作 者 ：陈海飞,冯洋,蔡红梅,徐芳森,周卫,刘芳,庞再明,李登荣
期 刊 ：植物营养与肥料学报 2014年 20卷 6期 页码：1319-1328
Keywords:rice, nitrogen fertilizeer, transplanting density, yield, population structure, nitrogen use efficiency,
摘 要 ：【目的】适宜施氮量和移栽密度影响着水稻的群体结构和产量,也影响着氮素的利用率。因此,开展了田间小区试验以确定低产水稻田最佳的适宜施氮量和移栽密度组合。【方法】本研究选择湖北省咸宁市崇阳县产量水平较低的低产田为对象,以水稻品种两优培九为供试品种,设置四个施氮水平(0、 135、 180、 225 kg/hm2)与三个移栽密度 (12×104、 16.5×104、 21×104 holes/hm2)的田间小区互作试验。在水稻各个生育期分别调查茎蘖动态、 成穗率、 灌浆期剑叶叶面积、 水稻产量及其构成因子、 地上部干重及收获指数,采用SPSS 17.0软件对不同处理的产量与相应群体指标间进行回归分析,获得产量与各因子之间的回归方程。同时测定地上部籽粒与秸秆氮含量,计算氮利用效率。【结果】施氮量与移栽密度对低产田水稻产量和相关指标有显著影响,且存在交互作用。1)产量与地上部干物重均随着施氮水平与移栽密度的提高而增加,但是在施氮量最高(225 kg/hm2)时,收获指数略有下降;收获指数随着移栽密度提高而降低。2)产量与每平米穗数、 灌浆期剑叶叶面积、 地上部干重关系密切,用二次方程拟合的曲线相关系数最高,经回归方程计算,理论上当灌浆期剑叶叶面积指数达到1.36,成熟期地上部干重达到24371 kg/hm2,每平米穗数达到338个,平均每穗粒数达到195粒时产量最高。3)随着施氮水平提高氮肥农学利用率(NAE)、 偏生产力(PFPN)、 氮肥吸收利用率(NRE)和氮肥生理利用率(NPE)均降低,尤其是NAE和PFPN降低程度较大;提高移栽密度显著增加NAE、 PFPN、 NRE,但是NPE无变化。【结论】在施氮较少的情况下,提高移栽密度增产效果明显。移栽密度为21×104 holes/hm2和施氮量为180 kg/hm2的组合产量最高,达到8220 kg/hm2,其群体结构指标与利用拟合模型估计的最优指数最为接近, 并且有较高的NAE、 PFPN、 NRE和NPE。综合考虑,本研究的供试低产水稻田施氮量为180 kg/hm2结合移栽密度为21×104 holes/hm2为本试验的最优处理,可以获得较高的水稻产量和较高的氮肥利用率。
Abstract:【Objectives】Both the nitrogen application rate and transplanting density affect the formation of good population structure and rice yield. The suitable coupling of the two factors are the base of reaching highest yield and nitrogen use efficiency. An experiment was carried out in low-yield paddy field to setup the optimal nitrogen application rate and transplanting density.【Methods】Regarding low-yield paddy as the object of this research, an interactive test of four levels of nitrogen application rate (0, 135, 180, 225 kg/ha) and three gradients of transplanting density (12×104, 16.5×104, 21×104 holes/ha) were conducted with a rice cultivar of Liangyoupei9 as tested material. The items are investigated including stem and tillerring dynamics, leaf area indices in different growth periods, the nitrogen contents in grain and straw, and the yield and yield components. The optimum structure index when the yield reaches the highest was calculated by the curvilinear regression of yield along with LAI, TAB, SPP and PN. The nitrogen use efficiencies were compared among the treatments.【Results】Both the N application rate and transplanting density have significant effects on yield, and effect of interaction exists between them. 1) Yield and total aboveground biomass are improved with the increase of nitrogen application rates and transplanting densities. When the nitrogen application rate reaches 225 kg/ha, harvest indices decrease, instead. The harvest index decrease with the increase of transplanting density. 2) The rice production is closely related to panicles per square meter, sword leaf area in filling stage and shoot dry weight. Quadratic equation best describes the correlations with the highest correlation coefficients. Calculated with the equation, the theoretical highest yield will be obtained when the sword foliage area index in filling stage is 1.36, the above ground dry weight is 24371 kg/ha, the panicle numbers per square meter is 338, the spikelet number per panicle is 195, respectively. 3) N agronomic efficiency (NAE), N partial factor productivity (PFPN), N recovery efficiency (NRE) and N physiological efficiency (NPE) are significantly decreased with the increase of nitrogen application rates, particular for NAE, PFPN. Increasing transplanting density could obviously improve the NAE, PFPN and NRE, but had not on NPE.【Conclusions】With less nitrogen application rate, higher yield can be acquired by increasing transplanting density. In the tested soil condition and the nitrogen application rate of 180 kg/ha, the suitable transplanting density can be as high as 21×104 holes/ha for the highest grain yield.Under the combination, the population structure indices and the nitrogen efficiency indices are all the highest. So the N application rate of 180 kg/ha with transplanting density of 21×104 holes/ha are the optimal choice in the low-yield paddy field in the tested area.
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