Effects Of Planting Densities And Fertilizer Application Levels On The Growth And Nutrients Uptake Of Oilseed Rape (Brassica Napus L.)

Studies on the changes of agronomic traits, grain yields, yield component, nutrients uptake amounts and fertilizer utilization rate of new hybrid winter oilseed rape variety (Xiang hybrid No.763) under the 6 planting densities and 5 fertilizer application levels treatments with field plot experiment.The 6 planting densities are included 75 thousand plants/hm2,150 thousand plants/hm2,225 thousand plants/hm2, 300 thousand plants/hm2,375 thousand plants/hm2 and 450 thousand plants/hm2. The 5 fertilizer application levels of N, P2O5, K2O, S, B are included 0,0,0,0,0 kg/hm2; 60,30,53,3.75,0.3 kg/hm2; 120,60,105,7.5,0.6 kg/hm2; 180,90,158,11.25,0.9 kg/hm2 and 240,120,210,15,1.2 kg/hm2 respectively, the number 0-4 are used as treatments number of fertilizer application levels respectively.1. Agronomic traits of oilseed rape during winter and flowering stages showed that, the dry weight per plant, plant height, branches number, root-stem diameter, stem diameter at 20cm point, total leaf number, green leaf number, leaf length and leaf width of oilseed rape under different planting densities and fertilizer application levels conditions are different. The values of above parameters are increased along with the increasing of fertilizer application levels under the same planting densities condition, while the increasing ranges are different along with the different planting densities, the increasing range is larger under the lower planting densities and the increasing range is smaller under the higher planting densities. The dry weight per plant, branches number, root-stem diameter at flowering stage, stem diameter at 20 cm point, total leaves, green leaves, leaf length and leaf width of oilseed rape are decreased along with the decreased of planting densities under the same fertilizer application levels condition. The changes of root-stem diameter during winter stage are different along with fertilizer application levels, the root-stem diameter of planting density 225 thousand plants/hm2 is the biggest under the 3 and 4 treatments, the plant height can not be affected by planting densities under all of fertilizer application levels. The dry weight per plant, branches number, root-stem diameter at flowering stage, stem diameter at 20 cm point, total leaves, green leaves, leaf length and leaf width of oilseed rape are the highest under the fertilizer application treatment 4 and plant density 75 thousand plants/hm2 conditions. The values of root-stem diameter during the winter stage are highest under the fertilizer application treatment 4 and planting density 225 thousand plants/hm2 conditions. The plant heights of fertilizer application treatment 4 are higher under the all of planting densities conditions.2. The results of chlorophyll determination showed that, the contents of chlorophyll a, chlorophyll b and total chlorophyll during winter and flowering stages are increased along with the increased of fertilizer application amount under the same planting dens ity. The content of chlorophyll a is decreased along with the increased of planting density during winter stage under the same fertilizer application treatment. But the content of chlorophyll b and total chlorophyll have no law like this.3. The results of grain yield showed that:whether density is high or low, grain yield under same planting density increased with applying fertilizer rate, but the intensity of yield increase under high planting density is smaller than that under low planting den sity; under same applying fertilizer rate, yield of lower applying fertilizer rate increa sed with planting density, but yield of high applying rate decreased, grain yield under high density and applying rate also decreased. grain yield are highest under the fertili zer application treatment 4 and planting density 225 thousand plants/hm2 conditions. Under same planting density, usage pods per plant,seeds per pod and 1000 seeds weight increased with applying fertilizer rate.Whether fertilizer rate high or low, both usage pods per plant and seeds per pod decreased with the increasing of planting density, while The difference of thousand seed weight under the all of treatments are not significant.4. The results of measured uptake amounts of nutrients indicated that under same planting density, uptake amounts of nutrient increased with applying rate, changes in trend of nutrient uptake was similar to yields; but under same applying fertilizer rate, the change in trend of nutrient uptake was not similar to yield. Under high applying fertilizer, uptake amounts of N, P, K were highest at planting density 225000 plant/hm2, under others applying rate, uptake amounts of N, P increased with density, while change of K uptake was smaller. The uptakes of S, B were not changed regularly with planting density.5. Under the fertilizer application treatment 4, grain yield,uptake amounts of nutrients and agronomic traits of oilseed rape is the best in planting density 225 thousand plants/hm2 conditions. Under fertilizer application treatment 3,the best is in 375 thousand plants/hm2 conditions. When fertilizer application treatment 0 to 2, which is planting density 225 thousand plants/hm2 conditions.