Synergestic effect of high density multiple cropping on soil productivity and yield of base crop (coconut)

摘要

The seasonal fluctuation of Azotobacter and the general bacterial population and soil health in the rhizosphere region and the net return from three different crop models were studied in Kahikuchi, Assam, India. The crop models consisted of: coconut+black pepper (Panniyur-1)+banana+Assam lemon+pineapple+ginger (model-I); coconut+betelvine+banana+Assam lemon+turmeric+colocasia (model-II); and coconut (monocropping; model-III). Among the models, model-I had the highest total population density of Azotobacter and general bacteria in rhizosphere region. Each crop in all three models showed the maximum number of Azotobacter and general bacterial populations in April, except for ginger in model-I and turmeric in model-II. From April onwards, bacterial populations tended to decrease up to July (lowest population count in the season). Thereafter, the population increased up to October. The population tended to decrease up to January but increased to April (maximum). In contrast to other crops, the general bacterial populations and Azotobacter populations in ginger (model-I) and in turmeric (model-II) increased to the maximum level in October. Among different crop species, the maximum populations of Azotobacter and general bacteria were recorded in the rhizosphere of banana, with model-I showing the highest populations. Model-I recorded the highest soil pH, organic carbon content, available N, P and K content of soil and net income per hectare per year, followed by model-II then model-III. The availableN, P and K content of each plot decreased with soil depth in all the models.