Improving Indigenous Technologies for Sustainable Land Use in Northern Mountainous Areas of Vietnam     

LeQuocDoanh HaDinhTuan 《山地科学学报》2004,1(3):270-275

More than 30 ethnic groups are now living in northern mountainous regions, Vietnam, mainly relying on shifting cultivation with the fallow period being shortened from time to time. Naturally, soil fertility reduces from cycle to cycle, entailing the reduction of productivity. Large areas of moderately sloping lands suitable for upland agriculture have become bare after many cultivation-fallow cycles. The soils there have been severely degraded with more toxicity, low porosity, low water retention capacity and poor floral diversity. Normally, these lands cannot be used for food crop cultivation. So farmers in uplands have to rely on slash-and-burn practices for their livelihood. As there is no more forest with good soil in medium slopes, farmers go to cut forests in watershed, high slope lands and old forests up to the mountains‘ top. There are ecologically and environmentally very sensitive areas, so their destruction will inevitably cause hazardous consequences in the whole basin. Meanwhile,cultivation in these areas has low economic efficiency and sustainability because the crop yield may decrease very fast due to severe erosion as the higher the slope, the more serious erosion. Consequently living standards of highland farmers remain low and unstable. Sustainable farming on these lands in the perspective of a seriously deteriorated ecology and environmental is not an easy task. There have been many projects trying to help mountainous farmers get out of their vicious circle. However, due to different reasons, the results gained are low, and in some cases,things ceased to move after the projects phased out. During past few years, based on the farmer experiences, the Vietnam Agricultural Science Institute has cooperated with local and international partners to implement different projects in order to solve the problems by developing simple, easy and cheap cultivation technologies, which can be accepted and applied by local poor farmers for sustainable agricultural production. The first results of our activities offered good opportunities for sustain food production, improve soil health, recharge of aquifers,and enhanced household income for better rural lively hoods in the upland eco-regions of northern Vietnam.  相似文献   

Spatial patterns and environmental factors influencing leaf carbon content in the forests and shrublands of China   总被引：1，自引：0，他引：1  

Hang Zhao  Li Xu  Qiufeng Wang  Jing Tian  Xuli Tang  Zhiyao Tang  Zongqiang Xie  Nianpeng He  Guirui Yu 《地理学报(英文版)》2018,28(6):791-801

Leaf carbon content (LCC) is widely used as an important parameter in estimating ecosystem carbon (C) storage, as well as for investigating the adaptation strategies of vegetation to their environment at a large scale. In this study, we used a dataset collected from forests (5119 plots) and shrublands (2564 plots) in China, 2011–2015. The plots were sampled following a consistent protocol, and we used the data to explore the spatial patterns of LCC at three scales: plot scale, eco-region scale (n = 24), and eco-region scale (n = 8). The average LCC of forests and shrublands combined was 45.3%, with the LCC of forests (45.5%) being slightly higher than that of shrublands (44.9%). Forest LCC ranged from 40.2% to 51.2% throughout the 24 eco-regions, while that of shrublands ranged from 35% to 50.1%. Forest LCC decreased with increasing latitude and longitude, whereas shrubland LCC decreased with increasing latitude, but increased with increasing longitude. The LCC increased, to some extent, with increasing temperature and precipitation. These results demonstrate the spatial patterns of LCC in the forests and shrublands at different scales based on field-measured data, providing a reference (or standard) for estimating carbon storage in vegetation at a regional scale.  相似文献   

1961～2000年中国生态区紫外辐射的时空演变特征   总被引：4，自引：0，他引：4  

黄梅玲  江洪  朱求安  余树全  周国模 《地理科学》2009,29(3)

通过ANUSPLINE空间插值以及气候学意义上的幂函数换算,探讨中国大陆生态区紫外辐射时空动态变化规律。结论如下:(1)紫外辐射多年平均值和多年季节平均值大致以季风区和非季风区分界为界线,呈现西部高东部低的总体格局,这主要与中国的地势和气候特点有关。(2)部分生态区40 a来年和四季紫外辐射呈显著减少趋势;冬季的紫外辐射年际间变化程度较大,其次是夏季和秋季,春季和年均紫外辐射年际变化较小;可分1961~1972、1973~1990、1991~2000年3个时段,大部分生态区第二时段年和季节紫外辐射平均值较小,第三时段普遍又开始增大,比第一时段小。  相似文献