Biophysical and economic water productivity of dual-purpose cattle farming

This study analyzes key factors influencing water productivity in cattle rearing, particularly in contexts characterized by water scarcity. This was done through year-round monitoring of on-farm practices within five smallholder farms located in the Saïss area (northern Morocco). The on-farm monitoring protocol consisted of characterizing: (i) volumes of water used for fodder production and distinguished by source (rainfall, surface irrigation and groundwater), (ii) virtual water contained in off-farm feed resources, (iii) total forage biomass production, (iv) dietary rations fed to lactating cows and their calves and (v) milk output and live weight gain. Findings reveal a mean water footprint of 1.62±0.81 and 8.44±1.09 m³/kg of milk and of live weight gain, respectively. Groundwater represented only 13.1% and 2.2% of the total water used to get milk and live weight gain, respectively, while rainfall represented 53.0% and 48.1% of the total water for milk and live weight gain, respectively. The remaining water volumes used came from surface irrigation water (7.4% for milk and 4.0% for live weight gain) and from virtual water (26.5% for milk and 44.7% for live weight gain). The results also revealed a relatively small gross margin per m³ of water used by the herd, not exceeding an average value of US $ 0.05, when considering both milk and live weight. Given the large variability in farm performances, which affect water productivity in cattle rearing throughout the production process, we highlight the potential for introducing a series of interventions that are aimed at saving water, while concurrently improving efficiency in milk production and live weight gain. These interventions should target the chain of production functions that are implemented throughout the process of water productivity in cattle rearing. Moreover, these interventions are of particular importance given our findings that livestock production depends largely upon rainfall, rather than groundwater, in an area afflicted with sustained droughts, overexploitation of groundwater resources and growing water scarcity.     

The water footprint of Tunisia from an economic perspective

This paper quantifies and analyses the water footprint of Tunisia at national and sub-national level, assessing green, blue and grey water footprints for the period 1996–2005. It also assesses economic water and land productivities related to crop production for irrigated and rain-fed agriculture, and water scarcity. The water footprint of crop production gave the largest contribution (87%) to the total national water footprint. At national level, tomatoes and potatoes were the main crops with relatively high economic water productivity, while olives and barley were the main crops with relatively low productivity. In terms of economic land productivity, oranges had the highest productivity and barley the lowest. South Tunisia had the lowest economic water and land productivities. Economic land productivity was found to explain more of the current production patterns than economic water productivity, which may imply opportunities for water saving. The total blue water footprint of crop production represented 31% of the total renewable blue water resources, which means that Tunisia as a whole experienced significant water scarcity. The blue water footprint on groundwater represented 62% of the total renewable groundwater resources, which means that the country faced severe water scarcity related to groundwater.     

基于水足迹的山东省农业水土资源匹配特征及短缺压力分析

高强度农业开发引起的农业水土资源生态问题日益增多,探究粮食及蔬菜（粮蔬）生产中水土资源空间配置及短缺压力对农业资源的可持续利用具有重要意义。从水足迹视角出发,分析了山东省3种主要粮食作物（冬小麦、玉米及大豆）和两种不同种植模式蔬菜（设施蔬菜和露地蔬菜）的生产水足迹空间特征;同时将资源数量及资源质量的概念纳入研究框架,分析了农业水土资源数量及质量匹配格局差异,并进一步探究了农业水土资源短缺压力及其影响因素。研究结果表明：（1）2019年,山东省粮食和蔬菜的生产总水足迹为811亿m³,其中粮食生产总水足迹占比78.50%,蔬菜生产总水足迹占比21.50%;粮蔬生产水足迹受地势影响明显,鲁西北及鲁西南平原地区的粮蔬生产水足迹占比较大。（2）考虑资源数量的水土资源匹配系数均值为0.622×10⁴ m³/hm²,考虑资源质量的匹配系数均值为0.416×10⁴ m³/hm²;水土资源数量及质量匹配系数在空间上呈现出一致性,表明山东省农业生产水土资源空间配置水平高的地区同时面临着较大的农业面源污染压力。（3）整体上,土地资源短缺压力略高于水资源短缺压力;基于生产视角的水土资源短缺压力受生产环境因素制约显著,受经济发展因素的影响具有差异性,社会因素对水土资源短缺压力无显著影响。研究可为农业资源可持续管理提供数据基础,为全面理解粮蔬生产所产生的水土资源短缺提供案例参考。     

Evaluation of water footprint and economic water productivities of dairy products of South Africa

Assessment of water footprint sustainability indicators and economic water productivities is regarded as a cornerstone of the world’s sustainability goal and the reduction of the fresh water scarcity risk. These assessments are gaining much prominence because about four billion people face severe water scarcity, globally. Attaining sustainable and economically efficient water use goals requires a thorough assessment of all the existing sectors that use water. This paper examined the water footprint and economic water productivities of dairy products in South Africa for the periods 1996–2005 and 2006–2013 using the water footprint network assessment methodology. We found the total water footprints of all the selected dairy products in South Africa to be higher than the global averages are. During the period of 1996–2005, South African dairy producers utilized more green water in their dairy production. The production of butter and cheese products, whether grated or not grated, powdered or not powdered, blue-veined and cheese of all kinds had the highest total water footprints among all the dairy products in South Africa. Dairy production under a sole grazing system has high water footprints and low economic water productivities, relative to mixed production systems, for the period 2006–2013. With blue water becoming scarcer in South Africa, it is time for dairy livestock producers to shift their production to a system that is highly productive and has low water footprints. The water footprints of most of the dairy products for period 2006–2013 have reduced by varying amounts, relative to 1996–2005, which shows that water users along the dairy industry chains are managing water cautiously. Our findings have revealed dairy products that have high economic water productivities, and suggest that profit maximising and environmentally sustainable dairy producers and water users should integrate both blue water sustainability and economic water productivity indicators in their production decisions.     

基于灰水足迹的中国城市水资源可持续利用综合评价

随着城市化的快速发展,中国城市水资源面临着水资源短缺与水环境恶化等挑战,因此加强城市水资源可持续利用对于中国可持续发展具有重要意义。基于灰水足迹核算对2016年中国地级市水资源可持续利用情况进行综合评价。研究结果表明：（1）中国城市灰水足迹水平差异大,平均值为23.40×10⁸ m³,主要集中在20.00×10⁸ m³以下。中国城市农业源灰水足迹比例占比主要在70%以上,工业源比例占比主要在20%以下,而生活源比例占比在40%以下;（2）全国灰水经济生产率在12.45-857.31元/m³范围内,地区差异明显。33%城市灰水足迹荷载系数均大于1,全国地级市灰水足迹荷载系数平均值为1.16,城市水资源利用已对水环境产生污染压力,用水不可持续;（3）城市水资源开发率与灰水足迹荷载系数呈一定程度的正相关关系,说明了城市发展对水资源利用的"量"和"质"的压力作用具有一定的协同关系;（4）水资源可持续利用程度呈现大型城市 > 特大型城市 > 超大型城市 > 中小型城市,城市发展一定程度上有助于水资源的可持续利用,但发展规模过大可能会造成用水高产而护水低效的现象。因地制宜的实行水资源循环经济发展模式以及适时纳入灰水足迹核算与管理体系,是当前城市化大背景下实现水资源可持续利用的重要途径。     

Water footprint assessment of sheep farming systems based on farm survey data

Water scarcity is among the main challenges making vulnerable the livestock farming systems in drylands. The water footprint (WF) indicator was proposed as a metric to measure the impacts of livestock production on freshwater resources. Therefore, this study aimed to assess water use in five different Tunisian sheep production systems using the Water Footprint Network methodology. The primary data were obtained from 1050 sheep farms located in 13 Tunisian provinces. A multivariate analysis was performed to characterize the different farming systems. A validation step of the WF modeled values of sheep meat was conducted in 12 sheep farms belonging to two different farming systems. This was done through year-round monitoring of on-farm practices using water metres and recording equipment’s taking into account the direct and indirect water use. The typology analysis came up with five sheep farming systems that are the mixed sheep-cereal (MSC), the agro-sylvo-pastoral (ASP), the agro-pastoral (AP), the extensive agro-pastoral (EAP) and the mixed sheep-olive tree farming systems. The WF of sheep meat produced under the target farming systems ranged from 8654 to 13 056 l/kg live weight. The evaluation of WF of five different sheep production systems figured out that sheep raised under the EAP farming system had the greatest WF per ton of live animal. However, the ASP farming system exhibited the lowest WF. Water used to grow feedstuffs for sheep production accounts for 98% of the total WF of sheep. The green WF accounts for more than 92% of the total WF in all farming systems. Results of monitoring water use at farm scale show that the modeled values of WF are overestimated by an average of 23.3% and 24.1% for the selected farms assigned to the MSC and AP farming systems, respectively. Water use for sheep production is high in most of the Tunisian farms. Therefore, the general assumption that ‘meat production is a driver of water scarcity’ is supported and should be considered as an important focal point in agricultural and water policies. Particular attention should be given to forage crops with low WFs and high contribution to dry matter to provide ration with low WF. The efficient use of green water along the meat value chain is essential to minimize the depletion of blue water resources and to reduce the economic dependency on virtual water through the import of feedstuffs.     

基于生态系统服务的广西水生态足迹分析

针对传统生态足迹对于水域仅考虑渔业生产功能的缺陷,研究者提出了水生态足迹.但当前水生态足迹基础理论与模型均存在较大不足.为此,提出了基于生态系统服务的水生态足迹概念和模型,并以2003-2010年的广西为例进行了计算与分析.结果表明:(1)水域-渔业账户中,淡水渔业生态足迹呈上升趋势,淡水渔业生物承载力较高且比较稳定,淡水渔业生态盈余较多同时淡水渔业生态压力较小;(2)水资源账户中,淡水生态足迹先较快上升随后缓慢下降,水资源承载力较高但2007-2010年波动幅度较大,水资源生态盈余较多同时水资源生态压力较小;(3)水环境账户中,水污染生态足迹先缓慢上升随后大幅下跌之后逐渐回升,水环境承载力变化趋势与水资源承载力相同,绝大多数年份表现为水环境生态赤字和水环境生态不安全;(4)淡水渔业生态压力＜水资源生态压力＜水环境生态压力,淡水生态系统基本已处于生态不安全状态.模型克服了传统模型的诸多缺陷与不足,是对广西近年来淡水生态系统服务供需及水生态安全状况的较客观全面的反映.     

基于ESTDA模型的中国水生态足迹及水生态压力评价

基于水足迹视角,测度了中国31个省份2000-2018年的水生态足迹广度、深度及水生态压力,采用ESTDA框架对其时空动态特征进行分析。结果表明：①研究期内,中国水生态足迹总量呈波动上升态势;水生态承载力波动幅度较大,空间分布格局整体呈现自东南向西北逐渐较少的趋势。②水生态足迹广度与水生态承载力呈同步变化趋势,整体上已接近水资源可提供的流量资本上限,各省市水生态足迹深度差异较大。③研究期内,水生态压力指数小于1的区域与水生态足迹深度为1的区域相吻合,水生态压力指数大于1的区域主要分布在华北及西北地区。④LISA时间路径表明,水生态足迹广度、深度及水生态压力的整体空间格局均具有较强的稳定性;三者的局部空间结构在空间依赖方向上的稳定性依次加强;空间格局演化的空间整合性呈现水生态足迹深度 > 水生态压力 > 水生态足迹广度,空间上,水生态足迹广度正向协同增长省份主要集中于南方省份,而水生态足迹深度和水生态压力正向协同增长区则分布于华北、西北地区;各要素的空间分布格局表现出较强的路径依赖及锁定特征。     

Water footprint and irrigation use efficiency of important crops in Northern Cyprus from an environmental,economic and dietary perspective

Availability of freshwater is currently one of the most important limiting factors for crop production and food security throughout the world. Northern Cyprus is one of the world’s most important countries that has been facing drought and salinization problems since the 1970 s. The present study aimed to determine the irrigation use efficiency (IUE), irrigation economic productivity (IEP), irrigation economic efficiency (IEE) and irrigation dietary efficiency (IDE) of some major crops in Northern Cyprus to ensure better planning for sustainable water management, not only for Northern Cyprus but also for all countries facing similar problems. The results of the present study showed that both carob and fig crops require the least amount (24 L) of irrigation to produce 1 kg of fruit, and “open field” lettuce and “greenhouse” eggplant require the least amount (10 and 16 L) of irrigation to produce 1 kg of vegetables in Northern Cyprus. The irrigation economic productivity (IEP) and irrigation dietary efficiency (IDE) of crops were also found to be significantly different and meaningful for different crops. Our results showed that reshaping the distribution of crops based on their water consumption would reduce the use of water resources while continuing to feed the population.     

基于SWAT模型的图们江流域蓝绿水资源供需平衡分析

随着经济快速发展和工农业各类用水量大幅增加,对河流的开发程度随之加强,流域水资源可持续利用受到不利影响。从蓝绿水视角出发,基于SWAT模型量化了图们江流域2015—2020年不同时间尺度下的蓝绿水资源并探讨了研究区水资源供需平衡情况。结果表明：研究时段内流域蓝绿水资源均具有明显的季节特征,年均蓝绿水资源量为117.16亿m³,其中蓝水资源量30.14亿m³,绿水资源量87.02亿m³,绿水占水资源量的74.27%。以年为尺度,蓝水资源供需评估指数>1,可利用蓝水资源量基本不能满足其需求量,降水少的年份蓝水资源供需矛盾突出,而绿水资源可以达到供需平衡,其供需评估指数集中在0.1—0.2之间。在月尺度分析中研究区蓝水供需评估指数出现极端值的频率较高,表明该地区蓝水供需不平衡,尤其是可利用蓝水资源一般在每年的7—8月才较为丰富,而蓝水需求用水集中分布于作物生长期,导致蓝水供应与蓝水需求在时间分配上不均衡,且在实际水资源分配中忽略了生态用水;月尺度绿水供需评估指数集中在0.1—0.4之间,有明显的季节变化特征,整体上绿水资...     

三江平原粮食作物生产水足迹时空特征及影响因素

水足迹是评价人类活动对水资源开采和水环境污染程度的重要方法,对农作物生长过程的绿水足迹、蓝水足迹和灰水足迹进行量化和分析,可以为农业用水综合评价和用水管理提供指导。以三江平原为研究区域量化粮食作物生产水足迹的时空特征,揭示粮食生产对区域水资源的占用情况,并分析水足迹的影响因素。结果表明:(1)三江平原粮食生产水足迹总量在2005-2018年间呈显著增加趋势,其中绿水足迹、蓝水足迹和灰水足迹在水足迹总量中的占比历年平均为28%、8%和64%;(2)粮食生产水足迹空间差异明显,在地市尺度,佳木斯市水足迹最高,占三江平原总量的47%,在县区尺度,富锦市、依兰县和桦南县是水足迹热点地区;(3)只考虑蓝水足迹,粮食生产给三江平原水资源造成轻度压力,而同时考虑蓝水和灰水足迹,粮食生产给三江平原水资源造成重度压力;各地市间水资源压力有较大差异,其中佳木斯市负担了该区域将近一半的粮食产量,水资源压力最高,鹤岗市则水资源压力最低;(4)降雨量、灌溉水利用效率、化肥施用量、粮食种植结构和作物单产水平等都会影响粮食作物生产水足迹,其中蓝水足迹响应种植结构的变化最敏感,灰水足迹响应化肥施用量的变化最敏感,而水足迹总量响应作物单产水平的变化最敏感。因此,建议减少化肥施用量、提高作物单产水平和优化作物种植结构纳入区域水资源可持续管理之中。     

人文因素对中国灰水经济生产率的影响

促进水资源环境与经济的可持续发展,已成为当前我国亟待解决的问题。以灰水经济生产率为研究主体,将其定义为GDP与灰水足迹之比,基于对我国31个省市(香港、澳门特别行政区和台湾省数据尚未统计)2000—2014年灰水经济生产率区域特征和空间相关性的分析,利用空间Durbin模型对人文因素与灰水经济生产率的关系进行了研究。结果显示:(1)我国灰水经济生产率整体呈现上升趋势,东部地区显著高于中、西部,西部地区最低;(2)各省区灰水经济生产率在空间分布上存在显著正自相关性且空间集聚程度较高,近年来区域间的分化加剧;(3)从全国范围来看,提升产业结构优化度、城镇化水平及社会福利有利于本地灰水经济生产率增长,提高受教育程度和社会福利对邻近地区灰水经济生产率具有正向影响;(4)从各分区情况来看,提升民众受教育程度、产业结构优化度、城镇化水平和社会福利都对东部地区灰水经济生产率具有显著积极效用,城镇化建设的发展和社会福利水平的提高有利于西部地区灰水经济生产率增加;在间接效应结果中,东部民众受教育程度的提高,中部社区服务机构的减少,西部社会福利的改善都对相应邻近地区灰水经济生产率产生了显著正向影响;此外,各地需缩小城乡差距,提高农村地区GDP,促进经济与环境健康发展。提出了推动我国水环境与经济协调发展的建议。     

The case for headland set-aside: consideration of whole-farm gross margins and grain production on two farms with contrasting rotations

Spreadsheet calculations were used to compare headland set-aside with rotational set-aside in terms of gross margin and grain production on two farms with contrasting rotations. At Broom's Barn, Suffolk there was a five course rotation consisting of sugar beet and four cereals, while at Bunny Park, Nottinghamshire oilseed rape was the break crop, followed by three cereals. For both farms a sensitivity analysis was used to investigate the effect of the proportion of the farm required to be set aside, the extent of headland yield reduction and the cereal price on the outcome of the spreadsheet calculations. In general headland set-aside out-performed rotational set-aside. Yields on headlands were always less than the main body of the field, but it was on the turning headlands where yield was particularly depressed. Thus the advantage, in terms of gross margin, of setting aside the headlands was greatest when the requirement could be fulfilled by fallowing most turning headlands, but no non-turning headlands. Generally, rotational set-aside reduced grain production more than headland set-aside, but when the spreadsheet models were adjusted to maintain the area of sugar beet, the situation was reversed. In this case headland set-aside produced a larger gross margin and had the greatest impact on grain production. An extension of the analysis is to ask the question: even if set aside is not an option, is it worthwhile to crop rather than fallow headlands? For cereals and oilseed rape the answer is in the affirmative; the gross margin for headlands remains positive, even when prices are much reduced, because the arable area payment more than offsets the variable costs. This does not hold for crops such as sugar beet that are not eligible for arable area payments. An additional benefit from headland set-aside is its potential to enhance the environment through increased habitat diversity and the provision of ‘buffer zones’ to prevent agrochemicals from drifting into hedges and watercourses.     

Pre-weaning management of calves on commercial dairy farms and its influence on calf welfare and mortality

Welfare and management of calves is of increasing interest and also influences performance of these animals in later life. The aim of this study was to assess management and environmental conditions under which pre-weaned dairy calves are reared on commercial Irish dairy farms. We included 47 spring-calving, pasture-based herds in this study. Herd and animal-specific data, such as mortality rate, age and breed, were gathered from all participants via the HerdPlus® database. Information pertaining to management practices was collected by conducting an interview with the principal calf rearer, while an assessment of calf housing facilities was conducted to identify conditions calves were reared in. The environmental assessment included measurements of space allowance per calf, as well as feeding equipment hygiene. To assess calf behaviour video observations were used, while accounting for the number of calves present in a group and the space available per calf. Faecal samples were also collected to determine the presence of enteric pathogens among calves. To compare calf space allowance, group size and presence of enteric pathogens early and late in the calving season each farm was visited twice. Calf mortality was not associated with either herd size, space allowance per calf or post-colostrum feeding practices. Higher calf mortality was identified among herds which reported experiencing an on-set of calf pneumonia during weeks 8 to 10 of the calving season. This study demonstrates that factors associated with calf welfare on commercial Irish dairy farms (e.g. space allowance, mortality rate) are independent of herd size. Some management practices however, such as methods used for treating health issues can affect rates of calf mortality experienced. Calf mortality, for example, was lower in herds which treated diarrhoea cases by administering electrolytes, while continuing to offer milk. Behavioural observations indicate that smaller group sizes could promote expression of positive behaviours, potentially resulting from an overall improvement in welfare. Space allowance per calf was not associated with observed behaviour frequencies. We also identified that similar rates of calf mortality are experienced across herds of different sizes.     

不同土壤水分条件下杨树人工林水分利用效率对环境因子的响应

运用涡度相关(Eddy covariance,EC)开路系统和微气象观测系统,于2007年对位于北京市大兴区永定河沙地杨树(Populus euramertcana)人工林与大气间碳、水和能量交换进行了连续测定.通过分析总生态系统生产力(GEP)、蒸发散(ET)以及水分利用效率(WUE=GEP/ET)随相对土壤含水量(REW)的变化趋势,探讨杨树人工林不同土壤水分条件下水分利用效率对气象因子以及下垫面因素的响应,为杨树人工林经营管理提供理论依据.研究结果表明:当REW＜0.1时,GEP和ET受到严重水分胁迫的影响维持在较低水平,环境因子对GEP、ET和WUE的影响较小;当0.1＜REW＜0.4时,GEP和ET随着土壤体积含水量(VWC)的增加而增大,WUE随VWC的增大而减小;REW＞0.4时,气象因子是影响碳固定和水分损耗的主要原因,由于ET对气象因子变化的响应较GEP更为敏感,因此,WUE随空气饱和水汽压差(VPD)的增大而减小.沙地土壤保水能力较差,不能保证土壤水分被植物有效利用,因此当VWC处于5.2%-8.8％(0.1＜REW＜0.4)范围时,碳固定与水分消耗达到最高效率.研究表明杨树人工林WUE随降水变化而变化,未来气候变化和变异有可能影响杨树林耗水和生产力之间的关系.     

外来树种的耗水特征及其对环境水资源的影响

外来树种常被作为"先锋树种"广泛引种,在荒山造林和水土保持方面发挥了积极作用;然而,不少外来树种具有高耗水和强抗旱的水分利用特性,耗水量大、水分消耗快,若不加甄别地引种会影响甚至危害本土森林生态系统的健康。目前,部分被引种的外来树种已造成入侵;同时,在当前水资源缺乏的形势下,外来树种的引种安全问题已成为全球关注的生态环境问题。本文综述了外来树种在生态系统、整树、叶片及枝条水平的耗水特性,分析了外来树种对引种地水资源的影响。前期的研究结果显示,被引种的外来树种在生态系统及整树水平的耗水量普遍高于乡土树种,但对水资源的影响却因受控于多个因素如环境、气候、植物个体等而不尽相同;同时还显示,外来树种在叶片和枝条水平的耗水特性更多地体现了其应对环境变化的水分利用策略。研究还就提高外来树种耗水特性研究的准确性和提升外来树种危害风险的预警能力方面,提出了若干研究方向,旨在为森林管理者和政府部门平衡外来树种的经济效益和生态效应提供借鉴和指导,以期降低外来树种引种风险,增进生态安全。     

Effect of volumetric water content on thermal properties of dairy cattle feces mixed with sawdust

This paper describes the thermal properties (effective thermal conductivity and thermal diffusivity) of an organic waste used to model the composting process in relation to volumetric water content at 20°C. The organic waste was a mixture of fresh dairy cattle feces and sawdust with a ratio of one-to-one on a dry weight basis. The thermal probe method was used to determine the effective thermal conductivity and diffusivity. The effective thermal conductivities were found to increase with volumetric water content, and ranged from 0.0500 to 0.202 W m⁻¹ K⁻¹ at volumetric water contents of 0% and 44.2%, respectively. The thermal diffusivity was not affected by the volumetric water content, and was found to have a mean value of 1.08 × 10⁻⁷ m² s⁻¹.     

基于ISO 14046的工业产品水足迹评价研究——以电缆为例

水足迹国际标准(ISO 14046)于2014年发布,基于生命周期评价(LCA)的思想,水足迹被定义为量化与水相关潜在环境影响的指标。在ISO14046的原则、要求和方法学框架基础上,介绍了工业产品水足迹的计算和评价方法,并以铜电缆和铝合金电缆为例进行研究,分别评价了两类电缆生命周期过程产生的与水相关环境影响。与水足迹网络(WFN)的方法侧重于计算生产产品所需要的水资源总量不同,ISO的方法更关注于产品全生命周期过程的环境影响评价。案例研究表明:铜电缆生命周期全过程耗水量与铝合金电缆相比少24.8%,水短缺足迹相比则少97.9%。这是因为铜电缆生产地江苏的水压力指数(WSI)小于铝合金电缆生产地河北的WSI。由此,在江苏地区生产电缆使用的水资源对当地水环境压力造成的影响远小于在河北地区生产电缆造成的影响。采用科学合理的水足迹评价方法,量化工业产品全生命周期带来的环境影响,能为我国实现工业布局的合理规划和水资源的可持续利用提供科学依据。