Effects of mixed Robinia pseudoacacia plantations on soil urease activities in saline land of the Yellow River Delta
Liu Yun, Li Chuanrong, Xu Jingwei, Bing Beibei, Lü Mengmeng, Cheng Ling
(1.Taishan Forest Ecosystem Research Station，Key Laboratory of Agricultural Ecology and Environment，Shandong Agricultural University，271018，Tai’an，Shandong,China； 2.Shandong Acodemy of Forestry Sciences，251014，Jinan,China)
Abstract：In this paper, the soil urease activity and its influencing factors of mixed forests of Robinia pseudoacacia (R. pseudoacacia+Ailanthus altissima plantation, R. pseudoacacia+Ulmus pumila plantation and R. pseudoacacia+Fraxinus chinensis plantation) at 26 years old were studied in the Yellow River Delta, and R. pseudoacacia plantation and bare land were taken as the contrast. The results showed that the urease activities were decreased with the soil layer deepening, meanwhile, the soil urease activities of four kinds of plantation increased by 4.02, 4.74, 5.08 and 5.01 times respectively, and that of mixed R. pseudoacacia plantation＞R. pseudoacacia plantation＞CK. In the aspect of soil factors which affect soil urease activity, compared with the R. pseudoacacia plantation, the mixed Robinia pseudoacacia plantations decreased soil density, pH value and salt content, increased the total porosity, enhanced the water storage capacity, increased the content of the total N, available N and organic C, and increased the number of the bacteria and azotobacter. This study found that the soil urease activity was strongly influenced by the total porosity, bacteria, azotobacter, total N and organic C, hence, they could be used as indicators for evaluating soil urease activity.
2013, Vol. 11 
