Energy of forest systems in the Three Gorge Reservoir area

The energies of three forest ecosystems in the Three Gorge Reservoir area were analyzed. The results showed that the existing energies were 151 2438, 139 2014 and 175 1659 (×10 10 J/hm 2), the annual net fixed energies were 38 8924, 31 2214 and 46 8231 (×10 10 J/hm 2), and the utilization efficiency of light energies were 1 16, 0 99 and 1 40 for the Quercus acutissima forest(Q.A.), the Pinus massoniana forest (P.M.), and the Queresus acutissima and Pinus massoniana mixed forest (Q.P.), respectively. In the Three Gorge Reservoir Area, the energy efficiency of Quercus acutissima and Pinus massoniana mixed forest is the best.

Ecological Benefits of Compound Ridge Culture in Hillside Orchard in the Three Gorge Reservoir Area

Based on contour tillage of wide ridge and furrow covering and agro-forestry, this paper sets up a compound ridge culture mode in hillside orchards and introduces a long-term observation to the mode＇s effects on ecological benefits of water and soil conservation. A five-year study shows that compound ridge culture in hillside orchards is effective in water and soil conservation, especially in reducing soil erosion. Compared with the traditional management modes of orchards, compound ridge culture has reduced runoff amount by 41.96%-57.96%, soil erosion amount by 55.47%-67.75%. Compound ridge culture also brings an obvious reduction of soil nutrient loss and of non-point source pollution, which is of great importance for keeping and increasing the productivity of hillside orchards in the Three Gorge Reservoir Area.

AN ANALYSIS ON THE STRUCTURE TYPES AND BENEFITS OFSLOPELAND AGROFORESTRY SYSTEMS-Taking the Three Gorge Reservoir Area As An Example

The modem term 'agroforestry system' is derived from agricultural practices. It is an organic combination of agriculture and forestry, ecology and economy, product variation and scientific management. On the basis of analyzing the types and structure of agroforestry system in the Three Gorges Reservoir area,the paper poins out that agroforestry system can be divided into diffend structutal levds. Taking some typical cases as examples, it compares the benefits of four kinds of structures. The result illustrates that the hedge row agroforestry system on slopeland is an effective way to realize coordinate development of ecology and economy.

Compound Planting of Bletilla striata under Forest in the Three Gorges Dam Area

[Objectives] The aim was to study the artificial cultivation of Bletilla striata to realize large scale and standardization planting. [Methods] The comparison tests were conducted on B. striata with different canopy densities of the Magnolia officinalis forests,different compound planting densities and different tending measures and management. [Results] When the stand canopy density was 0. 4-0. 6,the per unit yield of B. striata was 5. 4%,6. 8% higher than that at the canopy density of less than 0. 4 and more than 0. 6,respectively. When the planting density was 30 cm × 30 cm,the per unit yield increased by 16. 1%,12. 0%,13. 1% respectively compared with the planting density of 20 cm × 20 cm,25 cm × 25 cm,35 cm × 35 cm. When B. striata was planted from October to November,the per unit yield was 5. 6% higher than that planted from December to January of the following year,and 21. 3% higher than that from February to March of the second year. When farmyard manure was applied during the cultivation,the per unit yield was 31. 7% and 18. 4% higher than the application of chemical fertilizer and compound fertilizer. When weeding 4 times per year,the per unit yield increased by 240. 1%,137. 0% and 43. 9% respectively from that weeding 1 times,2 times,3 times per year. [Conclusions]When planting B. striata,the stand canopy density of 0. 4-0. 6 could make it receive absolutely shelters and the lighting conditions required for the growth,thereby bringing in high emergence rate,good growth potential and high yield. The best planting effect of B. striata could achieve by planting from October to November with the planting density of 30 cm × 30 cm,which can play the maximum benefit of individual plants. Moreover,weeding 4 times per year combined with the use of farmyard manure can promote the development and growth of tubers,which can greatly improve the yield of B. striata.