Evolution pattern of soil total N content and its distribution in typical hilly red soil regions Trends of grassland NPP and its response to human activity in Northern Tibet Changes in the dominant pathogens causing Fusarium dry rot of potato in rhizospheric soil under continuous potato cropping systems based on real-time quantitative PCR Rapid detection of Rhizoctonia in rhizosphere soil of potato using real-time quantitative PCR Ecological Environment Change in the North Slope of the Qilianshan Mountains