Use of Organic Materials for Upland Soil Improvement

Abstract

This paper reviews options for improving soil fertility of upland soil in Thailand. Soil organic matter under dryland cropping conditions has been depleted repidly as a result of the humid tropical climate. This phenomenon and poor management have resulted in soil degradation and rapid crop yield reduction. Leaving crop residues in teh field and suitable cover cropping can improve degraded land. Continued application of organic substances such as compost, cattle manure, or green namure, and appropirate cropping systems with crop residue in corporation improve chemical, physical and biological properties of the soil. Organic fertilizers also enhance crop responses to chemical fertilizer. Although it is not easy to apply great amounts of organic materials, there is at present no beter management at low cost than the above practices. Therefore the use of organic substances as much as possible should be recommended right away because it takes a long time for any apparent soil productivity improvement.