【作者】 王子胜；

【导师】 周治国；

【作者基本信息】 南京农业大学 ， 作物栽培学与耕作学， 2011， 博士

【摘要】 东北特早熟棉区是我国短季棉育种与生产的重要基地,短季棉产量与品质是制约该地区棉花产业发展的主要因素,通过合理的种植密度与氮肥运筹建立高效的群体结构是棉花产量提高的基本途径。我们以自育的品种辽棉19号和美棉33B两个品种为材料,于2007-2009年在东北特早熟棉区(辽宁辽阳,41026’N,123°14’E)开展了“种植密度和施氮量对东北特早熟棉区棉花生物量和氮素累积的影响”的研究,设置了棉花种植密度和施氮量试验,研究了棉花群体生物量与氮素动态累积特征的差异及其与产量品质形成的关系,建立了不同群体棉花的临界氮稀释模型,并对不同群体棉花生长的氮营养状况进行诊断。主要研究结果如下：1.种植密度对东北特早熟棉区棉花生物量和氮素累积的影响棉花群体生物量和氮素的累积动态随生育进程的变化符合“S”型曲线,氮素累积快速起始期及终止期均较生物量的累积提前10d左右。两品种均以97500株/hm2密度下的棉花生物量、氮素动态累积过程最为优化,皮棉产量最高,纤维品质最优；密度过高条件下尽管群体生物量、氮素累积量较高,但经济产量下降。2.施氮量对东北特早熟棉区棉花生物量和氮素累积的影响棉花生物量和氮素累积量随生育进程的动态变化符合“S”型曲线,氮素的快速累积起始日较生物量早10～12d；辽棉19号和美棉33B均以240kg/hm2施氮量棉花生物量和氮素累积速率峰值出现时间最早,累积速率最高,生物量、氮素累积量和皮棉产量最高,纤维品质最优,同时氮素利用效率较高。480kg/hm2施氮量不仅降低棉花生物量和氮素累积速率及累积量,而且降低了生殖器官分配系数,导致产量较低。3.施氮量和种植密度对东北特早熟棉区棉花生物量和氮素累积及氮素利用率的影响棉花生物量和氮素累积量随生育进程的动态变化符合“S”型曲线,种植密度和施氮量显著影响其动态特征,进而影响棉花产量与品质；氮素的快速累积起始日较生物量早13d左右；两个品种均以97500株/hm2密度、240kg/hm2施氮量的棉花生物量、氮素动态累积模型的特征参数最为协调,皮棉产量最高,纤维品质最优,同时氮素利用效率较高。4.施氮量和种植密度对东北特早熟棉区棉花棉铃生物量和氮素累积分配的影响棉铃各组分生物量和氮素累积随生育进程的动态变化符合“S”型曲线,种植密度和施氮量可显著影响其动态特征,并进而影响棉花产量与品质；当单铃、棉籽、纤维均达到生物量累积最大时：(1)生物量累积对应的快速累积起始时间和终止时间较其他处理提前但快速累积持续期较短,同时快速累积最大速率较高、出现时间提前；(2)氮素累积对应的快速累积起始时间和终止时间亦提前,快速累积持续期较短、累积速率较平缓；(3)生物量和氮素在铃壳中的分配系数最低,在棉籽和纤维中最高,当纤维生物量最大时纤维品质最优。本研究推荐东北特早熟棉区种植密度97500株/hm2和施氮量240kg/hm2处理最适宜。5.东北特早熟棉区不同群体棉花临界氮浓度稀释模型的建立及应用棉花的临界氮浓度与最大生物量间均符合幂函数关系(Nc=αWmax-b),模型参数口值和b值在不同群体和不同品种间存在差异表明,同一种植密度下生产相同的生物量美棉33B的氮吸收量高于辽棉19号,而同一品种下随着种植密度的增大生产相同的生物量需氮量逐渐增加。基于临界氮浓度稀释条件下的异速生长参数、氮素营养指数及动态临界氮素累积量等指标得到的东北特早熟棉区不同群体适宜施氮量的结果一致。本研究中,当种植密度和施氮量组合分别为75000株/hm2和360kg/hm2、97500株/hm2和240kg/hm2、120000株/hm2和360kg/hm2时,氮稀释曲线较适宜棉花的生长。综上所述,棉花生物量和氮素的累积动态随生育进程的变化符合“S”型曲线,棉花生物量和氮素存在异速累积现象,生物量的快速累积是以氮素的大量累积为前提,较早的生物量和氮素快速累积起始日以及较高的累积速率有利于产量的形成。通过协调种植密度和施氮量使生物量和氮素快速累积起始时间和终止时间适当、提高累积最大速率,同时提高棉铃生物量向纤维中的分配以获得高产优质。基于临界氮浓度稀释条件下的异速生长参数、氮营养指数及动态临界氮素累积量等指标得到的东北特早熟棉区不同群体适宜施氮量的结果一致。结合产量和品质因素,东北特早熟棉区最为适宜的种植密度和施氮量组合为97500株/hm2和240kg/hm2。更多还原

【Abstract】 Cotton is an important crop in our national economy. The cotton extremely early-maturation region in the Northeast China is one important base for early-season cotton breeding and planting. Optimizing of planting population and nitrogen application rate are two key ways to improve fiber yield and fiber quality. To determine the effects of planting population and nitrogen rates on accumulation and distribution of biomass and nitrogen for short-season cotton, field experiments with three nitrogen levels and different population were carried out in Liaoyang using two cotton cultivars Liaomian19and NuCTON33B as materials from2007to2009. Based on the critical N dilution model and the plant biomass accumulation model, the critical N accumulation model, the critical N demanding model, the N absorption model and the N diagnosis model were developed. And subsequently, plant nutrition status of the cotton in different population was diagnosed.1. Effects of planting population on cotton biomass and nitrogen accumulation in the cotton extremely early-maturation region in the northeast China.The dynamic of cotton plant biomass and nitrogen accumulation followed the "S" shape curve, and planting population variation might change the characters of the biomass and nitrogen accumulation progress, and subsequently influenced fiber yield and fiber quality. The beginning time or the ending time of the high speed accumulation stage for nitrogen was about10days earlier than that for the biomass. Fiber yield and fiber quality was the highest in the97500plant/hm2population for both the two cultivars, and reduction of fiber yield would be caused in excessive higher population though biomass and nitrogen accumulation would be increased. The results suggested that nitrogen was not synchro-accumulated with biomass in cotton plants, mass accumulation of plant biomass would started in condition that mass nitrogen had already been accumulated. Reproductive growth stage could be advanced by set fitting planting population, and the97500plant/hm2population setting could lead to higher fiber yield than that in the two other population conditions by advancing the reproductive growth stage in the cotton extremely early-maturation region.2. Effects of nitrogen application rates on biomass and nitrogen accumulation of cotton in the cotton extremely early-maturation region in the northeast China.The accumulated dynamic of biomass and nitrogen of cotton were described by logistic curve equation. The beginning time of speed accumulation for nitrogen was10-12days earlier than that for biomass. At nitrogen240kg·hm-2, the biomass and nitrogen accumulation amount were the highest, the eigenvalues of the dynamic accumulation model of cotton were the most harmonious, the nitrogen recovery rate was the highest, thus the lint yield was highest and the cotton fiber quality was the best. At nitrogen480kg·hm-2, the accumulation amount and rate of biomass and nitrogen decreased, the distributive indices of biomass in reproductive organ and lint yield reduced.3. Effect of nitrogen application rates and planting population on biomass, nitrogen accumulation and nitrogen fertilization recovery rate of cotton in the cotton extremely early-maturation region in the northeast China.The total dry matter and nitrogen uptake amount continuously increased with the progress of plant growth, and the general pattern of crop growth followed a sigmoid function of time. Plant densities and nitrogen application rate might change the characters of biomass and nitrogen accumulation progress, and subsequently influenced fiber yield and fiber quality. The beginning times of speed accumulation period for nitrogen were about13days earlier than that for dry matter in all treatments. The eigenvalues of the dynamic accumulation model in the treatment of97500plant·hm-2×240kg/hm2were more harmonious than that of other treatments. Earlier beginning time of speed accumulation period is in favor of accumulating biomass and nitrogen, and higher yield.4. Effect of nitrogen application rates and planting population on biomass, nitrogen accumulation and nitrogen fertilization recovery rate in cotton boll in the cotton extremely early-maturation region in the northeast China.The characters of accumulation and distribution of biomass and nitrogen were influenced by population and nitrogen rates of cotton. The biggest biomass of cotton boll, cotton seed and cotton fiber were based on the following,(1) The earlier time when speed biomass or nitrogen accumulation started (t1), the earlier time when speed biomass or nitrogen accumulation terminated (t2), the earlier time when the rate of speed biomass or nitrogen accumulation reached the maximum (tm), the shorter duration of the rapid biomass or nitrogen accumulation period (T, T=t2-ti) and the higher maximal rate of speed biomass or nitrogen accumuation (Vm).(2) There was a similar regularity in eigenvalue for accumulation between nitrogen and biomass.(3) The distribution indices in cotton shell were the lowest in cotton seed and the highest in cotton fiber. Higher biomass accumulation of fiber was positively correlating to higher fiber quality. So we could try to improve fiber quality by altering the emergence time of t1, t2, tm and Vm to improve biomass accumulation. Based on the results of this study, we recommended that97500plant/hm2×240kg/hm2treatment was the best application in the cotton extremely early-maturation region.5. Development and application of critical nitrogen concentration dilution model for cotton grown in the cotton extremely early-maturation region in the northeast China. The relationship between the shoot dry matter and critical N concentration can be described by power equation. The difference of the coefficients a and b between the two genotype showed that, the NuCOTN plant had a higher capacity of N accumulation in shoot biomass than that of Liaomian19. The coefficients a increased with the increasing plant population also showed that the cotton plant in higher plant population had a higher capacity of N accumulation in shoot biomass than that in lower ones. The different estimate of b in the critical dilution curve indicates that genotypes and plant population affect the slope of the critical N dilution curve. Based on the critical N dilution model and the allometric relationships between N uptake and dry matter accumulation in shoot, the model for N nutrition index (NNI) and the model for N demand at different growth stages for potential growth and yield were developed. According to the allometric growth coefficient, NNI and N accumulation rate under critical N concentration, it could be conclude that the optimal rate of N application in97500plant/hm2should be lower than that in75000and120000plant·hm-2, and240kg/hm2was the optimal N application rate in97500plant/hm2in the cotton extremely early maturity in the northeast china.更多还原