Incorporating Geological Effects in Modeling of Revegetation Strategies for Salt-Affected Landscapes

The work highlights the difficulties of using standard sampling and statistical techniques to investigate regional phenomena and presents an integrated approach combining small-scale sampling with broad-scale observations to provide input into a modeling exercise. It is suggested that such approaches are vital if landscape- and regional-scale processes are to be understood and managed. The way in which the problem is perceived (holistically or piecemeal) affects the way treatments are designed and their effectiveness: past approaches have failed to integrate the various scales and processes involved. Effective solutions require an integrated holistic response.     

Dryland characteristics and its optimized eco‐productive paradigms for sustainable development in China

Dryland area occupies 37% of the national territory in China. Desertification and other disasters have limited dryland sustainable development. Here we overview the dryland characteristics and desertification status and introduce four regionally optimized eco‐productive paradigms for dryland sustainable development, i.e., the mountain‐oasis paradigm in arid desert; the small watershed‐based paradigm on the Loess Plateau; the integrated animal husbandry paradigm on the Inner Mongolia Steppe and the agro‐pastoral transitional region; and three circle paradigm on the Ordos Plateau. These paradigms are established on the basis of regional landscape patterns and their underlying material and energy flow rules, and different functional belts are determined and capitalized upon with the integrated consideration of regional biogeophysical processes, biogeochemical cycles and biogeosocial relations. These paradigms cannot cover all complex landscape types, but provide theoretical frameworks and practicable models for dryland sustainable development in China.     

Grazing greatly reduces the temporal stability of soil cellulolytic fungal community in a steppe on the Tibetan Plateau

Excessive livestock grazing degrades grasslands ecosystem stability and sustainability by reducing soil organic matter and plant productivity. However, the effects of grazing on soil cellulolytic fungi, an important indicator of the degradation process for soil organic matter, remain less well understood. Using T-RFLP and sequencing methods, we investigated the effects of grazing on the temporal changes of cellulolytic fungal abundance and community structure in dry steppe soils during the growing months from May to September, on the Tibetan Plateau using T-RFLP and sequencing methods. The results demonstrated that the abundance of soil cellulolytic fungi under grazing treatment changed significantly from month to month, and was positively correlated with dissolved organic carbon (DOC) and soil temperature, but negatively correlated with soil pH. Contrastingly, cellulolytic fungal abundance did not change within the fencing treatment (ungrazed conditions). Cellulolytic fungal community structure changed significantly in the growing months in grazed soils, but did not change in fenced soils. Grazing played a key role in determining the community structure of soil cellulolytic fungi by explaining 8.1% of the variation, while pH and DOC explained 4.1% and 4.0%, respectively. Phylogenetically, the cellulolytic fungi were primarily affiliated with Ascomycota (69.65% in relative abundance) and Basidiomycota (30.35%). Therefore, grazing substantially reduced the stability of soil cellulolytic fungal abundance and community structure, as compared with the fencing treatment. Our finding provides a new insight into the responses of organic matter-decomposing microbes for grassland managements.     

The Historical Dynamics of Social–Ecological Traps

Environmental degradation is a typical unintended outcome of collective human behavior. Hardin’s metaphor of the “tragedy of the commons” has become a conceived wisdom that captures the social dynamics leading to environmental degradation. Recently, “traps” has gained currency as an alternative concept to explain the rigidity of social and ecological processes that produce environmental degradation and livelihood impoverishment. The trap metaphor is, however, a great deal more complex compared to Hardin’s insight. This paper takes stock of studies using the trap metaphor. It argues that the concept includes time and history in the analysis, but only as background conditions and not as a factor of causality. From a historical–sociological perspective this is remarkable since social–ecological traps are clearly path-dependent processes, which are causally produced through a conjunction of events. To prove this point the paper conceptualizes social–ecological traps as a process instead of a condition, and systematically compares history and timing in one classic and three recent studies of social–ecological traps. Based on this comparison it concludes that conjunction of social and environmental events contributes profoundly to the production of trap processes. The paper further discusses the implications of this conclusion for policy intervention and outlines how future research might generalize insights from historical–sociological studies of traps.     

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.     

Understanding transitions in farming systems and their effects on livestock rearing and smallholder livelihoods in Telangana,India

Increasing food demands are causing rapid transitions in farming systems, often involving intensified land and resource use. While transitioning has benefits regarding poverty alleviation and food outputs, it also causes environmental and social issues over time. This study aims to understand the transitions in farming systems in a region in Telangana, from 1997 to 2015, and their effect on livestock rearing and smallholder livelihoods. We also examine the impact of the transitions on lower caste groups and women in particular. We collected data using a combination of methods, i.e., a household survey, focus group discussions, and secondary data sources, to build a comprehensive picture of the transitions in the region. We found that subsistence mixed farming systems transitioned to market-orientated specialized systems over a short time span. As the transition process gained momentum, households either intensified their production or got marginalized. Technological interventions, development programs with integrated approaches, and market demand for certain agricultural produce triggered increased regional production but also led to the scarcity of water, land, and labor. The transitions marginalized some of the households, changed the role of livestock in farming, and have been inclusive of both lower caste groups and women in terms of increased ownership of large ruminants and access to technologies. However, for women specifically, further increase in workload in the context of farming is also found.     

宝鸡渭北冰雹地理分布及减灾对策

采用宝鸡渭北地区40年（1961～2000年）的冰雹资料,结合实际调查,分析了渭北冰雹的地理分布及其移动路径.结果表明：宝鸡渭北地区降雹的年、月、日变化比较显著,降雹强度与地理环境密切,北部山区降雹多于渭河川原,主要分布于泾河与千河之间的分水岭南侧及喇叭口形的谷地中,冰雹移动路径与河谷走向基本一致.根据当地情况,提出了加强预测预报、人工消雹,以及建造林带和改良土壤,从而改变下垫面条件的减轻冰雹灾害的对策.     

Water resource conservation promotes synergy between economy and environment in China’s northern drylands

•Considering evenness provides a more accurate assessment of sustainable development. •Water resource conservation drives industrial transformation. •Synergy between economic development and environmental protection is achieved. •Regional collaboration over water could promote sustainable development in drylands. Water resource availability is the major limiting factor for sustainable development in drylands. Climate change intensifies the conflicting water demands between people and the environment and highlights the importance of effective water resource management for achieving a balance between economic development and environmental protection. In 2008, Inner Mongolia, typical dryland in northern China, proposed strict regulations on water exploitation and utilization aimed at achieving sustainable development. Our study is the first to investigate the effectiveness and performance of these long-standing water conservation regulations. Our analyses found that the regulations drove industrial transformation, evidenced by the decreasing proportion of environmentally harmful industries such as coal and steel, and the increasing proportion of tertiary industries (especially tourism). Following industrial transformation, economic development decoupled from industrial water consumption and subsequently led to reduced negative environmental impacts. Based on these results, adaptive strategies were developed for 12 cities by revealing and integrating their development pathways and relative status in achieving sustainable development. Integration and cooperation between cities were proposed, e.g., a water trade agreement between eastern Inner Mongolia (an economically underdeveloped region with relatively abundant water resources) and central Inner Mongolia (an economically developed region with high water stress). Such an agreement may enable the holistic achievement of sustainable development across regions. By integrating the findings of our research, our study presents a reproducible framework for water-management-based sustainable development strategies in drylands.     

渭北旱塬土地利用方式对土壤团聚体稳定性及其有机碳的影响

揭示果园、农耕地两种土地利用方式对土壤团聚体分布、稳定性及有机碳含量的影响,为渭北旱塬乃至黄土高原区土壤碳库的优化管理提供科学依据.通过同步采样及湿筛法将果园和农耕地这2种土地利用方式进行土壤粒径分组,得到大团聚体( 2 mm)、中间团聚体(0. 25～2 mm)、微团聚体(0. 053～0. 25 mm)及粉黏粒(0. 053 mm)组分质量分数,测定各组分团聚体有机碳含量,并计算出0～40 cm土层各组分有机碳储量.结果表明,在0～20 cm土层,农业土地利用方式对土壤团聚体含量分布、稳定性具有显著影响.果园不同粒级团聚体( 2、0. 25～2、0. 053～0. 25和0. 053 mm)含量均值分别为12. 9%、51. 3%、28. 8%和7. 0%,农耕地土壤各粒级团聚体含量分别为8. 3%、49. 7%、33. 6%和8. 4%, 0. 25 mm团聚体含量显著高于农耕地.在0～40 cm土层,农耕地土壤平均重量直径(MWD)和几何平均直径(GMD)均显著低于果园(P 0. 05).不同土地利用方式对土壤各团聚体内有机碳含量影响主要在0～10 cm土层,与农耕地相比,果园大团聚体、中间团聚体、微团聚体和粉黏粒内有机碳含量分别提高了56. 0%(P 0. 05)、57. 1%(P 0. 05)、40. 8%(P 0. 05)、13. 0%(P0. 05).各粒径团聚体内有机碳(粉黏粒除外)储量均为果园高于农耕地.果园增加了 0. 25 mm大团聚体及其有机碳含量,缓解了农耕地对土壤团聚体的破坏,并提高了有机碳的稳定性.因此,与农耕地相比,果园土壤团聚体稳定性及有机碳含量较高,提高了团聚体对土壤有机碳的物理保护作用,有利于土壤有机碳积累,促进了土壤固碳.     

渭北旱塬生态用地降水资源化潜力的估算及评价

针对黄土高原地区水资源严重短缺的态势和生态环境建设的需要，以黄土高原典型地区的渭北旱塬为例。对该区各种生态用地降水资源化理论潜力、可实现潜力和现实潜力进行初步估算。并进行相应评价。结果表明：农、林、牧、果业生产结构布局不合理，使得区内各地、市各种降水资源化潜力差异较大；林地、园地、牧草地的自然降水利用率较大：生态用地降水资源化现实潜力开发度与可实现潜力开发度有11．06％差距．现实潜力开发度与理论潜力开发度相比有36．22％潜力尚待开发。证明该区降水资源化潜力较大，但生态环境建设还是受水盗源短缺限制。