Effects Of Arbuscular Mycorrhizal Fungi On Soil Fertility In Mountain Land

In order to explore an effective way to improve soil fertility and supplement reserve cultivated land resources,the effects of Arbuscular mycorrhizal(AM)fungi,combined with different planting or fertilization patterns on maize yield and soil fertility in mountain land were studied under field conditions.The experiment design was a split plot design,with maize(Zea mays L.),sweet potato(Ipomoea batatas Lam.),soybean(Glycine Max Merr.)selected as experiment plants.AM fungi Acaulospora laevis 90034 was selected in this experiment.In the intercropping experiment,three treatments such as maize monoculture(C),maize-sweet potato intercropping(C-P),maize-soybean intercropping were set,each with AM inoculation and non-inoculated control.In the fertilization experiment,three treatments such as organic fertilizer(OM),compound fertilizer(NPK)and organic-compound fertilizer(OM+NPK)were set,each with AM inoculation and non-inoculated control.Each treatment has three replicates.Maize yield,soil nutrient contents and enzyme activities were determined after harvest.Soil enzyme activities were measured by fluorescence microporous plate assay and the aggregate composition was measured by wet sieve method.The results are as follows:(1)Intercropping significantly(P<0.05)increased the yield of maize,but AMF have no significant impact on it.Considering soil nutrients,soil pH and available nitrogen increased significantly in maize monoculture(C),while soil available phosphorus increased greatly in C-P treatment by the AM fungi inoculation.In comparison with control,the percentage of macroaggregates(>2 mm)was significantly higher in C in AMF inoculation treatment,AMF significantly increased soil protease,acetyl glucosaminidase activities in C treatment,and urease,cellobiohydrolase activities in C-P treatment,but decreased β-glucosidase,phosphatase activities in C-S treatment.Redundancy analysis showed that soil organic matter and available nitrogen contents had significant impact on soil enzyme activities(P<0.01).(2)No matter whether AM fungus was inoculated or not,compound fertilizer alone(NPK)and organic fertilizer-compound fertilizer combination(OM+NPK)significantly increased maize yield(P<0.05),and the content of available potassium and available phosphorus in NPK treatment was significantly higher than that in OM treatment.The chlorophyll content of maize in OM+NPK treatment was significantly higher than those in OM and NPK treatments.Soil pH in NPK treatment was highest among the three treatments,and soil pH in OM+NPK treatment was significantly higher than that in NPK treatment.The activities of urease,beta-glucosinase and fibrinodisaccharide hydrolase in NPK treatment after AM inoculation were significantly higher than other two fertilization treatments(P<0.05),and the activity of beta-glucosinase in NPK treatment with inoculation was significantly higher than that of uninoculated NPK treatment.The activity of cellobiohydrolase and N-acetyl-beta-glucosinolase in AM inoculated OM treatment was significantly higher than that of the other two fertilization treatments,and significantly higher than that of OM treatment without AM inoculation.