Crop Response to Lime and Phosphorus on New Bench Terraces in the Tropics
- D. R. Schmidt ,
- M. D. Casler and
- A. Saefuddin
Population growth in many tropical areas has led to the cultivation of steeply sloped hillsides. Soil disturbance from construction of conservation terraces to reduce land degradation in humid tropical areas often intensifies P deficiency and problems related to acidity. This trial measured the response of food crops to lime and P application for 2.5 yr following construction of bench terraces. Factorial combinations of 0, 2, and 4 Mg ha− lime and 0, 10, 20 and 40 kg P ha− were applied on a deep, well-drained clay of volcanic origin (Typic Haplumbrept) at Andapraja, West Java, Indonesia. A pretrial soil test indicated pH of 5.0, available P (Bray 1) of 5.9 mg kg− and exchangeable Al saturation of 17%. Upland rice (Oryza sativa L.) responded strongly to P application. Three crops averaged 0.35, 2.45, 2.89 and 3.46 Mg ha− of unmilled grain from respective applications of 0, 10, 20 and 40 kg P ha−. Lime had no effect on rice yield. Soybean [Glycine max (L.) Merr.] and cowpea [Vigna unguiculata (L.) Walp.] responded to both lime and P but yields were low because of disease. Mean lime and no-lime yields were 0.48 and 0.62 Mg ha− for soybean. Cowpea yields were maximum (0.15 Mg ha−) at the 2 Mg ha− lime rate. Mean P and no-P yields were 0.13 and 0.64 Mg ha− for soybean and 0.01 and 0.13 Mg ha− for cowpea. Cassava (Manihot esculenta Crantz) root yield response to P was less pronounced than the response by rice and the legumes, and was the only crop to show a lime ✕ P interaction. This was attributed to limited response to P when lime was applied, significant response to P with zero lime and marked response to lime with zero P. The efficiency of return from applied P indicated that the 10 kg P ha− rate applied to rice, soybean or cassava had the highest efficiency, producing yields 70 to 80% of the 40 kg P ha− rate.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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