东北黑土区农地水土流失现状与综合治理对策

Current status and comprehensive control strategies of soil erosion for cultivated land in the Northeastern black soil area of China

东北黑土区是我国重要的粮食产区和商品粮基地，对稳定粮食市场、保障国家粮食安全具有重要作用，但长期的重开垦轻保护导致了严重的水土流失，已经影响到了粮食生产的地位。以东北松嫩黑土区面积约2080万hm^2的区域为研究对象，根据950个野外调查点资料，推算研究区农地面积为1727．40万hm^2。通过径流小区和137Cs监测资料，估算该地区农地水土流失强度。东北黑土区农地土壤流失量与坡度的关系为A=0．7379θ。利用美国SRTM90m×90m地面高程资料，得出研究区总体地形平缓，坡度1°以下面积占72．25％，1°-5°面积占27．05％，5°以上面积仅占0．70％；但由于坡面较长，观测与计算结果表明，水土流失面积已达到1339．45万hm^2，占研究区总土地面积的64．40％，占研究区农地面积的77．54％。东北黑土区水土流失已经十分严重，开展针对该地区水土流失特点的水土保持措施建设已刻不容缓。同时，为全面了解东北地区水土流失状况，需要进一步加强对整个东北地区水土流失监测与土壤侵蚀规律的研究。

Northeastern black soil area is one of important regions for crop production and commodity grains in China, which takes the key role in stabilizing national grain markets and keeping national food security. The long term cultivation with less soil conservation has caused serious soil erosion and threatened food production in this area. This paper focused on the black soil region in Songhuajiang-Nenjiang plain, which is about 20.8 million hm^2, and estimated soil loss from the cultivated land by using 950 point survey data and soil loss data measured from plots and 137Cs. The cultivated land is about 17.274 million hm^2 in the study area. The soil loss prediction equation for crop land is A = 0.737 90. The analysis result showed that the study area has rolling hill topography by using SRTM elevation data with resolution of 90 m × 90 m. The percentage is 72.25% of the total area for slope steepness less than 1°, 27.05% for slop ranges of 1° - 5°, and only 0.70% for slope steeper than 5°. But the large slope length caused serious soil erosion for the crop land. Soil loss calculated from both plot and 137Cs measured data showed that the area of soil erosion is about 13.394 9 million hm^2, which is 64.40% of the study area and 77.54% of the crop land in the study region. It is urgent to take practices for soil conservation. In addition, to understand the soil loss rate for the northeastern China, it is necessary to strengthen the soil loss monitoring and soil erosion research.