Comparison of Different Intercropping Systems for Reducing Nutrients Loss from Farmland

XIANG Jiamin;DING Zhifeng;YANG Qiongyao;ZHANG Mingkui;College of Environmental and Resource Sciences, Zhejiang University;

source-sink farming systems;;nutrient loss;;drainage;;recycling

【Objective】Nutrient loss from agricultural soils is a great environmental concern in many countries, and rotating crops and intercropping are believed to be one solution to slowing down this loss. The aim of this paper is to investigate the efficacy of different intercropping systems in reducing the loss of suspended solids and major dissolved nutrients from farmland.【Method】 The experiment was conducted from 2014 to 2017 in Zhejiang province, southeast China. We compared five intercropping systems: vegetable-Zizania latifolia, vegetable-paddy rice, orchard-Zizania latifolia, mulberry-paddy rice and orchard-lotus pond, with traditional cultivation used by local farmers taken as the control. In each system, we measured the reduction in sediment loss, change in total and soluble phosphorus(P), total and soluble nitrogen(N).【Result】Compared with the control, all five intercropping systems reduced the loss of suspended solid and P and N by more than 70% on average. In particular, they reduced the total P loss by 90.63%, soluble P loss by 89.14%, suspended solid loss by 88.72%, soluble N loss by 86.75%,and total N loss by 86.64%. In terms of efficacy, the five systems were ranked in the order of orchard-lotus pond >vegetable-Zizania latifolia > orchard-Zizania latifolia > mulberry-paddy rice > vegetable-paddy rice.【Conclusion】The mechanisms underlying the intercropping systems for reducing loss of suspended solids and nutrients from soils was the reduced drainage and the increased ability of soil to absorb nutrients. Intercropping is a low-cost but efficient technology to ameliorate nutrient loss from farmland systems. For the five intercropping systems we compare, lotus pond-Zizania latifolia was most effective.