Mechanism Study On The Effect Of NPK Fertilizer On Rapeseed Yield And Lodging Resistance

Rapeseed is one of the largest oilseed crops in China.However,in recent years,with the increasing yield of rapeseed,fertilizer has been used at a high level,while maintaining a higher fertilization level to obtain higher yields,but also increased the risk of lodging in direct-seeding rapeseed,which is not conductive to mechanized harvesting.Based on this,four rapeseed cultivars(two hybrids and two conventional species)with large differences in the lodging resistance of the stem were tested in the experimental field of Huazhong Agricultural University in 2014-2016,respectively.The amount of nitrogen,phosphorus and potassium in the main area,sub-region and sub-sub-region,respectively.Measuring and analysising the rapeseed yield composition and stem lodging index tostudy the characteristics of the rapeseed stem on different treatments,which provided parameters and theoretical basis for high yield cultivation and fine varieties of cultivation of rapeseed.The main results of this experiment are as follows:1.Under certain conditions,increasing nitrogen,phosphorus and potassium fertilizer could increase the yield of rapeseed,and the interaction effect was significant.Among them,nitrogen and potash fertilizer mainly increased the yield of rapeseed by increasing the number of pods per plant and the number of seeds per pod.Phosphate increased the yield mainly by increasing the number of pods per plant.2.Different nitrogen,phosphorus and potassium also affect rapeseed stem lodging resistance,and there was a significant interaction effects.In terms of composition,different nitrogen,phosphorus and potassium fertilizer resulted in a change in the composition of the rapeseed stem,which in turn affected its lodging resistance.The increase of the amount of nitrogen fertilizer could reduce the cellulose content of the stem,resulting in weakened stem lodging;Phosphate increased C content of stem,thus enhancing stem lodging resistance;Potassium increases the lodging resistance strength of stem.In terms of structure,the number of epidermal cells increased,the cell gap narrowed,which enhanced the intercellular adhesion and lodging resistance of stem,cells of pith ray in stronger lodging resistance of the main stem and the cells surrounding the cambium are better connected,which formed the the network frame and increased the lodging resistance of stem.3.Under the conditions of this experiment,the N2P1K2 treatment achievedto high yield and middle resistance level,with the content of cellulose and pectin in stem were 33% ~47% and 2.5%~5.5%.The N1P2K2 treatment achieved the middle yield and highresistance level,with the content of cellulose and pectin in stem were 31.3%~32.5% and 0.6%~1.6%.