林带对黑土坡面土壤养分侵蚀-沉积规律的影响

Effects of Shelterbelt on Soil Nutrient Erosion-Deposition Laws of Slope Land in Black Soil

在黑龙江省西北部的克山农场(东经125°7′40″~125°37′30″,北纬48°11′15″~48°24′7″)内,选择坡度、坡向、坡长、前茬作物基本一致的有农田防护林带和无林带的坡面为试验地,在每个试验地内分别布设1条垂直等高线水平距离为390 m的样线,每条样线上按垂直等高线水平距离30 m等间距设置12个样方,每个样方内按照不同土壤深度(h)范围分别采集表层(0<h≤20 cm)和下层(20 cm<h≤40 cm)土壤样品用于土壤有机碳、全氮和全磷质量分数的测定,分析农田防护林带对黑土坡面土壤养分侵蚀-沉积规律的影响。结果表明:(1)林带对黑土坡面土壤有机碳、全氮、全磷的侵蚀-沉积分布规律,均通过改变侵蚀-沉积周期、缩减甚至消除侵蚀区范围、阻断侵蚀区并实现侵蚀区向沉积区转变而产生影响。(2)林带直接消除了坡面中上部的有机碳和全氮侵蚀区,阻断了坡面中下部土壤有机碳和全氮侵蚀区,并通过缩减侵蚀区范围、实现侵蚀区向沉积区转变对坡面土壤全磷分布规律产生影响。建议:将黑土坡面农田防护林带配置间距调整为120~140 m。

In Keshan Farm in the northwest of Heilongjiang Province(125°7′40″-125°37′30″E,48°11′15″-48°24′7″N),the slope with farmland shelterbelt and without shelterbelt were selected as test sites,and the slope,aspect,slope length and previous crops were basically the same.In each test site,a sample line with a vertical contour line of 390 m and a horizontal distance of 390 m was set up,and 12 sample squares were set at equal intervals on each sample line according to the vertical contour line and the horizontal distance of 30 m.To determine soil organic carbon(SOC),total nitrogen(TN)and total phosphorus(TP),soil samples were collected from surface layer(0<h≤20 cm)and lower layer(20 cm<h≤40 cm)according to different soil depth(h)in each sample squares.We explored the effect of shelterbelt on soil nutrient erosion-deposition laws of slope land in black soil.The effect of shelterbelt on the distribution of SOC,TN and TP on slope land was caused by changing the erosion-deposition cycle,reducing or even eliminating the scope of erosion area,blocking the eroded area and realizing the transformation from eroded area to deposition area.The effect of shelterbelt on the distribution of TP was caused by directly eliminating the eroded area of organic carbon and total nitrogen in the middle and upper part of slope,blocking the eroded area of organic carbon and total nitrogen in the middle and lower part of slope,reducing the scope of eroded area and realizing the transformation from eroded area to deposition area.Therefore,the spacing of shelterbelt of slope land in black soil should be adjusted to 120-140 m.