Effects Of Chemical Fertilizer Reduction On Soil Properties And Key Pollution Factors Of Facility Vegetables

In recent years,China’s facility vegetables have flourished in agricultural production.However,there are still insufficient use of organic fertilizers in the production of facility vegetables,excessive fertilizers,low fertilizer utilization rate,deterioration of soil physical and chemical properties,and increased soil heavy metal content,which affects soil environmental quality.Sustainable production of vegetables and vegetables.This study takes the facility vegetable production base in Lingyuan City,Liaoning Province as the sampling site,and sets up five treatment modes in the study area: CK(not fertilized),T2(80% fertilizer + organic fertilizer),T3(70% fertilizer + organic Fertilizer),T4(60% chemical fertilizer + organic fertilizer),T5(50% chemical fertilizer + organic fertilizer),through the application of chemical fertilizer reduction and organic fertilizer application,study the different fertilization modes on farmland soil nutrients,soil enzyme activities and soil The key pollution factors are heavy metals and di(2-ethylhexyl)phthalate(DEHP),and risk assessment of heavy metals and DEHP in farmland in Lingyuan demonstration area,in order to improve the quality,improvement and guarantee of facility vegetables.Provide scientific basis for farmland soil environmental quality.The test yielded the following results:1.The application of chemical fertilizer reduction and organic fertilizer application had certain effects on soil properties and cucumber fruit quality.Under T3 treatment conditions,soil properties and cucumber fruit quality were better than other treatment modes.The content of soil organic matter increased significantly under different treatments,and the growth rate of organic matter under T3 treatment was the fastest,reaching 22.80%.The soil available nitrogen,phosphorus and potassium nutrients were the highest in the T3 reduction mode,and remained relatively high in the final stage of the experiment.At the same time,the cucumber in the T3 treatment mode is of good quality and higher nutritional value than other treatments.2.The application of fertilizer reduction and organic fertilizer application have different effects on soil enzyme activities in different soil layers.Compared with CK treatment,fertilization can increase soil urease and soil sucrase activity,and T2 treatment and T3 treatment are better.The highest urease activity is 2.10 mg NH3-N/g and 2.07 mg NH3-N/g,sucrose.The enzyme activities reached 184.30 mg glouse/g and 274.29 mg glouse/g,respectively.The change law of urease is similar to the change of nitrogen in soil.With the decrease of chemical fertilizer use,urease activity decreases gradually.Fertilization can increase the activity of soil catalase,but the activity of catalase is inversely proportional to the amount of fertilizer applied.The order of soil catalase activity between different treatments is T5>T4>T3>T2>CK.The activity of three enzymes in soil layer above 60 cm was higher.As the depth of soil layer deepened,the activities of invertase and catalase decreased gradually,and the activity of urease increased first and then decreased.3.Fertilizer reduction and organic fertilizer application will reduce the content of heavy metals Pb,Cd,Cr and Cu in soil and increase the degradation rate of DEHP in soil.In this study,the contents of four heavy metals in the soil under fertilization treatment were higher than those in CK treatment on the 14 th day after fertilization.It was found that the increase of chemical fertilizer application increased the content of heavy metals in soil,and the content of heavy metals in T2 treatment soil was the highest.According to the results of single factor index evaluation and geological accumulation index evaluation,heavy metals Cd,Pb,Cu and Cr in the facility soil showed little pollution,which was the same as the Nemero index evaluation.The results of potential ecological risk assessment showed that there were slight potential ecological hazard risks of Cd,Cu,Pb and Cr in farmland soils in the demonstration study area.The comprehensive potential ecological hazard risk index RI was 21.86,which was a light potential ecological hazard risk.4.Combined with soil properties,cucumber fruit quality and soil enzyme activity,the T3 reduction mode is the optimal mode.Under the optimal fertilizer reduction condition,the content of DEHP in the soil of the facility was studied.The results showed that the reduction of fertilizer could promote the transformation of DEHP to MEHP.The content of MEHP in T3 treated soil was 2.90 mg/kg,which was 1.12 times higher than that of CK soil.In summary,under the T3 treatment mode,soil nutrient high content,soil urease and sucrase activity are better,cucumber fruit quality is good,nutritive value is high,key pollution factor heavy metal pollution level is relatively low and DEHP is in soil the degradation rate is faster,which is the optimal mode among the four treatment reduction modes.This result provides technical support for ensuring soil fertility,improving agricultural production efficiency,and ensuring soil environmental quality.