A new rainwater harvesting and recycling system for transforming sloping land into terraced farmland

Transforming sloping land into terraced land is an effective approach to cope with the problems including farmland shortage and severe soil erosion. This paper introduces a new system based on rainwater harvesting and recycling technology, which may effectively improve farmland productivity rainwater use efficiency and reduce water and fertilizer inputs. The new system consists of three subsystems: 1) A plough layer with the dual function of crop cultivation and rainwater harvesting; 2) A tank below the plough layer for storing water; 3) An irrigation-drainage subsystem. The plough layer and the storage tank, both treated for reducing seepage, are connected through the irrigation and drainage system. Results showed that, compared with the traditional paddy fields, rice evapotranspiration (and crop coefficient) in the test field remained at a similar level, while the irrigation amount was reduced by 44.3% under the condition of basin irrigation, and the drainage amount decreased by 86.6%, and the non-point source pollution was reduced to 67.7%～87.9%, and the rainwater utilization efficiency increased by 30% and reached 95.4%, and crop yield of middle-season rice reached 9,975 kg/hm², which was only 0.4% lower than that in the traditional paddy field in the terms of dry matter. The new technology sheds light on new possibilities for transformation of hilly sloping land.