李园节肢动物群落与各亚群落之间在均匀度、优势度、优势集中性上的关系

对李园非天敌亚群落、天敌亚群落与总群落之间在优势集中性、优势度和均匀度上的关系进行分析得出,非天敌亚群落与总群落在优势度和优势集中性的关系上均极相关,在均匀度上不相关,天敌亚群落与总群落之间在3个指标的关系上均不相关.     

金沙江流域退耕还草效益分析

2002年,在金沙江流域-云南昭通地区彝良县海拔2 000 m的半山区进行了退耕还草试验,选用9种牧草进行引种,并进行了不同草种组合的混播处理.2003年对产草量、株高、生长速度等生产性能指标进行了调查和分析.结果表明,9种禾本科牧草均能安全越冬,且各性状表现较好,均可作为半山区退耕还草的选用品种,尤其是苇状羊茅Festuca arundinacea,无芒雀麦Brome inermis(多福)的长势和产量优异,其次为多年生黑麦草Lolium perenne,紫羊茅F. robra.牧草品种混播组合试验的结果表明:白三叶Trifolium repens 多年生黑麦草的组合适应性较好,白三叶 草地早熟禾Poa pratensis的产量较好.退耕还草不仅提高了经济效益,在当地干旱多风的自然条件下,还起到稳定保水、保肥、防风、固土生态屏障作用.     

恩施州不同气候型旱地土壤肥力变化及肥力因子变异特征

分析了恩施州不同气候型旱地土壤肥力变化及肥力因子的变异特征。结果表明:(1)不同海拔带土壤类型随着海拔的上升和生物气候的变化而有规律地形成土壤垂直带谱;(2)随着海拔的升高,土壤pH值、速效磷含量保持相对的稳定,但土壤有机质、速效钾、碱解氮含量表现出明显的上升趋势;(3)土壤pH的变异最小,土壤有机质、碱解氮的变异次之,土壤速效磷和速效钾的变异系数明显大于其它3个土壤肥力因子;土壤速效磷和速效钾的变异系数表现出随着海拔的增加变异系数减小的趋势;(4)恩施州土壤肥力状况较20年前相比发生了明显的变化,尤其是土壤速效磷和碱解氮含量表现为明显的增加趋势。     

猪IFN-γ基因多态及功能分析

本研究对IFN-γ进行了不同猪品种间的基因组测序,以揭示核苷酸水平的突变,结果在IFN-γ基因中发现了3个SNP。其中2个SNP为中国地方猪种二花脸所特有,另一SNP在不同品种中具有广泛的多态分布。对于具有多态分布的SNP位点,建立了对应的PCR-SSCP检测标记。功能关联分析,尚没有发现IFN-γ基因与猪健康状况的现场记录直接相关,不过却可能关系到猪的繁殖性能表现。     

东北半干旱区主要农田防护林树种蒸腾速率研究

以黑龙江省西部半干旱地区主要农田防护林树种为研究对象,采用快速称重法对樟子松、落叶松、小黑杨和银中杨的蒸腾速率进行了研究。结果表明,各树种月蒸腾速率的变化不同,樟子松的蒸腾速率始终最小。樟子松蒸腾速率的月变化差异最小,各防护林树种的蒸腾速率均呈现抛物线变化趋势。农田防护林在多种环境因子的综合作用下,其蒸腾速率受大气温度和太阳总辐射的影响较大,并且蒸腾速率与大气温度、太阳总辐射和土壤水含量均表现出正相关,与相对湿度和风速均表现出负相关。     

New Vision and Policy Recommendations for Nutrition-Oriented Food Security in China

After four-decade significant economic growth and development, China sets a series of goals aiming at sustainable medium to high speed economic growth,reasonable equity, and better market oriented economy. In this pursue, agriculture will take a crucial role. Under the Health China 2030, National Nutrition Plan (2017-2030) and Rural Vitalization Strategy, more attention has been paid on nutrition both in policy and research field, meanwhile the linkage between agriculture and nutrition is enhancing, but the integration of Agriculture-Food Security-Nutrition system is not yet completed. During the economic transformation, agriculture and food industry will play a key role, especially when considering the nutrition and health status will impact the national physical fitness and therefore influence the economic transformation approach. It may also impact whether China can move out of the Middle Income Trap to some extent. In the new development era, China needs a new food security development strategy to improve the national nutrition status and sets of policies to strengthen the integration of agriculture and nutrition. This paper reviewed the major challenges about China’s food security and put forward a new vision based on international experiences, which aimed at providing recommendations for designing China’s food security strategy. The key food security challenges include natural and environmental pressure, such as insufficiency and degradation of land resources, shortage and pollution of water resources, climate change and extreme disaster, fiscal pressure caused by increasing agriculture subsidy, Triple Burden of malnutrition, food safety issues and food loss and waste. It requires institutional and technical innovations for the transformation of agriculture development which means that more value added, nutritious and healthy food should be produced, the productivity and efficiency of water, land and energy should be improved, and environmentally friendly social inclusive development should be considered. All of those call for a transformation of China’s food security strategy. This paper put forwards a new vision for China’s food security: China should set nutrition-oriented food security strategy with nutrition indicators as key targeted goals, aim to eliminate hunger and undernutrition by 2025 while effectively reducing overweight/ obesity and food safety risks. Therefore policy innovations are recommended including: Improve nutrition governance, Market motivated and nutrition oriented agriculture support system, Promote Nutrition-based Food Production, Establish efficient, safe, and inclusive food value chains, Policy innovation for sustainable nutritious diet and nutrition education, and Evidence based research to support policy making.     

黄土残塬沟壑区刺槐林枯落物水源涵养功能综合评价

为了对黄土残塬沟壑区刺槐林枯落物水源涵养功能综合评价,并提供以功能导向型的林分改造理论依据。于2017年7—8月在山西省吉县蔡家川流域选取475,900,1 575,1 850,2 525株/hm~2不同密度的刺槐林为研究对象,采用坐标综合评定法对不同密度刺槐林分枯落物层水源涵养功能进行综合评价。结果表明,5种林分密度梯度中,当林分密度为1 575株/hm~2时,刺槐林枯落物层能充分发挥其水源涵养功能,而林分密度过高(2 525株/hm~2)或者过低(475株/hm~2)枯落物发挥水源涵养功能的能力均急剧减弱。为了使刺槐林枯落物水源涵养功能正常发挥,其林分密度应控制为1 500株/hm~2。建议现有林分改造中,宜将刺槐林向该密度进行调控。     

小五台山不同海拔土壤理化性质垂直变化规律

以河北小五台山不同海拔18块样地土壤为研究对象,分析和比较了不同海拔下土壤物理性质、持水能力、养分特征等14项指标,研究小五台山不同海拔土壤理化性质的垂直变化规律。结果表明:(1)随海拔的升高小五台山土壤容重逐步降低,总孔隙度逐步升高,毛管孔隙度变化不明显;随土层深度增加土壤容重变大,总孔隙度降低。(2)土壤含水量、毛管持水量、最大持水量、田间持水量随海拔升高逐渐升高,随土层深度增加逐渐降低,这种降低趋势随海拔增加逐渐扩大。(3)土壤有机质、全氮、全磷、碱解氮含量随海拔升高而逐渐升高,随土层深度增加而降低;土壤全钾含量随海拔升高表现为"先升后降"的抛物线型,在2 100～2 200m达到峰值。0—20cm土层速效钾和速效磷含量随海拔升高没有明显变化趋势;20—60cm土层速效钾含量随海拔升高而升高,40—60cm速效磷含量随海拔升高而降低。(4)土壤有机质、全氮、碱解氮含量有明显的"表聚现象",且海拔越高越明显;土壤全磷和速效钾含量也有明显的"表聚现象",海拔越高越不明显;土壤速效磷含量存在一定的"表聚现象",但并不明显;土壤全钾含量没有"表聚现象"。     

建设和谐的大学生宿舍文化

学生宿舍是学生重要的生活和学习场所,宿舍文化对大学生的影响深刻而久远。构建和谐的大学生宿舍文化应坚持和谐的理念,把安全稳定、思想政治教育、学风建设和学生综合素质的提高结合起来,不断深化和丰富宿舍文化的内涵。