| Agricultural sciences |
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| Effects of nitrogen fertilizer on the accumulation and allocation of dry matter and nitrogen for maize cultivars with different low nitrogen tolerance |
| Li Qiang, Ma Xiaojun, Cheng Qiubo, Dou Pan, Yu Donghai, Luo Yanhong, Yuan Jichao, Kong Fanlei |
| (1. Key Laboratory of Crop Ecophysiology and Farming System in Southwest China, Ministry of Agriculture/ College of Agronomy, Sichuan Agricultural University, Chengdu 611130, China; 2. Dongpo Agriculture Technology Extension Station, Meishan 620032, Sichuan, China; 3.Tobacco Production Technology of Dissemination and Apply of Yibin Tobacco Corporation in Sichuan, Yibin 644002, Sichuan, China) |
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Abstract Nitrogen is a major limiting factor on plant growth and yield formation, and a moderate amount of nitrogen fertilizers can increase crop yields every year. The tolerance to low N-fertilized level is different among maize cultivars, meanwhile the response of different maize cultivars are also significantly different under different N-fertilized levels. What’s more, different maize cultivars have significant difference in the dry matter production and nitrogen utilization efficiency. Related researches indicate that dry matter and nitrogen accumulation of low nitrogen tolerant maize cultivars were remarkable higher than that of low nitrogen sensitive maize cultivars, besides, low nitrogen tolerant maize cultivars had larger green leaf areas to increase the nitrogen absorption in the late growth stage, and the difference of those in two types maize cultivars is mainly performed after the silking stage.
A split plot experiment using the screened maize cultivars Zhenghong 311 with low nitrogen tolerance and Xianyu 508 with low nitrogen sensitivity as materials was conducted to investigate the difference of growth and development, dry matter and nitrogen accumulation and allocation in different low nitrogen tolerant maize cultivars under six nitrogen levels, and the different maize cultivars (Zhenghong 311 and Xianyu 508) were used as main plot and nitrogen fertilization rate (0N-0 kg/hm2, 90N-90 kg/hm2, 180N-180 kg/hm2, 270N-270 kg/hm2, 360N-360 kg/hm2 and 450N-450 kg/hm2, 50% base fertilizer and 50% panicle fertilizer) were used as sub-plot. The aims were to provide the theoretical and practical data for the reasonable nitrogen management of different low nitrogen tolerant maize cultivars in hilly areas.
The results showed that the accumulation and allocation of dry matter and nitrogen in stem-sheath and leaf of low nitrogen tolerant Zhenghong 311 were higher than that of low nitrogen sensitivity Xianyu 508 in all stages, while the dry matter and nitrogen allocation ratio of panicle in Xianyu 508 were higher. Compared with low nitrogen sensitive cultivar, low nitrogen tolerant cultivar increased the accumulation and allocation ratio of dry matter and nitrogen in leaf, and reduced that in panicle. The higher dry matter and nitrogen accumulation and allocation ratio of vegetative organs in low nitrogen tolerant cultivar were beneficial to keep higher nutrition absorption and dry matter productivity, and the yield of Zhenghong 311 was significantly higher than Xianyu 508 because the Zhenghong 311 delayed the senescence of leaf and prolonged the time of high photosynthesis rate under low nitrogen tolerant stress. Nitrogen fertilization significantly increased plant height, stem diameter, leaf area, dry matter accumulation, nitrogen absorption, yield and yield component, while the effect of nitrogen fertilization on the allocation ratio in dry matter and nitrogen were slight. Excessive nitrogen was not conducive to the growth and development of maize, meanwhile it reduced the harvest index that go against the increase of yield.
It is concluded that the low nitrogen tolerant cultivar Zhenghong 311 has higher dry matter and nitrogen accumulation to keep higher yield under low nitrogen levels, while the low nitrogen sensitive cultivar Xianyu 508 needs higher nitrogen fertilizer to get higher yield. Therefore, we can reduce nitrogen fertilization for low nitrogen tolerant cultivar Zhenghong 311 or plant it in poor soil of hilly region to make good use of the yield advantage under low nitrogen environment. On the contrary, the nitrogen fertilization of the low nitrogen sensitive cultivar Xianyu 508 should be increased or planted in a fertile region to guarantee its high stable yield.
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Published: 20 September 2015
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氮肥对不同耐低氮性玉米品种干物质及氮素积累与分配的影响
选用前期筛选出的玉米耐低氮品种正红311和低氮敏感品种先玉508为试验材料,采用裂区试验在6个氮水平下研究不同耐低氮性玉米品种的生长发育、干物质及氮素积累与分配差异。结果表明:正红311各阶段干物质及氮素积累量和积累速率、各时期茎鞘和叶片干物质及氮素分配比例均高于先玉508,而先玉508雌穗干物质及氮素分配比例更高。与先玉508相比,正红311提高了各主要生育时期叶片干物质及氮素积累量与分配比例,降低了雌穗干物质及氮素积累量与分配比例。正红311营养器官较高的干物质及氮素积累与分配比例有利于其保持较高的养分吸收和干物质生产能力,延缓叶片的衰老和延长高光合速率使其产量显著高于先玉508。施氮可显著提高玉米株高、茎粗、叶面积、干物质积累、氮素吸收、产量及产量构成,而对干物质和氮素在各器官的分配比例影响较小。过量施氮不仅不利于玉米生长发育,还会使玉米收获指数显著降低，从而不利于产量的提高。正红311施氮量在180 kg/hm2时产量最佳,而先玉508需要氮肥360 kg/hm2才能充分发挥其产量潜力。因此对于耐低氮品种正红311可适当降低施氮量或在土壤贫瘠的丘陵山区种植以充分发挥其低氮条件下的产量优势,而低氮敏感品种先玉508则应适当增加施氮量或种植在肥沃土壤的地区以保证其高产稳产。
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