Nutrient management in Vertisols in the Indian semi-arid tropics
1989
Burford, J.R. | Sahrawat, K.L. | Singh, R.P.
At ICRISAT Center, yields of rainy-season sorghum were reliable. Nutrient inputs were a much more important determinant of sorghum yield than variations in seasonal rainfall. Use of 15N-labeled fertilizer showed that rainy-season sorghum was quite efficient in the use of added fertilizer-N, except in the much wetter (1200 mm/a rainfall) than normal (800 mm/a) year where fertilizer-N was applied using traditional means. Compared with improved application methods, uptake of N by the crop was reduced from 45 per cent to 30 per cent, and losses (presumably as gases) increased from 7 per cent to 25 per cent. Preliminary research on phosphorus confirmed lower requirement for fertilizer-P on Vertisols and the need to reevaluate soil-test procedures, and the modest rate of phosphorus fixation by Vertisols
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