种植密度和施氮量对油菜生长发育及产量的影响

Effects of Planting Density and Nitrogen Application Rate on Growth and Yield of Rapeseed

为探究氮肥与密度互作对甘蓝型油菜生长发育和产量的影响,以‘云油杂28号’为材料,设置3个密度梯度,D_(1):15万株/hm^(2);D_(2):28.5万株/hm^(2);D_(3):42万株/hm^(2),4个施氮量水平,N_(1):0 kg/hm^(2);N_(2):75 kg/hm^(2);N3:150 kg/hm^(2);N4:225 kg/hm^(2),测定不同处理下的生育期、农艺性状、干物质重量和产量等指标。结果表明:同一种植密度下,全生育期随施氮量的增加而延长,盛花期根茎粗、叶面积、总叶数和绿叶数在D_(1)密度下随施氮量的增加先上升后降低;干物重和产量在各密度下均随施氮量的增加先升高后降低,均在D_(1)N_(2)下达到最大值。同一施氮量下,全生育期随种植密度的增加呈缩短趋势;根茎粗、总叶数、绿叶数和叶面积在抽薹期和盛花期均随种植密度的提高而降低;各时期的干物重和产量随种植密度的增加而降低。种植密度和氮肥对油菜生长发育前期的影响较小,主要从抽薹期和开花期开始产生影响;调整种植密度对产量和干物重的影响大于施氮量,密度和施氮量主要通过单株有效角果数影响油菜产量。在密度与氮肥的互作处理下以D_(1)N_(2)处理(即密度为15万株/hm^(2),施氮为75 kg/hm^(2))最优,其株高最高,总叶数和绿叶数最多,根茎粗和叶面积较大,单株产量和小区产量最高。

To explore the effects of nitrogen fertilizer and planting density on the growth and yield of Brassica napus L,‘Yunyouza 28’was used as materials to measure the growth period,agronomic traits,dry weight and yield under different treatments.3 density gradients(D_(1):150000 plants/hm^(2),D_(2):285000 plants/hm^(2),D_(3):420000 plants/hm^(2))and 4 nitrogen application levels(N_(1):0 kg/hm^(2),N_(2):75 kg/hm^(2),N3:150 kg/hm^(2),N4:225 kg/hm^(2))were set for the study.The results showed that under the same planting density,the whole growth period was extended with the increase of nitrogen application,the root neck diameter,leaf area,and total and green leaf numbers increased at the beginning and then decreased with the increase of nitrogen application under D_(1)density at flowering stage.Dry matter weight and yield both increased firstly,reached the maximum value under D_(1)N_(2)and then decreased with the increase of nitrogen application under each density.Under the same nitrogen application,the whole growth period was shortened with the increase of planting density.The root neck diameter,total leaf numbers,green leaf numbers and leaf area decreased with the increase of planting density at bolting and flowering stage.The dry matter weight and yield decreased with the increase of planting density in various periods.Planting density and nitrogen fertilizer had little influence on early growth and development,mainly from bolting and flowering stage.Planting density had greater effects on the yield and dry matter weight than nitrogen application,which affected the yield through the number of effective pods per plant.With the interaction of density and nitrogen fertilizer,D_(1)1N_(2)treatment(density of 150000 plants/hm^(2),nitrogen application amount of 75 kg/hm^(2))was the best,which had the highest plant height,the highest total number of leaves and green leaves,root neck diameter and leaf area,and the highest yield per plant and per unit area.