Correlation Analysis and Dynamic of Soil Physicochemical Properties under the Eucalyptus-grass Compound Management Models

Based on 6 kinds of compound management mode about Eucalyptus interplanting grass( Pennisetum americanum × P. purpureum) × Pennisetum purpureum, Tephrosia candida and Stylosanthes guianensis,using Eucalyptus pure forest as control,dynamic of main factors of soil physicochemical properties in different soil layers of Eucalyptus-grass compound management models was analyzed,and the better model to improve the soil physicochemical properties was selected by the method of gray system.The results showed that during the same period of the same soil layer,the differences of soil bulk density,total porosity and capillary porosity,field capacity,organic matter,total N,P,K and available N,P,K among different models reached significant level( P 0. 05) or extremely significant level( P 0. 01). At the same period,all of the soil total porosity and capillary porosity,field capacity,organic matter,total N,available N,available P and available K of soil layer from 0cm to 20 cm were greater than soil layer from 20 cm to 40 cm,while soil bulk density was opposite. As the change of planting period,soil bulk density,capillary porosity,field capacity of all models at the same soil player were increasing,while soil total porosity decreased. Changing trends of the soil nutrient content in the different planting patterns and different soil layers were different. The best model to improve the soil physical properties and soil nutrient content was A2,which was Eucalyptus( 2m × 3m) + Tephrosia candida with the highest upper and lower correlation.