淮北地区水稻品种氮肥群体最高生产力及氮素吸收利用特性

Yield, Nitrogen Absorption and Utilization of Rice Varieties with the Highest Population Productivity of Nitrogen Fertilization in Huaibei Area

以淮北地区有代表性的34个中熟中粳品种为试材,设置7个氮肥水平（0、150.0、187.5、225.0、262.5、300.0、337.5 kg hm–2）,得出各品种在这7个氮肥水平下出现的最高产量,将该最高产量定义为氮肥群体最高生产力。在此基础上,按氮肥群体最高生产力高低将品种划分为4个等级,即顶层水平（≥10.50 t hm–2）、高层水平（9.75~10.50 t hm–2）、中层水平（9.00~9.75 t hm–2）和底层水平（≤9.00 t hm–2）,比较研究不同氮肥群体最高生产力等级品种的产量及其构成因素、群体光合物质生产和氮素吸收利用差异。结果表明,所有品种的氮肥群体最高生产力均出现在225.0、262.5、300.0 kg hm–2三个氮肥水平,不同氮肥群体生产力差异极显著;随着生产力水平的提高,单位面积穗数先增加后降低,每穗粒数与群体颖花量显著增加,结实率显著下降;茎蘖成穗率、叶面积指数、光合势、有效叶面积率、高效叶面积率、粒叶比、总干物质积累量均以顶层水平最高,底层水平最低;移栽至拔节阶段的氮素积累比例表现为底层〉中层〉高层〉顶层水平,拔节至抽穗、抽穗至成熟阶段表现为顶层〉高层〉中层〉底层水平;移栽至拔节、拔节至抽穗及抽穗至成熟阶段的氮素吸收速率以顶层最高,顶层水平较底层水平分别高36.59%、34.36%和51.85%;随着氮肥群体生产力等级的提高,氮素吸收利用率和百千克籽粒吸氮量均提高;中熟中粳稻品种有氮低效型、氮中效型、氮较高效型和氮高效型,武运粳27、中稻1号、宁粳4号、连粳7号为高产氮高效品种。

The field experiment was carried out using 34 medium-maturing medium japonica rice varieties grown in Huaibei area with seven nitrogen application levels（0, 150.0, 187.5, 225.0, 262.5, 300.0, and 337.5 kg ha–1） to investigate their yield and nitrogen absorption and utilization. We defined the highest rice yields under different nitrogen levels as the highest population productivity of N fertilization. According to the highest population productivity of N fertilization, rice varieties were classified into four types including top type（TT）, high type（HT）, middle type（MT）, and low type（LT）. Yield components, population photosynthate production and N absorption and utilization of the four types rice varieties were compared. The main results indicated that optimum N levels of tested varieties corresponding to their highest population productivity of N fertilization converged in the range of 225.0-300.0 kg ha–1, while the highest grain yields were significantly different among tested varieties. With increasing productivity level, panicles per unit area increased firstly and decreased then, spikelets per panicle and total spikelet number increased and seed-setting rate declined percentage of productive tillers, leaf area index, photosynthetic potential, ratio of leaf area of productive tillers, ratio of leaf area from flag leaf to 3rd leaf, grain-leaf ratio and total dry matter accumulation increased. The ratio of nitrogen accumulation shown trend of LT〉 MT〉 HT 〉TT from transplanting to jointing stage and TT 〉HT 〉MT 〉LT from jointing to heading stage and from heading to maturity stage. N uptake rate was the fastest in the top type, and the slowest in low type and 36.59%, 34.36%, 51.85% higher in top type than in low type at translating to jointing, jointing to heading and heading to maturity growing stages. N use efficiency and N requirement for 100 kg kernel increased with increasing productivity level. According to the N use efficiency, 34 varieties were divided into low ANRE（apparent nitrogen recovery efficiency）, middle ANRE, higher ANRE and high ANRE. Wuyunjing 27, Zhongdao 1, Ningjing 4, and Lianjing 7 belonged to high yield and high ANRE varieties.