覆膜砂质农田土壤水分和CO_(2)分布特征及玉米根叶衰老响应  

Root and leaf senescence of maize subject to spatial differentiation of soil water and CO_(2)in sandy fields with plastic film mulching

作　　者：周立峰 杨宇翔 杨荣 ZHOU Lifeng;YANG Yuxiang;YANG Rong(Faculty of Modern Agricultural Engineering,Kunming University of Science and Technology,Kunming 650500,China;Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]昆明理工大学现代农业工程学院,昆明650500 [2]中国科学院西北生态环境资源研究院,兰州730000

出　　处：《中国生态农业学报（中英文）》2024年第1期83-94,共12页Chinese Journal of Eco-Agriculture

基　　金：中国科学院战略性先导科技专项项目(XDA23060302);国家自然科学基金项目(52369006);云南省基础研究计划项目(202201BE070001-023)资助。

摘　　要：干旱区新垦绿洲沙地灌溉强度大,农田覆膜后往往出现春玉米早衰现象。为探讨土壤水分和通气性是否是引发早衰的原因,本研究在河西走廊绿洲春玉米农田设置不覆膜(NM)和覆膜(PFM)处理,探求覆膜条件下土壤水分和CO_(2)分压(pCO_(2))对玉米根系生长、绿叶面积衰减、光合生理以及籽粒产量与品质的影响。覆膜处理中,覆膜区域的土壤pCO_(2)较未覆膜区域高40%以上;未覆膜处理中,对应区域的土壤pCO_(2)差异为13.9%~24.0%。相比不覆膜处理的对应区域,覆膜处理覆膜区域过高的土壤pCO_(2)使玉米花期根系活力下降19.7%,但非覆膜区根长密度和根系活力分别增加22.7%和9.6%。覆膜提高了春玉米拔节期叶片光合速率(20.0%)和蒸腾速率(8.5%),但抑制了花后叶片光合速率(−40.0%)和蒸腾速率(−18.0%);覆膜处理相对绿叶面积衰减启动时间和衰减最大速率时间分别提前1.7 d和7.1 d,而平均衰减速率和最大衰减速率分别增加6.7%和21.7%。覆膜的上述效应未显著影响玉米籽粒产量,但使籽粒淀粉含量和蛋白质含量分别降低20.1%和22.1%。以上结果表明,在干旱区新垦绿洲沙地,覆膜根区土壤pCO_(2)过高可能是导致玉米花后早衰和籽粒品质下降的重要原因,后期建议开展适时揭膜、控制灌溉(如亏缺灌溉、分根交替灌溉)或加气灌溉对覆膜新垦绿洲农田土壤通气性的改善研究。High intensive irrigation is commonly found in newly reclaimed oasis sandy land in arid area,which easily causes plant senescence of spring maize in farmland with plastic film mulching.The previous studies have found that land cover significantly affected soil moisture and soil aeration,but the data of spatial differentiation of soil moisture and soil aeration under mulching condition was lacking.In order to explore whether soil moisture and aeration causes plant senescence,an experiment was conducted to in-vestigate the effects of plastic film mulching on spatial differentiation of soil water and partial pressure of soil CO_(2)(pCO_(2))in root zone,root growth,green leaf duration,leaf photosynthetic physiology,grain yield and grain quality of spring maize in a sandy farmland in the Hexi Corridor(100°12′E,39°20′N,1370 m above sea level).Two treatments[plastic film mulching(PFM)and no mulching(NM)]were set up in this experiment.In the current study,oven drying method was used to determine soil water content.Soil gas was collected by gas well method,which was composed of collecting pipe,transmission pipe and a sampler.The CO_(2)concentration of gas samples was analysed by a gas chromatograph(Agilent 7890A,Agilent,Palo Alto,USA).Plant roots were sampled using a steel drilling,washed into a nylon mesh bag,scanned with root a scanner(EPSON Perfection V700)and then obtained root length density(RLD)using WinRHIZOPro software.Soil moisture showed no significant difference in horizontal direction in NM treatment,whereas,the average soil moisture of mulched soil(narrow row and wide row at 5 cm distance from plants)was 28.1%(P<0.05),15.2%(P<0.05)and 21.7%(P<0.05)higher than that under non-mulched soil(wide row at 25 cm distance from plants)before,6-days after,and 9-days after irrigation.In PFM treatment,soil pCO_(2)in mulched zone was 40%higher than that in the in non-mulched zone.Compared with NM,the excessively high soil pCO_(2)under mulched zone under PFM treatment decreased the maize root activity by 19.7%,but the

关 键 词：绿洲化 地膜覆盖 土壤通气性 玉米 早衰 

分 类 号：S275.6[农业科学—农业水土工程]