SOIL-NUTRIENT PATCH CONTRAST MODIFIES INTENSITY AND DIRECTION OF CLONAL INTEGRATION IN GLECHOMA LONGITUBA Proliferation and growth of plant fine roots and the influences from nutrient variation―implications from the split-root experiments of Ailanthus altissima, Callistephus chinensis and Solidago canadensis Effect of diffusion of urea patch on microbial communities in soil Gas Exchange in Response to Heterogeneous Nutrient Environments in Panicum miliaceu