局部灌水施氮下玉米根系形态特征与产量的关系研究

Study on Relationships Between Maize Root Morphological Traits With Grain Yield Under Partial Root-zone Supply of Irrigation Water and Nitrogen

为了阐明局部灌水施氮下玉米根系形态变化特征及其与产量的关系。以“金西北22号”玉米为试供材料,连续2 a在大田条件下采用垄植沟灌技术。试验采用灌水方式与施氮方式2因素完全随机组合设计,灌水方式包括交替隔沟灌溉(AI)、固定隔沟灌溉(FI)、常规沟灌(CI);施氮方式包括交替施氮(AN)、固定施氮(FN)、均匀施氮(CN)。分别在玉米拔节期、大喇叭口期、抽雄期、灌浆期、成熟期监测0~100 cm土层各层(每20 cm为一层)植株的根系长度、质量和表面积,并折算对应的根密度。收获时测定籽粒产量及其构成。抽雄、灌浆和成熟期,0~100 cm土层的总根量(总根长、总根干质量、总根表面积)表现为:任一施氮方式下,AI>CI>FI;任一灌水方式下,AN与CN差异不显著,但显著大于FN。交替隔沟灌溉均匀施氮(AICN)和交替隔沟灌溉交替施氮(AIAN)的总根量最大,而固定隔沟灌溉固定施氮(FIFN)的总根量最小。玉米产量与抽雄期、灌浆期和成熟期0~40 cm土层的根长密度及根干质量密度呈显著正相关,其中灌浆期的相关系数达到极显著水平。穗粒数及千粒质量与根长密度、根干质量密度和根表面积密度呈显著正相关。可见,交替隔沟灌溉条件下采用均匀施氮或交替施氮有利于促进玉米抽雄、灌浆和成熟期0~100 cm土层根系的生长,提高灌浆期0~40 cm土层根长密度、根干质量密度和根表面积密度值有利于获得较高的籽粒产量。

The aim of this study was to investigate the characteristics of maize root morphology and its relationship with yield under local irrigation and nitrogen application.The corn of“Jinxibei 22”was used as the test material for 2 consecutive years under the field condition by ridge planting and furrow irrigation.Different irrigation methods(AI with alternating furrow irrigation,FI with fixed furrow irrigation,CI with conventional furrow irrigation)and nitrogen application methods(AN with alternating nitrogen application,FN with fixed nitrogen application,CN with uniform nitrogen application)were used in the experiment.The root length,mass and surface area of maize plants in each layer of 0~100 cm soil layer(each layer was 20 cm)were monitored at jointing,trumpet,tasselling stage,filling and maturity stages,and the corresponding root density was converted.Grain yield and its composition were measured at harvest time.At tasselling,filling and maturity stages,the total root quantity(total root length,total root dry weight and total root surface area)in 0~100 cm soil layer was as follows:AI>CI>FI under any nitrogen application method(P<0.05).Under any irrigation method,there was no significant difference between AN and CN,but it was significantly higher than FN(P<0.05).The total root amount was the largest in alternating furrow irrigation with uniform nitrogen application(AICN)and alternating furrow irrigation with alternating nitrogen application(AIAN),while the total root amount was the smallest in fixed furrow irrigation with fixed nitrogen application(FIFN).The grain yield was positively correlated with root length density and root dry mass density in 0~40 cm soil layer at tasselling,filling and maturity stages,and the correlation coefficient reached a highly significant level at filling stage.The number of grains per ear and weight per thousand grains were positively correlated with root length density,root dry mass density and root surface area density.In conclusion,uniform nitrogen application under alternate furrow irrigation and alternate nitrogen application under alternate furrow irrigation could promote the root growth in the 0~100 cm soil layer at tasselling,filling and maturity stages of maize,and increase the root length density,root dry mass density and root surface area density in the 0~40 cm soil layer at filling stages of maize,which was beneficial to obtain higher grain yield.