جستجوی مقالات مرتبط با کلیدواژه "water productivity" در نشریات گروه "آبخیزداری، بیابان، محیط زیست، مرتع"

Karkheh watershed is located in the western to southwestern region of Iran and in a dry to semi-arid region. The existence of different agricultural systems, including irrigated and rainfed agriculture, low water efficiency, the existence of production limitations (salinity and drainage management in the downstream), poverty and lack of livelihood of local communities (upstream), the issues of upstream-downstream impacts of the basin, environmental issues, etc., led to the proposal of the Karkheh watershed as a suitable model in the country for the CGIAR Global Water and Food Challenge Program (known as CPWF). Therefore, this basin was chosen as one of the representative watersheds among the other nine watersheds of this global program, as a model for arid and semi-arid regions of the world, and the program was implemented during phase one of the program (2004 to 2008). In the implementation of this program, approaches, organization and mechanism, management structure, technical and program criteria, basin management principles, stakeholders' participation, innovations and ways of presenting outputs, in different stages of basin selection, program start and during The implementation of projects approved by the program were adopted and used. The main objective of this article is to document the methodology used during the process of implementing the CPWF international research and development program in the Karkheh Basin, so that its hidden knowledge is revealed, related experiences and achievements are documented, and used for future uses in other similar projects in this or other basins in the country. The study method is mainly based and derived from the study and analysis of program documentation archives, reports, discussions held during the meetings, the results of workshops and national and international conferences and the reports of the field visits carried out during the implementation of the global CPWF program and the implementation of this program in Karkheh basin. Among the important achievements and methodologies and the documented indicators of the program, one can include the methodology of collaborative development of technologies, the examination of the paths of project results, the criteria for selecting research sites, and the methodology for determining the principles of integrated watershed management which are presented and explained in detail in this article.

The Qaleh Chai watershed as one of the watersheds of Lake Urmia has 36 rural settlements that are often active in agriculture. This area has been experiencing a reduction in available water for the past 20 years or so. Water scarcity has doubled the need to improve water productivity. The present study was conducted with the aim of forecasting water productivity in 36 rural settlements of the Qaleh Chai watershed. Data collection was in the form of a Delphi questionnaire with the participation of experts, which was analyzed with Micmac software. The number of components studied included 20 components affecting the promotion of water productivity. Data analysis led to the identification of 9 key components affecting the improvement of water productivity in the Qaleh Chai watershed. The most important key components identified are canal renewal, reducing irrigation time and increasing frequency, reducing the land area in steep areas, improving the quality of management and taking a comprehensive approach, transferring water from the source to the farm using Indoor canals, using of agricultural inputs with less water requirement, subsidies for sprinkler and drip irrigation, use of advanced equipment to reduce water consumption and improve villagers' water productivity skills respectively with scores 767, 766, 655, 654, 632, 609, 608, 541 and 496. The results of prioritizing the villages in terms of key components showed that the Harglan village, the Almalo village, and the Tutakhaneh village have the highest score (0.042, 0.045, 0.051), respectively. According to the research findings, It can be said that the realization of strategies to improve water productivity in the group is the simultaneous attention to all components and the adoption of a comprehensive approach.

Fort the purposes of this study, data were collected using a questionnaire on crop rotations in Isfahan Province alongside field observations and commonly used indices. It was found that the rotations common in all the three cold, temperate, and warm climatic zones identified in the province were often short-termed with two or three crops grown. The temperate zone, however, is characterized by 30 dominant types of rotation. Land use efficiencies of 43-98%, 60-95%, and 50-81% were recorded for the temperate, warm and cold zones, respectively. Production efficiency in the rotations was found to have declined to levels below 40 kg per rotation day depending on the type of crop grown, cultivation of small grains such as wheat and barley or certain oilseeds such as rapeseed and safflower, and fallow periods allowed between rotations. The presence of high-yield forage crops (such as fodder corn), especially when combined with tuberous crops (such as sugar beet) and summer crops (such as watermelon and honeydew melon), was found to increase the production efficiency of the rotations (sometimes to more than 200 kg day-1 in the temperate zone). Water productivity in crop rotations across the three zones rarely ever exceeded 6 kg m-3. Crop diversification in the rotations, therefore, seems to be the most urgent measure that should be taken in the three climatic zones. Finally, more extensive cultivation of tuberous crops in the temperate and warm zones as well as wider growth of pulses in the cold zones seem not only to be feasible but also economically rewarding.

Water Utility Index (WUI), first introduced by D. White (1958), is defined as one kg of crop produced per one cubic meter of water evpotranspired. This concept was later replaced with the more inclusive one of ‘water productivity’ (WP). The objective behind this latter concept was to provide a measure for interpreting the results of field experiments of water consumption used in making proper provisions for irrigation management, detecting opportunities for water saving and enhancing water productivity, and developing water allocation decision-making support systems. In order to address the water crisis at the national level, the present article presents a detailed definition of the index and the challenges facing its application to develop realistic water saving measures. It is claimed that evaluations solely based on the WP Index, in which the water applied (or, water withdrawn) is the denominator (WPAW), are to some extent misleading. It is argued that the index does not represent real amounts of water saved or effectively used, especially when it comes to the assessment of the so-called ‘water-saving irrigation systems (e.g., pressurized irrigation). To overcome this inadequacy, it is initially proposed that the ET-based WP (i.e., WPET), rather than the plain WP index, should be used for this purpose. In a second stage of the study, a simple computational methodology is developed that is based on the currently available and cost-effective data on ETc and crop yields across the nation (as reported in the national document on water or in the statistical reports on agriculture). As an illustration, the data available on the Karkheh River Basin and the WPET values measured for the major crops of wheat, barely, alfalfa, potato, silage maize, clover, grain maize, sugar beet, onion, tomato, cucumber, and watermelon grown in the basin are computed to be 1.32, 1.49, 1.22, 5.74, 7.93, 1.73, 1.37, 6.17, 6.61, 8.24, 5.07, 6.94, and 2.05 kg/m3, respectively, which are then used to calculate the average value of 2.05 kg/m3 for the whole basin. Finally, WP values reported in the literature and measured using the conventional filed methods (i.e., WPAW) for the above crops grown both in the study basin and across the state are used to derive a proper regression relation between WPET and WPAW, which exhibits a satisfactory goodness of fit (R2=0.96). Using this relation, the average value of WPAW for the basin is obtained to be about 1.20 kg/m3, which is consistent with the values reported elsewhere. Based on the above observations, application of the proposed method as a low-cost and reasonably accurate one is recommended for the estimation of WPET and, thereby, WPAW.

A major challenge facing sustainable agricultural production is that of selecting cropping patterns that observe the restrictions on such natural local capacities as soil, climate, and renewable water resources. This important issue has also been reflected with due emphasis in the state laws and national documents on water and agriculture as evidenced by the number  of laws and national documents (13) approved/adopted on the cropping pattern issue, standing second only to that of “Efficient use of water” (with 25 laws/documents). In this paper, a comprehensive analytical review and a SWOT analysis are initially conducted of the laws and national documents on cropping pattern practices before recommendations and suggestions are formulated for the practical implementation of a national cropping scheme at the state level. Among the important conclusions to be drawn from this review is that despite the legally binding requirements (such as The Enhancing Productivity in Agriculture and Natural Resources Sectors Act), no serious and effective measures have yet been taken in this filed except in such cases as greenhouse crop production and extraterritorial farming. In the few cases where actions have been taken, they have been mostly restricted to those within a specific sector in the absence of an integrated approach or coordination with other sectors or organizations involved. It is also observed that little attention has been paid in the relevant laws and regulations to capacity building and training on cropping pattern issues while the published research and field studies in the this area are quite scant as well. Another area neglected in the development of a national cropping scheme is the inclusion of indigenous and under-utilized crops in such schemes, or introduction of exotic crops with low water demand but high economic value for adaptation to the present climate at the state level that ensure sustainable agricultural production. Finally, a long time has elapsed since these laws and legal documents were adopted/passed during which time the climate has drastically changed and new farm technologies have emerged. These considerations necessarily require revisions in the existing laws and regulations or development of brand new ones.

Sustainable agriculture in each region relies heavily on monitoring production in that region to gain statistically accurate information. The present study was conducted in 2013‒2014 in Fereidan, Isfahan Province, to determine the actual yield (average yield in the area) and the easy access yield (yield by pioneering farmers in the region) in an attempt to estimate possible water savings. Based on the data collected through questionnaires from the statistical population studied, certified tuber seeds, disinfection of the tubers, and application of potassium fertilizers were identified as the major factors affecting agricultural production that had been duly observed by 43, 66, and 59%, respectively, of the beneficiary farmers in cultivating the Agria cultivar. The figures obtained for the same parameters in the case of the Marfona variety were 42, 65, and 74%, respectively. Results indicated that observing these three factors would lead to increases of 12.2 and 12.3 t­ ha‒1 in the actual yields of the two Agria and Marfona cultivars, respectively, while the practice would also prepare the grounds for achieving easy access yield. Based on actual yields of the Agria and Marfona cultivars, water productivity values were 2.95 and 2.56 kg m‒3, which will expectedly rise to 4.06 and 3.86 kg m‒3 if agricultural production in the region is raised to the easy access yield level. The net potato irrigation demand in Fereidan region was measured to be 5809 m3 ha‒1; this indicates an annual saving of 387200 m3 of water for the approximately 4,000 hectares under potato cultivation if proper agricultural practices are implemented and easy access yield is achieved in the region.