冀东地区晚播春玉米氮素积累、分配与转运特性

为明确冀东地区晚播春玉米氮素积累、分配与转运特性,2017—2018年以京农科728和MC812为供试材料进行了2年的田间试验,以常规播期(5月1日)为对照,分析了冀东地区晚播(5月30日)春玉米氮素积累动态和阶段积累特性及其在各器官中的分配和转运特性。结果表明,冀东地区春玉米氮素的积累动态符合Logistic模型,与常规播期比较,晚播春玉米氮素积累的渐增期和缓增期持续时间缩短,而快增期持续时间延长;氮素平均积累速率、渐增期和缓增期积累速率提高,氮素总积累量增加。晚播显著促进抽雄期-成熟期植株对氮素的吸收,此阶段京农科728和MC812氮素吸收量比常规播期分别增加72.56%和18.39%,阶段吸收百分率均达45%以上。晚播使春玉米茎鞘中氮素分配率提高,叶片的氮素分配率降低,同时还促进了叶片向籽粒转运氮素,使其转运量、转运率以及对籽粒的贡献率提高;成熟期晚播春玉米籽粒氮素分配比例达73.82%~77.41%。另外,晚播提高了春玉米产量,使氮素收获指数和氮素偏生产力同步提高;百公斤籽粒氮素吸收量基本不受播期的影响。综上可知,在晚播春玉米生产中,应注意增加氮肥施用量,选择基施肥效较长的缓释肥或在春玉米生长后期追施氮肥,以保证春玉米生育后期土壤有效氮的充足供应,保持叶片活力,维持叶片光合能力,促进春玉米增产。本研究对冀东地区晚播春玉米氮肥合理施用具有一定的指导意义。

Characteristics of Nitrogen Accumulation,Distribution and Translocation of Late Sowing Spring Maize in Eastern Hebei Province

In order to clarify the characteristics of N accumulation, distribution and translocation of late sowing spring maize(Zea mays L.) in Eastern Hebei province, a two-year field experiment was conducted in 2017—2018 with genotypes (Jingnongke 728 and MC812). The dynamics of N accumulation, characteristics of N stage-accumulation, distribution and translocation of late-sowing spring maize(May 30) were analyzed with conventional sowing maize as control(May 1). The results showed that the N accumulation dynamics of spring maize was consistent with the logistic model. Compared with conventional sowing spring maize, the following phenomena occurred in late sowing spring maize, the duration of gradual growth period and slow increase period of nitrogen accumulation were shortened, but the duration of rapid growth period was prolonged. The average N accumulation rate, the N accumulation rate of gradual growth period and slow increase period were increased, furthermore, total nitrogen accumulation was increased. The nitrogen absorption from tasseling stage to maturity stage was improved significantly with delaying sowing date, the stage absorption of Jingnongke 728 and MC812 were increased by 72.56% and 18.39%, respectively, and the stage absorption percentage were more than 45%. When the spring maize sowing date was delayed from May 1 to May 30, the nitrogen distribution rate in stem and sheath increased, while the distribution rate in leaf decreased, the amount, ratio and contribution ratio of nitrogen translocation from leaf to grain increased. The proportion of nitrogen distribution in grain of late sowing spring maize reached 73.82%~77.41% at maturity. The nitrogen absorption of 100 kg grain was not affected by sowing date. To sum up, attention should be paid to increasing the amount of nitrogen fertilizer in the production of mid-late-sowing spring maize, choosing slow-release fertilizer with longer basal fertilization effect or top-dressing nitrogen fertilizer in the late growth stage of spring maize. These can ensure the sufficient supply of soil available nitrogen in the late growth stage of spring maize, maintain leaf vitality, maintain leaf photosynthetic capacity, and promote spring maize yield. This study provided meaningful guidance for rational application of nitrogen fertilizer in late sowing spring maize in Eastern Hebei province.