红壤不同地力条件下直播油菜对施肥的响应

2009至2010年度在江西、湖南两省的典型红壤区设置8组直播油菜氮磷钾硼肥田间肥效试验,旨在研究红壤不同地力条件下直播油菜对施肥的响应,探寻养分限制因子。结果表明,红壤直播油菜的长势受到地力的显著影响,高、中、低地力田块基础地力产量(不施肥处理产量)平均分别为1230、721和191kg hm-2。施肥不同程度促进了直播油菜的生长发育,养分吸收与累积,提高了籽粒产量并影响收获指数,各地力田块均以氮磷钾硼配施(NPKB)处理最好,其高、中、低地力田块平均产量分别为2529、1681和1065 kghm-2,产量水平随地力上升而大幅提高,但增产率则呈下降趋势。在其他养分配施基础上增施不同肥料的增产增收效果顺序为N>P>B>K,表明红壤直播油菜的养分限制因子依次为氮、磷、硼和钾,但受土壤养分状况差异的影响,不同地力条件下施肥的效果也存在差异,低地力田块施肥的相对增产效果好,绝对增产量及施肥收益仍以高地力田块较好。红壤区直播油菜的氮、磷、钾肥吸收利用率平均分别为34.5%、26.7%和65.4%,且各肥料利用率随地力上升而提高。试验结果说明,红壤区直播油菜的养分管理应重视氮磷钾硼肥的配合施用,缓解养分限制,从而有效增产。通过长期合理施肥以培肥土壤、提高地力,达到持续高产稳产。

Responses of direct-seeding rapeseed to fertilization in fields of red soil different in fertility

In order to study responses of direct-seeding rapeseed to fertilization in fields of red soil different in fertility,and to find out limiting factors of direct-seeding rapeseed in nutrition,eight field experiments on crop response to NPKB fertilizers were conducted in typical red soil regions of Jiangxi and Hunan provinces in 2009—2010.Results show that growth of the direct-seeding rapeseed was significantly affected by soil fertilit.The yield of the field with basic soil fertility being high,middle and low was 1 230,721 and 191 kg hm-2,respectively.Fertilization promoted growth and nutrient uptake of the crop,increased its seed yield and influenced its harvest index to a varying degree.In all the experiment fields,Treatments NPKB were the highest in yield at each soil fertility level,The average yield of the treatments was 2 529 kg hm-2 in fields high in soil fertility,1 681 kg hm-2 in fields moderate in soil fertility and 1 065 kg hm-2 in fields low in soil fertility.Obviously yield of the crop increased with the soil fertility level by a large margin,but the margin tended to be narrower with the yield going up.The yield-increasing effect of additional fertilizer besides the combined recommendation followed the order of N>P>B>K,which also indicated the order of importance of the four elements as limiting factor in nutrition of the crops.However,as affected by different in soil nutrient status,crop response to fertilization in fields different in soil fertility also varied.Relative yield response to fertilization was higher in fields low in soil fertility,while absolute yield and benefit responses were still better in fields high in soil fertility.N,P and K recovery rate of the direct-seeding rapeseed in the red soils was 34.5%,26.7% and 65.4%,respectively,which increased with the soil fertility level.These findings demonstrate that in nutrient management of direct-seeding rapeseed,it is essential to pay high attention to combined application of N,P,K and B and elimination of nutrient limiting factors,to achieve effective yield increase.Long-term rational fertilization can build up the soil,improve soil fertility and hence sustain high and stable yield of the crops.