Construction Of Comprehensive Benefit Evaluation Ststem On Complex Management Model Of Eucalyptus Afforestation And Evaluation Of Comprehensive Benefit

Taking Qipo Forest Farm, Bobai Forest Farm and Pingtianshan Forest Farm which were the main planting areas of Eucalyptus afforestation in Guangxi as experimental sites, the experimental forests and sample forests of Eucalyptus complex management were constructed with design of inter-planting method, design of experimental sites, design of Eucalyptus complex management model and design of observation sites of conserving surface runoff by different Eucalyptus complex management models. The change of soil mineral elements, benefit of soil and water conservation and optimization and selection of management technologies were observed and studied. Management auxiliary technologies were summarized. Optimal management models were selected and evaluated. Evaluation system was constructed. The main results were as follows:1. Experimental sample forests with18cultivating models of complex management of Eucalyptus afforestation were constructed with3species and9kinds of crops, forages and traditional Chinese medicinal materials planted in Guangxi generally. Designs of forestation were developed and construction technologies were studies. A set of reasonable space deposition models and management auxiliary technologies was summarized.2. Combining analytic hierarchy process, frequency analysis and experts consultation methods, comprehensive benefit evaluation index system on complex management model of Eucalyptus afforestation was divided into five classes, adopting9variable indexes to express three benefits, designing48concrete content indexes to construct a scientific and reasonable comprehensive benefit evaluation index system on complex management model of Eucalyptus afforestation.3.6kinds of management models with better economic benefit were selected preliminarily, in which3kinds were narrow line models which inter-planted Tephrosia candida, Pennisetum Purpereum Schum. Guimu-1and Ahrus cantoniensis in Eucalyptus afforestation with2m×3m row space and3kinds were wide line models which inter-planted Tephrosia candida, Stylosanthes guianensias SW. No.184and Abrus cantoniensis in the6m row space of Eucalyptus afforestation with two lines2mx3m row space and two lines2mx6m row space. The annual net economic income of these6models achieved1600yuan/hm2, which was1400yuan/hm2higher than that of Eucalyptus pure plantation, and the net income ratio was21.23%～84.60%, which was18.44%～44.10%higher than that of Eucalyptus pure plantation. It was suggested to extend and apply these models in management of Eucalyptus afforestation.4. The comprehensive benefit of complex management model of Eucalyptus afforestation was analyzed. By comprehensive evaluation, the direct economic income was1.5715million for three years, in which the income of Eucalyptus was1.3874million and the income of inter-planting crops was184.1thousand. The complex management model of Eucalyptus afforestation increased effectively the content of organic matter, total N, P and K, and available N, P and K. The soil erosion and sediment loss decreased4418.45t and660.3t respectively, and1508.15t Co2were absorbed with releasing1110.3t O2in sample forests with an area of71hm2every year. The social benefits included that bettered local environment, promoted the bumper harvest of agriculture, improved the quality of productive workers, increased the income of forest farms, drove the development of relative industry chain and maintained the regional ecological security.