نشریه مدیریت آب در کشاورزی
سال دوم شماره 1 (پیاپی 3، بهار و تابستان 1394)

In order to investigate the effects of water quantity on grain yield and water productivity of bread wheat genotypes¡ a field experiment was conducted in agricultural research center in Miandoab¡ located in West Azerbayjan during 1386-87. Different water level includes I1¡ I2¡ I3 and I4 corresponding with 70¡ 100¡ 130 and 160 mm evaporation from class A pan¡ was applied on ten genotypes of bread wheat includes: Zarrin¡ Shahriyar¡ Alvand¡ Sardari¡ C-80-4¡ C-81-10¡ C-81-4¡ C-83-3¡ C-83-8 and C-84-9. Optimal yield genotype was Zarrin and gained in I1 irrigation level with 7159.7 Kgha-1. The average water productivity of ten genotypes calculated for I1¡ I2¡ I3 and I4 about 0.98¡ 1.38¡ 1.36 and 1.29 Kgm-3. The maximum water productivity gained 1.79 Kgm-3 for C-84-9 genotype in I4 irrigation level. Based on results¡ under net benefit objective function the Zarrin genotype in I1 level and under net water productivity objective function the C-83-8 and C-84-9 genotypes in I4 level were purposed.

Subsurface drip irrigation with an efficiency of over than 90 percent is one of the method for row crops that can be used for cereals and trees. In this regard¡ the present study was done to investigate the distribution of moisture and capillary rise of water in a silty clay soil with subsurface tape drip irrigation in the city of Rasht in the summer of 2012. The experiment was carried out with three irrigation volumes of 10¡ 15 and 20 liters and three tape installing depths of 10¡ 20 and 30 cm with three replications¡ in the Agricultural and Natural Resources Research Center. Capillary rise of wetting front in tape installing depths of 10 and 20 cm for all volumes of irrigation water from zero to 10 cm layer of soil moisture reached to field capacity moisture level and covered the all optimal planting depth of seed. With 30 cm depth installation and 10 liters of irrigation volume¡ wetting front capillary rise was not reached to zero to 10 cm soil layer and in volumes of 15 and 20 liters of irrigation volume¡ capillary rise of wetting front reached to 6 to 7 cm beneath the soil surface. Best tape installing depths was 10 and 20 cm¡ but because of interruptions to tillage¡ tape installation depth of 30 cm with an appropriate irrigation volume or with light irrigation for germination in the case of dry springs¡ is recommended.

An experiment was conducted at the Agriculture and Natural Resources Research Center of East Azarbaijan (Khosroshahr) to model dry forage production under corn root zone drying conditions. The experiments were as Randomly Complete Blocks with three replications and with treatments of the full irrigation during corn growth period (T1)¡ root zone drying conditions with full irrigation at dough stage (T2)¡ root zone drying conditions with full irrigation at flowering stage (T3) and root zone drying conditions with full irrigation at flowering and dough stages (T4). The root zone during was considered for initiation of rapid growth of corn till the end of the maturity period. There is length and width of experimental plots was 10 and 5.2 m with the plot and furrow spacing as 2 m and 75 cm¡ respectively. Results showed that irrigation treatments produced significant and different forage. The produced forage weights compared and achieved mean weights at 273.5±5.70¡ 259.7±66¡ 194.1±59 and 173.4±75 gr per plant from T1 to T4¡ respectively. Therefore¡ full irrigation from 6-7 leaves stage till the end of maturity can de deleted to increase water productivity. The forage productions were modeled as a function of applied water. For irrigation treatment plots¡ dry forage weight models as a function of days after planting were acquired which these models can be applied to predict or forecast forage production at the subsequent time based on before times of growth.

Development of agriculture and sustainable crop production in the arid and semi-arid regions depends mainly on improving water productivity (WP) at the field scale¡ which is referred to as water use efficiency (WUE). The WUE index is indicative of the amount of crop produced per unit amount of water consumed at the field level. This index increases with the increase in crop yield¡ reduction in water used¡ and both of the effects of these two factors together. The issues and sources of inefficiencies leading to the low values of WUE at the field scale could be various. The field scale is the domain which all of the agronomic practices¡ including land preparation¡ cultivation¡ crop treatments¡ and crop harvest occur in this environment. Moreover¡ the field is the place which all of the water management activities¡ from the source of water to the location of consumption¡ are all for this place. Therefore¡ the problems and issues of this water management scale directly and significantly affect on the extents of water use and the yield¡ which is the final goal of the producers. Considering interrelation and linkage of different scales¡ the issues of the field scale¡ causes higher scale problems¡ e.g.¡ environmental pollution¡ over exploitation of water resources¡ and socio-economic problems.Through facilitated brain storming meetings and harvest of the ideas of experts¡ resource persons¡ and the stakeholders from water management sector in general and the agricultural water in specific¡ the issues¡ problems¡ and challenges regarding improvement of WUE in the field scale in Iran were systematically and in a participatory way was identified. The experts were gathered and participated in the different brain storming meetings to identify the relevant problems¡ issues¡ and the challenges. The research outputs were mainly in the form of problem-tree. However some related measures and strategic executive and research pivots and objectives were also developed.Based on the results¡ the main sources of inefficiencies in field-scale WP (WUE) could be summarized in six main category as: 1) Low irrigation efficiencies¡ 2) Inadequate sources of reliable irrigation water resources¡ 3) Low quality of soil and water resources¡ 4) Low values of mechanization indices¡ 5) Problems associated with the irrigation systems¡ 6) Low levels of farmer’s knowledge and skills. From quantitative aspects¡ the number of problems in each of the six categories included 10.9¡ 9.3¡ 13.9¡ 39.5¡ 17.1¡ and 9.3 percent of the total problems respectively. From the strategic view points¡ the results of this research indicated that the issues and measures of improving WUE should not only followed in the water management sector but the agronomic issues and measures¡ especially agricultural mechanization¡ also play and important role in this aspect.

CropSyst model is one of crop models that is being used by researcher in recent years. One of the unique characteristics of CropSyst model is a multi-crop and multi-year that provides long time analysis. This model is used for long time assessment after excellent calibration and validation in Rasht in 2005-2007 (measurement of CRM and NRMSE on validation year for rice were 0.11 and 9.7%¡ respectively). Results of running model were presented after collection data of determined years. In this study¡ different irrigation treatments were simulated and yield of each treatment was determined. Water productivity based on evapotranspiration was used in assessment. Because of results water productivity were variable in 0.42 to 1.01 kg m-3. Three day irrigation treatment was selected as optimum treatment after analyzing of model outputs.

Sensors and new technologies such as wireless sensor networks have developed significantly in the industrial sector and recently have been caused dramatic changes in the precision farming area. Using these technologies and instruments¡ more information will be gathered from field condition and it is possible to control inputs¡ efficiently. Considering wireless sensor network capability in data collection and controlling of the actuators¡ this technology has attracted many customers in the domestic¡ industrial and military sectors. But due to lack of sufficient information on sensors and new technologies¡ they have not been used in Iran’s agriculture. So this paper tries to introduce sensors and modern technologies that have been used in agriculture and also to investigate advantages and limitations of the WSN in agriculture.

There are different viewpoints in estimating basic drainage parameters¡ especially pipe drain depth. Each of these viewpoints considers different agricultural needs (aeration and salinity control)¡ environmental consideration (quality and quantity of drain water) and economic matters (drains density¡ trencher efficiency relative to the depth). Consider each one of these matters could lead drains to be shallow or deep. This paper introduces different viewpoints in determining pipe drain depth and scrutiny their results. Then¡ due to local circumstances of Azadegan plain drainage project how is under construction¡ drain depth determined by each of these viewpoints. Results shown that considering environmental matters and drain depth will be the minimum and considering salinity control will be the maximum. Results also shown that using controlled drainage in the study area for keeping groundwater table up in the irrigation season¡ avoiding over drainage¡ and keep it down in no irrigation season to avoid salt uprising could be the best solution.