保护性耕作对黄壤坡耕地水土流失及作物产量的影响

Effects of Conservation Tillage on Crop Yield and Soil Erosion in Sloping Land of Yellow Soil

[目的]分析保护性耕作对黄壤坡耕地水土流失及作物产量的影响,为贵州省坡耕地水土流失治理及农业可持续发展提供科学依据。[方法]在西南地区典型黄壤坡耕地设置不施肥+顺坡平作(TR 1)、常规施肥+顺坡平作(TR 2)、优化施肥+顺坡平作(TR 3)、优化施肥+横坡垄作(TR 4)、优化施肥+横坡垄作+秸秆覆盖(TR 5)、优化施肥+横坡垄作+秸秆覆盖+等高植物篱(TR 6)共6个不同试验处理的监测小区,于2017-2018年监测了不同处理间作物产量、地表径流量、氮磷流失量、土壤养分含量的差异,并分析其相关性。[结果]①TR 4,TR 5,TR 6较TR 3的径流量分别减少了59.72%,74.13%和89.18%,氮磷流失总量与径流量趋势相同;②TR 5,TR 6对全量养分含量影响最大,其中全氮比TR 4作高20.00%,23.67%,比TR 3高23.53%,27.31%;③TR 4,TR 5,TR 6处理下的玉米在保持较高产量的同时,作物产量稳定性(SI)和可持续性(SYI)最好;④玉米、油菜产量与全氮、全磷、有效磷、有机质呈极显著正相关(p<0.01),与速效氮呈显著正相关(p<0.05);玉米产量与氮素流失量、磷素流失量、径流量呈极显著负相关(p<0.01)。[结论]在坡耕地实施保护性耕作能有效降低地表径流发生,减少氮磷流失,保持土壤养分肥力的同时促进作物高产,并实现稳产及可持续生产,且实施综合保护性耕作的效能大于单项保护性耕作。

[Objective]The effects of conservation tillage on crop yield and soil erosion in sloping land of yellow soil were analyzed in order to provide scientific basis for soil and water loss control an agricultural sustainable development in Guizhou Province.[Methods]In the typical slopping land of yellow soil in southwest China,nitrogen and phosphorus loss,surface runoff and soil nutrient content were investigated under different tillage systems from 2017 to 2018.Six monitoring plots were set up,including no fertilization+downslope conventional tillage(TR 1),conventional fertilization+downslope conventional tillage(TR 2),optimized fertilization+downslope conventional tillage(TR 3),optimized fertilization+cross ridge tillage(TR 4),optimized fertilization+cross ridge tillage+straw mulching(TR 5),optimized fertilization+cross ridge tillage+straw mulching+contour hedgerow(TR 6).[Results]①Compared with TR 3,the runoff of TR 4,TR 5,TR 6 were reduced by 59.72%,74.13%and 89.18%respectively,and the total loss of nitrogen and phosphorus showed a same varying trend.②TR 5 and TR 6 had the greatest impact on total nutrient content,of which total nitrogen was 20.00%and 23.67%higher than TR 4,23.53%and 27.31%higher than TR 3,respectively.③Maize yield stability(SI)and sustainability(SYI)were the best with TR 4,TR 5 and TR 6 treatments while maintaining a high yield.④The yield of maize and rape was significantly and positively correlated with total nitrogen,total phosphorus,available phosphorus and organic matter(p<0.01),and positively correlated with available nitrogen(p<0.05),while negatively correlated with nitrogen loss,phosphorus loss and runoff(p<0.01).[Conclusion]Conservation tillage in sloping land could effectively reduce surface runoff,the loss of nitrogen and phosphorus,maintain the soil nutrient fertility and promote high yield of crops,and achieve a stable and sustainable production,and the effect of comprehensive conservation tillage measure is greater than that of single conservation tillage measure.