FERTILIZER ECONOMY IN RELATION TO POTATO BASED CROPPING SYSTEMS IN IRRIGATED SOUTH BIHAR ALLUVIAL PLAINS

Abstract

In a field experiment conducted during 1997-98 to 1999-2000 in a sandy clay loam alkaline soils at Patna under south Bihar alluvial plains, it was revealed that irrespective of whether crop residues of previous crop were buried or not, potato-mentha-rice was better and remunerative over potato-sunflower-rice crop sequence. However, in absence of crop residue incorporation, all the component crops in in these sequences should be fertilized with optimum NPK (100%) except in sunflower as it produced similar seed yields under residual (NPK) fertility of the preceding crops vis-à-vis its fertilization with NPK. Contrarily, when crop residues of previous crop were incorporated in the succeeding crop in the sequence, the first crop of potato in these systems should be fertilized with optimum NPK while the subsequent crops in the respective systems viz., sunflower/mentha and rice should be fertilized with 50% of recommended N only for better economy in fertilizer use and realizing higher yield. Therefore, crop residues incorporation in absence of organic manures is vital for augmenting the overall productivity of both the cropping systems over the years by improving fertility status of soils under prevailing soil-climatic conditions of south Bihar alluvial plains.