Quadruple Cropping Patterns in Bangladesh: Scope and Limitations

Growing crops in a piece of land influence soil fertility depending on adopted management practices and intensity of cropping. Farmers in many cases do not use balanced fertilizers because of socio-economic conditions and thus nutrient mining is inevitable. We hypothesize that soil degradation is likely along with reduced crop productivity in future with researcher proposed four crops production packages. Semi-structured questionnaire, and IDRISI3.2 were used for data collection and mapping, respectively. Net quadruple cropped areas were about 7.09%. Soil fertility scores of those areas were 40–50 and above 50, covering about 4.56% and 3.66%, respectively of the net cropped areas indicating medium fertility status. Apparent nutrient balances for nitrogen, phosphorus, potassium, sulfur, calcium, magnesium and silicon were negative with researcher's introduced cropping patterns and fertilizer management compared to existing patterns. Zinc with all introduced cropping patterns and boron with Potato–Boro–T Aus–T Aman pattern are increasing but other micro nutrients are diminishing. Phosphorus and Sulfur build ups are taking place under farmer's practice in Mustard–Boro–T Aman, Potato–Boro–T Aman and Boro–Fallow–T Aman patterns. Zinc build up is taking place under farmer's managed cropping patterns; but iron, copper, boron, molybdenum and chloride are deteriorating from the soils. These indicate that growing four crops in a year with existing fertilizer recommendations are not sustainable in terms of soil fertility. Adoption of such intensive crop culture by the majority of the farmers is unlikely except in some sporadic areas having market driven economy of vegetable cultivation.