华南坡地利用与改良:重要性与可行性

SLOPELAND UTILIZATION AND AMELIORATION: IMPORTANCE AND FEASIBILITY

华南由于近年工商业的迅速发展,贫富差距较大,且对农林牧产品的需要不断增加。土地自然生产力又有下降趋势。作者论述了在全局观点的指导下,与周到而必要的科学研究相结合,可凭借速生植物利用和改良坡地,解决以上问题。

Slopeland accounts for some 70% of the total land area of South China. With minor exceptions, its productivity is rather low and is declining as a result of soil depletion and degradation and various processes of denudation. And the off-site damages of denudation are no less serious. It is possible to maximize the productivity and maintain or improve the soil as the natural medium for plant growth with certain fast growing plants. As fast growing plants fix more carbon from the atmosphere, the corresponding requirement of nutrients from the soil is higher. For this reason, plants that fix nitrogen and plants that send roots deep to draw nutrients from the subsoil should be included in the production system. In the choice of plants, it is imperative to strike a good balance between the demands of the local inhabitants and cash product markets far away. Since capital is in general a limiting factor in China, elements allowing quick returns merit special attention. To reducerisks from natural hazards and changes in markets, diversification in the system is an essential feature, multipurpose plants in particular may serve as a device of spreading risks,Awise practice is to take a small watershed as a basic unit for planning, in which plots and belts of different functions are laid out' so as to maximize productivity without des truction, With all these points in view, the geographic background of the slopeland of South China is discussed in conjunction with Acacia auriculiformis, A, decurrens, A.mangium, A, mearnsii, A, saligna, Ailanthus altissima, Albizia falcataria, Alnus acu-minata, A, rubra, Amaranthus tricolor, Calliandra calothyrsus, Canavalia ensiformis, C, gladiata, Cassia siamea, Casuarina glauca, Crotalria juncea, Dalbergia sisso, Derris indica, Desmodium spp, Eucalyptus pellitta, Gledtsia triacanthos, Hibiscus cannabicus, Lespedeza spp, Leucaena leucocephala, Muucana spp, Psophocarpurs palustris,P, tetragonolobus, Robinia pseudoaca-cia, Sesbania grandiflora, Sorghum bicolor,S, sudnense and Trenia orientalis as examples. The exercise has led to the conclusion that there is every possibility to ameliorate the environment and enhance the overall productivity of the land. This seems beyond the shadow of a doubt, but efforts to this end may not always meet with success, unless they are supported by appropriate experimental research and areal investigations, Some priority themes for study are recommended and explained.If slopeland utilization and amelioration as recommended is successfully executed, its importance cannot be exaggerated. Recent years have seen accelerated economic development in South China, The demands for agricultural and forest products, both at home and abroad, have increased rapidly. The pressure is further accentuated by the growth of population and the shift of interest or people in the rural areas to activities other than agriculture and forestry.On the plains,the standard of living is much higher than earlier, and the man/land ratio is exceedingly high. The slopeland regions are much Jess developed and the inhabitants there are under a living condition essentilly the same as tea years ago. The problems thus arising are more and more acute, especially when the slopeland deterioration, is taken into consideration, Adop-t.ing the proposed strategy, steps to solve the problems will be directed to the right quarter.