Relationship between stable carbon isotope discrimination and water use efficiency under regulated deficit irrigation of pear-jujube tree

To investigate the relationship between stable carbon isotope discrimination (Δ) of different organs and water use efficiency (WUE) under different water deficit levels, severe, moderate and low water deficit levels were treated at bud burst to leafing, flowering to fruit set, fruit growth and fruit maturation stages of field grown pear-jujube tree, and leaf stable carbon isotope discrimination (Δ_L) at different growth stages and fruit stable carbon isotope discrimination (Δ_F) at fruit maturation stage were measured. The results indicated that water deficit had significant effect on Δ_L at different growth stages and Δ_F at fruit maturation stage. As compared with full irrigation, the average Δ_L at different growth stages and Δ_F at fruit maturation stage were decreased by 1.23% and 2.67% for different water deficit levels, respectively. Δ_L and Δ_F among different water deficit treatments had significant difference at the same growth stage (P < 0.05). Under different water deficit conditions, significant relationships between the Δ_L and WUE_i (photosynthesis rate/transpiration rate, P_n/T_r), WUE_n (photosynthesis rate/stomatal conductance of CO_2, P_n/g_s), WUE_y (yield/crop water consumption, Y/ET_c) and yield, or between the Δ_F and WUE_y and yield were found, respectively. There were significantly negative correlations of Δ_L with WUE_i, WUE_n, WUE_y and yield (P < 0.01) at the fruit maturation stage, or Δ_L with WUE_i and WUE_n (P < 0.01) over whole growth stage, respectively. Δ_F was negatively correlated with WUE_y, WUE_n and yield (P < 0.05), but positively correlated with ET_c (P < 0.01) over the whole growth stage. Thus Δ_L or Δ_F can compare WUE_n and WUE_y, so the stable carbon isotope discrimination method can be applied to evaluate the water use efficiency of pear-jujube tree under the regulated deficit irrigation.     

Agro-environmental evaluation of irrigation land: I. Water use in Bardenas irrigation district (Spain)

Non-point agrarian contamination makes its allocation to a specific territory difficult. This first part of the study seeks to analyze contamination resulting from water use in 54,438 ha of Bardenas irrigation district included in the Arba basin (BID-Arba). To this end, water balances were carried out in BID-Arba by means of measuring or estimating the main inputs, outputs and water storage between 1 April 2004 and 30 September 2006. Also, the spatial-temporal variability in water use was analyzed.The semester error balances were acceptable (between 11% and −6%), which permits the attribution of the mass of pollutants exported in drainage to the irrigation area evaluated, the objective of the second part of the study. Irrigation efficiency (IE) in BID-Arba was high (90%) despite the fact that Irrigation Sub-District VII (ISD-VII), with considerable flood irrigation drainage (27%), and ISD-XI with considerable losses due to evaporation and wind drift in sprinkler irrigation systems (15%), brought down the average (IE_VII = 73%; IE_XI = 83%). Irrigation management was inadequate as there was a water deficit (WD) of 9%, partly affected by the 2005 drought (WD_{Apr-05/Sep-05} = 21%) and the low irrigation doses applied in ISD-XI (WD_XI = 12%).To sum up, intense re-use of water caused a water use index (percentage of water used by the crops) of 85% which surpassed 90% in periods of drought. Nevertheless, irrigation management should be improved in order to annul the water deficit and to maximize the productivity of the agrarian system.     

内蒙古达里诺尔湖水质现状调查

通过应用各种物理及化学仪器分析了达里诺尔湖水温、酸碱度、溶解氧、各种离子、总含盐量等因子,根据以往水质调查结果及这次测定数据比较,达里诺尔湖的pH有不断上升的趋势,这将危及到雅罗鱼及水中生物的生存,而其他各种离子均有小幅度的上升,溶解氧基本能满足鱼类的生存需求.通过水质的调查结果分析,使瓦氏雅罗鱼及其他水生生物更好地发挥在达里诺尔湖中生存的潜力.     

茭白新品种"金茭2号"的选育及其栽培技术

介绍了金茭2号的选育背景、选育过程、产量表现及其特征特性和主要栽培技术。     

Farmer participation in irrigation management: The case of Doroodzan Dam Irrigation Network, Iran

The importance of farmer participation in system design and management has been emphasized in previous studies. The purpose of this study was to identify the factors affecting farmer participation in irrigation management using survey research. The study was conducted in Doroodzan Dam Irrigation Network in Fars province, Iran. Multistage stratified random sampling was used to collect data from 270 farmers as the research sample. Results reveal that farmers’ attitudes toward participation in irrigation management, attitudes toward personnel of the State Water Authority and the Agricultural Extension Service Centers (AESCs), family size, the problem perception, dependence on the dam for water, and educational background have influenced their participation in irrigation management. By contrast, contact with information sources, animal units, sociability, age and agricultural experience did not affect farmers’ participation. Moreover, based on farmers’ perspectives, unequal water distribution among farms, dissatisfaction with Water Authority operators and high water fees and charges were the main problems and obstacles toward farmer participation in irrigation management.     

中国水土流失问题的初探

长期以来,水土流失直接威胁着人们赖以生存的环境,在所有的生态破坏中,水土流失称之为“环境破坏第一杀手”。针对我国山地丘陵面积大、地质条件复杂、人为破坏加速、水土流失严重的实际情况,通过丰富的历史资料和整治经验及野外工作所积累的大量数据分析,以生态恢复学为指导,总结了水土流失的基本特点,研究了水土流失治理与经济可持续发展的关系,探讨了水土流失给生态安全造成的巨大危害,展望了水土保持的预期目标,根据中国的实际情况,提出了综合治理的基本思路。     

An integrated water trading-allocation model, applied to a water market in Australia

Temporary water trading is an established and growing phenomenon in the Australian irrigation sector. However, decision support and planning tools that incorporate economic and biophysical factors associated with temporary water trading are lacking. In this paper the integration of an economic trading model with a hydrologic water allocation model is discussed. The integrated model is used to estimate the impacts of temporary water trading and physical water transfers. The model can incorporate economic and biophysical drivers of water trading. The economic model incorporates the key trade drivers of commodity prices, seasonal water allocations and irrigation deliveries. The hydrologic model is based on the Resource Allocation Model (REALM) framework, which facilitates hydrologic network simulation modelling. It incorporates water delivery system properties and operating rules for the main irrigation and urban centres in a study area.The proposed integration method has been applied to a case study area in northern Victoria, Australia. Simulations were conducted for wet and dry spells, a range of commodity prices and different irrigation distribution system configurations. Some example analyses of scenarios incorporating water trading were undertaken. From these analyses potential bottlenecks to trade that constrain the economic benefits from temporary water trading were identified. Furthermore, it was found that in certain areas of the system, trading can make impacts of long drought spells worse for water users, e.g. irrigators. Thus, the integrated model can be used to quantify short-term and long-term third party impacts arising from temporary water trading. These findings also highlight the need to link “paper trades” (estimated by economic models) to physical water transfers (estimated by biophysical models).     

土壤水分下限对番茄光合速率、品质及产量的影响

通过盆栽试验,研究了土壤水分下限对番茄苗期、初花期和结果期的光合速率、蒸腾速率及果实品质、产量和水分利用效率的影响,试验结果表明,当土壤水分下限控制在苗期45%、初花期55%、结果期75%田间持水量范围内,可以提高果实品质,获得较高的产量和水分利用效率。     

Effects of water stress at different development stages on yield and water productivity of winter and summer safflower (Carthamus tinctorius L.)

A field study was carried out to determine the effects of water stress imposed at different development stages on grain yield, seasonal evapotranspiration, crop-water relationships, yield response to water and water use efficiency of safflower (Carthamus tinctorius L.) for winter and summer sowing. The field trials were conducted on a loam Entisol soil in Thrace Region in Turkey, using Dincer, the most popular safflower variety in the research area. A randomised complete block design with three replications was used. Three known growth stages of the plant were considered and a total of 8 (including rainfed) irrigation treatments were applied. The effect of irrigation or water stress at any stage of development on grain yield per hectare and 1000 kernel weight, was evaluated. Results of this study showed that safflower was significantly affected by water shortage in the soil profile due to omitted irrigation during the sensitive vegetative stage. The highest yield was observed in the fully irrigated control and was higher for winter sowing than for summer sowing. Evapotranspiration calculated for non-stressed production was 728 and 673 mm for winter and summer sowing, respectively. Safflower grain yield of the fully irrigated treatments was 4.05 and 3.74 t ha⁻¹ for winter and summer season, respectively. The seasonal yield response factor was 0.97 and 0.81 for winter and summer sowing, respectively. The highest total water use efficiency was obtained in the treatment irrigated only at vegetative stage while the lowest value was observed when the crop was irrigated only at yield stage. As conclusions: (i) winter sowing is suggested; (ii) if deficit irrigation is to apply at only one or two stages, Y stage or Y and F stages should be omitted, respectively.     

喷锌对蕹菜锌含量及产量的影响

不同喷施浓度及喷施次数对蕹菜产量及茎叶锌含量的影响结果表明：喷施０．０５％及０．１％的硫酸锌液均能提高蕹菜的产量，但以０．０５％的处理对产量的提高作用最明显，浓度超过０．１％时，对蕹菜生长有抑制作用提高喷锌浓度，蕹菜锌含量的增加为叶片大于茎；喷施１～２次，有明显的增产效果，喷施超过２次反而减产；随着喷施次数的增加，蕹菜锌含量也增加。