Use of Organic Materials to Maintain Soil Quality by Thai-Lao Rice Farmers in Northeast Thailand

Sujitra Yodda,A Terry Rambo,Suwit Laohasiriwong

doi:10.24259/fs.v5i2.14044

Abstract

Maintaining soil quality is a major problem for traditional farmers in the tropics. Many rely on organic amendments to enhance the productivity of their fields. However, indigenous knowledge about soil organic matter (SOM) and its management has received relatively little attention from researchers. This paper describes the use of organic materials to maintain soil quality by Thai-Lao farmers in a rice-growing village in Northeast Thailand. In-depth semi-structured interviews were conducted with twelve farmers to: 1) identify the indicators of soil fertility they employed; 2) inventory the organic materials they used; 3) determine changes in the use of amendments over time; and 4) understand their concept of SOM. They used many physical and biological indicators of soil quality. They used nine different organic materials: rice straw and stubble, cattle, buffalo and pig manure, rice husks, sunn hemp plants as green manure, charcoal, commercial compost, homemade compost, and tree leaf litter. Recently, use of livestock manure, rice husks, charcoal, and leaf litter has declined because of supply shortages. They do not appear to have a general concept of organic matter nor is there a commonly used word for “organic” in their language. Most of the farmers would use larger quantities of organic amendments but are constrained by their scarcity and high cost. Ways to increase local supplies of organic materials must be found if the government’s efforts to encourage the adoption of organic agriculture are to be successful.

Highlights

The land degradation that is an almost inevitable consequence of agriculture has presented a serious problem to farmers since they first began cultivating the soil many thousands of years ago
Human night soil was widely used throughout the ancient world and continued in widespread use in China, Japan, and Korea until recent years (Kawa et al, 2019) but has rarely been employed by Southeast Asian farmers who rely on livestock manure, green manures, tree leaves, rice husks and other organic residues to maintain soil quality in their fields
In order to better understand how they think about organic matter, we presented each farmer with samples of eight different commonly used soil amendments and asked them to sort the samples into similar groups

Summary

Introduction

The land degradation that is an almost inevitable consequence of agriculture has presented a serious problem to farmers since they first began cultivating the soil many thousands of years ago. Traditional subsistence farmers in many parts of the world have attempted to maintain soil quality by adding organic amendments to their fields (Hossain, 2001; Grossman, 2003). This practice is widespread among modern commercial farmers (Hijbeek et al, 2018). Human night soil was widely used throughout the ancient world and continued in widespread use in China, Japan, and Korea until recent years (Kawa et al, 2019) but has rarely been employed by Southeast Asian farmers who rely on livestock manure, green manures, tree leaves, rice husks and other organic residues to maintain soil quality in their fields. Farmers in Northeast Thailand collect black organic soils from termite mounds and areas under the canopies of trees to incorporate in their commercial vegetable plots (Marten & Vityakon,1986), while farmers in the central plain of Laos spread termite mound soil on their paddy fields to fertilize their rice crops (Miyagawa et al, 2011)

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Discussion

Conclusion