each plant part. In terms of nitrogen (N), there were high values of N in the leaves as it is needed for photosynthetic activity. However, it was below the optimum concentration needed for plant growth (Marschner, 1995). With regards to P, there were high values of the nutrient in treatments not added with P. It may be due to the mycorrhizae present in the roots of the study plants after 6 months of application. For K, solubility played a factor since there was an inhibition of nutrients to be taken up especially between N and K.

The presence of ectomycorrhizae (EcM) was also observed in the roots of the study plants of the control (T1) and NK (T5). Various studies have proven that mycorrhiza aids in the growth of a plant as it enhances the absorption of nutrients and water (Marschner, 1995; Read, 1991). The result also coincides with the study of Turner et al., 1992 as EcM infection may serve as a purpose when dipterocarps are grown in nutrient-poor conditions.
Nutrient addition could very well be adapted as a nutrient management strategy for the seedling establishment of Yakal yamban in ophioitic soils; Treatment 5 enhanced the root-shoot ratio of the study plants, thus these seedlings are of good quality. This implies that during establishment of the seedlings in an open area, they are most likely to survive due to its adaptive mechanism (e.g. enhance root growth in p-deficient environments) and the potential fungus-root association in the soil.
The above article is a summary of the BSEM thesis by the author which won as 2017 Phi Delta Outstanding Thesis in Applied Biological Sciences at VSU, Baybay City, Leyte. More information can be obtained from the author. Email:

Friday, September 29, 2017

Heavy metals in vegetables sold in some cities in the Visayas, Philippines

Every time we buy vegetables in the market, we do not doubt the quality of these farm products. We think they are clean, safe, nutritious and good for our health.

But the worsening environmental pollution due to the overuse and misuse of agricultural chemicals such as pesticides, the improper waste disposal, the manufacturing industry, and the transportation system may be affecting the quality of the food crops we eat everyday. Specifically, heavy metals most of which are toxic to humans at elevated concentrations, are starting to contaminate the vegetables we love to eat.

The scientific principle is simple: a contaminated soil will generally produce contaminated crops.

An interesting and very relevant student research conducted a few years ago revealed such alarming reality. Conducted to determine and compare the Pb, Cu and Zn contents of Alugbati (Basella rubra), Ampalaya (Momordica charantia), Kalabasa (Cucurbita maxima), Kangkong (Ipomoea aquatica), Pechay (Brassica rapa), and Talong (Solanum melongena) sold in markets in the cities of Baybay, Ormoc, and Tacloban (Leyte, Philippines), the study revealed that Ampalaya from Tacloban and Baybay contained excessive levels of Cu and may pose health problems to consumers. 

Likewise, Pechay from Baybay, Ormoc and Tacloban exceeded the safe level for Zn. All vegetable samples collected from the three cities were not contaminated with Pb. Cu and Zn levels varied with crop (vegetable) species and origin (production area). 

The results are very relevant in that they support and confirm the fear among consumers that some food crops sold in the local markets are not safe and may be one of the reasons for the various health problems experienced by many people.

The study was conducted in 2012 by Anna Luisa Ventulan, Christine Gay Cala, and Johannes Reiner Asio, all senior students at VSU Laboratory High School. The research adviser was Luz Geneston Asio of the Central Analytical Services Laboratory, Visayas State University, Baybay City, Leyte.

Tuesday, April 18, 2017

Ecological quality, macroinvertebrate communities and diversity in rivers in Leyte, Philippines

Researchers from the Laboratory of Environmental Toxicology and Aquatic Ecology, Ghent University, Belgium, in collaboration with researchers from the Institute of Tropical Ecology and Environmental Management of Visayas State University in Leyte have published scientific evidence of a strong link between ecological quality and macroinvertebrate communities and diversity in rivers in Leyte.

In a paper published this year (2017) in the prestigious journal Ecological Indicators, Vol. 77 and pages 228-238, Marie Anne Eurie Forio and colleagues assessed the macroinvertebrate communities, diversity, and ecological quality of 85 rivers on Leyte island. Specifically, they evaluated the biological (macroinvertebrates), chemical, physical and hydromorphological characteristics. Canonical Correspondence Analysis (CCA) and multivariable linear regression (LRM) were performed to relate the environmental variables and macroinvertebrates.

Eurie Forio and Daphne Radam during the field sampling in Cabintan, Ormoc
(at the central highlands of Leyte) in 2015
The researchers found several taxa of snails, shrimps, dragonflies, beetles, bugs and caddisflies. Although many sites had good to very good ecological quality and high diversity, about 41% had moderate to very bad ecological quality and low diversity. Based on CCA, the researchers concluded that macroinvertebrate communities were associated with velocity, sediment, conductivity and dissolved oxygen. They also observed that sensitive and tolerant taxa were encountered at high and low flow velocities, respectively. Moreover, LRM indicated that macroinvertebrate diversity and ecological quality were associated with physical (turbidity), chemical (chlorophyll), hydromorphological characteristics (bank slope & pool/riffle class), habitat degradation (gravel/sand quarrying, erosion) and the presence of logs and twigs.

Eurie Forio (lead author) and Prof. Peter Goethals (lead scientist)
This ecological study, the first of its kind (i.e. covering 85 rivers of an entire tropical island) to be conducted in the Philippines, supports the use of invertebrates as indicators of certain environmental conditions and the results of this investigation can serve as a basis to set up dedicated experiments to further prove the causality of these discovered relations. 

The study also revealed that organic pollution, as reflected by biological oxygen demand and chemical oxygen demand, was weakly related to invertebrate composition, diversity and ecological quality. This was linked to the low input in most sites and the relatively short rivers which are closely connected to the marine system. Thus, typical midstream and downstream systems were not encountered and the accumulation of these pollutants along the river is less likely. Although the island encounters intensive natural disturbances (e.g. severe typhoons), the taxa (families) were similar to those in other tropical systems and the effects of the environmental conditions were comparable.

The findings of this collaborative research are relevant and valuable in understanding the ecology of tropical islands. They also provide insights into the effects of environmental conditions on stream invertebrates, which aids in protecting and conserving tropical insular systems.


Forio, M.A.E., K. Lock, E.D. Radam, M. Bande, V.B. Asio and P.L.M. Goethals (2017). Assessment and analysis of ecological quality, macroinvertebrate communities and diversity in rivers of a multifunctional tropical island. Ecological Indicators 77 (2017) 228–238

Tuesday, January 3, 2017

Cape Bojeador, Paoay Sand Dunes, Kapurpurawan White Rocks, Bangui Windmills, Pagudpud Resorts, and Cagayan River: Just a few of North Luzon’s wonders worth visiting

A tour around the northern tip of Luzon is really an amazing experience. For those interested in our natural environment, it is a must. This short report describes briefly some of the wonderful places that one can visit starting from Vigan City in the west (1) to Cagayan Valley in the east (10).

Vigan City
Vigan is an old city in Ilocos Sur with well-preserved Spanish colonial and Asian architecture. This UNESCO World Heritage site reminds me of some small towns in southern Spain. It is without question the most beautiful old city in the Philippines.

The Paoay Sand Dunes
The sand dunes area appears to be a raised sea bed. First evidence of this is the fact that it is directly adjacent to the sea. Second reason is the presence of shells of marine organisms in many parts of the area. Third, a road cut exposure east of the sand dunes reveals thick sandstones (formed under the sea) which could be the source, through weathering, of the sand particles. The subduction of the Sunda Plate underneath the Philippine Mobile Belt produced the Manila Trench in the South China Sea and has resulted in the uplift of northwest Luzon. Decades of soil mismanagement and the resulting soil erosion have without doubt contributed to the spread of the sand dunes.   

Cape Bojeador
This is the headland at the northwestern tip of Luzon in Burgos, Ilocos Norte. The raised marine terrace is flanked to the east by steep-sided volcanic and greywacke hills and to the west by the turbulent South China Sea. Perched on top of the hill at about 90m asl is the famous Cape Bojeador Lighthouse constructed in 1892 during the Spanish Colonial period.

Kapurpurawan White Rock Formation
The famous white rock formation in Kapurpurawan, Burgos, is actually a raised reef limestone that has been carved by the waves through time. The raised limestone is associated with the uplifting of northwest Luzon as a result of the subduction of the Sunda Plate underneath the Philippine Mobile Belt as has been mentioned above.

Bangui Windmills
Standing 70 m tall on the black sand beach of Bangui, Ilocos Norte, are 20 giant wind turbines (giant fans) facing the South China Sea in the direction of Taiwan. The area is so windy making it ideal for such a modern energy harvesting facility.

Pagudpud Resorts
A large resort and convention center called Hanna’s Beach Resort is found near the northernmost tip of Luzon and hidden from the highway by the mountain range in Balaoi, Pagudpud, Ilocos Norte.  The bay, which has fine white sand, is unique in its location and local geography. A chat with the locals would reveal controversial stories about the real owner of the resort.

Patapat Viaduct
One of the many major infrastructure projects of former President Marcos is the Patapat Viaduct in Pagudpud, Ilocos Norte. The 1.3 km bridge is elevated about 30 meters above the sea and connects the Maharlika Highway from Laoag, Ilocos Norte  to the Cagayan Valley Region. It is now part of the Asian Highway network (AH 26).

Anahaw Plantations
Anahaw or anahau (Livistona rotundifolia) is an erect palm that is widespread in northern Luzon particularly in Claveria, Cagayan. This makes the landscape in this part of Luzon different to the monotonous coconut plantations in the Visayas.

The Cagayan River
The Cagayan River (the Rio Grande de Cagayan) is considered as the second largest river in the Philippines next to the Rio Grande de Mindanao. The mighty river in the Cagayan Valley region traverses the provinces of Nueva Vizcaya, Quirino, Isabela and Cagayan and has a drainage area of about 27,300 square kilometers. The picture below shows the river from the Magapit Bridge in Magapit, Cagayan.

Soil Degradation in Cagayan Valley
Deforestation followed by decades of grazing (pasture) have caused widespread soil degradation in Cagayan Valley. This is clearly observable from Tuguegarao City down to Enrile and Sta Maria, Cagayan where the traveler sees an endless view of denuded and degraded hills and mountains.