Soil Organic Carbon and Inorganic Carbon Accumulation Along a 30‐year Grassland Restoration Chronosequence in Semi‐arid Regions (China)

Carbon accumulation is an important research topic for grassland restoration. It is requisite to determine the dynamics of the soil carbon pools [soil organic carbon (SOC) and soil inorganic carbon (SIC)] for understanding regional carbon budgets. In this study, we chose a grassland restoration chronosequence (cropland, 0 years; grasslands restored for 5, 15 and 30 years, i.e. RG5, RG15 and RG30, respectively) to compare the SOC and SIC pools in different soil profiles. Our results showed that SOC stock in the 0‐ to 100‐cm soil layer showed an initial decrease in RG5 and then an increase to net C gains in RG15 and RG30. Because of a decrease in the SIC stock, the percentage of SOC stock in the total soil C pool increased across the chronosequence. The SIC stock decreased at a rate of 0·75 Mg hm⁻² y⁻¹. The change of SOC was higher in the surface (0–10 cm, 0·40 Mg hm⁻² y⁻¹) than in the deeper soil (10–100 cm, 0·33 Mg hm⁻² y⁻¹) in RG5. The accumulation of C commenced >5 years after cropland conversion. Although the SIC content decreased, the SIC stock still represented a larger percentage of the soil C pool. Moreover, the soil total carbon showed an increasing trend during grassland restoration. Our results indicated that the soil C sequestration featured an increase in SOC, offsetting the decrease in SIC at the depth of 0–100 cm in the restored grasslands. Therefore, we suggest that both SOC and SIC should be considered during grassland restoration in semi‐arid regions. Copyright © 2016 John Wiley & Sons, Ltd.     

A New Dryland Development Paradigm Grounded in Empirical Analysis of Dryland Systems Science

Global drylands face a host of urgent human and environmental challenges with far‐reaching impacts. Improving smallholder agriculture remains a key development pathway to tackle these challenges. The dryland development paradigm (DDP), introduced in 2007, presented a highly influential framework for dryland development based on systems research. This paper empirically derives a new, updated DDP. It assesses recent, cutting‐edge dryland science, combining literature review with qualitative and quantitative analysis of research published by the world's largest dryland science and development research initiative. The new DDP comprises eight characteristics that are distilled into three integrative principles: Unpack , Traverse and Share . The new DDP is applied and tested to identify key dryland knowledge and development gaps. A future research agenda is then elucidated, grounded in a research in development approach, in which research anchored in the three integrative principles is embedded within the context it seeks to improve. Supported by greater trans‐disciplinarity and knowledge co‐production, operationalization of the new DDP can deliver both novel scientific insights and development impact in line with the aspirations of the 2030 Sustainable Development Goals. © 2017 The Authors. Land Degradation & Development Published by John Wiley & Sons Ltd.     

PWT自动根焊+药芯半自动焊管道焊接工艺

结合长输管道工程实践,分析并研究了国内外不同的管道焊接工艺。提出了PWT自动根焊 药芯半自动焊的管道新型焊接工艺。试验研究和应用实践的结果表明,该新型焊接工艺性能优异,焊接质量上乘,焊接速度快,经济效益显著,具有推广使用价值。     

杏枝条电导率与花器官耐霜性的关系

通过测定6个杏品种1 a生休眠期枝条的电导率,并配置Logistic方程确定其半致死温度(LT50),再对LT50与花器官的耐霜性进行相关性分析。结果表明,LT50与花器官耐霜性之间呈显著正相关,r=0.96**,即杏枝条的LT50越低,其花器官的耐霜性越强,反之越弱。杏休眠期1 a生枝条的LT50可以作为鉴定杏品种花器官耐霜性的生理指标之一。     

陶赛特与半细毛羊杂交一代生长发育的观察

对陶赛特与青海半细毛羊杂交一代羔羊的生长发育进行观察,结果表明：①陶半杂一代羔羊与同龄青海半细毛羊羔羊出生重差异不显著,3月龄、6月龄时陶半杂一代体重、日增重均高于青海半细毛羊（P〈0．01）;②陶半杂一代产肉性能显著高于青海半细毛羊（P〈0．01）。     

乌鞘岭半农半牧区冷季暖棚全舍饲对绵羊生产效益的影响

于2008年12月－2009年4月在乌鞘岭半农半牧区随机选择10个牧户,各牧户草地类型一致,绵羊体况相近,其中5户采用全舍饲的饲养模式（试验组）,另外5户采用放牧+补饲的饲养模式（对照组）,开展冷季不同饲养模式对绵羊生产效益影响的试验。结果表明,试验组和对照组母羊体质量在产羔后1个月内分别下降了1.17和2.71 kg。产羔1个月后试验组母羊体质量开始恢复,而对照组母羊体质量持续降低;产羔后3个月对照组母羊平均掉膘5.96 kg,占体质量的13.91%,试验组体质量增加0.68 kg。两组羔羊的初生体质量差异不显著(P>0.05),但试验组羔羊生长速度高于对照组,羔羊2月龄体质量及出栏体质量显著高于对照组(P<0.05)。经济效益分析表明,试验组收入较对照组高出20.27元·只-1。     

Farmer Perceptions and Responses to Soil Degradation in Swaziland

Soil degradation is globally concerning due to its adverse effects on the environment and agricultural production. Much of Swaziland is at risk from degradation. This paper assesses farmer perceptions and responses to soil degradation in 2002 and 2014, focusing on two land uses that underpin rural livelihoods: arable land and rangeland areas. It uses repeat household surveys and semi‐structured interviews, in two case study chiefdoms in the country's middleveld (KaBhudla and Engcayini) in the first longitudinal study of its kind. We find that observations of land degradation are perceived mainly through changes in land productivity, with chemical degradation occurring predominantly on arable land and physical degradation and erosion mainly in rangeland areas. Changes in rainfall are particularly important in determining responses. While perceptions of the causes and impacts of degradation largely concur with the scientific literature, responses were constrained by poor land availability, shorter and more unpredictable cropping seasons because of changing rains and low awareness, access to or knowledge of agricultural inputs. We suggest that sustainable arable land management can be enhanced through improved access to alternative sources of water, use of management practices that retain soil and moisture and greater access to agricultural inputs and capacity building to ensure their appropriate use. We suggest collaborative management for settlement planning that integrates soil conservation and livestock management strategies such as controlled stocking levels and rotational grazing could improve land quality in rangeland areas. Together, these approaches can help land users to better manage change. © 2016 The Authors. Land Degradation & Development published by John Wiley & Sons Ltd.     

Stretching Soil Sampling to Watershed: Evaluation of Soil‐Test Parameters in a Semi‐arid Tropical Watershed

Soil sampling is an integral component of fertility evaluation and nutrient recommendation for efficient use of nutrients in crop production. Little attention has been devoted to evaluating methodology for sampling watersheds under dryland agriculture. A stratified random sampling methodology for sampling the Appayapally watershed in Mahabubnagar district of Andhra Pradesh state in the semi‐arid tropical region of India was adopted and evaluated. The watershed has an area of about 500 ha, with gentle sloping lands (<1% slope), and 217 farmers own land in the watershed. The soils are Alfisols. A total of 114 soil samples were collected from the top 15‐cm layer to represent the entire watershed. Each sample was a composite of 7–8 cores, randomly collected from the area represented by a crop and group of farmers. The soil samples were air dried, ground, and analyzed for pH, electrical conductivity (EC), organic carbon (C), total nitrogen (N), and extractable phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), sulfur (S), zinc (Zn), manganese (Mn), iron (Fe), copper (Cu), and boron (B). Statistical analysis of the results on soil fertility parameters showed that the mean‐ or median‐based results of soil tests performed in the study did not differ significantly when the sample set size varied from 5 to 114 (100% of the population). Our results indicate that farmers' fields in the Appayapally watershed are uniform in the chemical fertility parameters studied, and even a small sample set size can represent the whole population. However, such a sampling strategy may be applicable only to watersheds that are very gently sloping and where fertilizer use is very low, resulting in an overall low fertility in the whole watershed.     

葡萄根和枝条抗寒性能测试仪的研制与试验

为了能方便准确的测定葡萄的抗寒特性,该文研制了一种在实验室内测定葡萄根和枝条抗寒性能的测试仪。该仪器利用测试箱持续降温的方法为试验提供测试环境,以STM32单片机为核心组成嵌入式控制平台,由温度传感器和热电模块采集温度信号、电压信号等试验结果,同时在上位机系统上显示试验结果和存储数据。试验结果表明,在试验的6个葡萄品种中光荣河岸和威代尔根系的抗寒性较强,光荣河岸枝条的抗寒性最强,且该仪器的精度达到0.96%,工作性能稳定可靠,可满足葡萄根和枝条抗寒性检测的要求。该文为培育新的抗寒品种提供了依据。