甘宁黄土高原地区重要水土保持植物共生固氮资源及特性研究

甘肃省黄土高原区不同生态条件下栽培和野生豆科植物根瘤菌资源及共生固氮特性的调查结果表明 ,从 112份 2 4属 5 3种根瘤样品中分离获得 87株根瘤菌。它们与豆科植物共生结瘤 6 3 .5 %为有效根瘤。不同种根瘤固氮活性差异较大 ,一般比较低 ,小于 1μmol/(g·h)占 35 %。大于 10 μmol/(g·h)仅占6 %。根据研究结果对这些豆科植物在水土保持中的作用及意义进行了讨论。     

云南高原盆地城市水源地土地利用空间结构

[目的]探究云南高原盆地城市水源地土地利用空间结构,为该区城市水源地土地利用结构调整提供依据。[方法]以洛伦兹曲线和分形方法相结合,对云南省9个典型高原盆地城市水源地土地利用空间结构进行了分析。[结果]9个典型高原盆地城市水源地土地利用类型中建设用地、草地和未利用地当前分布欠缺合理性,很不均衡,而未利用地和水域的空间结构镶嵌程度复杂,稳定性差。[结论]各个水源地现存的土地利用空间结构缺乏从水源保护角度出发的统一规划,土地利用问题突出。     

青藏高原正常有机土与草毡寒冻雏形土地温观测的比较研究

在海拔高度相同、距离相近的纤维正常有机土与草毡寒冻雏形土地区，虽然区域气候一致，但二者地温具有显著的分布差异。从不同类型土壤４０～８０ｃｍ层次地温分布特征来看，草毡寒冻雏形土区域地温年平均３．０℃，变化剧烈，年较差大，０℃等值线可延伸至很深处。纤维正常有机土地温年平均１．４℃，变化较为平稳，０℃等值线只延至８０～９０ｃｍ左右。二类型地区地温随深度变化也有很大的不一致性。     

Environment of the East Carpathian Foreland during periods of Palaeolithic man's activity

Several Palaeolithic sites have been discovered in the Halyč Prydnistrov'ja (East Carpathian Foreland) during the last 20 years; thereby this region becomes important when studying the development of Palaeolithic cultures in Eastern Europe. The cultural layers are associated with different horizons of paleosols in loess profiles. Palaeolithic materials were found in four stratigraphic horizons: two of them are of Middle Palaeolithic and two others of Upper Palaeolithic. Palaeogeographical and stratigraphical studies of loesses were the basis of reconstructions of the past landscapes. The palaeopedological study as well as pollen analysis give information about the past environment. Moreover, the molluscan fauna indirectly shows the character of vegetation cover. Relatively open deciduous or mixed forests were the environment of the older Middle Palaeolithic phase of settlement, open forests with patches of steppe and meadow habitats characterized the younger one. Open vegetation dominated during the Upper Palaeolithic. The qualities of local relief as well as local climate and environment in the East Carpathian Foreland and especially in the Dniester River valley were favourable for Palaeolithic hunters.     

黄土丘陵沟壑区退耕地植物群落优势种对显著影响因子的响应

根据在黄土高原丘陵沟壑区具有代表性的安塞县退耕地植被样方的调查资料,利用TWINSPAN对退耕地植物群落的类型及其优势种进行了确定,即退耕地植物群落主要有猪毛蒿(Artemisia scoparia)为优势种的群落、达乌里胡枝子(Lespedeza davurica)和长芒草(Stipa bungeana)为优势种的群落、铁杆蒿(Artemisia gmelinii)为优势种的群落和白羊草(Bothriochloa ischaemum)为优势种的群落。典范对应分析(Canonical Correspondence Analysis)得出:显著影响黄土高原丘陵沟壑区退耕地物种变化的主要因子为退耕年限、全磷、速效磷和土壤水分。结合物种生活型特征,认为白羊草和达乌里胡枝子在黄土高原丘陵沟壑区具有较强的适应性,可作为退耕地的适宜引种物种,以调控和加速植物群落演替,控制土壤侵蚀。     

加速黄土高原综合治理开发的重大举措─—对山西省拍卖“四荒”的调查

山西省的拍卖“四荒”始于１９８３年,１９９２年以来形成高潮,至１９９３年５月已拍卖１５０余万亩,拍卖“四荒”,是对以户包小流域治理为主的水土保持责任制体系的进一步完善和深化是水土流失区非耕地土地使用制度的重大改革;是小流域经济全面进入市场经济的基础;是丘陵山区生产关系的重大变革;是推进山区生产力发展的重大举措。拍卖“四荒”的主要程序是：广泛宣传,深入发动,建立组织、加强领导,统一规划、界定范围,合     

中国华东地区农田大气硫沉降

Atmospheric sulfur deposition onto typical farmland in East China was investigated using both field measurements and numerical modeling. The field measurements were conducted at the Experiment Station of Red Soil Ecology, Chinese Academy of Sciences, 10 km from Yingtan, Jiangxi Province, East China, between November 1998 and October 1999, and at the Changshu Ecological Experiment Station, Chinese Academy of Sciences, in a rapidly developing region of Jiangsu Province, East China, between April 2001 and March 2002. The regional acid deposition model system (RegADMS), in which the dry deposition velocities of SO2 and sulfate aerosols (SO4^2-) were estimated using a big-leaf resistance analogy model, was applied to simulate air sulfur deposition over East China and sulfur deposition onto lands of different use types in East China. The wet scavenging coefficients were parameterized in terms of precipitation rate, and the effect of sub-grid processes due to inhomogeneous land use on dry deposition velocity was also included. Results of the field measurements showed that over 83% of the total sulfur deposition at the Yingtan site was dry deposition, while at the Changshu site 42% was dry deposition. The total sulfur deposition was much larger at the Yingtan site than at the Changshu site, which suggested contrasting air pollution and meteorological situations. The modeling results revealed that the total annual sulfur deposition over East China was 1.88 Mt, of which 72.8% was deposited onto farmland, and dry deposition accounted for 43% of the total sulfur deposited. The modeling results were generally in agreement with those from the observations.Overall, this study suggested that atmospheric sulfur deposition played an important role in the soil sulfur balance, which could have a significant effect on agricultural ecosystems in the study region.     

陕西中部地区水土保持规划初探

陕西中部既是传统农业的发祥地，也是黄河中游水土流失的重点地区之一，该在探讨该地区水土流失规律的基础上，选用偏离一份额分析法进行了分区分类研究，提出了该地区水土保持的目标与对策。     

略述黄土高原综合治理经济问题研究

为适应今后黄土高原综合治理研究与实践的需要，必须强化经济问题研究。为此，笔者分析屯黄土高原综合治理经济问题研究所处的地位、研究方法和研究重点等。     

Nutrient flows and balances at the field and farm scale: Exploring effects of land-use strategies and access to resources

Nutrient flux and balance studies are valuable tools to assess the sustainability of agro-ecosystems and potential consequences for agricultural productivity. This paper presents results from a study at the field/farm scale representing mixed farming systems typical for the East African Highlands. We selected catchments in the Dega (cool highlands and Woina Dega (warm-to-cool mid-highlands) of the Central Highlands of Ethiopia, to get more insight on how individual land use strategies and access to resources affect the magnitude of nutrient flows and resulting balances and to explore some of reasons of the variability within and between farming systems at different altitudes. Our results show that environmental condition, farming system (e.g. choice of crop), access to resources (e.g. land, livestock and fertilizer) and smallholders’ source of off farm income influence the magnitude of nutrient fluxes and the degree to which nutrient fluxes may be imbalanced.