Study On The Characteristics Of Nutritional Quality Changes And Fungal Community Structure Of Alfalfa After Cutting In Saline-alkali Soil

Alfalfa is known as the king of forage and plays an important role in the development of animal husbandry.The development of alfalfa in saline-alkali land is following the national development strategy of grassland and animal husbandry.Due to the lack of systematic processing of alfalfa theory in saline-alkali land,alfalfa products have been difficult to meet the needs of high-quality development of animal husbandry.Therefore,it is necessary to carry out theoretical research on alfalfa processing in saline-alkali land.In this study,four treatments were setted,LS(salt content 1.66 ‰,alkalinity 2.60 %),MS(salt content 2.33 ‰,alkalinity 3.09 %),HS(salt content 4.33 ‰,alkalinity 8.02 %),and CK(salt content 0.91 ‰,alkalinity 1.74 %),Zhongmu No.3 alfalfa as test material,The purpose of this study is to reveal the differences of stem and leaf structure,physiological characteristics,nutritional quality,fungal community of alfalfa at bud stage in saline-alkali land,and the dynamic changes and their correlation of various indexes during drying.The key factors affecting the drying rate and nutrients of Alfalfa in saline-alkali soil were analyzed to provide data support for the processing of Alfalfa in saline-alkali soil..The main conclusions are as follows.(1)Soil salinization resulted in thickening of the upper epidermis wax layer and stem cortex of alfalfa,which was not conducive to water loss of alfalfa.LS treatment could significantly increase the respiration rate and Intercellular carbon dioxide concentration(Ci)of alfalfa(P < 0.05).MS and HS treatment significantly inhibited the transpiration rate(Tr)of alfalfa(P < 0.05).During the drying process(0 ? 34 h),the respiration and Tr decreased of alfalfa in saline-alkali soil,the respiration stopped at 30 ? 32 h,and the stoma closed at34 h.With the increased of salinization,the drying rate,respiration rate,and Tr of alfalfa were decreased.(2)Soil salinization can affect the accumulation of nutrients in the growth process of alfalfa,and crude protein(CP)increased by 0.40 % compared with CK,while acid detergent fiber(ADF)and neutral detergent fiber(NDF)decreased 0.53 % and 1.24 % compared with CK.The CP content and the relative feeding value(RFV)of alfalfa in HS treatment were 20.67 % and 146.00,respectively.The nutritional quality of alfalfa in HS treatment was higher than in LS and MS treatment.During the drying process(0 – 34 h),the effects of salinization degree,drying time,and the interaction between the two factors on the nutrient of alfalfa was extremely significant(P < 0.01).At 34 h,the nutritional quality of alfalfa in LS treatment was the highest,with the CP content was 22.00 % and RFV was 157.67.(3)Alfalfa fungal community in saline-alkali soil belongs to 345 genera of 3 phyla,Cryptococcus and Alternaria are the dominant genera,and Alternaria has salinity tolerance.During the drying process(0 – 34 h),the abundance of the genus and the diversity decreased in saline-alkali soil.The order of mildew risk from low to high was MS < LS < HS.(4)Through comprehensive analysis,It is concluded that during the drying process(0? 34 h),the main nutrients of alfalfa in saline-alkali soil were greatly affected by stem and leaf structure,respiration,and fungal community.The key factors affecting the nutritional quality of alfalfa in saline-alkali soil field were leaf stomatal area,water content,stomatal conductance,Hannaella and Alternaria during drying.