Integrated Nutrient Management for Production, Economics, and Soil Improvement in Winter Vegetables

Abstract

ABSTRACT There is concern that use of inorganic fertilizers alone cannot sustain high levels of productivity and cause deterioration of the soil and environment. The use of vermicompost (VC) and microbial inoculants (Azotobactor® and phosphorus-solubilizing bacteria) to improve plant nutrition may address these issues. Effects of VC and microbial inoculants in combination with inorganic fertilizers on growth and yield of crops and soil health need to be better understood. The eastern Ghats region of Orissa, India, has a favorable climate for year-round cultivation of vegetables. An on-farm experiment with seven treatments including chemical fertilizers, VC, cow manure (CM), and microbial inoculants was carried out for 3 consecutive years during winters of 2001 to 2003, at Koraput, India, on a red soil to determine the most effective integrated nutrient management option for enhancing productivity of cabbage (Brassica oleracea L. Capitata group) and bell pepper (Capsicum annuum L.). Vermicompost appeared to be the best soil additive in both crops in terms of yield, net economic return, and water use efficiency (WUE). In bell pepper, use of VC+50% recommended rate of synthetic fertilizers (RRF) produced significantly higher yield over 100% RRF, with a net return increase of 29.8%. There was a similar effect for yield of cabbage. In the 50% RRF+VC treatment, WUE was 32.6% higher in bell pepper and 6.2% higher in cabbage over treatment with 100% RRF. Bulk density of the surface soil after 3 years was reduced; its organic carbon and available N and P status improved due to treatment with CM and VC. The data indicate that 5 Mt·ha−1 of VC can meet 50% of the fertilizer requirement of bell pepper and cabbage while providing higher productivity, income, and residual soil fertility.