耕作措施对玉米生长期黄壤坡耕地径流及可溶性有机碳流失的影响

Effects of Tillage Practices on Runoff and Dissolved Organic Carbon Loss from Yellow Soil Sloping Farmland During Maize Growth Periods

为探明黄壤坡耕地不同耕作措施下径流及可溶性有机碳(dissolved organic carbon, DOC)迁移途径与流失特征。以顺坡垄作、平作和横坡垄作措施下玉米种植坡耕地为研究对象,采用野外径流小区监测与室内分析相结合的方式,探讨自然降雨条件下坡耕地地表径流、壤中流及其DOC流失特征。结果表明:(1)种植玉米坡耕地径流量及DOC通量均受雨量等级影响显著,随雨量等级增大而增大,且玉米成熟期流失量均最大。(2)地表径流、0-20 cm壤中流和20-40 cm壤中流分别占总径流量的78.98%,9.05%,11.97%,DOC流失通量分别占总通量的74.90%,11.97%,13.13%。(3)横坡垄作DOC流失量显著小于顺坡垄作,横坡垄作径流量分别是平作的0.93倍,是顺坡垄作的0.86倍;横坡垄作DOC通量是平作的0.85倍,是顺坡垄作的0.79倍。雨量等级增加将显著加剧玉米种植坡耕地径流及DOC流失,研究区玉米成熟期径流及DOC流失最为严重,地表径流是坡面径流及DOC流失的主要途径,横坡垄作措施可以有效减少坡面径流及DOC流失。

The purpose of this study was to explore the migration path and loss characteristics of runoff and dissolved organic carbon(DOC) in sloping farmland of yellow soil at each maize growth period under different tillage measures. Taking the down slope ridge planting, flat planting and cross ridge planting as the research object, the surface runoff, interflow and DOC loss under natural rainfall were discussed by combining field runoff plot and laboratory analysis. The results showed that:(1) The slope runoff and DOC flux at each growth stage of maize were significantly affected by rainfall levels, and increased with the increase of rainfall levels and the losses were the largest at maturity.(2) The surface runoff, interflow of 0-20 cm and interflow of 20-40 cm accounted for 78.98%, 9.05% and 11.97% of the total runoff respectively, and DOC flux accounted for 74.90%, 11.97% and 13.13% of the total loss flux respectively.(3) The amount of DOC loss on the slope of cross ridge planting was significantly less than that of down slope ridge planting, and the runoff of cross ridge planting was 0.93 times that of flat planting and 0.86 times that of down slope ridge planting. The DOC flux of cross ridge planting was 0.85 times that of flat planting and 0.79 times that of down slope ridge planting. The increase of rainfall levels would significantly aggravate the slope runoff and DOC loss. Surface runoff and DOC flux had the largest loss during maize maturity in the study area and the surface runoff was the main way of slope runoff and DOC loss, the cross ridge planting could effectively reduce slope runoff and DOC loss.