秸秆还田量对不同基因型夏玉米产量及干物质转运的影响

Effects of Straw Returning Amount on Grain Yield, Dry Matter Accumulation and Transfer in Summer Maize with Different Genotypes

【目的】科学客观评价秸秆直接还田的综合效应,对提高秸秆资源利用率、促进农业绿色可持续发展意义重大。本研究在黄淮海冬小麦-夏玉米一年两熟区设置大田定位试验,探究不同基因型夏玉米对秸秆还田量的响应,为该区秸秆还田技术的综合评价和秸秆还田量的优化提供依据。【方法】试验于2017年10月至2018年10月在河南原阳进行,采用裂区试验设计,设置秸秆还田量和基因型两个因素。秸秆还田因素为主区,设置4个秸秆还田量处理,分别为秸秆不还田(S0)、半量秸秆还田(S1)、全量秸秆还田(S2)和倍量秸秆还田(S3);基因型为副区,供试品种分别为浚单20(XD20)和郑单958(ZD958)。分析2个品种在不同秸秆还田量处理下叶面积指数(LAI)、干物质积累与转运、产量性状的差异。【结果】与秸秆不还田处理相比,秸秆还田能维持玉米花后较高的叶面积指数,且基因型与秸秆还田量间存在显著的交互作用。玉米开花期,XD20和ZD958的LAI均随秸秆还田量的增加而增加,在S3处理下最高。玉米成熟期,XD20和ZD958的LAI降幅随秸秆还田量增加而呈先降后升的趋势,XD20在S1处理下最低,ZD958在S2处理下最低;且2个品种成熟期LAI随秸秆还田量增加呈先升后降的趋势,XD20在S1处理下最高,ZD958在S2处理下最高。花后较高的叶面积指数有利于玉米花后维持较高的干物质生产能力,从而显著提高花后干物质积累量,优化干物质积累与分配特性。基因型和秸秆还田量互作显著影响花前营养器官的干物质转运量(DMR)和转运率(DMRE)、花前干物质转运对籽粒干物质积累贡献率(DMRCG)、花后干物质积累量(DMAA)及其对籽粒干物质积累贡献率(DMAACG)。随秸秆还田量增加,XD20花前营养器官(茎鞘+叶片)的DMR、DMRE和DMRCG呈先降后升趋势,均在S1处理下最低,而花后DMAA和DMAACG则呈先升后降趋势,均在S1处理下达到最高值;ZD958花前营养器官(茎鞘+叶片)的DMR、DMRE和DMRCG以及花后DMAA均呈先升后降趋势,均在S2处理最高。玉米花后干物质积累量的增加,有利于增加粒重,进而提高籽粒产量。与S0处理相比,S1、S2和S3处理均提高了玉米籽粒产量,但玉米籽粒产量并未随着还田量的增加而持续增加;XD20在S1处理下2年籽粒产量最高,2年平均高于其他处理3.5%-17.7%,ZD958在S2处理下2年籽粒产量最高,2年平均高于其他处理0.4%-16.8%。【结论】在黄淮海冬小麦-夏玉米一年两熟潮土区,适量秸秆还田可延缓玉米生育后期叶片衰老进程,优化玉米干物质积累与分配特性,提高花后干物质积累量,增加粒重,进而提高玉米籽粒产量。但不同基因型玉米对秸秆还田量的响应有很大差异,在推广秸秆还田时,不仅要考虑秸秆还田量,还要考虑作物遗传因素对秸秆还田效应的影响。

【Objective】 Scientific and objective evaluation of the comprehensive effect of straw returning is important to improve the utilization rate of straw resources and to promote the green and sustainable development of agriculture. In this study, a field located experiment was conducted in wheat-maize cropping system on the North China Plain, to clarify the responses of different genotypes summer maize to various straw returning amounts. The purpose of this paper was to provide support for the comprehensive evaluation of the straw returning technology and for the optimization of straw returning amount. 【Method】 The experiment was conducted from October 2017 to October 2018 at Yuanyang, Henan province. The experimental design was a split plot. The main plot was four straw returning amount, no straw returning to field(S0), 50% amount of straw returning to field(S1), 100% amount of straw returning to field(S2) and 200% amount of straw returning to field(S3), and the subplot was genotype, including XD20 and ZD958. The differences in leaf area index(LAI), dry matter accumulation and transfer, and grain yield under different treatments were analyzed. 【Result】 Compared with no straw returning to field, the straw returning increased LAI after silking, and there was a significant interaction between genotypes and straw returning amount on LAI. At anthesis stage, the LAI of XD20 and ZD958 increased with the increasing of straw returning amount, and were the highest under S3 treatment. At maturity stage, with the increasing of straw returning amount, the decline in LAI for XD20 and ZD958 showed a trend of first decreasing and then increasing, and was the lowest under S1 for XD20 and S2 for ZD958. In addition, the LAI of XD20 and ZD958 at maturity stage showed a trend of first rising and then falling with the increasing of straw returning amount, and were the highest under S1 for XD20 and S2 for ZD958. Higher post-silking LAI was conducive to maintain higher post-silking dry matter production capacity, eventually significantly increased post-silking dry matter accumulation and optimize dry matter accumulation and distribution characteristics. The interaction of genotype and straw returning amount significantly affected the dry matter remobilization(DMR), dry matter remobilization efficiency(DMRE), contribution of dry matter remobilization to grain(DMRCG), dry matter accumulation after anthesis(DMAA) and contribution of dry matter accumulation after anthesis to grain(DMAACG). With the increasing of straw returning amount, DMR, DMRE and DMRCG of the vegetative organs(stem sheath + leaf) in XD20 firstly decreased and then increased, and were the lowest under S1 treatment. Meanwhile, DMAA and DMAACG showed an increasing trend first and then a decreasing trend, which were the highest under S1 treatment. The DMR, DMRE, DMRCG and DMAA of the vegetative organs(stem sheath + leaf) of ZD958 all showed an ascending and then descending trend with increasing of straw returning amount, and those were the highest under S2 treatment. The increase of dry matter accumulation was beneficial to increase grain weight and grain yield. Compared with S0 treatment, S1, S2 and S3 treatment improved the grain yield, but the grain yield did not increase continuously with the increasing of straw returning amount. For XD20, the highest grain yield was obtained under S1 treatment, which was 3.5% to 17.7% averagely higher than other treatments. For ZD958, the highest grain yield was achieved under S2 treatment, which was 0.4% to 16.8% averagely higher than other treatments. 【Conclusion】 Our results showed that, for wheat-maize cropping system on the North China Plain, appropriate amount of straw to the field could delay the leaf senescence process in the later growth stage of maize, optimize the dry matter accumulation and distribution characteristics, improve the post-silking dry matter accumulation and grain weight, and thereby improve the grain yield of maize. However, the responses of different maize cultivars to straw returning amount vary greatly. When promoting straw returning to the field, the effects of crop genetic factors on straw returning should also be considered.