Rice-Prawn Farming System: Impacts on Soil Quality and Land Productivity for Modern Varieties of Paddy Production in Bangladesh

The rice-prawn gher (RPG) farming system, locally known as the White Revolution, is an advanced, indigenous agricultural technology solely developed by local farmers in southwestern Bangladesh in the mid-1980s. This paper examined the impact of RPG farming on soil quality and land productivity of paddy production of modern varieties (MV) in Bangladesh. Two contrasting farming systems — RPG and year-round modern varieties (YRMV) — were considered. A total of 40 farmers (20 farmers from RPG and 20 from YRMV paddy farming) were randomly selected. Each of the sampled 20 RPG and 20 YRMV paddy farmers owned 30 farm plots. Soil sample collection procedures were conducted in two phases — at the beginning of paddy transplanting and during harvesting — in both farming systems. RPG farming has significant impacts on soil quality and land productivity in Bangladesh. The findings indicate that the leftover feeds of prawn production provide a significant amount of soil nutrients, such as nitrogen, soil organic matter, phosphorus, potassium, to soils in fields for paddy production under the RPG farming system. As a result, RPG farmers use comparatively less chemical fertilizers per unit of MV paddy production compared to YRMV farmers. Moreover, per unit yield of MV paddy was higher in RPG farming than in YRMV paddy farming.