CAJ | 학술논문

过量施肥造成的农业面源污染已成为太湖水质下降及富营养化的主要原因之一。该试验在距离太湖湖岸带约1 km的小麦种植区对2种杨麦间作密度（其株距均为2 m，行距分别为5 m (AS1)和15 m (AS2)）削减土壤氮流失效应进行研究。结果表明：杨树林冠层对降雨的截留主要集中于4－10月，AS1间作密度下林冠层对降雨的截留幅度达8.6%～44.5%。由于林冠层对降雨的再分配作用导致的径流量AS1R（去除枯落物：Remove litter）处理显著低于AS2R和MSL0（单作麦地中未铺设枯落物处理）处理（P<0.05）。在整个小麦生长季，AS1S（有枯落物覆盖：Save litter）处理径流中TN、NO3--N平均浓度、流失量均显著低于MSL0（P<0.05）。60 cm土层AS1S平均淋溶水量、TN、NO3--N平均浓度和流失量与AS2S、MSL0之间均存在显著差异（P<0.05）。在杨树落叶期，AS1系统有枯落物覆盖下地表径流量、TN、NO3--N平均浓度和流失量均显著低于无枯落物处理（P<0.05）。而 AS2系统有无枯落物覆盖之间差异则不显著（P>0.05）。在去除冠层及枯落物影响后，AS1R处理60 cm土层淋溶水量、TN和NO3--N淋溶流失量均显著低于20cm土层（P<0.05），而MSL0系统下20、40、60 cm之间差异均不显著（P>0.05）。由此可见，株行距为2 m×5 m的杨麦间作密度对地表径流、淋溶及氮流失的削减效应更显著。
과량시비조성적농업면원오염이성위태호수질하강급부영양화적주요원인지일。해시험재거리태호호안대약1 km적소맥충식구대2충양맥간작밀도（기주거균위2 m，행거분별위5 m (AS1)화15 m (AS2)）삭감토양담류실효응진행연구。결과표명：양수림관층대강우적절류주요집중우4－10월，AS1간작밀도하림관층대강우적절류폭도체8.6%～44.5%。유우림관층대강우적재분배작용도치적경류량AS1R（거제고락물：Remove litter）처리현저저우AS2R화MSL0（단작맥지중미포설고락물처리）처리（P<0.05）。재정개소맥생장계，AS1S（유고락물복개：Save litter）처리경류중TN、NO3--N평균농도、류실량균현저저우MSL0（P<0.05）。60 cm토층AS1S평균림용수량、TN、NO3--N평균농도화류실량여AS2S、MSL0지간균존재현저차이（P<0.05）。재양수락협기，AS1계통유고락물복개하지표경류량、TN、NO3--N평균농도화류실량균현저저우무고락물처리（P<0.05）。이 AS2계통유무고락물복개지간차이칙불현저（P>0.05）。재거제관층급고락물영향후，AS1R처리60 cm토층림용수량、TN화NO3--N림용류실량균현저저우20cm토층（P<0.05），이MSL0계통하20、40、60 cm지간차이균불현저（P>0.05）。유차가견，주행거위2 m×5 m적양맥간작밀도대지표경류、림용급담류실적삭감효응경현저。
Agricultural non-point pollution caused by the overuse of fertilizer in farmland has become one of the main factors for water quality deterioration and eutrophication in Taihu Lake. In order to select suitable agroforestry intercropping system to control soil nitrogen loss in Taihu Lake basin, a study was conducted at a distance of 1 km away from the lakeshore to find out how poplar-wheat intercropping system with 2 kinds of densities (AS1:poplar spacing 2 m×5 m;and AS2:poplar spacing 2 m×15 m) affected the amount of surface runoff, leaching and soil nitrogen loss. The interception of rainfall by the poplar canopy was mainly concentrated from April to October and ranged from 8.6%to 44.5%. The control effects of canopy layer on sprinkle and moderate rain (<1.0 mm/h) were obvious, which were reduced by 47.7% on average. Rainfall interception by canopy was mainly related to the LAI (leaf area index). The volume of rainfall difference between AS1 and MS (monoculture system) was only 0.8%during the defoliated period while the control effect of AS1 was raised to 6.4%during the growing period. Compared to AS2R (means removing litter) and MSL0 (monoculture of wheat without litter coverage), the runoff amount of AS1R decreased by 9.1% and 11.2%, respectively. There was a significant difference between AS1R and AS2R/MSL0 (P<0.05), while the difference between AS2R and MSL0 was not significant (P>0.05). Compared to MS, the volume of surface runoff, leaching and soil nitrogen loss were all effectively controlled by the 2 poplar-wheat intercropping systems. The control effects were more significant under the higher intercropping density. There was no significant difference between the average runoff volume of AS1S (means saving litter) and AS2S/MSL0 during the whole growing period (P>0.05), while their average concentration and leaching amount of total nitrogen (TN) and NO3--N were both significantly lower than MSL0 (P<0.05). The average leaching water amount of AS1S in the depth of 60 cm was significantly different from that of AS2S and MSL0 (P<0.05), while the difference between AS2S and MSL0 was not significant (P>0.05). The difference of average concentration and leaching amount of TN and NO3--N in 20 cm was not significant among AS1S, AS2S and MSL0 (P>0.05) while that in 60 cm was significant (P<0.05). The average runoff amounts of 2 intercropping systems without litter coverage were both higher than those with litter coverage during the poplar defoliated period. It was obvious that the runoff amount, average concentration and leaching amount of TN and NO3--N with litter coverage were lower than those without litter coverage in AS1 (P<0.05), while there was no significant difference between AS2 with litter coverage and without (P>0.05). The litter volume was the major factor to decide whether there was significant difference between the surface runoff and leaching loss. The average surface runoff, concentration and leaching amount of TN and NO3--N with the litter coverage of 0.4 t/hm2 were significantly lower than those of 0.2, 0.1 and 0 t/hm2. The average leaching water volumes of AS1R in 20 and 40 cm soil depth were higher than those of MSL0 while the result in 60 cm was opposite. The decreasing range of leaching volume of AS1R in 60 cm depth was 1.3 times higher than that of MSL0, and the leaching volume of AS1R were different significantly in 20 and 60 cm (P<0.05), while there was no significant difference among 20, 40 and 60 cm for leaching volume of MSL0 (P>0.05). There was significant difference between average concentration of TN in 20 and 60 cm for AS1R, which were respectively 1.8 and 1.5 times lower than those for MSL0. The leaching loss of TN and NO3--N in 60 cm for AS1R was significantly lower than those in 20 cm. Thus it can be concluded that the effects of surface runoff, leaching and nitrogen loss reduction are more significant under the poplar-wheat intercropping system with the spacing of 2 m×5 m.