Field Guide of Discovery-based Exercises for - Aseanipm ...

LIVING SOIL AND INTEGRATED SOIL NUTRIENT MANAGEMENT
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Field Guide of Discovery-based Exercises for Organic Vegetable Production
The principle of ecology is a primary concern in organic agriculture. It states that production
is based on ecological processes and recycling. Nourishment and well-being are achieved
through ecology of specific production environment. For example, in case of crops, this is
a living soil 40 . Hence, in an organic agriculture perspective, integrated soil nutrient management
(ISNM) will require provision of environment-friendly soil nutrient management options for
improvement of some important interrelated soil properties (e.g., physical, biological, and chemical),
which will result to better crop productivity and higher farm income 41 . In organic vegetable
production, organic matter is a vital component in maintaining a living soil because of its capacity
to supply both macro- and micronutrients to plants. Also, it promotes favorable soil properties
such as aggregation and good soil tilth for efficient aeration, root penetration, and increased water
holding capacity.
However, organic matter level in soils is difficult to maintain unless green manures or organic
residues are applied continually every season. Some farm wastes such as rice straws and hulls,
animal manures, weeds, which are abundant on-farm, can also be used in maintaining organic
matter content of soil provided these are given appropriate treatments for composting. Microbialbased
fertilizers can also be applied to seed, soil, or composting materials to increase the number of
microorganisms and accelerate certain microbial processes. The desired microbial processes may
improve nutrient availability by promoting nutrient forms that can easily be assimilated by plants 42 .
Such microbial processes may include: (a) nitrogen conversion from air into forms usable by plants;
(b) dissolution of phosphates by acid-secreting bacteria; or (c) breakdown of organic matter by
bacteria, fungi, and actinomycetes 43 .
Thus, there are two very important physical properties of soils to be considered in this sub-section: soil
texture and soil structure. Soil texture is concerned with the size of mineral particles. Specifically,
it refers to the relative proportions of particles of various sizes in a given soil. No less important is
soil structure, which is the arrangement of soil particles into groups or aggregates. Together, these
properties help determine not only the nutrient-supplying ability of soil solids but also the supply
40 IFOAM. 2006. Principles of Organic Agriculture. International Federation of Organic Agriculture Movements (IFOAM). As cited in: Philippine Organic
Agriculture Information Network. http//www.pcarrd.dost.gov.ph/phil-organic/what.
41 Settle, W. 1999. Living Soil: A Source Book for IPM Training. United Nations-Food and Agriculture Organization (UN-FAO) Programme for Community
IPM IN Asia, Jl. Jati Padang, Pasar Minggu, Jakarta, Indonesia. pp5.
42 PCARRD (ed.). 1999. The Philippines Recommends for Soil Fertility Management. Committee on Organic Fertilizer Production and Utilization.
Philippine Council for Agriculture, Forestry and Natural Resources Research and Development (PCARRD), Department of Science and Technology, Los
Baños, Laguna, Philippines. Philippine Recommends Series No. 92. pp78-95.
43 PCARRD (ed.). 2006. The Philippines Recommends for Soil Fertility Management. Committee on Soil Fertility Management. Philippine Council
for Agriculture, Forestry and Natural Philippine Council for Agriculture, Forestry, and Natural Resources Research and Development (PCARRD),
Department of Science and Technology, Los Baños, Laguna, Philippines. Philippines Recommends Series No. 36-C. pp68-90.