不同种植模式对西南坡地水土保持及作物产值的影响

通过3年定位监测试验研究了小麦/玉米/大豆全程免耕全程秸秆覆盖、小麦/玉米/大豆半程免耕半程秸秆覆盖、小麦/玉米/大豆全程翻耕不覆盖秸秆和小麦/玉米/甘薯全程翻耕不覆盖秸秆4种不同种植模式对西南坡地水土保持、土壤肥力及作物产值的影响.结果表明：在水土保持方面，小麦/玉米/大豆全程免耕全程秸秆覆盖模式的3年平均土壤侵蚀量和地表径流量最低，分别为1189 kg·hm^-2和215 m³·hm^-2，显著低于其他处理，比小麦/玉米/甘薯全程翻耕不覆盖秸秆模式分别低10.6%和84.7%.在土壤肥力方面，3种小麦/玉米/大豆模式都能增加土壤有机质、全氮、速效钾和碱解氮含量，以小麦/玉米/大豆全程免耕全程秸秆覆盖模式增加幅度最大，分别增加15.7%、18.2%、55.2%和25.9%，显著高于其他模式，小麦/玉米/大豆半程免耕半程秸秆覆盖模式次之，小麦/玉米/甘薯全程翻耕不覆盖秸秆模式最低.在作物产值方面，以小麦/玉米/大豆全程免耕全程秸秆覆盖模式的3年平均总产值和纯收入最高，分别为18809元·hm^-2和12619元·hm^-2，比其他几个处理分别增加2.2%～20.6%和3.8%～32.9%，总体效益最好.总之，小麦/玉米/大豆模式比传统的小麦/玉米/甘薯模式能更好地保持水土，减少土壤侵蚀量和地表径流量，增加土壤肥力和作物产值.

Effects of planting system on soil and water conservation and crop output value in a sloping land of Southwest China

A three-year experiment was conducted to study the effects of wheat/maize/soybean with total no-tillage and mulching (NTM), wheat/maize/soybean with part no-tillage and part mulching (PTM), wheat/maize/soybean with total tillage without mulching (TWM), and wheat/maize/sweet potato with total tillage without mulching (TWMS) on the soil and water conservation, soil fertility, and crop output value in a sloping land of Southwest China. The　average soil erosion amount and surface runoff of NTM were significantly lower than those of the other three planting systems, being 1189 kg·hm^-2and 215 m³·hm^-2, and 10.6%and 84.7% lower than those of TWMS, respectively. The soil organic matter, total N, available K and available Ncontents of NTM were increased by 15.7%, 18.2%, 55.2%, and 25.9%, respectively, being the highest among the test planting systems. PTM and TWM took the second place, and TWMS pattern had the least. NTM had the highest annual crop output value (18809 yuan·hm^-2) and net income (12619 yuan·hm^-2) in three years, being 2.2%-20.6% and 3.8%-32.9% higher than other three planting systems, respectively. In a word, the planting system　wheat/maize/soybean was more beneficial to the water and soil conservation and the improvement of soil fertility and crop output value, compared with thetraditional planting system wheat/maize/sweet potato.