Thermodynamic modeling of the partitioning of biomolecules in aqueous two-phase systems using a modified Flory–Huggins equation

A modified Flory–Huggins equation accounting for the solvation of polymer molecules by water molecules was used to model the phase behavior of aqueous two-phase systems (ATPS) formed by poly(ethylene glycol) (PEG) and dextran. The parameters of the equation were obtained by fitting experimental equilibrium data either accounting for or disregarding dextran polidispersity. The modified equation was subsequently applied to calculate partition coefficients of biomolecules in these systems. It was found that accounting for polidispersity did not affect significantly the calculated phase equilibrium, but increased the agreement of calculated partition coefficients with experimental data. Further improvement was obtained by using a size dependent interaction parameter for dextran pseudo-components.     

不同畦长灌溉对小麦耗水特性及产量的影响

在2009-2010和2010-2011年小麦生长季,设置10、20、40、60、80和100 m 6个畦田长度,研究不同畦长对小麦耗水特性及产量的影响.结果表明： ≤80 m畦长处理下,随畦长的增加,灌水量逐渐增加,灌水量占总耗水量的比例增加,土壤贮水消耗量减少,小麦拔节至开花期的耗水量和生长季总耗水量均减少,开花期0～200 cm各土层土壤含水量增加,土壤供水能力提高,籽粒产量和水分利用效率逐渐提高.与80 m畦长处理相比,<80 m畦长处理的灌水量少,上层土壤含水量低,促使小麦吸收更多的深层贮水,总耗水量增加,不利于节水;而100 m畦长处理的灌水量、土壤贮水消耗量和总耗水量均增加,由于一次性灌水量过多且灌溉水分布不均匀,导致小麦千粒重降低,籽粒产量和水分利用效率显著下降,也不利于节水高产.     

不同带长微喷带灌溉对土壤水分布与冬小麦耗水特性及产量的影响

于2010-2012年度冬小麦生长季,选用高产冬小麦品种济麦22,采用测墒补灌方式,设置40 m(T₄₀)、60 m(T₆₀)和80 m(T₈₀)3种带长的微喷带灌溉处理,研究不同带长微喷带灌溉对土壤水分分布及冬小麦耗水特性和产量的影响.结果表明： 拔节期和开花期采用微喷带补灌,随微喷带带长缩短,灌溉水在土壤中的水平分布均匀系数显著增加.拔节期补灌,T₄₀和T₆₀处理在距畦首0～40 m范围内各小麦行间的0～200 cm土层土壤含水量均无显著差异;T₈₀处理在距畦首38～40 m、58～60 m和78～80 m处各小麦行间的0～200 cm各土层土壤含水量变化规律一致,均表现为随距微喷带的距离增加而减小.T₄₀处理的小麦在拔节至开花期间和开花至成熟期间分别对40～60 cm和20～80 cm土层土壤贮水的消耗量显著高于T₆₀和T₈₀处理,而对深层土壤贮水消耗量和总土壤贮水消耗量、开花期补灌水量、总灌水量和总耗水量显著低于T₆₀和T₈₀处理.随微喷带带长缩短,小麦籽粒产量、产量水分利用效率显著升高,而流量降低,在灌水量一定的情况下,单位时间内的有效灌溉面积减小.综合考虑小麦籽粒产量、水分利用效率和流量,40和60 m是本试验条件下的适宜微喷带带长.     

A methodology for measuring drainage and nitrate leaching in unevenly irrigated vegetable crops

The objective of our study was to establish a methodology to determine drainage and nitrate leaching in unevenly irrigated vegetable crops. It was conducted in a tomato crop (Lycopersicum esculentum Mill) with drip irrigation in the summer of 2000 in the Ebro Valley, Spain. Two soil management techniques and two irrigation treatments were evaluated bare soil (S1) and soil mulched with black plastic (S2), with irrigation calculated according to the Crop Evapotranspiration (ETc) for bare soil (R1) and for mulched soil (R2). Volumetric soil water content (θv) was measured weekly to 1 m depth in six positions transverse to the drip line. Drainage was calculated by applying the water balance equation to the data from: (i) all six positions (method 1) and (ii) to the positions located under the plants and between the rows, respectively (method 2). Soil solution was extracted at 1 m depth with porous ceramic cups and analysed for nitrate. Nitrate leached to 1 m depth was calculated as the product of volume of drainage accumulated weekly and the nitrate concentration of the soil solution. Drainage and nitrate leaching were evaluated for two different crop periods crop establishment and crop growth. Method 2 produced results that were not significantly different from those from method 1. However, method 1 was more accurate and identified more differences between treatments. The greater drainage occurred during the crop establishment period, which also favoured the leaching of nitrates previously stored in the soil profile and later applied as fertilizer before planting. During establishment the crop was unable to use all available nitrate and the quality of groundwater deteriorated. The results suggest that further studies are required to adjust crop coefficients (Kc) to the actual needs of tomato crops grown with drip irrigation under bare soil and plastic mulching conditions.     

内蒙古典型草原作物系数的动态模拟与确定

作物系数是计算作物需水量必不可少的参数。利用2008年野外水分试验和4个气象站近26年的土壤水分和气象等常规观测资料, 以相关分析和回归分析等统计学方法为基础, 根据水量平衡原理计算了内蒙古典型草原区的作物系数, 分析了其在生长期和不同站点间的变化规律; 建立了典型草原标准作物系数与返青后年日数和大于0 ℃积温的模拟方程, 相关指数在0.94以上。在分析湿润指数、叶面积指数和盖度与作物系数关系的基础上, 提出标准作物系数的气候修正方法和胁迫条件下作物系数的修正方法。同时, 与修正后的联合国粮农组织(FAO)推荐值比较后得出, 生长季标准作物系数的平均值为0.60, 最大值为1.02; 不同生长阶段作物系数的典型值分别为: 初始生长期0.40, 生长中期0.93, 生长后期0.80, 相应的阈值范围为0.35-0.45、0.85-1.00和0.70-0.90。通过旬蒸散量的模拟计算值与蒸渗仪实测结果的比较, 平均相对误差在20%-24%之间, 生长旺盛期大多低于10%, 从而初步证明该文提出的方法在内蒙古典型草原区有较好的适用性。     

Mass-energy balance of the growth of phototropic purple bacteria

The principles of the theory of mass-energy balance of the growth of cellular populations are described. Based on this theory, the effect of biochemical parameters of cell metabolism on the efficiency of phototrophic growth of bacterial culture was studied. The metabolism of phototrophic bacteria was subdivided into constructive and energetic partial metabolisms. The stoichiometric coefficients describing the energetics of the two metabolism types were calculated. An equation system of the mass-energy balance for the flows of reductivity, high-energy bonds, and protons--carriers of the transmembrane electrochemical potential was derived. Equations for biomass quantum yield were obtained. The calculated yield values are in agreement with experimental data.     

黄淮平原冬小麦灌溉需水量的影响因素与不同年型特征

以黄淮平原区80个气象站点46～54年的降水资料和10个站点100 cm深度的土壤湿度资料为基础,运用麦田水分平衡原理,分析了冬小麦灌溉需水量与冬小麦需水量、生育期降水量和土壤底墒水的关系,并就不同气候年型分析了冬小麦灌溉需水量的变化特征.结果表明:黄淮平原冬小麦灌溉需水量等值线基本呈纬向分布,自南向北逐渐增大.正常年零值线位于许昌、扶沟、柘城,鹿邑、亳州、萧县至徐州一带,此线附近冬小麦需水量和供水量基本平衡,可以不进行灌溉或进行少量灌溉;此线以北则必须进行灌溉,其灌溉量愈向北愈大,依次为60～100和100～190 mm,要分别灌1～2水和2水;此线以南,可不进行灌溉.丰水年零值线北移约0.5～1.0个纬度,全区灌溉面积和灌溉量明显减小.欠水年零值线南移约1.0～1.5个纬度,灌溉面积和灌溉量显著增大.

Abstract：

By using the last 46-54 years precipitation data from 80 meteorological stations and the 0-100 cm soil water content data at 10 stations in the Huanghuai Plain, the relationships be-tween the irrigation water requirement and water requirement by winter wheat, and between the precipitation in winter wheat growth season and the soil water content at planting time were ana-lyzed, based on the principles of farmland water balance. In the meantime, the characteristics of irrigation water requirement by winter wheat in different climatic years were studied. In the study area, the isoline of irrigation water requirement by winter wheat was basically in latitudinal distri-bution, with the requirement increased gradually from .south to north. In normal years, the zero isoline was located in Xuchang-Fugou-Zhecheng-Luyi-Bozhou-Xiaoxian-Xuzhou. Along this line, the water requirement by winter wheat was in balance with water supply, and no or less irrigation was required. However, in the north of this line, irrigation should be made, with the irrigation a-mount increased northward, being about 60-100 mm and 100-190 mm and irrigating 1-2 times or 2 times. In the south of this line, no irrigation was required. In the years of plentiful precipita-tion, the zero isoline moved northward by 0. 5-1.0 latitude, and the irrigation area and irrigation amount decreased obviously; while in the years of short precipitation, the zero isoline moved south-ward by 1.0-1.5 latitude, and the irrigation area and irrigation amount increased obviously.     

基于温度的作物需水量估算方法

科学准确地估算作物需水量是灌溉预报和农业用水管理的基础,本文探索如何充分利用温度这一定量信息估算作物需水量,并对不同时间尺度的估算精度进行评判分析,以更好地服务于灌区的灌溉预报和水土资源管理.利用新乡市1970—2010年的气象数据对Hargreaves公式的3个基本参数和McClound公式的2个参数进行了订正;针对冬小麦生育期,筛选出Hargreaves公式作为参考作物需水量（ET₀）的估算方法,然后结合基于温度的作物系数计算模型建立了基于温度的作物需水量计算模型,根据2011年10月—2012年5月新乡气象和灌溉试验资料对不同时间尺度（1、3、7 d）的ET_c进行了预测和精度评估.结果表明： 1、3、7 d ET_c的预测值与实测值的相关系数分别达到0.883、0.933、0.959,一致性指数分别达到0.94、0.95、0.97,预测误差随时间尺度增大而减小,误差<1 mm·d^-1的预报准确率均>80%,误差<2 mm·d^-1的预报准确率均>90%,各时间尺度的预报精度都较高,可为灌区灌溉预报和农业用水管理提供较为可靠的数据支撑.     

灌溉量对苹果园内紫花苜蓿生物量与生理特征的影响

以苹果园内2年生紫花苜蓿为材料,设0.150、0.225(正常水平)和0.300m3/m2共3个灌溉量处理,研究不同灌溉量对紫花苜蓿生物量、光合生理指标、叶绿素含量、脯氨酸含量及电导率的影响。结果显示:(1)灌溉量对紫花苜蓿地上生物量有显著的影响,且随灌溉量的增加而增加;灌溉量大的处理苜蓿吸收根分布有浅层化趋势。(2)不同灌溉量处理的紫花苜蓿叶片净光合速率(Pn)与光合有效辐射(PAR)的变化趋势基本一致,均表现为在低PAR时Pn迅速增加,达到一定PAR后,Pn增幅渐趋平缓;净光合速率均随灌水量的增加而增加。(3)灌溉后土壤含水率和苜蓿叶片叶绿素含量随灌溉量的增加而升高,苜蓿叶片相对电导率随着灌水量的增加而呈现降低的趋势,低灌溉量可导致紫花苜蓿叶片中脯氨酸含量大量积累。研究表明,适当的灌溉可以有效改善苹果园土壤水分状况,提高紫花苜蓿光合生产力。     

Opportunities for woody crop production using treated wastewater in Egypt. II. Irrigation strategies

An Egyptian national program targets annual reuse of 2.4 billion m3 of treated wastewater (TWW) to irrigate 84,000 ha of manmade forests in areas close to treatment plants and in the desert. To evaluate the feasibility of such afforestation efforts, we describe information about TWW irrigation strategies based on (1) water use of different tree species, (2) weather conditions in different climate zones of Egypt, (3) soil types and available irrigation systems, and (4) the requirement to avoid deep percolation losses that could lead to groundwater contamination. We conclude that drip irrigation systems are preferred, that they should in most cases use multiple emitters per tree in order to increase wetted area and decrease depth of water penetration, that deep rooting should be encouraged, and that in most situations irrigation system automation is desirable to achieve several small irrigations per day in order to avoid deep percolation losses. We describe directed research necessary to fill knowledge gaps about depth of rooting of different species in sandy Egyptian soils and environments, tree crop coefficients needed for rational irrigation scheduling, and depth of water penetration under different irrigation system designs. A companion paper addresses recommendations for afforestation strategies (see Zalesny et al. 2011, this issue).     

引黄灌区土壤有机碳密度剖面特征及固碳速率

为揭示灌溉耕作对土壤有机碳密度剖面(0—100 cm)分布产生的影响,通过在宁夏引黄灌区进行实地调查与采样,以无灌溉耕作的自然土壤作为对照,研究不同灌溉耕作时间序列下灌区土壤有机碳密度的剖面分布特征,并估算其平均固碳速率。结果表明:灌区土壤有机碳含量具有随土层深度增加而下降的剖面分布特征,灌溉耕作对增加表层土壤有机碳含量作用最明显;灌区土壤剖面碳密度与灌溉耕作时间和土壤类型均显著相关(P0.01),相关系数分别为0.63和0.74,且因灌溉耕作时间和土壤类型的不同,土壤有机碳密度差异性显著(P0.05);灌溉耕作影响的土层深度及剖面土壤有机碳密度的增加量因灌溉耕作时间长短的不同而异;引黄灌区5类土壤的平均固碳速率为0.53 MgC·hm-2·a-1。引黄灌溉耕作在增加农田土壤固碳中发挥着重要作用。     

农田灌溉对气候的影响研究综述

过去200年全球灌溉农田面积迅速扩张,灌溉对气候的影响逐渐受到世界各国研究者的关注。回顾了过去有关灌溉对气候的影响研究,归纳了前人的研究手段,指出了目前研究中存在的问题和困难,并提出了未来灌溉对气候的影响研究应该注重如下几个方面:1)同时利用观测数据分析方法和模型模拟研究方法进行灌溉对区域气候的影响,并将两者的结果进行对比分析,以求做到互相验证;2)对于缺乏地面观测数据或者地面数据受其他因素(比如:城市化)影响大的区域,建议利用遥感观测数据进行灌溉对地表参数的影响研究;3)注意对灌溉四大属性(灌溉位置、灌水量、灌溉方式和灌溉时间)的精确模拟,可以考虑耦合气候模型和作物模型进行模拟研究,并注意区分灌溉旱地和灌溉水田。4)提倡利用多模式集合的方式研究灌溉对区域气候的影响,以减少灌溉对气候影响(强度和方向)模拟结果的不确定性;5)未来也应该考虑模拟灌溉和气候变化间的互馈影响。     

Much Improved Irrigation Use Efficiency in an Intensive Wheat-Maize Double Cropping System in the North China Plain

Crop yield and water use efficiency （WUE） in a wheat-maize double cropping system are influenced by short and uneven rainfalls in the North China Plain （NCP）, A 2-year experiment was conducted to investigate the effects of irrigation on soil water balance, crop yield and WUE to improve irrigation use efficiency in the cropping system, Soil water depletion （~SWS） by crop generally decreased with the increase of irrigation and rainfall, while ASWS for the whole rotation was relatively stable among these irrigation treatments, High irrigations in wheat season increased initial soil moisture and ASWS for subsequent maize especially in the drought season, Initial soil water influenced mainly by the irrigation and rainfall in the previous crop season, is essential to high yield in such cropping systems, Grain yield decreased prior to evapotranspiraUon （ET） when ET reached about 300mm for wheat, while maize showed various WUEs with similar seasonal ET, For whole rotation, WUE declined when ET exceeded about 650 mm, These results indicate great potential for improving irrigation use efficiency in such wheat-maize cropping system in the NCP, Based on the present results, reasonable irrigation schedules according to different annual rainfall conditions are presented for such a cropping system.     

Much Improved Irrigation Use Efficiency in an Intensive Wheat-Maize Double Cropping System in the North China Plain

Crop yield and water use efficiency (WUE) in a wheat-maize double cropping system are influenced by short and uneven rainfalls in the North China Plain (NCP). A 2-year experiment was conducted to investigate the effects of irrigation on soil water balance, crop yield and WUE to improve irrigation use efficiency in the cropping system. Soil water depletion (△SWS)by crop generally decreased with the increase of irrigation and rainfall, while △SWS for the whole rotation was relatively stable among these irrigation treatments. High irrigations in wheat season increased initial soil moisture and △SWS for subsequent maize especially in the drought season. Initial soil water influenced mainly by the irrigation and rainfall in the previous crop season, is essential to high yield in such cropping systems. Grain yield decreased prior to evapotranspiration(ET) when ET reached about 300 mm for wheat, while maize showed various WUEs with similar seasonal ET. For whole rotation, WUE declined when ET exceeded about 650 mm. These results indicate great potential for improving irrigation use efficiency in such wheat-maize cropping system in the NCP. Based on the present results, reasonable irrigation schedules according to different annual rainfall conditions are presented for such a cropping system.     

一种改良的质粒DNA小量提取法

对碱裂质粒小量法进行了改进,并且在提取过程中增加了ＬｉＣｌ处理。实验证明这种方法结果稳定,提取的质粒ＤＮＡ产量高、质量好,符合大多数分子生物学常规实验的要求。     

水肥异区交替灌溉对夏玉米生理指标的影响

以夏玉米品种‘户单4号'为材料,通过防雨棚内微区试验研究了两种灌水量(450 m~3/hm~2和900 m~3/hm~2)条件下水肥异区交替灌溉和均匀灌溉对夏玉米生长以及某些生理指标的影响.结果显示:(1)在节水50%的条件下,水肥异区交替灌溉与高灌水量均匀灌溉的夏玉米生物量、产量均无显著差异.(2)低灌水量时,水肥异区交替灌溉下的玉米根系伤流液、叶片可溶性蛋白含量、硝酸还原酶活性、光合速率、蒸腾速率等均高于均匀灌溉施肥处理,而植株全氮含量及叶片水分利用效率与均匀灌溉施肥的差异不显著.(3)高灌水量时,水肥异区交替灌溉处理除根系活力、光合速率以及蒸腾速率高于均匀灌溉处理外,其他指标均低于后者.研究表明,在低灌水量条件下,水肥异区交替灌溉能使夏玉米保持较高的根系活力和正常生理代谢,提高其叶片水分利用效率,从而达到了节水增产的目的.     

Influence of Long Term Irrigation with Pulp and Paper Mill Effluent on the Bacterial Community Structure and Catabolic Function in Soil

Microbial communities play a vital role in maintaining soil health. A multiphasic approach to assess the effect of pulp and paper mill effluent on both the structure and function of microbial soil communities is taken. Bacterial communities from agricultural soils irrigated with pulp and paper mill effluent were compared to communities form soils irrigated with well water. Samples were taken from fields in the state of Uttarakhand, India, where pulp and paper mill effluent has been used for irrigation for over 25 years. Comparisons of bacterial community structure were conducted using sequencing of the 16S rRNA gene from both isolates and clone libraries attained from the soil. Community-level physiological profiling was used to characterize the functional diversity and catabolic profile of the bacterial communities. The multiphasic approach using both physiological and molecular techniques proved to be a powerful tool in evaluating the soil bacterial community population and population differences therein. A significant and consistent difference in the population structure and function was found for the bacterial communities from soil irrigated with effluent in comparison to fields irrigated with well water. The diversity index parameters indicated that the microbial community in pulp and paper mill effluent irrigated fields were more diverse in both structure and function. This suggests that the pulp and paper mill effluent is not having a negative effect on the soil microbial community, but in fact may have a positive influence. In terms of soil health, this finding supports the continued use of pulp and paper mill effluent for irrigation. This is however only one aspect of soil health which was evaluated. Further studies on soil resistance and robustness could be undertaken to holistically evaluate soil health in this situation.     

森林蒸散模型参数的确定

以长白山阔叶红松林为研究对象,利用长白山阔叶红松林气象观测塔安装的常规气象梯度观测系统、开路涡动相关系统的观测数据,依据空气动力学基本理论与能量平衡方程建立了森林蒸散机理模型,确定了模型参数,即风速廓线稳定度订正函数ψm、温度廓线稳定度订正函数ψh和零平面位移高度d。其中,研究地的零平面位移高度d为17．8m,是平均冠层高度(26m)的0．68。同时,给出了ψm和ψh随梯度理查逊数Ri变化的数学表达式。     

交替灌溉的节水调质机理及同位素技术在作物水分利用研究中的应用

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