The Influence Of Caragana Korshinskii Woodland On The Soil Quality Of Ningnan Mountain

The wide planted shrub lands of soil and water conservation in Loess Plateau can prevent soil and water loss and have important effect on both revegetation and the ecological environment construction. This research aimed at the soil quality problem of shrub lands, took Caragana Korshinskii Kom.(CKK) in Gu yuan City as research object. This thesis systematically researched the basic feature, the vertical and horizontal distribution and comprehensive assessment of soil quality by soil sample collection, field investigation,laboratory analysis on soil physical, chemical and soil enzyme indicators, and statistic methods of variance analysis, correlation analysis. The main results were as follow:1. The content of soil moisture of CKK was low generally, and had no significant difference between the different points. The content of organic carbon, total N(TN),alkali-hydrolyzed nitrogen(AHN), total P(TP)of CKK was mostly“middle”level, the content of total K(TK) and CaCO3 was“high”level, while CEC of CKK was“lower”level. The content of organic carbon of CKK had been improved compared with the matched group, is higher than 20-40 cm soil layer; The variation tendency of organic carbon content in different slope positions and different aspects were upper slope>middle slope>bottom slope and shady slope>half sunny slope>sunny slope respectively.2. The content of TP of CKK in upper layer was higher than 20-40 cm layer slightly, and TP content had an increase compared with controls; The content of TP in different slope positions and aspects were upper<middle<bottom slope and sunny<half sunny<shady slope.3. The TK content between different layers of CKK showed no significant difference and had little change in various slope position and slope aspects. The CEC content in upper layer and 20-40 cm layer of CKK had significant variation. The content of CaCO3 of surface layer was lower than 20-40 cm layer and have marked differece.4. Compared with 10 years old CKK, the 20 and 30 years old ones had less TP and CaCO3, but had more organic carbon, TN, AHN, TP and CEC. In a word, the soil nutrition contents and soil quality will improve with the increase of age of shrubs.5. The invertase activities declined gradually with the increase of layer of CKK; The invertase activities had been hardly affected by slope direction; However it had been affected by slope position significantly,and invertase activities of upper slope higher than lower slope markedly. The soil enzyme activities enhanced as the tree ages increasing.