| Alfalfa is an important leguminous forage,is mainly planted in barren fields because of its fertility improvement and forage production.Multiple mowing will also increase the consumption of soil mineral elements and the lack of organic matter.In addition,there is little or no fertilization and extensive management in the process of planting alfalfa,which leads to the failure and to give full play to the productive potential of alfalfa.Rational application of organic fertilizer combin with some chemical fertilizers probably will become one of the main technical measures to effectively improve the physical and chemical properties of the soil,and will improve the quality and yield of alfalfa,and it is an important way solving the contradiction between economic and ecological benefits.In order to explore the best fertilization scheme for alfalfa planting and improve its production performance and nutritional quality.In 2020,we were using the Zhongmu No.2alfalfa planted in Tuoketuo County,Hohhot as the material,the growth and nutrition indexes of alfalfa under different fertilization treatments of chemical fertilizer and organic fertilizer and their effects on the characteristics of alfalfa rhizosphere soil were studied.The conclusions are summarized as follows:1.In the first crop of alfalfa,the growth condition of the plant was the best in Area 1where chemical fertilizer was only applied.The yield,plant height,soluble sugar,total chlorophyll and crude protein content of alfalfa in the second and third crop of alfalfa growth were significantly higher than those in other fertilizer treatment areas in 8 areas with 1/2 times chemical fertilizer plus self-made organic fertilizer and 5 areas with 1/2times chemical fertilizer plus self-made organic fertilizer.And the content of neutral and acidic washing fiber were significantly reduced,and the relative feeding value was improved.2.The p H value and EC value of the soil were increased significantly after applying chemical fertilizer alone in Area 1.Compared with the control,the contents of available potassium,available phosphorus,total nitrogen and organic matter in each treatment area was significantly increased.The contents of available potassium,available phosphorus,total nitrogen and organic matter were significantly higher than other plots in area 1 of the first crop,in area 8 of the second crop and in area 5 of the third crop3.The activities of alkaline phosphatase of soil,polyphenol oxidase of soil,catalase of soil,sucrase and urease of soil was the highest in area 1 of the first crop,and values was0.41mg/d/g,1.79 mg/d/g,0.92 mg/d/20 min,15.54 mg/d/g and 1.23 respectively.4.Compared with CK,the richness,diversity and uniformity of microbial bacteria and fungi communities of alfalfa rhizosphere soil were improved in different fertilization treatments.Especially,the 1/2 times of chemical fertilizer and 1 time of self-made organic fertilizer were applied,the microbial diversity was significantly improved in soil of the third crop,which promoted the sustainable development of soil ecological environment.To sum up,the application of 1/2 times of chemical fertilizer and 1 time of self-made organic fertilizer in area No.8 had the most significant effect on improving the yield and quality of alfalfa,physical and chemical properties and microbial diversity of soil.At the same time,considering the comprehensive factors such as chemical fertilizer reduction and slow release of organic fertilizer,1/2 times of chemical fertilizer plus self-made organic fertilizer will recommend as the best fertilization scheme for alfalfa planting. |
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