淡水渔业与水体气候的关系

以生态观战简述了淡水渔业中水体气候的若干问题；研究鱼类的生长环境应以水体的生态气候因子为可靠依据；我国淡水鱼类依温度生态型的差异有不同适宜生长分布区；各地水体因光，热差别产生不同有浮游植物气候生产力，淡水渔业气候区划主要应以水体气候资源特征及其对鱼类分布，生长和对水体初级生产力的影响为依据。     

五种气候生产力模型在华北土石山区的适用性分析

植被净初级生产力(Net Primary Productivity,NPP)是陆地植物的净固碳量,对于全球碳估算研究具有重要意义。华北土石山区作为中国林业工程重点区域,是典型的干旱半干旱气候区,准确估算该地区NPP大小及其变化特征对林业生态工程建设具有重要意义。本文基于河南小浪底森林生态系统国家野外科学观测研究站1980-2020年气候数据,利用Miami模型、Thornthwaite Memorial模型、Chikugo模型、朱志辉模型及周广胜模型共5种气候生产力模型估算,分析NPP的变化趋势,运用随机森林算法探讨NPP影响因素,并以区域MODIS NPP数据为标准进行评价,以探究适合估算该地区NPP的气候生产力模型。结果表明：(1)华北土石山区年平均气温、最高气温、最低气温和降水量均呈上升趋势,变化速率分别为0.05℃·a^-1、0.04℃·a^-1、0.05℃·a^-1和1.58mm·a^-1;年平均太阳辐射和平均相对湿度则呈下降趋势,变化速率分别为0.46MJ·m^-2·a     

水稻气候生产力对气候变暖的响应问题的模拟计算

模拟计算了未来2×CO_2气候情景下我国南方两种种植方式下(自动灌水和雨育),双季稻和单季稻气候生产力的变化,得出了在现有品种不变前提下水稻气候生产力普遍有所下降的结论.造成下降的主要原因依次为:生育期缩短、呼吸消耗加大和光合作用减弱,尤以双季稻更明显.考虑了大气中CO_2浓度提高对水稻光合作用的正效应,这种下降又有不同程度的减缓.     

南繁甜菜块根气候生态与产质量关系的研究

对露地越冬甜菜(简称南繁甜菜)块根的气候生态及其与产量、质量的关系进行研究.结果表明:南繁块根年前增长大于翌年增长比例是甜菜种子增产的生物学基础.因南繁生态环境下的甜菜块根增长曲线呈双峰型,而翌年块根大量增长影响其生殖生长,应予控制.利用其内在的制约关系,“扬前”潜在效应是“抑后”.冬前积温(x)与块根直径(y)呈极好的线性相关,其公式为y=-3.157 0.004x,计算得,冬前积温每增加250度??日,块根直径增长1cm.冬前块根与采种株产、质量关系密切,较大块根为建立良好株型创造条件,控制翌年块根增长,协调营养和生殖生长的养分分配,结实性状良好,增产优质效果明显.因而得出,培育冬前大中块根是获取高产优质甜菜种子的基础.     

黄土丘陵沟壑区气候与气候生产力变化分析--以延安市为例

通过整理延安宝塔区1980-2007年气象资料,在分析延安气候变化趋势的基础上,应用Thornthwaite Memorial模型,计算了气候生产力变化情况。结果表明,该区降雨量以2．73mm／a的速度递减,气温以0．05℃／a的速度递增,风速和相对湿度的变化趋势是逐年递减,日照时数的变化趋势是逐年递增。气候生产力总体呈增加趋势,但递增幅度不显著;降雨量是该区气候生产力提高的主要限制因子,“暖湿型”气候对作物气候生产力最有利。     

我国甘蔗的气候生产力特征分析

根据广西柳州９县１９５２～１９９０年甘蔗逐年产量和７县２５年含糖量资料，在采用方差分析和滑动相关分析确定影响甘蔗产量和品质的关系发育期及气候影响因素的基础上，建立气候影响方程，并提出气候产量和气候含糖量的影响指数（Ｃｙ与Ｃｓ）。结合甘蔗产区３８站１７年气象整编资料，对我国蔗区作出气候生产力分析和区划，为今后扩大甘蔗种植面积提高单产和品质提供切实有效的分析数据。     

我国近40年降水的变化及对气候生产力的影响

本文采用1950--1990年全国大体分布均匀的350个站的降水资料,分析了近40年我国降水量的时空变化特征及不同年代降水量对植物气候生产潜力的影响。     

云南省野生食用菌气候生境特征与评价

云南省地处低纬,属高原山区。受地理和季风气候的共同影响,境内光热资源丰富、气候立体、干湿分明、雨热同季,为野生食用菌生长提供了优质的气候生境。为揭示云南省野生食用菌气候生境特征及其与全国部分野生食用菌产地间的气候生境差异,选取了云南省125个县及全国部分野生食用菌产地(5—10月)的气温、地温、降水、日照、湿度和海拔高度,进行多因子影响的主成分分析、干燥度计算和单个气象因子分析,最后在arcgis平台上做IDW插值。结果得出:云南省野生食用菌菌丝体向子实体过渡初期光、热量充足,干湿转换明显,子实体收获期长,收获盛期热量和降水适中,且变幅小,昼夜温差大。晴雨交错的野生食用菌气候生境特征惟云南独有,并可大致划分为滇中以北高海拔冷凉气候生境区、滇中及周边中海拔温暖气候大宗菌类生境区和滇南温热气候生境区;其中滇中楚雄州为中心向东西延伸的同纬度、同海拔地带的5月、6月、7—9月的平均气温为20℃、21℃、20℃,降水量为80 mm、150 mm、480 mm,相对湿度为67%、77%、83%,日照时数为220 h、160 h、380 h,与野生食用菌最适宜气温、降水和空气湿度条件一致,是云南省野生食用菌大宗品种丰富区和产量最高区。     

The relation between the moisture-release curve and the structure of soil

The limit to the precision with which moisture-release data may be related to soil structure is examined. Thin sections in two orthogonal planes were prepared from cores for which moisture release data and saturated conductivity measurements were also collected. Structural parameters are inferred indirectly through estimation of the mass fractal dimension from the moisture-release curve, and directly through measurement of the scaling properties of the pore space and solid matrix from the thin sections using image analysis. Theoretical results are presented which show that, in the absence of additional information, the interpretation of the moisture-release curve is ambiguous for several reasons. A power-law exponent is a consequence of either a fractal pore volume; a fractal solid volume; a fractal pore wall; or a non-fractal, self-similar pore wall, and one cannot infer from the measurement which is the case. Experimental results are presented which confirm that direct measurement of the fractal dimension of the solid matrix is a good predictor of the Brooks–Corey exponent for the soils studied here. Therefore, although a specific structural parameter characterizes the moisture-release curve, the latter cannot be used as a detailed measure of soil structure.     

夹持式鲜菱角脱壳机设计与试验

针对鲜菱角手工脱壳率低、菱仁损伤率高等问题,该研究以湖北省浠水县两角菱为对象,设计了一种夹持式鲜菱角脱壳机。对鲜菱角外形尺寸和力学性能参数进行了测量,确定采用夹持板与链条夹持输送、圆形齿刀横切菱角两侧弯角、对辊挤压碾搓脱壳的技术方案。对夹持板、弹性压紧装置、横切刀片和脱壳装置等主要部件结构进行设计和分析,确定了结构和运动参数。运用ANSYS Explicit Dynamics模块对横切过程进行仿真,根据理论分析和仿真结果试制了脱壳样机,开展了横切试验和脱壳试验。横切试验表明,成熟度、输送速度和刀片转速均对切壳率影响显著（P<0.05）,对菱仁损失率影响不显著（P>0.05）。运用Design Expert 12优化得横切装置最优工作参数为：脆熟菱角、输送速度0.1 m/s、刀片转速1 000 r/min,该参数下的平均切壳率为79.41%,平均菱仁损失率为9.82%。采用Box-Benhnken试验设计开展三因素二次回归正交组合试验,优化得到脱壳装置最优工作参数为：脆熟菱角、慢辊转速59r/min,线速比1.5,验证试验的平均脱壳率为66.52%,平均菱仁破损率为12.83...     

Interactions between climate and desertification

Deserts are known to mankind, but the term desertification has always been an elusive concept. It is now defined in the United Nations Convention to Combat Desertification (UNCCD) as land degradation in the drylands (land falling within arid, semi-arid and dry sub-humid areas) resulting from various factors, including climatic variations and human activities. This definition, which is now being used worldwide to describe desertification and its impacts, leads to the need to consider carefully the two-way interactions between climate and desertification. Dramatic changes in agricultural practices during the last several decades are one of the main driving forces for land degradation in the drylands and examples of land degradation are given for several regions around the world. The effects of desertification on climate have been described mainly in terms of changes in land use and land cover leading to land degradation; overgrazing; biomass burning and atmospheric emissions; agriculture's contribution to air pollution; forest and woodland clearing and accelerated wind erosion; anthropogenic land disturbances and wind erosion; and the impact of irrigated agriculture on surface conditions in drylands. It is equally important to consider the impact of dryland climates on soils and vegetation and the impact of climate change on desertification. It is important to adopt uniform criteria and methods to assess desertification and encourage monitoring of dryland degradation in all the regions around the world. To better understand the interactions between climate and desertification, it is also important to identify the sources and sinks of dryland carbon, aerosols and trace gases in drylands.     

Effects of salt water cooling tower drift on water bodies and soil

Detailed calculations of possible incremental increase in the salinity of soil, irrigation water and bodies of fresh water due to the operation of salt water cooling towers are discussed. The calculations make use of water balance equations and empirical relations to determine the soil salinity. Salt deposition levels from a typical 1000 MWe natural and mechanical draft cooling towers with a water circulation rate of 31.5 m³ s^?1 and drift rate of 0.002 % of the total circulating water were calculated using current available deposition models. The results obtained from these calculations indicate that the incremental effects of salt water cooling towers upon the surrounding soil and water are generally minimal, if the drift rate is controlled by appropriate eliminators. Some extreme cases may develop under severe weather conditions, but these will be infrequent and will represent a small fraction of the total operating time.     

The relation between soil acidification and element cycling

Controversy about the contribution of acidic deposition to soil acidification partly arises from different concepts of soil acidification. Differentiating between actual and potential soil acidification has proved to be appropriate for properly identifying and quantifying the natural and anthropogenic sources of protons. Actual soil acidification is primarily manifested by leaching of cations from the soil, regulated by the mobility of major anions. Leaching of HCO₃ ^? and RCOO^? occurs naturally whereas leaching of NO₃ ^? and SO₄ ^2? is mainly caused by land use in agricultural soils and by acidic deposition in forest soils. Potential soil acidification is primarily due to accumulation of atmospherically derived N and S. This potential acid threat is partly realized by mineralization processes after the removal of vegetation.     

考虑品种差异的冷鲜猪肉含水率高光谱信号补正算法

为提高含水率高光谱校正模型对不同品种冷鲜猪肉样本的适用性,该文提出了1种品种敏感波段选择结合分段直接校正的高光谱信号补正方法。首先用主品种偏最小二乘回归模型和添加了7个从品种样本后更新模型的模型回归系数相对差异值,以此选出对品种敏感的波段,然后采用分段直接校正算法对选中波段的光谱信号补正,以消除品种差异对模型预测效果的影响。以猪肉含水率为检测指标,以零号土猪肉为主品种,以恩施山黑猪为从品种,经该算法补正后,主品种模型对从品种样本的预测均方根误差从补正前的1.42%减小到0.50%,预测决定系数从0.20提高到0.84,预测偏差比率(residual prediction deviation,RPD)从0.91提高到2.58。结果表明,该文提出的补正算法能显著提高零号土猪肉含水率模型对恩施山黑猪含水率的预测能力。     

The effects of fresh and stabilized pruning wastes on the biomass,structure and activity of the soil microbial community in a semiarid climate

The incorporation of organic amendments from pruning waste into soil may help to mitigate soil degradation and to improve soil fertility in semiarid ecosystems. However, the effects of pruning wastes on the biomass, structure and activity of the soil microbial community are not fully known. In this study, we evaluate the response of the microbial community of a semiarid soil to fresh and composted vegetal wastes that were added as organic amendments at different doses (150 and 300 t ha⁻¹) five years ago. The effects on the soil microbial community were evaluated through a suite of different chemical, microbiological and biochemical indicators, including enzyme activities, community-level physiological profiles (CLPPs) and phospholipid fatty acid analysis (PLFA). Our results evidenced a long-term legacy of the added materials in terms of soil microbial biomass and enzyme activity. For instance, cellulase activity reached 633 μg and 283 μg glucose g⁻¹ h⁻¹ in the soils amended with fresh and composted waste, respectively. Similarly, bacterial biomass reached 116 nmol g⁻¹ in the soil treated with a high dose of fresh waste, while it reached just 66 nmol g⁻¹ in the soil amended with a high dose of composted waste. Organic amendments produced a long-term increase in microbiological activity and a change in the structure of the microbial community, which was largely dependent on the stabilization level of the pruning waste but not on the applied dose. Ultimately, the addition of fresh pruning waste was more effective than the application of composted waste for improving the microbiological soil quality in semiarid soils.     

太湖渔业发展对水环境的影响与对策

阐述了太湖渔业的发展现状,人工放流与封湖休渔对渔业的影响,网围养殖由粗放型向集约型和效益型发展,网围养殖对湖泊的富营养化有较大影响,渔业小型化趋势和低值鱼产量增加趋势明显。并提出太湖渔业治理湖泊富营养化和可持续发展的对策。