Thursday, April 12, 2012

Characteristics and fertility constraints of degraded soils in Leyte, Philippines

Contributed by
Dr. Ian A. Navarrete
Humboldt Fellow
Soil Science of Tropical and Subtropical Ecosystems
Georg-August Univesity Göttingen
Gottingen, Germany

Soil degradation, a process that lowers the capacity of the soil to produce goods or services, is a prevalent agricultural and environmental problem in the Philippines (Asio et al. 2009). However, to date, the nature and characteristics of degraded soils in the Philippines have been poorly understood, in that there have been few studies on this subject (Asio et al. 2009; Navarrete et al. 2009). Although various crop production technologies have been developed for marginal areas these technologies have not been successfully adapted by farmers or have failed to alleviate crop production (Cramb 2001). Cramb further stated that the introduction of unsuitable soil management technologies to farmers has intensified the soil degradation processes occurring in these areas. Thus, knowledge on the characteristics and fertility status of degraded soil is fundamental in planning suitable soil management strategies for crop production purposes. Because the degree of soil degradation immensely varies among sites depending on soil forming factors, soil management strategies must be location specific, every degraded soil has to be evaluated in terms of its properties and constraints.

In our recent study published in the international journal Archives of Agronomy and Soil Science (Navarrete et al. 2012), 60 soil horizon samples were collected from five locations (across an elevation gradient between 97 and 735 m above sea level) at Ormoc, Baybay, Bontoc, Bato and Matalom on the western side of Leyte island, Philippines. The samples were subjected to various physical, chemical and mineralogical analysis. Results revealed that the most important physical constraint in most of the soils evaluated is the high clay content particularly in the soils of Baybay and Bato because it is a problem for cultivation. The strongly acidic and strongly alkaline pH, low available P and, in some cases, low exchangeable K are the chemical constraints. Most of the variations in the physical and chemical constraint of these degraded soils can be explained directly or indirectly by the nature of the parent material, geomorphic position and anthropogenic effect. Soil fertility characteristics are distinct within similar soil types, primarily because they are related to the dominant soil-forming processes (see for example Figure 1 below). Consideration of the soil physical and chemical constraints is essential for the long-term planning of soil management strategies that will lead to sustainable utilization of these problematic soils.

Figure 1. Plots of the first and second principal components (PC) extracted from the principal component analysis (PCA) of all selected properties. (a) distribution of soil samples and soil types (b) distribution of soil properties

Asio VB, Jahn R, Perez FO, Navarrete IA, Abit SM, Jr. 2009. A review of soil degradation in the Philippines. Annals Tropical Research 31: 69-94.
Cramb RA (ed). 2001. Soil conservation technologies for smallholder farming systems in the Philippine uplands: a socioeconomic evaluation, ACIAR, Australia.
Navarrete IA, Tsutsuki K, Asio VB, Kondo R. 2009. Characteristics and formation of rain forest soils derived from late Quaternary basaltic rocks in Leyte, Philippines. Environmental Geology 58: 1257-1268.
Navarrete IA, Tsutsuki K, Asio VB. 2012. Characteristics and fertility constraints of degraded soils in Leyte, Philippines. Archives of Agronomy and Soil Science. DOI /10.1080/03650340.2012.663908


Timeless said...

Very Nice article. There are a number of things you mention of importance here. One is a farmer's educational background on latest technologies and proceedures. Farmer's should be held to the same ethical and principle standards in learning the latest technologies and proceedures as Doctors are held accountable against a possible malpractice.

In both cases, Farmers & Doctors often rely to heavily on the research and ultimate truthfulness of the Chemical & Pharmicudical Companies whse salesman working on commission tries to sell them on the ideas and proceedures of the Big Biz Giant. Truthfully and realistically, neither the Doctor nor the farmer has the time and ability to actually do their own personal research or homework, but given to dasasterous nature of the condition of our planet, perhaps they should. Honesty and integrity of both Chemical & Pharmicudical Giants in our modern times have come into question. Monsanto comes to mind.

Our whole planet is shackled to an old school line of thinking which is still controlled by powerful political and big business forces who don't won't to let go of the reins of power so easily when more holistic approaches to land management which actually replicate what really occurs in nature actually does with regards to a healthy recycling of the Earth resources that have been revealed by other scientists or modern day researchers.

Sadly, the Environmental Ecology movement today never had a "Manhattan Project" for which the so-called Green Revolution was born. During WWII chemicals were found to be great at making bombs explode, but they were also found to stimulate plant growths. Hence it was advertised that these chemicals were going to save mankind and green up the deserts. We can only imagine what would have happened if all that money and resources spent on WWII had been used by ALL nations involved went into actually learning how the Earth really functions and operates and what practical applications could be had from these.

I enjoyed your article on Jackfruit. I'm assuming it's an indigenus crop to Philippines. I think more work should be done in many developing nations to look to native crops as opposed to European and other western crops and practices for those local areas. Understanding the soil dynamics and what crops have and will work as opposed to the old standards brought by the west. Farmers most likely need re-education on more holistic methods. Proper education is one of the most vital things needed. The Monsanto disasters in India and Africa and elsewhere are a prime warning example with what happens when the good ol'boys club pushes a sale as opposed to actually helping their client. Aside from the fact that Monsanto and others in their fields have diliberately ignored a more heathful approach to land conservation and holistic rebuilding.

These degraded soils took years to gradually play out and there is no quick fix. It may take years to rebuild them back up to a health standard for which crops can be grown again, but it's going to take dramatic education to erradicate old ideas. Teaching the old Dog new tricks applies here. It will definitely be a challenge. Especially when you have forces out there who work against it.

Once again, thanks for a nice article. BTW, are you still in Germany or back in Philippines ?

Thanks again, Kevin

Timeless said...

Wow, who would have thought above Annonymous has just spammed.

On another important nore for Dr. Victor B. Asio. You just posted a article about Prague or rather Czech Republic, but it's not coming through when I click.

Thanks - Kevin

Victor B. Asio said...

Thanks Kevin. I did not notice the spam. About the new post, I was still editing the new post when I "published" it unintentionally.Sorry about that. Now it is OK.