不同灌水量下除草剂对玉米生长与籽粒农药残留量的影响

Effects of Herbicides on Maize Growth and Grain Pesticide Residues under Different Irrigation Amounts

【目的】探讨玉米生育期内灌水量与24%烟嘧·莠去津可分散油悬浮液对作物生育指标和玉米产量的影响,解决河套灌区水资源短缺和除草剂的使用量大等问题。【方法】通过不同水药处理:(1)同一施药量P2(当地施药量1.875L/hm^(2)减少10%),设置3个灌溉水平W1P2(0.8ET)、W2P2(ET)、W3P2(1.2ET);(2)同一灌溉定额W2(ET),设置3个施药量W2P1(当地施药量1.875 L/hm^(2)减少30%)、W2P2(当地施药量1.875 L/hm^(2)减少10%)、W2P0(人工除草),制定河套灌区发展绿色农业的灌溉制度和施药水平。【结果】W2P2处理和W2P1处理叶片的叶绿素相对量(SPAD)在施药后由于胁迫均产生短时间的下降,大约施药9d后可恢复正常水平。W2P2处理与W2P0处理相比,百粒质量、干物质量、产量仅减少了1.2%、3.8%、1.7%(p>0.05)。与W1P2处理相比,W2P2处理的百粒质量、干物质量、产量增加了5.0%、35.1%、19.0%(p<0.05)。各处理玉米籽粒中农药残留量均低于国家标准,莠去津在成熟玉米籽粒中的残留量大致相同;而W1P2处理、W2P2处理、W3P2处理、W2P1处理烟嘧磺隆的残留量分别为87.83、42.76、37.86、21.82μg/kg,与施药量正相关,与灌溉定额负相关。施药各处理的水分利用效率(WUE)表现为W2P2处理>W2P0处理>W2P1处理。灌溉各处理的WUE表现为W2P2处理>W1P2处理>W3P2处理,(p<0.05)。与当地灌溉水平(约420mm)相比,W2P2处理节水20.8%,节水效果明显,且该处理经济效益高于其他处理。【结论】以节水减药为目的,W2P2处理为适合当地发展绿色农业和减少资源浪费的最优生产模式。

【Background】The use of agrichemicals in agricultural production could lead to environmental pollution and result in the chemicals entering the food chain.However,how irrigation affects dissemination and transfer of agrochemicals in soil-plant system is poorly understood.【Objective】The aim of this paper is to understand how irrigation and herbicide Nicosulfuron-Atrazine combine to affect maize growth and residue of the herbicide in the maize grains.【Method】The experiments were conducted in lysimeters at Hetao Irrigation District;it compared three herbicide applications:0(W2P0),1.31 L/hm2(W2P1)and 1.69 L/hm2(W2P2),and three irrigation amounts:80%(W1P2),100%(W2P2)and 120%(W3P2)of evapotranspiration(ET).For each treatment,we measured growth traits of the maize and herbicide residue in the grains after harvesting.【Result】When irrigation amount was W2P2,applying herbicide temporarily reduced the relative chlorophyll content(SPAD)in the leaves,but it recovered after nine days.W2P2 reduced 100-grain mass,dried biomass and maize yield by 1.2%,3.8%and 1.7%(p>0.05)respectively,compared with W2P0,while compared to W1P2,it increased these traits by 5.0%,35.1%and 19.0%(p<0.05)respectively.Regardless of irrigation amount and herbicide application rate,herbicide residues in the maize grains were lower than the national standards.The residue of Atrazine in the grains was approximately the same in all treatments,but the residue of Nicosulfuron varied between irrigation amount and herbicide application rates,with its content in the maize grains under W1P2,W2P2,W3P2 and W2P1 being 87.83,42.76,37.86 and 21.82μg/kg respectively.Herbicide application also affected water use efficiency(WUE).When the irrigation amount was W2P2,the WUE of different treatments was ranked in the order of W2P2>W2P0>W2P1.Without applying herbicide,the WUE of different irrigation amounts was ranked in the order of W2P2>W1P2>W3P2,with WUE in W2P2 significantly higher than that in W1P2 and W3P2(p<0.05).Compared with the irrigation amount used by local farmers(420 mm),W2P2 saved 20.8%of water.【Conclusion】Of all the treatments we studied at Hetao Irrigation district,W2P2 was most effective in improving water use efficiency and reducing herbicide residues in the maize grains.