秋季耕作方式对旱地麦-玉二熟区小麦产量形成的影响

为明确秋季耕作方式对旱地麦-玉二熟体系小麦籽粒产量形成的影响，于2019年6月至2021年6月，在豫西典型旱作麦-玉二熟区的洛阳市孟津区小浪底镇明达村，选择前茬夏玉米免耕的田块，设置秋深松、秋免耕和秋旋耕3种耕作方式，分析了不同秋季耕作方式下两个试验年度的小麦籽粒产量及其构成因素和穗部性状以及2020-2021年度的小麦群体茎蘖数、孕穗后的旗叶净光合速率（P_n）和干物质积累转运特性。结果表明，秋季耕作方式对小麦产量、穗部性状、旗叶P_n和干物质积累转运特性均有显著的调节作用。与秋旋耕相比，秋深松的小麦茎蘖数除返青期外均显著增加，穗数增加5.74%~16.06%；秋深松虽然对小麦旗叶P_n无显著影响，但提高灌浆中后期的旗叶SPAD值，显著改善了干物质积累转运特性，从而使千粒重增加，其中2019-2020年度使穗长和小穗数分别提高7.50%和9.42%，最终使籽粒产量提高9.77%~19.09%。秋免耕后，小麦孕穗和抽穗期的叶片P_n、返青至开花期的干物质积累量、花前干物质转运量及其对籽粒产量的贡献率也较秋旋耕均显著降低，而花后干物质对籽粒产量贡献率提高7.35个百分点，从而保证了籽粒产量无显著下降。与秋免耕相比，秋深松下不同生育时期的茎蘖数均显著增加，孕穗至灌浆中后期的叶片P_n，灌浆中后期的旗叶SPAD值，返青-成熟期的干物质积累量，花前干物质转运量、转运效率及其对籽粒产量的贡献率分别提高7.16%~18.41%、10.27%、12.25%~19.97%、42.19%、4.02个百分点和11.95个百分点，其中2019-2020年度穗长和小穗数分别增加7.50%和8.41%，穗数和籽粒产量分别提高16.74%~17.63%和10.31%~23.63%。综上，秋深松不仅可增加小麦穗数，而且可改善旗叶光合及干物质积累转运特性，进而提高籽粒产量，是旱地麦-玉二熟区实现小麦高产的耕作方式。

Effects of Tillage Modes in Autumn on Yield Formation of Wheat in Dryland Wheat-Maize Double Cropping Area

In order to understand the effects of tillage modes in autumnon grain yield formation of wheat under double cropping systems of wheat and maize in dryland,a field experiment of three tillage managements including autumn subsoiling (AST), autumn no-tillage (ANT), and autumn rotary tillage (ART) was set up in Mingda Village, Xiaolangdi Town, MengJin District, Luoyang City, a typical dryland wheat-maize double cropping area in western Heman, where the previous summer maize was no-tillage from June 2019 to June 2021. The grain yield and its components, and spike traits in the two experimental years, the tiller number of wheat population, the net photosynthetic rate (P_n) of flag leaves after booting and the characteristics of dry matter accumulation, translocation and distribution in 2020-2021 were investigated. The results showed that different tillage managements in autumn significantly regulated wheat yield, spike traits, flag leaf P_n and dry matter accumulation, translocation and distribution. Compared with ART, the tiller number in AST was significantly increased except regreening stage, leading to the increase rate ranging from 5.74% to 16.06% for spike number. Although there was no significant difference on leaf P_n between ART and AST,compared with ART, the SPAD value of flag leaves in AST during the middle and late grain filling stage, as well as the characteristics of dry matter accumulation and translocation was significantly increased, thus 1 000-grain weight was increased.Moreover,the spike length and spikelet number in 2019-2020 were increased by 7.50% and 9.42%, respectively, and the grain yield was significantly increased by 9.77%-19.09%. Compared with ART, the leaf P_n at booting and heading stages,dry matter accumulation from regreening to anthesis, and pre-anthesis dry matter translocation and its contribution rate to grain in ANT were also significantly decreased, while the contribution rate of post-anthesis dry matter to yield in ANT was significantly increased by 7.35 percentage points, thus stabilizing the grain yield. Compared with ANT, the tiller number in AST was significantly increased at each growth stage;the leaf P_n from booting to middle and late grain filling stage was significantly increased by 7.16%-18.41%;leaf SPAD value at middle and late grain filling stage was increased by 10.27%; the dry matter accumulation from regreening to maturity was increased by 12.25%-19.97%;the pre-anthesis dry matter translocation amount, translocation rate and contribution rate to grain was improved by 42.19%, 4.02 percentage points and 11.95 percentage points, respectively. The spike length and spikelet number in AST was 7.50% and 8.41%, respectively, higher than those in ANT in 2019-2020. Finally, the ear number and grain yield in AST was significantly increased by 16.74%-17.63% and 10.31%-23.63%, respectively, compared with ANT.In conclusion, AST can not only increase the ear number, but also improve the photosynthetic characteristics of flag leaves and dry matter accumulation and translocation characteristics, and thus increase wheat yield. Therefore,subsoiling in autumn is an alternative tillage mode to achieve high yield of wheat in dryland wheat-maize double cropping area.