Characteristics of soil organic carbon and nitrogen distributed in different density fractions of mollisols under long-term continuous cropping and natural restoration Analysis of the fungal community in continuous cropping cotton field of Xinjiang using 18S rDNA-PCR-DGGE Physiological activity and material production in processing tomato under continuous cropping Effect of potato continuous cropping on genetic diversity of soil microorganisms Identification and autotoxicity of root exudates of continuous cropping potato at different growth stages Response of soil enzyme activity and microbial community structure, diversity to continuous cotton cropping in northern Xinjiang Effect of planting patterns on crop yield, nutrients uptake and interspecific competition in maize-soybean relay strip intercropping system Analysis of functional diversity of soil microbial communities under different cultivation patterns at different growth stages of maize Effect of continuous cropping on Angelica sinensis diurnal photosynthetic dynamics