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991.
992.
Zhang Guo-zhen Yang Li Xu Wei Sun Bao-ping 《中国林学(英文版)》2006,8(1):59-64
The historical formation and development of the abandoned channel of the Yellow River is reviewed and its causes of formation and present condition of prevention and control are analyzed in this paper. Based on this analysis, some ideas about control, critical problems and countermeasures in the next period are proposed with two typical control models as examples. We suggest that in preventing and controlling the wind-drift sandy lands in the region, the emphasis should be to develop, with a greatly expanded effort, a recycling economy. This should realize a combination of two ideas, i.e. integrate combating desertification with a structural adjustment of agricultural and an increase in the income of farmers. 相似文献
993.
994.
湖南造林困难地类总面积达 10 0万hm2 。通过对 5个县 658hm2 试验示范林历时 9年的研究 ,解决了植被恢复技术问题。选出适宜的树、划种有马桑、芦竹、苦槠、牡荆和栓皮栎 5种 ,有发展前景的树种有柏木、铅笔柏和藏柏。选出了林分结构稳定 ,组成种长势好 ,可以肯定的有马桑十墨西哥柏浅层钙质幼年性岩性土等 6个配置模式。并提出和推广了撩壕整地和芦竹下挖上堆 ,施肥促长等造林技术。同时 ,定义了“三岩”造林困难地 ,提出了“三岩”造林困难地的生态环境特点。从土种的水平研究了树种与立地的适应性。 相似文献
995.
Impact of agroforestry intervention on farm income under the subsistence farming system of the middle hills, Nepal 总被引:2,自引:0,他引:2
Practices that minimize the rate of soil degradation, increase crop yields and raise farm income are key to sustaining agricultural productivity in the hills of Nepal. The use of farmland is undergoing rapid changes in response to increasing population pressure, deforestation and subsistence needs. Against this background, this study examined the impact of an agroforestry intervention project on farm income based on a sample of subsistence farm households in Dhadhing district. The project was implemented by Nepal Agroforestry Foundation in 1993/94 to increase fodder production through the promotion of agroforestry. A total of 223 households (82 with project and 141 without project) were interviewed during May–October 1998 to collect information on production and agroforestrys' impact on farm income. The benefit-cost analysis showed that the agricultural system including agroforestry was more profitable than the conventional one. The results also showed that the introduction of mulberry trees for sericulture could further enhance the profitability of an agroforestry-based system. Thus, agroforestry has great potential for enhancing food production and farmers' economic conditions in a sustainable manner through its positive contributions to household income.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
996.
Patterns of shoot elongation of 2-yr seedlings from native North American populations of ponderosa pine and Douglas-fir were compared to those of Argentine land races originating from unknown provenances. The comparisons were conducted in Moscow, Idaho (USA), and suggested that the ponderosa pine land race was descended from a California provenance at low or middle elevations but that the growth potential of the land race was only mediocre in comparison to eight native populations. The Douglas-fir land race exhibited a relatively high growth potential in comparison to 19 native provenances and undoubtedly originated from a mild coastal environment. The results provide concrete recommendations for upgrading the growth potential of the Argentine land races by importing germ plasm of specific provenances. 相似文献
997.
日本的森林生态效益补偿制度及最新实践 总被引:11,自引:0,他引:11
系统介绍了日本的保安林制度和水源税制度等2种森林生态效益补偿制度,对我国森林生态补偿制度存在的问题进行了分析,借鉴日本的经验,提出了加大宣传力度,提高全社会对森林生态效益的认识;建立多渠道、多层次的资金筹措机制;进一步完善配套措施,建立多途径、多方式的补偿机制;建立损失评价制度,提高补偿标准;理顺管理体制,明确补偿重点等政策建议。 相似文献
998.
为有效地治理和改善矿区恶劣生态环境,使废弃的土地资源得以充分利用,通过对阜新海州露天矿土地复垦示范区土壤有机质、全N、有效P、速效K、EC、pH值、含水量、容重、紧实度等指标进行测定,开展了复垦土壤质量综合评价。结果表明:不同复垦示范区土壤质量差异较大,沙打旺、冰草示范区土壤质量最好;杨树、油松示范区次之;耕地、侧柏示范区土壤质量较差。 相似文献
999.
1000.
城市景观绿地规划问题与对策 总被引:1,自引:0,他引:1
指出了良好的城市景观绿地是城市生活的载体,体现了城市的文化与特色。概述了城市景观绿地的概念、分类和作用,提出了城市景观绿地规划设计原则和方法,为城市建设更好的发展提供参考。 相似文献