残膜污染对滴灌玉米土壤水分和根冠生长的影响

Effects of residual plastic film pollution on soil water content and root-shoot growth of maize under drip irrigation condition

为充分分析残膜量对河套灌区农业生产的影响,进一步认识和评价残膜污染的负面效应,制定合理的田间残膜防治措施.2019~2020年在河套灌区九庄农业综合节水试验站开展了2年田间试验,设置0(CK)、150(T1)、300(T2)、450(T3)和600kg/hm^(2)(T4)5个残膜量处理,研究不同残膜量对土壤水分、玉米叶片光合特性、根冠生长及产量的影响.结果表明,当残膜量在0~300kg/hm^(2)范围内,残膜以阻滞水分入渗为主,增加了0~30cm土壤含水率;当残膜量≥450kg/hm^(2)时,水分阻隔效益减弱,同时产生优先流,导致0~30cm土壤含水率减少.残膜量增加还会降低玉米的光合性能,减少玉米根干重和冠层干物质量,破坏根冠生长平衡,特别是在生育前期,与0kg/hm^(2)处理相比,600kg/hm^(2)处理苗期的根干重、干物质量和根冠比分别平均减小48.66%、34.63%和18.17%.另外,残膜污染的加剧严重影响了玉米产量形成和水分有效利用,600kg/hm^(2)处理的产量和水分利用效率较0kg/hm^(2)处理分别平均下降34.05%和28.85%.研究表明,残膜污染持续加剧的情况下,会影响土壤水分入渗,降低玉米光合能力,抑制玉米生长,最终导致玉米减产.因此,采取适当的农田残膜污染治理措施,有利于平衡根冠生长,改善光合性能,推进河套灌区膜下滴灌玉米农田绿色可持续发展.

To evaluate the impact of the residual plastic film(RPF)amounts on agricultural production,a two-year field experiment was conducted during 2019 and 2020 in Jiuzhuang Agricultural Comprehensive Water-saving Experimental Station,Hetao Irrigation District.The variations of SWC,photosynthetic performance,root-shoot growth,and crop yield were analyzed under different RPF amounts with 0(CK),150(T1),300(T2),450(T3),and 600kg/hm^(2)(T4).Moreover,a reasonable field management strategy was formulated.The results showed that SWC in the 0~30cm soil layer under the RPF amount of 0~300kg/hm^(2) was increased due to the reduction of water infiltration caused by the RPF.However,SWC in the 0~30cm soil layer under the RPF amount with≥450kg/hm^(2) was decreased due to the formation of preferential flow.Meanwhile,the maize photosynthetic performance,maize root-shoot dry weight,and the root-shoot growth rate were decreased under high RPF amount(≥450kg/hm^(2)),especially in the early crop growth stage.The root dry weight,shoot dry weight,and the root-shoot ratio under the T4 treatment were 48.66%,34.63%,and 18.17%lower than that of the CK,respectively.Additionally,crop yield and water use efficiency(WUE)were limited by the RPF.Crop yield and WUE under the T4treatment decreased by 34.05%and 28.85%compared with that of the CK,respectively.In general,the increase of RPF amount resulted in the decreases of soil water infiltration,maize photosynthetic capacity,maize growth,and maize yield.Therefore,it is of great necessity to determine a reason management strategy for RPF pollution.The reason management strategy would increase root and shoot growth,improve photosynthetic performance,and promote the green sustainable development of the dripped irrigation field under plastic film mulching in Hetao Irrigation District.