典型黑土侵蚀区不同耕作措施的水土保持功效研究

Tillage Effect on Soil Erosion in Typical Black Soil Region

通过田间定位实验,测定了免耕、少耕、传统耕作和横坡垄作4种措施的地表径流量、侵蚀量、土壤储水量,同步测定了降雨量、降雨强度等指标,综合的评价了4种耕作措施的保水、保土功效。研究结果表明,免耕和横坡垄作年径流量分别比传统耕作少97.7%和96.8%,侵蚀模数分别比传统耕作少98.9%和99.2%,而少耕未降低土壤侵蚀。免耕秸秆覆盖和横坡垄作能够有效地控制土壤侵蚀和地表径流的发生,为作物生长提供更多的土壤有效水分。相关分析表明,4种耕作措施的径流量都与I30和I60达极显著水平;4种耕作措施地表径流主要发生在6-8月份,土壤侵蚀主要发生在6-7月份。

Rainfall, runoff, sediment, and soil moisture from 5 m× 12 m plots were recorded in an experiment in which four treatments were compared in typical black soil Northeast China in 2008. Conventional tillage （CT） system, plowed field three times in a year and rotated surface soil in depth of 15 cm in fall. Reduced tillage （RT） system, added the furrow plowing deeply in depth of 25 cm compared CT before first rain in summer, and both of CT and RT had the larger runoff （RT 54.81 mm, CT 54. 37 mm） and the soil loss （RT 5 309.6 t/km^2, CT 3 083.1 t/km^2）. No-tillage with straw covered （NT） system, controlled weed-free with herbicide. Contour tillage （TT） system, plowed the field along the contour line, compared with CT, both of NT and TT had the least runoff （NT 1.23 mm; TT 1.73 mm） and sediment （NT 34.30 t/km^2 ; TT 23.2 t/km^2 ）. The relationship of runoff with rainfall, I30 and I60 were significant. Runoff mainly taken place from June to August, and sediment was caused from June to July, because high density mainly distributed in these months, especially lower cover in July. NT and TT reduced water loss, saved much water for plant growing from August to October. Soil moisture of NT and TT were lower in depth 1-170 cm than RT and CT from August to October, because leaf of area index were higher both of NT and TT than CT and RT, and increased the transpiration in plants. These results indicated that NT and TT were the feasible soil and water conservation practices in typical black soil Northeast China, and RT was not significant to reduce runoff and soil loss than CT.