Chen, Shuai; Li, Zizhong; Cao, Shuming; Li, Chenxi; Yu, Fei
Abstract
Maize row planting creates distinct in-row and inter-row zones with heterogeneous canopy cover and root distributions, leading to differences in rainfall and soil characteristics that are critical factors influencing water erosion. However, horizontal differences in water erosion between in-row and inter-row positions and the effects of rainfall and root heterogeneity remain unclear. To address this gap, simulated rainfall experiments (40-120 mm h- 1) were conducted on a 3 degrees sloped maize field under conventional flat rotary tillage at the full canopy stage in the black soil region of Northeast China. Micro-runoff plots were established in each in-row and inter-row position to measure stemflow, throughfall, runoff, and sediment yield. After the rainfall simulations, soil and root properties at the two positions were determined. In-row zones received more rainwater (averaging 60.5% of total rainfall, comprising 43.5% stemflow and 17.0% throughfall) than inter-row zones (receiving only 31.2% throughfall). Runoff depth did not differ significantly between zones, but in-row runoff coefficients were markedly lower (mean = 35.4%) than inter-row coefficients (mean = 68.2%). Nevertheless, in-row erosion comprised 11.7-27.0% of total sediment loss, whereas inter-row zones generated 73.0-88.3%. The driving effect of throughfall on inter-row soil erosion was stronger than that of the combined stemflow and throughfall on inrow soil erosion, but the soil intrinsic resistance to raindrop splash and flow scouring did not differ significantly between zones. In-row soil infiltration and saturated hydraulic conductivity were significantly higher and associated with greater root mass density, which promoted rainwater infiltration and reduced runoff conversion. This study provides the first quantitative evidence that inter-row zones are hotspots for water erosion owing to their throughfall's stronger erosion-driving effect and lower soil infiltration capacity. Targeted conservation measures of improving infiltration or applying ground cover in inter-row positions are crucial for reducing water erosion in sloping maize farmland.
Differences in water erosion between in-row and inter-row positions of maize in sloping farmland.pdf
