氮肥用量对玉米-油菜和水稻-油菜轮作模式下油菜产量及氮素吸收利用的影响

Effects of nitrogen fertilizer application levels on yield and nitrogen absorption and utilization of oilseed rape under maize-oilseed rape and rice-oilseed rape rotation fields

旱-旱和水-旱轮作是我国长江流域冬油菜的典型种植模式,氮养分缺乏是油菜产量主要限制因子。利用2016—2023年在湖北省武汉市布置的裂区同田对比定位试验,探究氮肥用量对不同轮作模式下油菜产量和氮素吸收利用的影响差异,为科学施氮提供依据。试验设计的主处理为旱地油菜(玉米-油菜)和水田油菜(水稻-油菜)2种轮作模式,副处理为4个氮肥用量(0 kg N hm^(-2)、75 kg N hm^(-2)、150 kg N hm^(-2)、225 kg N hm^(-2)),分析了油菜产量、产量构成因子和氮素积累量等相关指标。7年试验结果表明,旱地和水田油菜的产量和氮素吸收在不同氮肥投入下的响应存在差异。当不施氮或低施氮(75 kg N hm^(-2))时,水田油菜产量显著高于旱地油菜,分别高出53.9%和20.8%,地上部氮素积累量分别高出57.8%和18.3%;当施氮量为150 kg N hm^(-2)时,2种轮作无显著差异;在高施氮(225 kg N hm^(-2))时,旱地油菜产量和氮素积累量较水田分别增加11.2%和16.0%。旱地油菜的氮肥农学利用效率、贡献率和表观利用率较水田油菜分别平均增加16.5%、20.5%和22.0%,氮肥对旱地油菜的增产潜力更大,但水田油菜季土壤基础氮素供应量较旱地高61.5%,对氮肥的依赖性更小。综上,增加氮肥用量显著提高了油菜产量和氮素积累,水田油菜在低氮投入下表现出较高的稳产性,而旱地油菜在较高氮投入下丰产潜力更高。因此,在实际生产中应根据不同轮作模式调整油菜施氮量,旱地油菜可以适当增加氮肥用量以获得高产,水田油菜要充分利用土壤供氮能力适当控制氮肥用量,以达到油菜高产高效生产和氮肥高效利用的目的。

Continuous upland and paddy-upland anniversary multiple cropping rotations are typical planting patterns of winter rape in the Yangtze River basin in China,and nitrogen nutrient deficiency is the main limiting factor for rapeseed yield.To provide a basis for scientific nitrogen application,a comparative positioning experiment of split area was conducted in Wuhan City,Hubei Province from 2016 to 2023,and the effects of nitrogen fertilizer application on rapeseed yield and nitrogen uptake and utilization under different rotation patterns was explored.The main treatments of the experimental design were two rotation modes of upland-oilseed rape(maize-oilseed rape rotation)and paddy-oilseed rape(rice-oilseed rape rotation),and the secondary treatments were four nitrogen application rates(0 kg N hm-2,75 kg N hm-2,150 kg N hm-2,and 225 kg N hm-2).The related indexes such as rapeseed yield,yield components,and nitrogen absorption were analyzed.The average results of seven-year experiment showed that there were differences in response to the yield and nitrogen uptake of rapeseed in upland and paddy fields under different nitrogen fertilizer inputs.When there was no nitrogen application or low nitrogen application(75 kg N hm-2),the yield of rapeseed in paddy fields was significantly higher than that in upland fields,which was higher by 53.9%and 20.8%,and the nitrogen accumulation was higher by 57.8%and 18.3%,respectively.When the nitrogen application rate was 150 kg N hm-2,there was no significant difference between the two rotations.When the nitrogen application rate reached 225 kg N hm-2,the yield and nitrogen accumulation of rapeseed in dry land were higher by 11.2%and 16.0%than those in paddy fields,respectively.The agronomic utilization efficiency,contribution rate,and apparent utilization rate of nitrogen fertilizer in upland rapeseed were higher on average by 16.5%,20.5%,and 22.0%than those in paddy field rapeseed,respectively.Nitrogen fertilizer had a greater yield increase effect on upland-rapeseed,but the soil background nitrogen supply in paddy field rapeseed season was 61.5%higher than that in upland,and its dependence on nitrogen fertilizer was less.In conclusion,the increase in nitrogen fertilizer application significantly increased rapeseed yield and nitrogen accumulation.There were differences in the response of rapeseed yield to nitrogen fertilizer between maize-oilseed rape rotation and rice-oilseed rape rotation.Paddy-oilseed rape exhibited higher stability under low nitrogen input,while upland-oilseed rape achieved higher yield under high nitrogen input.Therefore,the nitrogen application rate of rapeseed should be adjusted according to different crop rotation modes in actual production.The nitrogen application rate of upland rapeseed can be appropriately increased to achieve high yield,while the nitrogen application rate of rapeseed in paddy field should be properly controlled by making full use of the nitrogen supply capacity to achieve the high yield and efficient production of rapeseed and efficient utilization of nitrogen fertilizer.