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通过对229个山地小流域年的土壤侵蚀资料分析表明,在较长系列中,大多数的土壤侵蚀来自几次大暴雨.在9个面积为1ha,土壤为粉沙壤残积土,坡度为B和C两种的小流域中,采取玉米——小麦——草——草的轮作方式,并在玉米年的春季进行犁耙、整地、除草等管理.在玉米收获后,即翻去作物前茬种植了冬小麦.在种植小麦或草的年份未进行耕作.其中的4个小流域采取顺坡条播种植,另外5个是等高种植.92%的侵蚀量发生在玉米年,其余则发生在小麦年.等高种植小流域的侵蚀量平均占顺坡条播处理的30%.在研究期间共发生4000次降雨,其中每个小流域都有5次最大的侵蚀,其总量占28年侵蚀总量的66%.有的小流域,一次暴雨侵蚀量可占长期总量的一半以上.
Analysis of annual soil erosion data from 229 mountain valleys shows that in the longer series, most of the soil erosion comes from several heavy storms, with 9 areas of 1ha, soil with silt soil, slope B and C two kinds of small watershed, take corn - wheat - grass - grass rotation mode, and corn in the spring rake, land preparation, weeding and other management.In the corn harvest, that is, turn the crop before crop Winter wheat was planted and no tillage was carried out in the years where wheat or grasses were planted. Four of these small watersheds were planted along the slope and the other five were planted in contour .92% of the erosion occurred in maize years and the rest in wheat Year. The erosion of the contour planted watershed averages 30% of the succession of the sowing slope. A total of 4,000 rainfalls occurred during the study period, of which 5 were the largest in each of the small watersheds, accounting for 28 years total erosion 66% of the amount of some small watershed, a heavy rainfall erosion can account for more than half of the total long-term.