Effect Of Long-term Fertilization On The Diversity And Community Structure Of Arbuscular Mycorrhiza Fungi In Northwest China

Arbuscular mycorrhizal fungi (AMF) are obligate symbiotic fungi forming mutualistic associations with the roots of most land plants. AMF diversity can affect the diversity and productivity of the host plant communities and, therefore, the functioning of the whole ecosystem. So scientists have paid more attention to ecology of AMF recent years.In this work, microscopic inspection of stained technique was utilized to investigate the effects of organic (M) and inorganic (N, NP) fertilizer on the diversity and community structure of soil arbuscular mycorrhizal fungi (AMF) in a wheat agroecosystem of long-term (29-year) fertilizer amendments (N, NP, SNP, M,MNP, CK) in Northwest China. The main results were abstracted as follow:1. The percent of AM colonization and spores density have significant difference among soils treated with inorganic fertilizer (N, NP), straw plus N (SNP), manure(M), manure plus N, P (MNP) and unfertilized control (CK). The percent of AM colonization is between 51.9%-76% and the range of spores density is from 19.7-27.3grades/20g soil. The percent of AM colonization is elevated when manure and N, P are both used. The use of P fertilizer could elevate spores density of soil. Different fertilization treatments could change space distribution of spore numbers.2. The present frequency of AMF species in different fertilization treatments are very different. The present frequency of Glomus is higher than other genus. Long-term fertilization could change the distribution of AMF species, and also change community structure and diversity of AMF. The diversity of AMF species is elevated when organic and inorganic fertilizer were used together . But organic fertilizer decreases the diversity of AMF species and inorganic fertilizer dosen't impact the diversity of AMF species.3. The wheat yields have significant difference among different soils treated. Organic and inorganic fertilizer used together elevated wheat yields.The increased content of N and P caused by long-term fertilizer amendments, which changed the soil fertility, may contribute to the change of wheat yields.4. Spores density and percent of AMF colonization were significantly correlated with some soil properties, especially the available P (AP) and Soil Organic Carbon (SOC) content of the soil; Wheat yeilds increased with increasing soil AP but decreased when infection rate of mycorrhizal fungi increased.5. Nitrogen additions could inhibit growth of AMF. And this effect will be more apparent if plants could acquire enough phosphorus.The results suggested that the percent of AM colonization, spores density, AMF diversity and community structure were affected by long-term fertilizer amendments, and organic and inorganic fertilizers used together have more significant impact, directly or indirectly, than organic or inorganic fertilizers used individually.