Effect Of Dolomite And Fungicide Application On Acidic Soil Reclaimation And Greenhouse Gas Emission

Soil acidification is a gradual and natural process.With the development of agricultural modernization,the process of acid deposition in the atmosphere has intensified,leading to a faster rate of soil acidification.Therefore,it is necessary to take effective measures to reduce the harm of soil acidification and slow down the process of soil acidification,and ensure the stability of agroecosystems through the improvement and restoration of acidified soils to achieve sustainable agricultural development.In recent years,China has made great progress in acidic soil improvement and fertility enhancement,etc.Therefore,in this experiment,dolomite was used in combination with fungicide to reduce the amount of chemical fertilizer input in response to the low level of soil p H,soil nutrient content,planted crops yield,and other problems in Xianning.The pot experiment was designed as a 2-factor 3-level completely randomized experimental design with dolomite dosage levels of(B₀:0 g·kg^-1,B₃:3 g·kg^-1,B₆:6 g·kg^-1),fungicide dosage levels of(H₀:0 g,H₃:1.5 g·kg^-1,H₆:3 g·kg^-1),and set the Control group as not applying any improver and fertilizer,each treatment 4 replicates,a total of 10 treatments were Control,B₀H₀,B₀H₃,B₀H₆,B₃H₀,B₃H_3,B₃H₆,B₆H₀,B₆H₃,B₆H₆.The main findings of the experiment were as follows:（1）The combined application of different ratios of dolomite and fungicide had a good acid-reducing effect throughout the growth period of pepper,which could reduce the soil Al toxicity and significantly increase the soil total exchangeable base and cation exchange capacity.The soil p H of the pepper fruiting period showed an increasing trend with the increase of dolomite and fungicide application.Among the treatments with different ratios of dolomite and fungicide,the B₆H₆treatment had the best acid reduction effect with soil p H of 6.59.（2）Different ratios of dolomite and fungicide significantly improved the soil nutrient status.In the fruiting period,the soil available potassium content of dolomite and fungicide treatments increased significantly compared to the transplanting period,and the treatment with the high amount(6 g·kg^-1)of dolomite had the most significant effect.The highest soil available potassium and B₆H₆treatments had the highest soil available phosphorus content.（3）Dolomite with fungicide significantly increased the activity of soil-related enzymes,and all four soil enzyme activities were significantly correlated with the amount of fungicide applied.The addition of dolomite significantly increased soil catalase activity during the transplanting period.Soil neutral phosphatase activity showed an increasing trend throughout the pepper growth period,and the application of fungicide alone significantly increased neutral phosphatase activity during the fruiting period.The addition of dolomite significantly increased the urease activity of pepper throughout the growth period,and the treatment with the high amount(6 g·kg^-1)of dolomite had the best effect.According to the correlation analysis of soil indicators with enzymes activity,it was found that soil urease activity was highly significantly and positively correlated with p H and exchangeable salt-based ions,and neutral phosphatase was significantly and positively correlated with soil fast-acting nutrients,indicating that dolomite and fungicide had improvement effect on soil nutrient status,etc.（4）The combined application of dolomite and fungicide promoted the growth and development of pepper.At the fruiting stage,plants’height and chlorophyll increased by42.08%and 31.43%in the B₆H₃treatment,and stem thickness increased by 43.89%in the B₃H₆treatment,respectively,compared with Control.The combined application of the high amount(6 g·kg^-1)of dolomite and fungicide significantly promoted above-ground biomass and below-ground biomass,and the fresh weight of above-ground biomass increased by 364.29%and 331.79%,and the fresh weight of below-ground biomass increased by 91.85%and 102.96%in B₆H₃and B₆H₆treatments,respectively,compared with Control.（5）The application of dolomite with fungicide promoted soil GHG emissions,and the trends of soil CO₂and N₂O emission fluxes were consistent among treatments.In terms of cumulative emissions,the cumulative CO₂emissions from high to low were B₀H₆>B₃H₆>B₆H₃>B₀H₃>B₀H₀>B₆H₀>B₃H₀>B₆H₆>B₃H₃>Control,and the cumulative N₂O emissions from high to low were B₃H₆>B₆H₃>B₀H₆>B₀H₃>B₃H₀>B₆H₆>B₆H₀>B₀H₀>B₃H₃>Control.The results of greenhouse gas emissions from different treatments were combined,and the combined application of dolomite and fungicide had an increasing effect on soil CO₂and N₂O emissions,with B₃H₃treatment having the lowest soil CO₂and N₂O emissions compared to the other treatment groups containing dolomite with fungicide.（6）Based on the integrated soil physical and chemical properties and crops growth,according to the principal component score,comprehensive score and ranking of each treatment,the ranking of improvement effect of each treatment by principal component analysis from highest to lowest was:B₆H₃>B₆H₆>B₃H₆>B₆H₀>B₃H₃>B₃H₀>B₀H₀>B₀H6>B₀H₃>Control,so the comprehensive effect of B₆H₃treatment was the best.In conclusion,the combined application of dolomite and fungicide has good effects on acidic soil improvement and pepper growth improvement,and the recommended dosage is 6 g·kg^-1dolomite and 1.5 g·kg^-1fungicide.This study provides a scientific basis for the improvement of acidic soil in Xianning region by combining dolomite and fungicide,which is of great significance for the improvement of acidic soil and the improvement of crop yield and quality in this area.