Improving productivity of vegetable cultivation in Ultisols of Sri Lanka

Improving productivity of vegetable cultivation in Ultisols of Sri Lanka

Shanhua, Tainan AVRDC Taiwan

1997

p.270-282

S631.3.M6

Ultisols predominate in the intermediate and wet zones of Sri Lanka. A variety of vegetable crops suited to the climatic conditions of the two zones are grown on these soils. Because income from vegetable production is high when compared to income from rice and most other field crops, vegetables have become an important component in almost every cropping system. Nevertheless, recent projections reveal that a three-fold increase in vegetable production is necessary to provide sufficiently for the country's growing population and also meet rising export demand. Although vegetables remove large quantities of plant nutrients, soils on which vegetables are grown often exhibit accumulations rather than depletions of nutrients. Excessive use of chemical and organic fertilizers have lead to high nutrient levels in the Ultisols of the upcountry region. Bicarbonate extractable (Olsen) P and ammonium acetate extractable K values as high as 300 mg/kg are not unusual in these soils. Soil productivity is feared to be on the decline because of the excesses. Recent research has shown that by using mixes of inorganic and organic fertilizers, significant yield increases can be obtained. Soil-test based fertilizer recommendations introduced recently by the Department of Agriculture have helped to prevent further nutrient accumulations in these soils. By encouraging adoption of recommendations based on soil tests, the productivity of the Ultisols can be improved and the cost of producing an equal or higher yield will be reduced.[AS]

Managing soil fertility for intensive vegetable production systems in Asia; Proceedings of an

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