The Effects Of Different Nitrogen Application Numbers And Slow Release Fertilizer On Rapeseed Growth And Yield

The excessive application of chemical nitrogen fertilizer in China leads to the low utilization rate of nitrogen fertilizer,resulting in waste of resources and environmental pollution.According to the law of nitrogen absorption in rapeseed,the application of suitable basal dressing ratio and suitable dressing time can reduce fertilizer input and increase yield.Carbon-based fertilizers use biochar porous structure to preserve fertility and water.Both fertilizers have the effect of multiple fertilization at one time.Long-term application of carbon-based slow-release fertilizers can be used for returning waste straw to the field,improving soil physical and chemical properties,providing plant organic nutrients and improving fertilizer utilization efficiency.Pot and field experiments were conducted with Shengguang 127 and Huayouza 9,which were widely planted in the Yangtze River valley.Different nitrogen fertilizer base-topdressing ratios?base-topdressing ratios were 10:0:0:0,5:0:5:0,5:0:2:3,3:2:2:3?and times of topdressing?1,2,3,4?,chemical slow-release fertilizer?chemical slow-release fertilizer for short?and carbon-based slow-release fertilizer?carbon-based fertilizer for short?were set up.The effects of different fertilization treatments on rapeseed growth process,individual growth and development,dry matter accumulation and distribution,yield and quality were studied.This research has certain reference value in reducing nitrogen and increasing efficiency,improving farmland environment and sustainable agricultural development.The main results are as follows:1.Effects of chemical fertilizer,carbon-based fertilizer and fractional fertilization on rapeseed growth periodChemical slow fertilizer and carbon-based fertilizer could significantly promote the growth process of rapeseed,and fractional fertilization could significantly prolong the whole growth period of rapeseed.The whole growth period of rapeseed was shortened by1-4,3-10 days compared with that of single fertilization,while the whole growth period of rapeseed was prolonged by 2-17 days by fractional fertilization.2.Effects of chemical fertilizer,carbon-based fertilizer and fractional fertilization on rapeseed agronomic traitsThe plant height,root neck diameter and total number of leaves from main stem were significantly increased by 3-6.25cm,3.5-9.0cm,0.32-0.55mm,0.11-0.41mm,2.25-3.25,1.17-2.25,1.66-1.25 and 117.2-455.4,310-560 cm²/plant respectively.The plant height,root neck diameter and total leaf number were significantly reduced by4.75-17.98 cm,0.84-2.69mm,1-4.25 leaves,1.75-3.75 leaves and 405.5-673.3 cm ²/plant respectively.3.Effects of chemical fertilizer,carbon-based fertilizer and fractional fertilization on dry matter of rapeseedChemical slow-down fertilizer and carbon-based fertilizer could significantly increase the dry matter accumulation in different organs of rape compared with one-time fertilization.The stem dry weight of chemical slow-fertilizer and carbon-based fertilizer was 3.11-3.77g/plant and 0.54-0.66g/plant respectively,and the fruit-bearing organs were0.55-10.86g/plant and 10.19-14.91g/plant,respectively.The total dry weight of shoot was1.39-12.60g/plant and 2.56-6.57g/plant respectively.The stem dry weight of fractional fertilization was 0.88-6.82 g/plant lower than that of single fertilization,the number of fruiting organs was 6.43-10.68 g/plant,and the total dry weight of shoot decreased by4.03-14.01 g/plant.4.Effects of chemical slow-fertilization and fractional fertilization on nitrogen use efficiency of rapeseedChemical slow fertilizer can significantly improve the nitrogen use efficiency of rapeseed.Compared with the one-time fertilization,the agronomic utilization rate of nitrogen increased by 1.59-1.65 kg/kg,the partial productivity of nitrogen increased by1.60-1.64 kg/kg,the absorption and utilization rate of nitrogen increased by 21.06-23.8percentage points,the nitrogen harvest index increased by 1-4.73 percentage points,the grain production efficiency of nitrogen increased by 0.50-1.25 kg/kg,the physiological efficiency of nitrogen increased by 2.50-3.11 kg/kg,and the net photosynthesis increased by 4.67 percentage points compared with the leaf area increased by 50-100mm²/g at flowering stage.The leaf area index?LAI?of field rapeseed increased by 0.5-1.16 with the increase of 12.56%.Nitrogen use efficiency was significantly increased by fractional fertilization compared with that by single fertilization.Compared with one-time fertilization,the agronomic efficiency of N increased by 1.57-2.25 kg/kg,partial productivity of N increased by 1.24-1.57 kg/kg,absorption and utilization of N increased by 3.73-14.33percentage points,nitrogen harvest index increased by 1.54-1.68 percentage points,grain production efficiency increased by 2.34-3.09kg/kg,and physiological efficiency of N increased by 0.66-4.74 kg/kg;leaf area increased by 300 mm²/g after anthesis,and flowers increased by 3.54-1.68 percentage points.Net photosynthesis increased by 4.37?molCO₂m^-2s^-1 and leaf area index increased by 17.49-30.80%.It significantly increased Postanthesis physiological activity and was conducive to Postanthesis yield formation.5.Effects of Chemical Fertilizer,Carbon-based Fertilizer and Segmental Fertilization on Yield Components and Yield of RapeseedThe length of main inflorescence increased by 1.90-3.80 cm,0.32-0.8 cm,the number of primary branches increased by 1-2,0.4-0.7,the number of secondary branches increased by 0.3-0.6,0.4-0.5,and the number of angular fruits per plant increased by21-28,26.8-45.33.There was no significant difference in 1000-grain weight between chemical slow fertilizer and primary fertilizer,and the 1000-grain weight of carbon-based fertilizer increased by 0.2-0.23g.The number of pods per plant and1000-grain weight increased by 22-64 and 0.17-0.31g respectively.Compared with one-time fertilization,the biomass per plant increased by 1.05-10.62g,2.60-21.89%and the economic yield per plant increased by 2.0-5.21g,23.80-29.28%.The biomass per plant increased by 3.34-20.58 g,8.31-42.42%and the economic yield per plant increased by 2.49-5.93 g,36.46-44.32%.The biomass per plant decreased by 8.55-24.60 g,15.05-36.89%and the economic yield per plant increased by 1.67-6.87 g,24.45-33.58%.6.Effects of chemical fertilizer,carbon-based fertilizer and fractional fertilization on Soil NutrientsCompared with one-time fertilization,the content of ammonium nitrogen,nitrogen,available phosphorus and potassium in the soil decreased by 0.12 mg/kg,4.49 mg/kg,2.44 mg/kg and 10.29 mg/kg respectively,and the E.C value increased by 0.67.Compared with one-time fertilization,the content of ammonium nitrogen,nitrate nitrogen,available phosphorus and potassium increased by 0.25 mg/kg,5.46 mg/kg,4.48mg/kg and 20.58 mg/kg respectively,and E.C value increased by 0.99.The ammonium nitrogen and nitrogen content in soil increased by 0.14-0.45 mg/kg,3.41-9.43 mg/kg,available phosphorus and potassium increased by 1.99 and 20.14 mg/kg,respectively,and EC value increased by 0.47-0.77.