Effect of Fertilizer Application on the Activities of Soil Urease in Rubber Plantations
An analysis was made of the distribution of the soil urease activities in rubber plantations and its relationship with fertilizer application. The soil urease was found higher in the 0~20 cm soil layer than in the 20~40 cm soil layer notably irrespective of rhizosphere soil or non-rhizosphere soil, and the rhizosphere soil contained higher urease than the non-rhizosphere soil in the same layer. Fertilizer treatments at different levels to the soil gave short-term obvious influence to the urease activities of rhizosphere and non-rhizosphere soil in 0~20 cm layer of the soil without fertilizer application, but not to the urease activities in 20~40 cm soil layer. The urease activities of the soil under different fertilizer treatments were in the order of the soil applied with organic and non-organic fertilizersoil without fertilizersoil applied with only chemical fertilizersoil at the bottom of hole applied with green manure. The soil urease activities decreased with the increase of soil depth. The urease activities of the soil having been applied with fertilizer or manure of years increased remarkably.