【作者】 王寅；

【导师】 鲁剑巍；

【作者基本信息】 华中农业大学 ， 植物营养学， 2014， 博士

【摘要】 油菜是我国重要的油料作物,长江流域作为我国最大的冬油菜产区,其油菜生产状况对国民经济发展和国家油料安全具有重要影响。直播和移栽是目前长江流域冬油菜的主要种植方式,两者的生育期、植株密度、个体形态及群体结构存在显著差异,因此施肥效果及养分管理策略也可能有所不同。当前我国冬油菜施肥及养分管理研究主要集中于移栽冬油菜,而直播冬油菜相关研究非常滞后。为此,本研究在长江中下游地区开展多年多点大田试验,通过结合大范围效果和同田对比验证研究,明确了直播和移栽冬油菜生长发育、产量与产量构成、干物质生产、养分吸收利用等方面对氮、磷、钾肥施用的响应差异及其机理,比较了两者的养分需求特性和推荐施肥量,并对当前生产条件下长江流域直播冬油菜的养分管理策略提出建议。主要结果如下：(1)当前生产条件下,长江中下游地区直播冬油菜的产量水平较移栽冬油菜偏低,尤其是在不施肥和缺磷条件下。相比氮磷钾配施处理(NPK),氮、磷、钾养分缺乏导致直播冬油菜分别减产1115kg/hm2(52.8%).655kg/hm2(65.6%)和257kg/hm2(17.6%),而移栽冬油菜分别减产1097kg/hm2(47.3%).469kg/hm2(38.4%)和269kg/hm2(14.5%)。冬油菜产量水平随氮、磷、钾肥用量增加均持续地显著提高,其中直播冬油菜的氮、磷增产效果显著高于移栽冬油菜。结果表明直播冬油菜的养分响应更显著,其养分管理应在平衡施肥基础上更重视氮、磷肥的施用。(2)适量施用氮、磷、钾肥可显著改善冬油菜的产量构成因素从而实现增产,其中氮素的影响最为全面和显著,其次是磷素,钾素影响相对较小。直播冬油菜收获密度显著高于移栽冬油菜,但单株产量构成因素较差,其主序角果数对总角果数的贡献显著更高。相关和通径分析结果表明移栽冬油菜可通过培育壮苗增加角果数实现增产,而直播冬油菜则应在较高植株密度基础上增加角果数。(3)直播冬油菜成熟期的干物质累积量和收获指数显著低于移栽冬油菜,个体长势和群体密度的差异导致两者的干物质累积过程显著不同。直播冬油菜群体密度在生育期内持续下降,NPK、-N、-P和-K处理的密度降幅分别为38.5%、73.3%、44.6%和44.1%,说明养分缺乏加重直播冬油菜群体的衰亡,尤其是氮素缺乏。施肥显著促进冬油菜生长发育和干物质累积,提高植株生理生化水平。直播冬油菜施肥后个体生长的显著改善减少了植株死亡,因而表现出更明显的施肥响应。结果表明直播冬油菜应通过合理施肥增强个体生长以维持高群体密度从而促进干物质累积。(4)直播冬油菜前期的养分含量显著低于移栽冬油菜,而且生育期内养分累积过程极易受到环境影响,最终成熟期养分累积量较低,但其磷、钾收获指数则显著较高。氮、磷、钾肥施用显著促进冬油菜对相应养分的吸收和累积,而直播冬油菜养分吸收动态受施肥影响更明显。当前生产条件下,直播冬油菜的氮、磷、钾肥回收利用率分别为36.2%、21.8%和42.9%,而移栽冬油菜则分别为36.3%、18.0%和45.0%,两者无显著差异。直播冬油菜的磷肥农学利用率、氮、磷肥贡献率以及百公斤籽粒养分需求量较移栽冬油菜则显著较高。结果表明直播冬油菜的养分管理策略有别于移栽冬油菜,应更注重苗期养分供应以促进个体生长和后期群体优势发挥。(5)直播冬油菜产量和养分吸收量的QUEFTS模型系数为aN=13.2,dN=33.4, aP=57.0,dP=184.0,aK=8.8,dK=25.0,而移栽冬油菜为aN=13.4,dN=30.1,aP=74.6, dP=196.7,aK=10.0,dK=25.4.目标产量为3000kg/hm2时,直播冬油菜的百公斤籽粒氮、磷、钾养分需求量分别为4.67kg N、0.96kg P和6.61kg K,移栽冬油菜则分别为4.68kg N.0.78kg P和5.89kg K.当前生产条件下,直播冬油菜的氮、磷、钾肥平均推荐施用量分别为228.1kgN/hm2.97.3kg P2O5/hm2和127.6kg K2O/hm2,而移栽冬油菜则平均分别为232.6kg N/hm2.90.2kg P2O5/hm2和111.8kg K2O/hm2.结果表明,相同目标产量水平下直播冬油菜比移栽冬油菜需要吸收更多的磷和钾,其磷、钾肥推荐用量也较高,而两者之间氮素需求及推荐施氮量则基本一致。更多还原

【Abstract】 Oilseed rape is a dominant oil crop in China. Yangtze River Basin (YRB) is the largest winter oilseed rape planting area in China, oilseed rape development in this region plays an important role in agricultural production and edible oil supply of China. Direct sowing and transplantation are major methods to establish winter oilseed rape in the current YRB. The contrasting growth duration, plant density, individual morphology, and population structure might cause different fertilization responses and nutrient management strategies between direct sown winter oilseed rape (DOR) and transplanted winter oilseed rape (TOR). For a long time, the study on fertilization response and nutrient management of oilseed rape in China had focused on TOR, but the relevant study on DOR was relatively lagged. In this study, field experiments were conducted in multiple years and sites in the middle and lower reaches of Yangtze River by combining large scale study and contrastive-tested study, aiming to evaluate the responses of DOR and TOR plants to N, P, and K fertilization in terms of plant growth, yield and yield components, dry matter production, nutrient uptake and utilization, to compare their nutrient requirement and recommended fertilizer rates, and to provide suggestions to the nutrient management strategy of DOR under the current production condition. The main results are summarized below.(1) Seed yield level was lower for DOR plants than TOR plants, especially in the non-fertilized and P deficiency conditions. Compared with the balanced NPK fertilization treatment, yield reductions of DOR plants was1115kg/hm2(52.8%) under N deficiency,655kg/hm2(65.6%) under P deficiency, and257kg/hm2(17.6%) under K deficiency. The corresponding yield reductions of TOR plants were1097kg/hm2(47.3%),469kg/hm2(38.4%), and269kg/hm2(14.5%), respectively. Both DOR and TOR yields showed significant increases with the increasing rates of N, P, and K fertilizers, and yield responses to N and P fertilizers were larger for DOR plants. The results indicated that DOR plant was more sensitive to N and P, suggesting that its nutrient management should focus on the application of N and P fertilizers on the basis of balanced fertilization.(2) The moderate N, P, and K fertilizers application improved significantly yield components and therefore increased rapeseed yields. Nitrogen fertilizer showed the most comprehensive and strongest effects on all the yield components, followed by P fertilizer, and the effects of K fertilizer were relatively less. Compared with TOR plants, DOR plants had significantly higher density, but its individual yield components were considerably poor. The pods contribution of main raceme was higher for DOR plants than TOR plants. The results of correlation and path analysis indicated that improving TOR yields requires to breed strong seedlings to increase pod number plant-1. For DOR plants, to improve seed yield needs to increase pod number plant-1based on the high plant density.(3) Both dry matter and harvest index were lower for DOR plants than TOR plants. The differences in individual growth and population density had resulted in the contrasting dry matter production processes between DOR and TOR plants. The DOR density showed continuous decrease throughout the growing season. Density reductions were38.5%,73.3%,44.6%, and44.1%in the NPK,-N,-P, and-K treatments, respectively, indicating that nutrient deficiency aggravated DOR density reduction, especially under N deficiency. The application of N, P, and K fertilizers improved significantly plant growth, physiology and biochemical levels, and dry matter production of DOR and TOR during the growing season. The larger fertilization responses of DOR plants were attributed to the reduced plant death with improved individual growth. The results indicated that the nutrient management of DOR plants should focus on the balanced fertilization to improve individual growth and obtain high plant density for increasing dry matter production.(4) The DOR plants showed significantly lower nutrient concentrations at the seedling stage, and the nutrient uptake process also was affected by environment conditions. At maturity, the nutrient uptake of N, P, and K in DOR plants were lower than those in TOR plants, but its P and K harvest indexes were significantly higher. The application of N, P, and K fertilizers improved significantly corresponding nutrient concentration and nutrient uptake in DOR and TOR plants, and the fertilization responses were larger for DOR plants. Under current production condition, the recovery efficiencies of N, P, and K fertilizers for DOR plants were36.2%,21.8%, and42.9%, respectively, and they were36.3%,18.0%,45.0%for TOR plants, respectively. Furthermore, compared with TOR plants, DOR plants showed higher agronomic efficiency of P fertilizer, higher fertilizer contribution rate of N and P fertilizers, and higher N, P, and K nutrient required for producing100kg rapeseed. The results indicated that the nutrient management of DOR plants should be different with that of TOR plants, which should focus on the nutrient supply at the seedling stage to improve individual growth at early the stage and population dominance at the late stage.(5) The parameters of the QUEFTS (Quantitative Evaluation of the Fertility of Tropical Soils) model for seed yield and nutrient uptake of DOR plants were aN=13.2, dN=33.4, aP=57.0, dP=184.0, aK=8.8, dK=25.0, and they were aN=13.4, dN=30.1, aP=74.6, dP=196.7, aK=10.0, dK=25.4for TOR plants. When the yield target was3000kg/hm2, nutrient required for producing100kg seeds were4.67kg N,0.96kg P, and6.61kg K for DOR plants, respectively, and they were4.68kg N,0.78kg P, and5.89kg K for TOR plants, respectively. Under current production condition, the mean recommended N, P, and K fertilizer rates were228.1kg N/hm2,97.3kg P2O5/hm2, and127.6kg K2O/hm2for DOR plants, respectively, and they were232.6kg N/hm2,90.2kg P2O5/hm2,111.8kg K2O/hm2for TOR plants, respectively. The results indicated that DOR plants need more P and K uptake to achieve the same yield target, and the recommended P and K fertilizer rates were also higher for DOR plants. The N requirement amount and recommended N fertilizer rate were equal between DOR and TOR plants.更多还原