陕西省关中,陕南地区初夏干旱特点及预测研究

应用1958～1995年38a6月份陕西省关中、陕南地区24站的降水资料，研究了关中、陕南6月份的降水特点；选取其中12站作为资料站，计算出关中、陕南6月份的降水指数f,研究了关中、陕南初夏（6月份）的干旱特点；就初夏干旱发生的高空500hPa环流形势与历年平均状况进行了对比分析，并对初夏干旱作了预测。     

Sensitivity of stand dynamics to grazing in mixed Pinus sylvestris and Quercus pubescens forests: A modelling study

Only recently, studies of forest succession have started to include the effects of browsing by wild or domestic ungulates. We aim to contribute to this topic by analysing the influence of goat grazing on the long-term coexistence of Scots pine (Pinus sylvestris L.) and pubescent oak (Quercus pubescens Willd.) in the low-elevation forests of an inner-Alpine dry valley. The forest gap model ForClim was first adapted to these site conditions by examining the site-dependent sensitivity of the model with regard to the species-specific parameterisation of the drought tolerance as well as the light demand of establishing and adult trees. In a second step, the behaviour of the model was investigated with respect to different grazing intensities and species-specific browsing susceptibilities. The last step was the application of a grazing scenario based on forest history, with 150 years of heavy browsing (by goats) at the beginning of the simulated forest succession, followed by less intensive grazing pressure.     

Building resilience to drought in desertification-prone savannas in Sub-Saharan Africa: The water perspective

Securing sustainable livelihood conditions and reducing the risk of outmigration in savanna ecosystems hosted in the tropical semiarid regions is of fundamental importance for the future of humanity in general. Although precipitation in tropical drylands, or savannas, is generally more significant than one might expect, these regions are subject to considerable rainfall variability which causes frequent periods of water deficiency. This paper addresses the twin problems of “drought and desertification” from a water perspective, focusing on the soil moisture (green water) and plant water uptake deficiencies. It makes a clear distinction between long‐term climate change, meteorological drought, and agricultural droughts and dry spells caused by rainfall variability and land degradation. It then formulates recommendations to better cope with and to build resilience to droughts and dry spells. Coping with desertification requires a new conceptual framework based on green‐blue water resources to identify hydrological opportunities in a sea of constraints. This paper proposes an integrated land/water approach to desertification where ecosystem management supports agricultural development to build social‐ecological resilience to droughts and dry spells. This approach is based on the premise that to combat desertification, focus should shift from reducing trends of land degradation in agricultural systems to water resource management in savannas and to landscape‐wide ecosystem management.     

河南省旱涝灾害的地域分异规律和减灾对策研究

河南省地处我国南北气候过渡地带,自古以来就以旱涝灾害频繁而著称。根据旱涝灾害的地域分异特点,可将全省分为五个区。减轻旱涝灾害的主要措施是:加强水利建设,进一步开发地下水;扩大引黄灌溉、抗旱、补源面积;走旱作农业的道路,广泛提高农田抗灾水平。     

1978年长江中下游地区夏季大旱及其影响

本文利用相对距平和Z—指数为指标分析了1978年长江中下游地区的夏季大旱,并着重研究了干旱对该地区水资源和农业生产的影响。     

一种新的时间序列预报方法及其应用

本文叙述了作者提出的时间序列预报方法的基本原理,介绍了这一方法在应用过程中的发展及在实际部门应用的情况,其中包括异常旱涝灾害预报及方法的改进等最新成果。     

Eight years of annual no-till cropping in Washington's winter wheat-summer fallow region

The tillage-based winter wheat (Triticum aestivum L.)-summer fallow (WW-SF) cropping system has dominated dryland farming in the Pacific Northwest USA for 125 years. We conducted a large-scale multidisciplinary 8-year study of annual (i.e., no summer fallow) no-till cropping systems as an alternative to WW-SF. Soft white and hard white classes of winter and spring wheat, spring barley (Hordeum vulgare L.), yellow mustard (Brassica hirta Moench), and safflower (Carthamus tinctorius L.) were grown in various rotation combinations. Annual precipitation was less than the long-term average of 301 mm in 7 out of 8 years. Rhizoctonia bare patch disease caused by the fungus Rhizoctonia solani AG-8 appeared in year 3 and continued through year 8 in all no-till plots. All crops were susceptible to rhizoctonia, but bare patch area in wheat was reduced, and grain yield increased, when wheat was grown in rotation with barley every other year. Remnant downy brome (Bromus tectorum L.) weed seeds remained dormant for 6 years and longer to heavily infest recrop winter wheat. There were few quantifiable changes in soil quality due to crop rotation, but soil organic carbon (SOC) increased in the surface 0–5 cm depth with no-till during the 8 years to approach that found in undisturbed native soil. Annual no-till crop rotations experienced lower average profitability and greater income variability compared to WW-SF. Yellow mustard and safflower were not economically viable. Continuous annual cropping using no-till provides excellent protection against wind erosion and shows potential to increase soil quality, but the practice involves high economic risk compared to WW-SF. This paper provides the first comprehensive multidisciplinary report of long-term alternative annual no-till cropping systems research in the low-precipitation region of the Pacific Northwest.     

遥感旱灾模型综合分析

本文在野外实验的基础上，对遥感旱灾模型进行综合分析和评价。运用四年的实地观测数据，校正了旱灾模型中的待定系数，使其能用于ＮＯＡＡ气象卫星对旱情的监测。对复杂的蒸散模型简化的可行性进行了尝试性研究。     

Drought-induced resettlement: a case study from Burkina Faso

As a result of the '16-year drought' that Burkina Faso experienced from the late 1970s to the mid-1980s, there has been significant movement of people from the north of the country to the south. The large numbers of people that were displaced as a result of this natural disaster put pressure on the production systems of the south and caused concern amongst development organisations that environmental degradation would follow. Through a 2-year research period, using participatory approaches, it was found that despite a doubling of the population and the introduction of foreign production systems, the process of communal land control has significantly limited environmental degradation. This paper explains how customary law has controlled the settlement of immigrants (the Mossi and Fulani) and how it has overseen land allocation in three villages. The conclusions of the study indicate that, firstly, the customary law mechanisms in the three villages are effective in addressing communal resource use and, secondly, there is an evolution in customary law systems as they respond to local change. Received: 24 February 1999 · Accepted: 15 May 1999