| The theory and practice of agroforestry, which has performed the powerful vitality, provides the effective approaches for realizing forestry ecological construction and harmonious development of forestry and agriculture. The Ginkgo agroforestry is popular to be distributed and accepted at the zone of Ginkgo cultivation. For comprehensively probing into the ecological and economical effects of Ginkgo agroforestry systems, based on the domestic and overseas study achievements, the paper studied the principal agroforestrys of the seven Ginkgo agroforestrys planted in years 1994 and 2004, monotypic Ginkgo and monotypic crop in the plain areas in Taixing Jiangsu, i.e. Ginkgo+Rape+Peanut (G+R+S), Ginkgo+Wheat+Peanut (G+W+S), Ginkgo+Broadbean+Peanut (G+B+S), Ginkgo+Mulberry (G+M), Wheat+Peanut (W+S), Rapeseed+Peanut (R+S) and monotypic Ginkgo (G), and further supplementary agroforestry systems of Ginkgo+ Chestnut+Tea (G+C+T), Chestnut+Tea (C+T) and monotypic Tea (T) in the areas of Mt.Dabie in Qianshan Anhui. The paper systematically probed the micro-climate character, photosynthesis characteristics, soil fertility, nutrition inputting and outputting, biological productivity, and quality of target harvest products, etc. And the paper used mathematic ways to comprehensively evaluate the ecological and economic effects of Ginkgo agroforestry systems. The main results were as follows:I. The daily change of light intensity, air temperature and soil surface temperature basically presented the Low-High-Low tendency in various agroforestry systems all the year, while the daily change of the atmosphere relative moisture presented the High-Low-High tendency. Ginkgo agroforestry systems presented that the forest interior light intensity was decreasing with small amplitude in winter, but decreasing with big amplitude in spring and summer. Ginkgo agroforestry systems could obviously keep the thermal preservation in winter through increasing the forest interior temperature, soil surface temperature and decreasing the atmosphere relative moisture. However, Ginkgo agroforestry systems could keep cooling the atmosphere temperature, soil surface temperature and increasing the atmosphere relative moisture in the growth seasons. On one hand, the Ginkgo systems could obviously reduce the wind speed, on the other hand, the soil water content becomed less.II. In different agroforestry systems or the same agroforestry systems along with the different depths of soils, all these (the contents of the soil oganic matters, total-N, hydrolysable N, total-P, available P, available K and the activity of sucrase, urease, dehydrogenase, phosphatase and protease) were violently different. The study comprehensively evaluated the soil fertility and quality in various models through the procedures of the improved analytic hierarchy process. The High-Low order of the soil fertility and quality in various models was 94G+M(FI=0.684)>04G+M(FI=0.574)>94G+B+S(FI=0.563)>04G+W+S(FI=0.50)>94G+R+S (FI=0.505)>04G+R+S(FI=0.466)>W+S(FI=0.454)>94G+W+S(FI=0.442)>R+S(FI=0.434)> 94G (FI=0.287) in Taixing, while G+C+T(FI=0.746)>C+T(FI=0.557) T(FI=0.453) in Qianshan. The study showed that the soil fertility is better in agroforestry systems than in monotypic models.III. Ginkgo agroforestry systems increased the contents of N, P, K and Mg in Ginkgo roots and stems, but decreased the contents of N, Ca and Mg in Ginkgo leaves and Ca in Ginkgo roots and stems. Agroforestry systems reduced the contents of N, P and K in Wheat, and the contents of N and K in the underneath part of Peanut and Ca in the overground part of Peanut. But the agroforestry systems increased the contents of Mg in Wheat and the contents of P, Mg and Ca in Peanut. The models 94G+R+S, 94G+M and 94G+W+S increased the ability for the absorption, return and taking amount of the nutrition elements, which increased the Circulation Ratio of the nutrition elements, but the models 94G+M and W+S decreased the Circulation Ratio.IV. The total biomass quantity and the target harvest yield were remarkably different among various agroforestry systems. Compared to the no-touch plots, the annual growth and the seeds yield of Ginkgo incresed to some extent, however, the annual biomass growth and the target harvest products of the intercrops decreaed obviously. In agroforestry systems, the total of the annual biomass of the main intercrops was more than that of Ginkgo, and the High-Low order was Wheat>Mulberry>Rape>Peanut>Ginkgo>Broadbean. However, the High-Low order of productivity was Wheat>Rapeseed>Peanut>Mulberry>Ginkgo>Broadbean, which was a little bit different than that of the biomass amount. The tea biological productivity in the models of G+C+T and C+T was much lower than that in the model T, but the contents of the tea chemical compositions (waterextraction, caffeine, tea polyphenol, amino acid, Mg, Mn, etc.) were higher than those of the tea monotypic model.V. It existed violent differences on the ecological value including carbon fixation, soil fertility maintenance and air purification, the model 94G+M had the highest total benefits, which was 19790 yuan·hm-2·a-1, and the following was the models 94G+R+S(14770 yuan·hm-2·a-1)and 94G+W+S)(9390 yuan·hm-2·a-1), and the lowest was the models 94G(5206 yuan·hm-2·a-1) and W+S(2410 yuan·hm-2·a-1). The economic benefit of agroforestry systems were generally better than that of pure forest or agriculture. The High-Low order of the economic benefit was 94G+W+S(44860 yuan·hm-2·a-1)>94G+R+S(36960 yuan·hm-2·a-1) >94G+M(28910 yuan·hm-2·a-1)>94G (21690 yuan·hm-2·a-1)>W+S (20470 yuan·hm-2·a-1). On the ecological value, the High-Low order was that the highest was the model 94G+W+S(54250 yuan·hm-2·a-1), the following was the models 94G+R+S(51730 yuan·hm-2·a-1), 94G+M(48700 yuan·hm-2·a-1) and 94G(26950 yuan·hm-2·a-1), the lowest was the model W+S(22880 yuan·hm-2·a-1).As the conclusion, Ginkgo agroforestry systems were superior to monotypic Ginkgo or crops cultivation. Different Ginkgo agroforestry systems had different ecological and economic benefits because of the different plants combinations. When soil fertility was considered, the models G+M, G+R+S were superior; when absorption and cycling of nutrition elements were considered, the models G+R+S, G+W+S were superior; when biomass and productivity were considered, the models G+W+S, G+R+S were superior; when economic benefits were considered, the models G+W+S, G+R+S were superior; when ecological benefits were considered, the models G+M, G+R+S were superior. Based on the comprehensive analysis of social, economic and ecological benefits, cost and output, etc., the models G+R/W+S could be promoted in rural areas, while the models G/C+T, G+M could be promoted in the mountains . |
PDF Full Text Request