Spatial Heterogeneity of Soil pH and Chromium Content in Tea Plantations in Plateau Mountainous Areas: a Case Study of Guiding County, Guizhou Province

• WANG Zonglei, 
• XU Ying, 
• LI Zuowei, 
• WEN Ximei, 
• ZHU Dong, 
• ZHAN Tianli