Effects of Different Cultivation Patterns of Rice on the Soil Urease Activity and Alkali-hydro Nitrogen

Soil urease is sensitive to the changes of the soil ecosystem and has an important impact on soil nitrogen metabolism.In order to study the influence of different rice cultivation patterns on soil urease activity,we measured soil urease activity and alkali-hydro nitrogen from double-crop rice fields with different cultivation modes in Liuyang county,Hunan Province.The typical double-crop rice fields were used as research objects and field plot experiment method was adopted.The results showed that:a)soil urease activity increased with the increasing of nitrogen fertilizer,the highest nitrogen treatment had the highest activity of soil urease,and the blank control was the lowest,and the trend of soil urease activity in different cultivation as follows:Super-yield cultivation high-yield-and-efficiency cultivation high-efficiency-and-super-yield cultivation local traditional cultivationblank control.b) The Alkali-hydro nitrogen in soil decreased with the depth increased,and the soil urease activity decreased with the depth increased in certain soil depth.c) In the 15-25cm layer of soil,super-yield cultivation could raise the content of alkali-hydro nitrogen and the activity of soil urease,which indicated that the super-yield cultivation could change the soil properties in deep layer.