Analysis Of Chemical Fertilizer And Pesticide Application Status In Oilseed Rape(Brassica Napus L.) Based On Farmers’ Survey

China is a big oil consumption and import country.The national edible vegetable oil self-sufficiency rate is less than 40%,and the gap between supply and demand is large.Increasing the planting area and output of oilseed rape in my country is an important measure to ensure the safety of national edible oil supply.In recent years,as domestic prices of agricultural materials have risen and labor costs have increased,the efficiency of oilseed rape planting has been low,and farmers’enthusiasm has been low.In addition,the unreasonable application of chemical fertilizers and pesticides has potential environmental risks.Therefore,in the context of the“Zero Growth Action for Chemical Fertilizers and Pesticides”proposed by the country,this study conducted a survey of farmers in the main rapeseed production areas of 18 provinces and cities across the country,and divided the national oilseed rape cultivation into the spring rapeseed area,the Huanghuai winter oilseed rape area,and the winter rapeseed plantation in the upper reaches of the Yangtze River.Areas,the winter oilseed rape planting area in the middle reaches of the Yangtze River,the winter oilseed rape planting area in the lower reaches of the Yangtze River,and the three-crop winter oilseed rape planting area in the south,to analyze the rape cultivation methods and yield characteristics,fertilizer and pesticide input characteristics and production cost characteristics in different regions.The research results can provide a basis for the sustainable development of the rape industry in our country.（1）Direct seeding is currently the main method of rapeseed planting for farmers,and its sown area reaches more than 85.0%in most areas.From the characteristics of sowing dates,the sowing dates of the Northwest spring rapeseed area are mostly from mid-March to early April（accounting for 72.2%）,and the Northeast spring rapeseed area is mainly concentrated in mid-to-early May（accounting for 96.5%）.The sowing dates of the direct-broadcast winter rape area are mainly concentrated in early September to mid to late October,and the sowing dates are mainly distributed in early October（30.0%-44.0%）.The average output of rapeseed by farmers in different regions was 1964-2430 kg/hm².Among them,the oilseed rape production in the lower reaches of the Yangtze River was higher,and the spring oilseed rape area and the triple cropping of Southern area were lower.High-yield farmers in different regions（yield levels of 2955-3475 kg/hm²）accounted for 17.6%-41.4%.（2）From the perspective of chemical fertilizer application,farmers in spring oilseed rape area mainly use urea（accounting for 92.0%）and diammonium phosphate（accounting for88.6%）,while farmers in winter rape area mainly apply compound fertilizer（accounting for93.7%）and urea（accounting for 78.0%）.The average input of nitrogen,phosphorus,and potassium fertilizer in rapeseed production in different regions（reduced to pure）is 106.7-208.1 kg N/hm²,60.9-90.9 kg P₂O₅/hm²,15.0-78.9 kg K₂O/hm²,and total nutrient input is212.6-367.5 kg/hm².The proportions of farmers with excessive nitrogen,phosphorus,and potassium fertilizer input in each region accounted for 35.0%-60.0%,37.8%-91.6%,and6.8%-61.8%respectively.The regions with the highest excess nitrogen,phosphorus,and potassium fertilizer rates were Huanghuai District and Spring District,respectively.Oilseed rape area and the southern three-cropping area.Analysis of samples with excessive fertilization found that the average reduction of nitrogen,phosphorus,and potassium fertilizers in different regions was 42.0-86.1 kg N/hm²,27.2-48.8 kg P₂O₅/hm²,and 9.3-36.4kg K₂O/hm².Comparing the fertilization characteristics of high-yield farmers in each region with the regional average,it is found that the high-yield farmers in the spring oilseed rape area obtain high yield through higher nutrient input,while the nutrient input of the high-yield farmers in the middle reaches of the Yangtze River is no different from the average value of the total survey sample.which is an increase of 41.8%compared with the average value of regional samples.（3）Pesticides used by farmers in various regions are concentrated.Among them,the herbicides in the winter rape area are mainly acetochlor（29.3%）,metolachlor（14.8%）and high-efficiency cyprofen（12.7%）,and the main insecticide is imidacloprid（48.3%）.The main agent is carbendazim（41.6%）,followed by Sclerotium（24.7%）and polyketones（14.4%）.The herbicides in the spring rape area are mainly high-efficiency and high herbicidal energy（35.9%）,quizalofop-p-ethyl（17.7%）and glyphosate（14.1%）.Insecticides are mainly pyrethroids（70.0%）.The main fungicides are It is imidamide（32.0%）,Sclerotium（26.0%）and Procymidone（18.0%）.The average amount of medicine used in different regions was1.6-3.3 kg/hm²,and the proportion of farmers in different areas overdose was 17.1%-60.1%.（4）The total investment in rapeseed planting in different regions the cash cost is 3845-4458 yuan/hm²,and the cash income is 5945-8474 yuan/hm².The average cost of producing1 ton of rapeseed in different regions the cash cost is 1724-2157 yuan/ton.The cash input cost includes the cost of seeds,fertilizers,pesticides,machinery,irrigation and drainage,labor and land rent.From the perspective of different planting scales,the proportion of farmers with a sown area of 50 mu or more of rapeseed in the Yangtze River Basin reached20.3%,and the planting scale showed a trend of expansion.Regardless of the subsidy for oilseed rape planting,with the expansion of the planting scale,the cash cost of oilseed rape planting gradually increased,and the net income was significantly reduced.By fitting the relationship between different planting scales and yield and cash cost,it is found that when the planting area is 1-50 mu,the production cost increases rapidly with the increase of the planting area,and the oilseed rape yield decreases;when the planting area is greater than 50mu,the cash cost growth rate slowed down,and the oilseed rape yield remained stable at120.0 kg/mu.The direct seeding of winter oilseed rape in the Yangtze River Basin has a good cash income when the sown area of each farmer is 30-50 acres,and it will not produce high cash costs.In summary,the main characteristics of rapeseed planting in my country are as follows:farmers in spring oilseed rape areas mostly sown from March to May,and the sown amount is 6.0-7.5 kg/hm²,and the average yield is 1964 kg/hm²,of which 17.6%High-yield farmer households（3475 kg/hm²）;farmer households use more fertilizer twice,respectively,urea and diammonium phosphate.35.0%and 91.6%of the farmers put too much nitrogen and phosphate fertilizer;most of the pesticide varieties are high-efficiency cyprofen（35.9%,herbicide）,pyrethroid（70.0%,insecticide）and imidamide（32.0%,fungicide）,The average value of pesticide input is 2.1 kg/hm²,17.1%of farmers’pesticide input is excessive,and the average value is 1.1 kg/hm² higher than the recommended value.The area of direct-directed rapeseed in the winter rape area is relatively high.Most farmers apply fertilizer twice,NPK ratio of 15-15-15 type compound fertilizer once,and urea once.Farmers who apply excessive nitrogen,phosphorus,and potassium fertilizer account for 36.5%,respectively.-60.0%,37.8%-74.5%and 38.0%-62.4%.Pesticides mostly choose acetochlor（29.3%,herbicide）,imidacloprid（48.3%,insecticide）and carbendazim（41.6%,fungicide）.23.5%-60.1%of farmers overuse the pesticide.The planting scale is showing a trend of expansion.The direct seeding of winter rape in the Yangtze River Basin can obtain a better income when the planting area of each farmer is 30-50 mu,and the cash cost is lower.