夏玉米种植条件下黄壤坡耕地径流及磷素流失特征

Characteristics of Runoff and Phosphorus Loss from Sloping Farmland in Yellow Soil Region Under the Condition of Summer Maize Growth

为揭示自然降雨条件下夏玉米生育期内黄壤坡耕地径流及磷素流失规律,采用野外径流小区观测试验与室内分析相结合的方法,探讨了自然降雨条件下地表径流、壤中流及其总磷的流失特征。结果表明:(1)顺坡垄作径流量显著高于其余两种耕作措施,其径流量分别为平作和横坡垄作的1.13倍和1.17倍。横坡垄作径流磷素流失总量显著低于其余两种耕作措施,其总磷流失量分别为平作和顺坡垄作的0.79倍和0.75倍。(2)随着玉米生育期的推进,径流量呈增加的变化趋势,表现为成熟期>抽雄期>拔节期、苗期。相较于苗期,成熟期径流量增加了9.35倍,径流磷素流失量增加了12.58倍。(3)地表径流、0—20 cm土层壤中流和20—40 cm土层壤中流量分别占径流总量的78.36%,10.20%,11.44%,其磷素流失量分别占径流磷素流失量的75.10%,9.90%,15.00%。综上,研究区以地表径流为磷素流失的主要途径,且在玉米成熟期达到最大值,横坡垄作措施对于坡面产流及磷素流失具有较好的控制效果。

To reveal the regulation of runoff and phosphorus loss in sloping farmland of yellow soil under natural rainfall with the condition of summer maize growth,runoff plots set in the field were conducted to investigate the characteristics of surface runoff,interflow and total phosphorus loss under natural rainfall.The results showed that:(1)the runoff of downslope ridge planting was significantly higher than that of cross planting and flat planting,accounting for 1.13 and 1.17 times higher than that of flat planting and cross planting,respectively;total phosphorus loss of cross ridge planting was significantly lower than that of the other two tillage measures,accounting for 79%and 75%of that of flat planting and down slope planting,respectively;(2)with the growth of maize,the amount of runoff showed an increasing tendency(mature stage>tasseling stage>elongation stage and seedling stage);compared with the seedling stage,the runoff and the phosphorus loss of mature stage increased by 9.35 and 12.58 times,respectively;(3)surface runoff,interflow in 0—20 cm and 20—40 cm accounted for 78.36%,10.20%and 11.44%of runoff,respectively,and their phosphorus loss accounted for 75.10%,9.90%and 15.00%of the total phosphorus loss,respectively.The surface runoff contributed mainly to phosphorus loss,which reached up to maximum at mature stage in the study area.It was efficient to decrease runoff and phosphorus loss by ridge planting.