Nitrogen, phosphorus and potassium requirements of some bean (Phaseolus vulgaris L.) cultivars

Abstract

Ninety bean (Phaseolus vulgaris L.) cultivars were grown till maturity in full strength nutrient solution and, after harvesting, analysed for N, P and K in the various organs. Yield potential and N, P and K requirements were estimated by assuming a population of 250 thousand plants per hectare. Major conclusions were as follows: (1) there were striking differences in the mineral composition of the cultivars; (2) leaf analysis should take into consideration the cultivar under study; (3) protein contents in the grain varied from 20.6 to 34.4%, with an average of 27.3%; (4) extraction of nutrients in kg/ha showed the follow ing variation: N-50 to 425; P-20 to 15; K-100 - 262; percentwise export of K was the lowest; (5) yield potential varied from less than 500 kg/ha to more than 5000; (6) higher requirements are not necessarily associated with higher yield potential thereby suggesting differences in nutritional efficiency of the various vultivars.