The Effect of Rhizosphere Competition on Seasonal Variations of Absolute and Specific Urease activities in Pure and Mixed Planting of Chestnut-Leaved Oak and Persian Maple

Root competition is one of the restricting factors of plant growth. Plants have different effects on nutrient cycling in rhizosphere during competition with respect to different root physiology and morphology, rooting systems and mixture composition. Rhizosphere is a hot spot with greatest enzyme activities that is affected mainly by roots of plants. Urease enzyme activity is an index of organic nitrogen mineralization and adjustment of nitrogen dynamics in soil. The purpose is to study the variation of absolute and specific urease activities on rhizosphere in pure and mixed planting of Quercus castaneifolia and Acer velutinium during different seasons. 18 rhizotrons were designed and assembled with sampling capability from different locations of rhizosphere and sequential times. Three planting treatments have five replicate while control have three. Results revealed that there were significant differences (p