长期施肥对新疆灰漠土土壤微生物群落结构与功能多样性的影响

Abstract

A long-term( 20 years) stationary experiment was carried out in a grey desert soil field of Xinjiang to study the effects of fertilization on soil microbial community characteristics and functional diversity. Traditional microbial cultivation method and Biolog technique were used to analyze soil microbial community,the number of bacterial physiological groups and microbial carbon utilization. Ten fertilization treatments were studied,i. e.,abandonment( CK0),cultivated without fertilization( CK),different chemical fertilizer treatments( N,NK,NP,PK,and NPK),NPK and organic materials( NPKM1),NPK and double organic materials( NPKM2),as well as NPK and straw( NPKS). Results showed that,( 1)compared with CK treatment,data on the cultivable microorganisms illustrated that the numbers of bacteria,actinomycetes and fungi in CK0 treatment all increased significantly( P 0. 05). Effects of different chemical fertilizer treatments were different. The numbers of bacteria( except PK treatment),and actinomycetes( except PK and N treatments) increased by8. 14—135. 70% and 15. 30—44. 78%,respectively. The numbers of fungi( except NK treatment) decreased by 10. 00—38. 33%. The numbers of microorganisms were the highest in NPKM1 and NPKM2 treatments. The bacteria numbers of NPKM1 and NPKM2 treatments increased by 162. 20% and 173. 75%,when comparing with CK treatment. The numbers of actinomycetes increased by 34. 39% and 39. 37%,while the numbers of actinomycetes increased by 63. 33% and 488.33%. However,the numbers of microorganisms decreased obviously( P 0. 05),the numbers of bacteria,actinomycetes and fungi decreased by 14. 17%,21. 27% and 63. 33%.( 2) Studies of soil bacterial physiological groups showed that,the amounts of Azotobacter and Nitrifier in CK treatment were higher than those of CK0 treatment( P 0. 05),but the amounts of Ammoniation and Cytophaga in CK treatment were lower( P 0. 05). Effects of different chemical fertilizer treatments and NPKS treatment were very different. Effect of NPK treatment was obviously the best( P 0. 05). However,NPKM1 and NPKM2 treatments could obviously improve the amount of soil bacterial physiological groups related with N transformation.( 3) Carbon utilizations of soil microbial community showed that,the order of soil microbial activities was,NK,NPKM1,NPKM2 N,NPK,CK PK,NPKS CK0,NP. Soil microbial diversity indices of CK0 treatment were the highest. Compared with CK treatment,all fertilization treatments were not significantly different in Simpson index and Mc Intosh index. Shannon index in NPKM1,NPKM2 and NK treatments were the highest,other fertilizer treatments were not significantly different from,or significantly lower than CK. Carbohydrates,Amino acids,Carboxylic acids and Amines /amides were the main carbon resources for microbial utilization.( 4) Cluster analysis indicated that carbon utilizations by soil microbial community for different N treatments were similar( except NP treatment). Correlation between bacteria,fungi and soil nutrient contents were significant, but no significant correlation relationships existed among the cultivable microorganisms,soil bacterial physiological groups and carbon utilizations of soil microbial community. To sum up,the effects of long-term fertilization on diversities of soil microbial community structure and function in grey desert soil of Xinjiang were remarkable. Long-term cultivation without fertilization decreased the diversities of soil microbial community structure and function. Different chemical fertilizer treatments had varied effects. NPK and NPKM treatments could improve the diversities of soil microbial community structure and function.