Effects Of Partial Replacement Of Fertilizer By Bio-organic Fertilizer On Soil Carbon And Nitrogen And Gaseous Loss In Vineyards

Grape(Vitis vinifera L.)is an important cash crop in China.The acreage of grapes in Hebei Province ranks the third in China.However,due to chronic overuse of fertilizer,soil organic matter is reduced,nitrate nitrogen accumulation,nitrogen loss in gaseous phase is serious,and the greenhouse effect is aggravated.Therefore,organic fertilizer instead of chemical fertilizer becomes an important measure to promote the green development of agriculture.In this study,five treatments were set:traditional fertilization(FP),optimized fertilization(Opt)and bio-organic fertilizer replacing 20%,40%and 60%of fertilizer nitrogen(BO20%,BO40%and BO60%).A three-year field experiment was carried out to analyze the distribution of soil carbon and nitrogen and the changes of microbial and enzyme activities in vineyard soil.Combined with yield,quality and economic benefits,the appropriate dosage of bio-organic fertilizer instead of chemical fertilizer was determined.In addition,through the indoor good gas culture experiment,carbon and nitrogen mineralization,enzyme activity and emission changes of CO2,N2O,CH4 and NH3 were monitored.The effects of bio-organic fertilizer replacing chemical fertilizer on soil carbon and nitrogen mineralization,gas loss and greenhouse effect in vineyard were clarified,which provided a theoretical basis for the sustainable development of grape industry.The main research results are as follows:(1)Bio-organic fertilizer instead of chemical fertilizer reduced grape yield but improved grape quality.The average yield of three years is Opt>BO40%>FP>BO20%>BO60%,and the economic benefit is Opt>FP>BO40%>BO20%>B060%.With the increase of years,the production,yield and yield to investment ratio of bio-organic fertilizer replacement treatment were significantly increased,while there was no significant difference between FP and Opt treatment.Compared with Opt,the yield of BO40%treatment in 2021 increased by 13.21%,and the contents of total phenols and anthocyanins in grape peel increased by 35.36%and 40.78%,respectively.(2)Bio-organic fertilizer could increase soil organic carbon and total nitrogen content and reduce nitrate nitrogen content.Compared with the germination stage,the nitrate nitrogen content in the 0～20cm soil layer at the mature stage decreased,while the nitrate nitrogen content in the 20～60 cm soil layer at the mature stage showed an increasing trend.In the 60～100 cm soil layer,there was no significant difference in the nitrate nitrogen content of bio-organic fertilizer replacement treatment,but the FP and Opt treatments showed a significant increase trend.In the 0～60 cm soil layer at mature stage,the average contents of soil organic carbon and total nitrogen increased by 41.78%and 15.39%under BO40%treatment,respectively,compared with that under FP treatment,while the nitrate nitrogen content decreased by 27.25%.The contents of soil organic carbon and total nitrogen increased with the increase of the replacement ratio of bio-organic fertilizer,butthere was no significant difference between BO40%treatment and BO60%treatment.(3)Bio-organic organic fertilizer instead of chemical fertilizer increased soil microbial quantity and enzyme activity.Compared with FP treatment,BO60%treatment significantly increased the number of soil bacteria and actinomyces,decreased the number of soil fungi,and increased the ratio of soil bacteria to fungi.The number ratio of bacteria/fungi showed the trend of B060%>BO40%>BO20%>Opt>FP,and the difference among treatments was significant.The ratio of soil bacteria/fungi in BO60%treatment was significantly increased by 240.33%compared with FP treatment.Field experiments showed that optimized fertilization treatment and bio-organic fertilizer replacement treatment could significantly improve soil enzyme activities,among which BO40%treatment showed better performance,and urease,sucrose,alkaline phosphatase and catalase increased 11.72%,35.79%,22.16%and 35.27%,respectively,compared with Opt treatment.(4)Bio-organic fertilizer instead of chemical fertilizer promoted soil organic carbon mineralization and reduced soil nitrate nitrogen accumulation mineralization.Compared with Opt treatment,the organic carbon mineralization rate and nitrate nitrogen mineralization rate of FP treatment increased by 19.28%and 131.06%,respectively.Compared with Opt treatment,the organic carbon mineralization rate of bio-organic fertilizer replacement treatment increased by 9.49%and nitrate nitrogen mineralization rate decreased by 29.50%.From 0 to 120 days,the cumulative mineralized amount of soil organic carbon was FP>B060%>BO40%>BO20%>Opt>CK,and the cumulative mineralized amount of organic carbon was 785.41 mg/kg under FP treatment.Compared with Opt treatment,the cumulative mineralized amount of organic carbon under bio-organic fertilizer replacement treatment increased by 4.99%to 15.36%.The cumulative mineralization amount of soil nitrate nitrogen was FP>Opt>BO20%>B060%>BO40%>CK.The cumulative minera-lization amount of nitrate nitrogen under FP treatment was 144.93 mg/kg,The cumulative mineralization amount of soil nitrate nitrogen under bio-organic fertilizer replacement treatment was significantly reduced by 69.49%and 29.50%compared with FP and Opt,respectively.The results showed that the cumulative mineralization of organic carbon was significantly positively correlated with the activities of urease and alkaline phosphatase,and significantly positively correlated with catalase.(5)Bio-organic fertilizer can significantly reduce soil nitrogen loss in gaseous phase,but promote soil CO2 emission.The cumulative N2O emission and NH3 volatilization of all treatments were 1212.06～3643.94μg/kg and 247.97～466.90 μg/kg,respectively,showing the trend of traditional fertilization>optimal fertilization>bio-organic fertilizer replacement>control.The cumulative emission of N2O and NH3 volatiles decreased by 22.62%and 13.82%in BO40%treatment compared with Opt treatment.The cumulative emissions of CO2 and CH4 showed the trend of traditional fertilization>bio-organic fertilizer replacement>optimized fertilization>control treatment.The cumulative emission fluxes of CO2 and CH4 in soil treated with BO40%increased by 1.43%and 23.93%,respectively,compared with Opt.In conclusion,the replacement of 40%fertilizer with bio-organic fertilizer in vineyards can increase grape yield and improve grape quality,increase soil organic carbon and total nitrogen content,reduce nitrate nitrogen content,increase soil microbial and enzyme activities,and effectively reduce global warming potential,which is an effective way for the high-quality development of Hebei grape industry.