Effects Of Fruit Waste And Its Biochars On Biochemical Properties, Greenhouse Gas Emissions Of Sandy And Loess Soil And Plant Growth

Global warming has become an important issue during the last few decades.The fruit peels are usually disposed by landfilling,open burning,and composting,which are becoming increasingly impractical due to environmental concerns such as greenhouse gas emissions of?CO₂,CH₄ and N₂O?as greenhouse gas from landfilling,possible discharge of toxic compounds from open burning and the poor air quality released during composting.Therefore,we have studied the effects of fruit waste and its biochars on sandy and loess soil biochemical properties,greenhouse gas emissions and plant growth under incubation and pot experiments.The main results and conclusion of the studies are presented below:1.A 90-day incubation experiment was conducted to investigate the effects of orange peel waste and waste-derived biochar amendments on greenhouse gas emissions?GHG?,soil biochemical properties,and soil enzyme activities.There were five treatments with different amendment levels:control without an amendment?Control?,orange waste 1%?W1?,orange waste 2%?W2?,orange waste biochar 1%?B1?,and orange waste biochar 2%?B2?.The results showed that,compared with control,the amendments decreased cumulative N₂O emissions by59.2%?B2?,45.2%?B1?,20.6%?W2?and 10.2%?W1?treatments,respectively;and increased cumulative CH₄ emissions by 81.7%?W1?,84.4%?W2?,75.8%?B1?and 74.9%?B2?.Cumulative CO₂ emissions decreased for the B1?29.3%?and B2?43.5%?over the waste treatments.While soil pH,SOC,nitrate nitrogen?NO₃^--N?and enzyme activities?urease and catalase?were significantly increased with the passage of time from the biochar amendments,ammonium nitrogen?NH₄⁺-N?and invertase activities did not show this trend with time.2.In this study,we compared the influence of banana peels waste and its biochar on greenhouse gas emissions,soil enzyme activities and chemical properties of soil at 90 days incubation period.There were five treatments of amendments:no amendment?Control?,banana peel 1%?P1?,banana peel 2%?P2?,biochar 1%?B1?and biochar 2%?B2?.Results indicated that biochar amendment significantly decrease cumulative nitrous oxide?N₂O?emissions?37.1%-54.8%?,whereas banana peels amendment did not significantly decrease?1.3%-5.3%?as compared to control.Biochar application decreased the soil ammonium nitrogen?NH₄⁺-N?and nitrate nitrogen?NO₃^--N?with an increasing rate.Cumulative carbon dioxide?CO₂?emissions for B1 and B2 decreased 20.0%and 24.0%in comparison to the banana peel amendment,respectively.Cumulative methane?CH₄?emissions were higher in peel waste than biochar amendment.Soil enzyme activities?urease,invertase and alkaline phosphatase?were significantly increased by biochar amendment.In contrast,banana peel amendment increased soil ammonium nitrogen,soil microbial biomass carbon?MBC?and microbial biomass nitrogen?MBN?,?-glucosidase and urease activities.3.In this study,we investigated the effects of fruit peels and milk tea waste-derived biochars on wheat growth,yield,root traits,soil enzyme activities and nutrient status.Eight amendment treatments were tested:no amendment?CK?,chemical fertilizer?CF?,banana peel biochar 1%?BB1+CF?,banana peel biochar 2%?BB2+CF?,orange peel biochar 1%?OB1+CF?,orange peel biochar 2%?OB2+CF?,milk tea waste biochar 1%?TB1+CF?and milk tea waste biochar 2%?TB2+CF?.The results indicated that chlorophyll values,plant height,grain yield and dry weight of shoot and root were significantly increased for the TB2+CF treatment as compared to other treatments.Similarly,higher contents of nutrients in grains,shoots and roots were observed for TB2+CF:N(61.3,23.3 and 7.6 g kg^-1),P(9.2,10.4 and 8.3 g kg^-1)and K(9.1,34.8 and 4.4 g kg^-1).Compared to CK,the total root length?41.1%?,surface area?56.5%?,root volume?54.2%?and diameter?78.4%?were the greatest for TB2+CF,followed by BB2+CF,OB2+CF,TB1+CF,BB1+CF,OB1+CF and CF,respectively.However,BB+CF and OB+CF treatments increased?-glucosidase and dehydrogenase,but not urease activity,as compared to the TB+CF amendment,while all enzyme activity decreased with increased biochar levels.4.The aim of this study was to assess whether milk tea waste?TW?amendment combined with chemical fertilizer?F?application can be used to improve the biochemical properties of sandy soil and wheat growth.The treatments included control without amendment?T1?,chemical fertilizers?T2?,TW 2.5%+F?T3?,TW 5%+F?T4?and TW 10%+F?T5?.The co-application of milk tea waste?TW?and chemical fertilizer to improve the biochemical properties of sandy soil and wheat growth.The results showed that the highest chlorophyll?a and b?and carotenoids,shoot and root dry biomass,and leaf area index?LAI?were significantly improved with all amendment treatments.However,the highest root total length,root surface area,root volume and diameter were recorded for T4 among all treatments.The greater uptake of N,P,and K contents for T4 increased for the shoot by 68.9,58.3,and 57.1%,and for the root by 65.7,34.3,and 47.4%compared to the control,respectively.Compared with the control,T5treatment decreased the soil pH significantly and increased soil enzyme activities such as urease?95.2%?,?-glucosidase?81.6%?and dehydrogenase?97.2%?,followed by T4,T3,and T2.We recommended that biochar derived from fruit peels waste should be tested under field conditions for mitigating of GHG emissions and reduce the environment and economic issues.Field experiments are encouraged to assess the potential of co-application of biochars and milk tea waste amendments with chemical fertilizer on the plant growth,soil biochemical properties and to get the economic benefits for the farmers.