耕作方式对冬小麦-夏玉米光合特性及周年产量形成的影响

摘要

[Objectives] Crop grain yields are greatly affected by photosynthetic characteristics and dry matter accumulation and translocation of crops,which are obviously influenced by different tillage methods.Comparison of the effects will provide a theoretical and practical basis for selecting suitable tillage method in the wheat-maize cropping system.[Methods] The research was conducted in a long-term tillage experiment located in the Huang-Huai-Hai Plain since 2003.Four tillage methods with straw returning were chosen:conventional tillage (PC) as control,zero tillage (PZ),subsoil tillage (PS) and rotary tillage (PR).Photosynthetic characteristics,dry matter accumulation and translocation,and yields of winter wheat and summer maize were measured during the 2014-2015 cropping year.[Results] The photosynthetic characteristics and yields of wheat and maize in the PZ,PS and PR were all significantly higher than in PC,and in order of PS ＞ PZ ＞ PR ＞ PC.The PZ,PS and PR significantly increased the chlorophyll contents,photosynthetic rates,stomatal conductance and transpiration rates of functional leaves of winter wheat and summer maize in the late growth stage.At the late filling stage of winter wheat,the chlorophyll contents of PZ,PS and PR were 97.0％,121.1％ and 71.4％ higher than PC,respectively,the photosynthetic rates were 57.6％,71.6％ and 51.2％ higher than PC.At the filling stage of summer maize,the chlorophyll contents were increased by 23.6％,28.1％ and 10.4％,the photosynthetic rates were increased by 18.6％,26.5％ and 19.2％.PZ,PS and PR delayed leaf senescence and maintained a high level of photosynthesis.As a result,the contribution ratio to grain by the accumulated assimilates after the anthesis of winter wheat in PZ,PS and PR reached 65.3％,67.8％ and 65.0％,respectively,and those of summer maize reached 66.3％,70.6％ and 63.4％,respectively,and those in winter wheat and summer maize in PC were only 59.3％ and 60.9％.The ears of PZ and PS were lower than those of PC and PR significantly,but the grains per ear and 1000-grains weight of them were higher than PR and significantly higher than PC.The annual yields ofPZ,PS and PR were increased by 15.4％,18.2％ and 11.0％,respectively.[Conclusions] All the zero tillage,subsoil tillage and rotary tillage show significant effects in enhancing photosynthetic characteristics,improving use ability of intercellular CO2 and reducing the non-stomatal limitation,enhancing dry matter accumulation after the anthesis and contribution ratio to grain in winter wheat and summer maize in the Huang-Huai-Hai Plain.Among them,the subsoil tillage with straw returning performs the best,followed by the zero tillage.%[目的]作物的光合特性及干物质积累与转运是影响产量的重要因素.研究不同耕作方式对冬小麦-夏玉米光合特性、干物质积累转运及周年产量的影响,以期为冬小麦-夏玉米两熟地区选择适宜的耕作方式提供理论和实践依据.[方法]以黄淮海地区2003～2014年连续12年定位试验为平台,在秸秆还田前提下,试验设4种耕作方式:传统翻耕(PC)为对照、免耕(PZ)、深松(PS)和旋耕(PR).对2014～2015季冬小麦和2015季夏玉米各项光合参数、干物质积累和产量进行了测定. [结果]长期不同耕作方式对冬小麦-夏玉米光合特性和周年产量影响显著,免耕、深松和旋耕处理的光合特性和周年产量均优于对照传统翻耕,依次为PS＞ PZ＞ PR＞ PC.PZ、PS和PR耕作方式显著提高了生育后期冬小麦和夏玉米功能叶的叶绿素含量、光合速率、气孔导度和蒸腾速率,其中冬小麦灌浆后期叶绿素含量分别提高了97.0％、121.1％和71.4％,光合速率分别提高了57.6％、71.6％和51.2％;夏玉米灌浆期叶绿素含量分别提高23.6％、28.1％和10.4％,光合速率分别提高18.6％、26.5％和19.2％,延缓了叶片衰老,使光合作用始终维持在较高水平.PZ、PS和PR处理冬小麦花后同化物对籽粒的贡献率分别达65.3％、67.8％和65.0％,夏玉米为66.3％、70.6％和63.4％,而对照处理(PC)冬小麦和夏玉米的贡献率仅为59.3％和60.9％.PZ和PS处理冬小麦和夏玉米的穗粒数和千粒重显著高于PC处理,穗数显著低于PC和PR.PZ、PS和PR可显著提高周年产量,分别提高15.4％、18.2％和11.0％.[结论]在黄淮海地区,采用长期秸秆还田下免耕、深松和旋耕均可提高冬小麦和夏玉米叶绿素含量和光合速率,提高胞间CO2利用能力,降低非气孔限制,增强花后干物质积累能力,增加花后同化物对籽粒的贡献率,协调产量构成因素的关系,提高单季和周年产量,其中深松效果最佳,免耕次之.