网球体能训练重点的决策研究

为了能科学地确定训练的重点，为网球教练员和运动员训练决策提供依据。综合使用测试法、变异系数和TOPSIS法对浙江省现役网球运动员体能的测试数据进行处理。结果：男队训练重点排序为：力量、爆发力、灵敏、速度、耐力；同理，女队训练重点的排序为：力量、爆发力、灵敏、耐力、速度；最后对每位运动员亟待加强指标进行排序。结论：变异系数和TOPSIS法计算的结果简单明了，节省资源，适宜不同专项、不同训练指标的训练过程的有效监控。     

河北省土壤有机质时空变化分析

采用BP神经网络和地统计方法,对1980~2009年间河北省耕地土壤有机质时空变化规律及影响因素进行对比分析。结果表明:河北省耕地土壤有机质具有西北高东南低的格局;随着时间的推移,有机质总体呈现上升趋势。1980年的低值区域到了2009年SOM上升变化明显,成为热点;北部坝上、西部太行山区及东部沿海地区到2009年SOM含量下降,成为冷点。分析表明,这种变化格局的形成与施用有机肥、实施秸秆还田等社会经济过程有关。本研究为预测有机质变化趋势、改善土壤质量、优化种植结构和耕地的可持续发展提供了一定依据。     

澳大利亚社区农园的发展及其对我国的启示

在一些发达国家,社区农园向人们提供了接触自然、放松身心的场所,已受到越来越多市民的喜欢。而我国社区农园的发展仍处于探索期,借鉴国外社区农园对于我国社区农园的发展有很大的裨益。对澳大利亚社区花园的发展状况进行了详细介绍。以三个分别位于居住区、校园、公园的社区花园为例,根据案例分析社区农园对孤独人群、老年人、儿童、残疾人这些弱势群体带来的益处,阐明其对人们身心健康的改善以及对社会可持续发展的重大意义。文末根据澳大利亚社区农园发展的成功经验和我国城市发展的现状,提出我国建设社区农园需要面临的挑战。     

The Relationship Between Vegetation Characteristics and Altitudes in Transitional Permafrost Zone in Xidatan,Qinghai-Tibetan Plateau

Many studies showed that permafrost has profound influence on alpine ecosystem. However, former researches were mainly focused on typical points by temporal scales. There were few studies about the correlation between vegetation characteristics and different altitudes covering a large region in spatial pattern, especially in transitional permafrost(TP). There were continuous permafrost(CP) discontinuous permafrost(DCP) and seasonal frozen ground(SFG) in this study region. The types of permafrost changed from SFG to DCP, and finally become CP as the altitudes of Xidatan increase. In this paper, 112 845 points interpreted by HJ1-B(environment and disaster monitoring and prediction small satellite constellation), vegetation investigation points, thawing layer thickness research sites, ground temperature and water content observation plots were used to examine the spatial pattern of vegetation which were located in different altitudes in Xidatan, a typical TP region, in Qinghai-Tibetan Plateau. Vegetation characteristics, soil moisture content(SMC) and thaw depths were collected in 15 August to 25 August2012. Characteristics of vegetation were mainly represented by fractional vegetation cover(FVC) derived from the normalized difference vegetation index(NDVI), as well as above ground biomass(AGB). In this paper, we analyzed that the distinction of vegetation characteristics in each range through statistics data. These ranges were divided by varied altitudes. For examples, the ranges were divided into 50 m or 100 m. In this study we use a large area plots method to further discuss the relationship between the features of vegetation and the different regions of permafrost based on altitudes shifts in Xidatan. A diagram described the vegetation characteristics variability with rising altitudes in transitional permafrost region was drawn in this paper. Our results illustrated the FVCs first increased in SFG region and then decreased in DCP zone slowly, and in CP region FVCs soared then dropped dramatically. With the altitudes increased, the curve of FVCs indicated a parabolic distribution except a little difference in the first 200 m range.     

新时代土壤化学前沿进展与展望

土壤化学是重要的土壤学基础分支学科。在回顾了土壤化学发展历程的基础上,梳理了土壤化学的四个前沿交叉方向,并展望了土壤化学与其他相关学科的交叉发展趋势,以期寻求新的学科增长点。土壤化学经历了从恒电荷到可变电荷土壤学说演变,我国在土壤电化学、根际土壤化学、土壤化学-物理-微生物界面反应等方向逐步领跑。新时代中国已经发展成为国际土壤化学的研究中心之一,尤其在土壤化学与微生物学、地球化学、矿物学、环境化学等交叉领域取得了突破性发展。同时,发展并运用同步辐射、微流控联用光谱能谱、高分辨显微镜、光谱电化学等实时、原位、高精度研究方法,推动土壤化学研究取得了长足的进步。新时代的土壤化学具有三个重要发展趋势,首先系统揭示地球表层系统中物质循环与能量交换的土壤化学机制,实现"0到1"的土壤化学原创性成果的突破;其次需要综合运用地球表层系统理论,从多界面、多要素、多过程的"三多"交互耦合;再次,需要加强与地球宜居性这一人类重大命题的交叉融合,为生态文明建设、土壤污染防治攻坚战、全球变化等国家重大需求提供理论支持。     

Short time effects of biological and inter-row subsoiling on yield of potatoes grown on a loamy sand,and on soil penetration resistance,root growth and nitrogen uptake

Soil compaction, especially subsoil compaction, in agricultural fields has increased due to widespread use of heavy machines and intensification of vehicular traffic. Subsoil compaction changes the relative distribution of roots between soil layers and may restrict root development to the upper part of the soil profile, limiting water and mineral availability. This study investigated the direct effects of inter-row subsoiling, biological subsoiling and a combination of these two methods on soil penetration resistance, root length density, nitrogen uptake and yield. In field experiments with potatoes in 2013 and 2014, inter-row subsoiling (subsoiler) and biological subsoiling (preceding crops) were studied as two potential methods to reduce soil penetration resistance. Inter-row subsoiling was carried out post planting and the preceding crops were established one year, or in one case two years, prior to planting. Soil resistance was determined with a penetrometer three weeks after the potatoes were planted and root length density was measured after soil core sampling 2 months after emergence. Nitrogen uptake was determined in haulm (at haulm killing) and tubers (at harvest). Inter-row subsoiling had the greatest effect on soil penetration resistance, whereas biological subsoiling showed no effects. Root length density (RDL) in the combined treatment was higher than in the separate inter-row and biological subsoiling treatments and the control, whereas for the separate inter-row and biological subsoiling treatments, RLD was higher than in the control. Nitrogen uptake increased with inter-row subsoiling and was significantly higher than in the biological subsoiling and control treatments. However, in these experiments with a good supply of nutrients and water, no yield differences between any treatments were observed.     

Evaluating biodegradability of soil organic matter by its thermal stability and chemical composition

The stability of soil organic matter (SOM) as it relates to resistance to microbial degradation has important implications for nutrient cycling, emission of greenhouse gases, and C sequestration. Hence, there is interest in developing new ways to quantify and characterise the labile and stable forms of SOM. Our objective in this study was to evaluate SOM under widely contrasting management regimes to determine whether the variation in chemical composition and resistance to pyrolysis observed for various constituent C fractions could be related to their resistance to decomposition. Samples from the same soil under permanent pasture, an arable cropping rotation, and chemical fallow were physically fractionated (sand: 2000-50 μm; silt: 50-5 μm, and clay: <5 μm). Biodegradability of the SOM in size fractions and whole soils was assessed in a laboratory mineralization study. Thermal stability was determined by analytical pyrolysis using a Rock-Eval pyrolyser, and chemical composition was characterized by X-ray absorption near-edge structure (XANES) spectroscopy at the C and N K-edges. Relative to the pasture soil, SOM in the arable and fallow soils declined by 30% and 40%, respectively. The mineralization bioassay showed that SOM in whole soil and soil fractions under fallow was less susceptible to biodegradation than that in other management practices. The SOM in the sand fraction was significantly more biodegradable than that in the silt or clay fractions. Analysis by XANES showed a proportional increase in carboxylates and a reduction in amides (protein) and aromatics in the fallow whole soil compared to the pasture and arable soils. Moreover, protein depletion was greatest in the sand fraction of the fallow soil. Sand fractions in fallow and arable soils were, however, relatively enriched in plant-derived phenols, aromatics, and carboxylates compared to the sand fraction of pasture soils. Analytical pyrolysis showed distinct differences in the thermal stability of SOM among the whole soil and their size fractions; it also showed that the loss of SOM generally involved preferential degradation of H-rich compounds. The temperature at which half of the C was pyrolyzed was strongly correlated with mineralizable C, providing good evidence for a link between the biological and thermal stability of SOM.     

浅谈生物技术专业物理化学教学改革的探索

作者根据生物技术专业培养目标,从教育创新的角度出发,对物理化学在生物技术专业中重要作用及基础地位进行了阐述,并通过对学科特点的深入理解,结合学校实际情况,从课程体系、教学内容及方法、科学评价体系、理论教学与生产实际相结合四个方面着手对物理化学课程的改革,重点探讨生物技术专业物理化学教学的改革方向,以及如何培养适应实际生...     

Environmental stress response limits microbial necromass contributions to soil organic carbon

The majority of dead organic material enters the soil carbon pool following initial incorporation into microbial biomass. The decomposition of microbial necromass carbon (C) is, therefore, an important process governing the balance between terrestrial and atmospheric C pools. We tested how abiotic stress (drought), biotic interactions (invertebrate grazing) and physical disturbance influence the biochemistry (C:N ratio and calcium oxalate production) of living fungal cells, and the subsequent stabilization of fungal-derived C after senescence. We traced the fate of ¹³C-labeled necromass from ‘stressed’ and ‘unstressed’ fungi into living soil microbes, dissolved organic carbon (DOC), total soil carbon and respired CO₂. All stressors stimulated the production of calcium oxalate crystals and enhanced the C:N ratios of living fungal mycelia, leading to the formation of ‘recalcitrant’ necromass. Although we were unable to detect consistent effects of stress on the mineralization rates of fungal necromass, a greater proportion of the non-stressed (labile) fungal necromass C was stabilised in soil. Our finding is consistent with the emerging understanding that recalcitrant material is entirely decomposed within soil, but incorporated less efficiently into living microbial biomass and, ultimately, into stable SOC.     

Contrasting development of soil microbial community structure under no-tilled perennial and tilled cropping during early pedogenesis of a Mollisol

A range of agricultural practices influence soil microbial communities, such as tillage and organic C inputs, however such effects are largely unknown at the initial stage of soil formation. Using an eight-year field experiment established on exposed parent material (PM) of a Mollisol, our objectives were to: (1) to determine the effects of field management and soil depth on soil microbial community structure; (2) to elucidate shifts in microbial community structure in relation to PM, compared to an arable Mollisol (MO) without organic amendment; and (3) to identify the controlling factors of such changes in microbial community structure. The treatments included two no-tilled soils supporting perennial crops, and four tilled soils under the same cropping system, with or without chemical fertilization and crop residue amendment. Principal component (PC) analysis of phospholipid fatty acid (PLFA) profiles demonstrated that microbial community structures were affected by tillage and/or organic and inorganic inputs via PC1 and by land use and/or soil depth via PC2. All the field treatments were separated by PM into two groups via PC1, the tilled and the no-tilled soils, with the tilled soils more developed towards MO. The tilled soils were separated with respect to MO via PC1 associated with the differences in mineral fertilization and the quality of organic amendments, with the soils without organic amendment being more similar to MO. The separations via PC1 were principally driven by bacteria and associated with soil pH and soil C, N and P. The separations via PC2 were driven by fungi, actinomycetes and Gram (−) bacteria, and associated with soil bulk density. The separations via both PC1 and PC2 were associated with soil aggregate stability and exchangeable K, indicating the effects of weathering and soil aggregation. The results suggest that in spite of the importance of mineral fertilization and organic amendments, tillage and land-use type play a significant role in determining the nature of the development of associated soil microbial community structures at the initial stages of soil formation.