Bell pepper yield and soil properties during conversion from conventional to organic production in Indian Himalayas

摘要

A conversion period of at least two years is required for annual crops before produce may be certified as organically grown. There is a need for better understanding of the various management options for implementing from conventional to organic production. The purpose of this study was to evaluate the effects of three organic amendments on growth and yield of bell pepper (Capsicum annuum L.), the benefit:cost ratio, soil fertility and enzymatic activities during conversion to organic production. For that purpose six treatments were established: composted farmyard manure (FYMC, T); vermicompost (VC, T); poultry manure (PM, T) along with biofertilizers (BF) [Azotobacter +phosphorus solubilizing bacteria (Pseudomonas striata)] and mix of three amendments (FYMC+PM+VC+BF, T); integrated crop management (FYMC+NPK, T) and unamended control (T). The bell pepper yield under organic management was markedly lower (33-53% and 18-40% less in first and second year of conversion, respectively) than with the integrated crop management (FYMC 10Mghap# +NPK - 100:22:41.5kghap#) treatment (T). Combined application of three organic amendments (FYMC 10Mghap# +PM and VC each 1.5Mghap# +BF, T) and T produced similar but significantly higher bell pepper yield (27.9 and 26.1Mghap#, respectively) compared with other organic amendment treatments. Both T and T greatly lowered soil bulk density (1.15-1.17Mgmpd), and enhanced soil pH (7.1) and oxidizable organic carbon (1.2-1.3%) compared with T and unamended control (T) after a two-year transition period. However, the N, P and K levels were highest in the plots under integrated management. T plots showed higher dehydrogenase activity values. However, acid phosphatase and o-glucosidase activities were higher in T plots whereas urease activity was greater in T plots compared with other treatments. Among the treatments involving organic amendments alone, T gave a higher gross margin (US $ 8237.5hap#) than other treatments. We conclude that T was found more suitable for enhancing bell pepper growth and yield, through improved soil properties, during conversion to organic production.