نشریه مدیریت آب در کشاورزی
پیاپی 1 (بهار و تابستان 1393)

Iran is located in dry region with limited precipitation. Therefore¡ drought is a recurrent event in the country. Using drought management strategies can enhance farmer''s adaptive capacity. Thus¡ any drought intervention approaches should take drought management practices in to consideration. This in turn would enhance farmers’ resilience and reduce vulnerability. The purpose of this descriptive study was to determine wheat farmers’ drought management strategies in Kermanshah Province during 2007- 2011. A population consisted of 370 wheat farmers in which 248 questionnaires distributed among wheat farmers using multi-stage stratified sampling. Data was analyzed using descriptive statistics. Results revealed that farmers mostly used the following drought management strategies: praying¡ hope for better future¡ talking to friends¡ using prior experience¡ appropriate planting date¡ reducing expenses¡ borrowing money from friends and relatives¡ controlling for weeds¡ using indigenous knowledge in predicting weather¡ communicating with extension specialists. Moreover¡ farmers used different resources to gain knowledge about drought management strategies. For example¡ using other farmers in the community¡ extension specialist¡ friends and neighbors. Results of this study have implications for drought management policy makers. For example¡ a realistic preventive program can be designed in the future.

Pressurized irrigation systems are most economical irrigation that use sufficient amount of water¡ fertilizers and other agricultural chemicals at proper time. Given the scarcity of water resources using modern methods of irrigation in agriculture will be inevitable. Today¡ process improvement¡ development and use of drip irrigation practices as one of the most advanced methods of irrigation in agriculture is increasing. Attention to international dimensions of water scarcity especially in arid and semi-arid regions of the world¡ the latest recommendation of the International Commission on Irrigation and Drainage (ICID) in 8th Micro-irrigation Congress which has been held on 2011 in Iran¡ was development of subsurface micro-irrigation methods as a global orientation. Recently¡ due to existence aridity and accruing several droughts in Iran¡ Subsurface drip irrigation system has been considered by farmers¡ experts and researchers. This study was conducted to determine the impacts of¡ drip irrigation method and different amount of water and their interactions on yield¡ water use efficiency (WUE) and quality characteristic of tomato (Mobile cultivar). Experimental design was randomized complete blocks (RCBD) in split split plot with three replications. Design treatments included different amount of water (60¡ 80 and 100% water requirement) in main plot¡ drip irrigation method (surface and subsurface) in sub plot. The combined analysis showed that irrigation water amount¡ irrigation method and mulch treatments had significant effect on yield and WUE (P≤ 0.01). Yield in 60¡ 80 and 100% water requirement treatments was 31.141¡ 54.575 and 62.265 ton/ha¡ respectively¡ which showed significant difference. The highest WUE (7.881 kg/m3) was in 80% irrigation treatment¡ followed by 60 and 100% (with 5.925 and 7.232 kg/m3)¡ respectively. There was significant difference between yield in surface and subsurface drip irrigation (that was 43.380 and 55.274 ton/ha)¡ respectively. Water use efficiency in subsurface drip irrigation was 7.927 kg/m3 that was greater than surface drip irrigation. In this irrigation method; Soil evaporation¡ surface runoff¡ and deep percolation are greatly reduced or eliminated. Reductions in weed germination and weed growth often occur in drier regions. Infiltration and storage of seasonal precipitation can be enhanced by drier soils with less soil crusting. In some cases¡ the system can be used for a small irrigation event for use in germination¡ depending on dripline depth¡ flow rate and soil constraints. Entering the soil to the dripper is one of most important problems in development of the subsurface drip irrigation (SDI) system. This happens when the pump is turning off and it causes the dripper clogging. Dripper enveloping can decrease the problem. But there is anxiety about soil wetting patterns changing because of the use envelope.

In this research the performance of Aquacrop model was calibrated and validated to predict crop yield and water use efficiency of Maize in Miandoab region. The field experiment was conducted on strip split plot based on completely randomized design for SC704 variety of maize under three irrigation treatments¡ with three repetitions include: 80¡ 100 and 120% crop water requirement and three planting densities (75000¡ 90000 and 105000 bushes in hectare) and planting in one and two rows under drip irrigation system during 2005 and 2006. The model was calibrated by first year’s (2005) data¡ and validated by second year’s (2006) data. Results show that the Aquacrop Model has a high accuracy in forecasting of yield and water use efficiency with perfect and precise calibration. Normalized Root Mean Square Error (NRMSE) of yield and water use efficiency prediction was obtained for validation about 1.92 and 1.82%. The Nash-Sutcliffe efficiency (EF) of yield and water use efficiency prediction were calculated for model validation about 82.5 and 97.7%¡ respectively that indicated modeling with high accuracy. Therefore¡ based on calibrated crop coefficient in this study¡ the Aquacrop model was suggested for applying of different irrigation level and crop density and implants type (one or two row) managements in this region.

Micro irrigation system is widely used to improve water use efficiency and water supply in most crop¡ especially vegetable and fruit crops. The micro irrigation system offers the highest irrigation uniformity compared with other irrigation systems. This irrigation systems can deliver water and nutri ents in precise amounts and at controlled frequencies directly to the plant’s root zone. The major cause of failure in micro-irrigation systems is emitter plugging. Emitter plugging can severely degrade irrigation system performance and application uniformity. Because the emitters are small and can easily plug¡ it is important to understand the filtration and maintenance requirements of these systems and be proactive to prevent plugging. Plugging hazards for micro-irrigation systems fall into three general categories: physical (sediment)¡ biological or organic (bacteria and algae)¡ and chemical (scale). Frequently¡ plugging is caused by a combination of these factors. The type of emitter plugging problems will vary with the source of the irrigation water. It is important to prevent plugging problems before they occur. The best prevention plan includes an effective filtration¡ water treatment¡ and maintenance strategy. A water analysis is vital to the proper design and opera tion of the micro-irrigation system. To assess irrigation system performance and to ensure that components like filters are working correctly¡ flow meters and pressure gauges must be properly installed to provide feedback to the system operator. Monitoring flow meters and pressure gauges over time can reveal system performance anomalies that may require attention. To prevent the accumulation of those contaminants and the resulting emitter plugging¡ flush the system periodically. Regular flushing is critical to system health and longevity. If the micro-irrigation system is equipped with a method for chemically treating the water source (most will be)¡ backflow protection¡ and other safety provisions¡ are necessary.

In order to select the appropriate crop for cultivation of potatoes¡ wheat¡ sugar beet and maize in Jiroft region¡ this research was conducted in years 2009 and 2010. The research methodology in this study was based on field studies¡ including the estimated volume of water¡ crop yield¡ water use efficiency¡ net benefit per drop and the water economic efficiency of the production. The results showed that maximum water use efficiency was in sugar beet cultivation (5.2 kg/m3) and the minimum was in wheat (0.49 kg/m3). Potatoes had the highest net benefit per drop (53 Milion-Rial) and wheat had the lowest net benefit per drop (10 Milion-Rial). Water economic efficiency of potato than in all of the four fields were examined further. Indicating more profitable than other crops in potato fields is investigated. Therefore according to the results of this study in terms of water use efficiency¡ net benefit per drop and water economic efficiency can be said the cultivation of potato products is preferred and is recommended for planners and operators.

Historically¡ water use in agriculture¡ as the large consumer of water¡ it seemed to mind the economic¡ social and political have occupied. The research of water productivity and efficiency is importance. One of the important goals of modern irrigation is increasing efficiency and improving productivity o water. In addition¡ a growing world population and limited resources made evident the importance of more attention to improving the productivity of production factors in the development process and many countries have achieved considerable success in this regard. Objectives of this research were measuring the efficiency and productivity and allocation of agricultural inputs in produsers that use modern and traditional irrigation. Data needed by the 89 questionnaires through the producers of Grapes Khorasan in 1391 were collected. To estimate the efficiency and productivity of factors of production¡ respectively the production function method and maximum likelihood method is used. The results indicate that the average technical efficiency of produsers has used modern irrigation is 81% and 59% of those who have been used tradition irrigation. Statistically significant differences were observed between the two groups. The productivity of factors of production in the first group was greater and generally¡ these groups have acted in a more rational use of inputs. Finally¡ the optimal pattern of use that are the combination of agricultural experience and knowledge of official extension agents and researchers¡ promote the efficient farmers and exploitate to non efficient farmers.

The main purpose of this research was to study development strategies of implementation of agricultural water management technologies from the perspective of farmers This research was a sort of survey studies and a questionnaire was used for collection of data and information. Questionnaire''s reliability was confirmed through computing cornbanch''s Alpha coefficient which was more than 0.70. Face validity of questionnaire was confirmed by a panel of expert judgment. Statistical population of this study was consisted of 20156 farmers; out of which 205 people were selected as sample using multi-stage sampling technique. Accordingly¡ lining along the irrigation channels¡ promoting the pumps to electrical type¡ prevention of leakage from the gates¡ education of the farmers for operation and maintenance of the pumps¡ and observation of distance between the wells are priorities for development of the technology for agricultural water managements. Also factor analysis results of reception of farmers to alternative of development of agricultural water management technologies application revealed six factors totally they explained 65.28 percent of total variance.