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Mehdi akbari; Fariborz Abbasi; Abolfazl Nasseri; Afshin Gomrokchi; mostafa goodarzi; Amir Eslami; masoud Farzamnia; r alimohammadi; Nader Kouhi Chellehkaran; Reza Bahramloo; Ali Ghadami Firouzabadi; seyed abolghassem Haghayeghi moghaddam; Ardalan Zolfagharan; Jamal Ahmadaali; Mohamad Abasi; Hamid Riahi; Mohammad Mehdi Nakhjavanimoghaddam
Abstract
In this study, volume of irrigation water, water productivity, and yield of alfalfa were measured in 300 farms in Zanjan, Fars, Chaharmahal and Bakhtiari, Hamedan, East Azerbaijan, Semnan, Khorasan-Razavi, Isfahan, West Azerbaijan, Central, Qazvin and Kerman provinces under farmers management and surface ...
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In this study, volume of irrigation water, water productivity, and yield of alfalfa were measured in 300 farms in Zanjan, Fars, Chaharmahal and Bakhtiari, Hamedan, East Azerbaijan, Semnan, Khorasan-Razavi, Isfahan, West Azerbaijan, Central, Qazvin and Kerman provinces under farmers management and surface and sprinkler irrigation, various water sources, different water salinities, soil conditions, and varieties, during the growing season of 2018-2019. The results showed that the difference between average volumes of water applied by farmers, yield, and water productivity, in the studied sites were significant at 1% probability level. The average amount of applied water by farmers was 8502, 8901, 9226, 9459, 11481, 12796, 14311, 14821, 15198, 15916, 18351 and 23920 m3/ha, respectively, and the average was 13284 m3/ha. The dry yield of alfalfa varied from 2500 to 30000 kg/ha with an average of 13841 kg/ha. Irrigation water productivity varied from 0.2 to 4.5 and its average was 1.28 kg/m3. The average irrigation water plus effective rainfall productivity for alfalfa was 1.19 kg/m3. The results showed that the average applied water and alfalfa yield in surface and sprinkler irrigation methods were 15076 and 10653 m3/ha, respectively, (p<1%). These results showed that in sprinkler irrigation method, applied water was 30% less and irrigation water plus effective rainfall productivity was 41% higher. Accordingly, in order to reduce the volume of irrigation water and improve alfalfa water productivity, it is recommended to use sprinkler method in suitable climatic conditions where irrigation water is of good quality and the technical criteria of design, implementation, operation, and economic considerations are met.
m y; Mohsen Ahmadee; s b; a h
Abstract
Climate change has important impacts on most of the natural processes, including hydrological cycle. Evapotranspiration, as a part of hydrological cycle, will also undergo these changes. Due to the importance of evapotranspiration in water resources and agricultural management, this research was ...
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Climate change has important impacts on most of the natural processes, including hydrological cycle. Evapotranspiration, as a part of hydrological cycle, will also undergo these changes. Due to the importance of evapotranspiration in water resources and agricultural management, this research was conducted to study climate change effect on evapotranspiration in Neyshabour plain. Evapotranspiration was calculated for five farms in Neyshabour plain using SWAP software and meteorological and agronomic data. In irrigated farms, the HADCM3, ECHAM5OM and CGCM3T47models were used to calculate crop actual evapotranspiration for 2020-2039 and 2080-2099 periods based on A2, B1 and A1B scenarios and the climate model used in rainfed farms was the HADCM3 based on A2 and B1 scenarios. The greatest calculated difference in evapotranspiration was found between the period 2080-2099 and base period (1992-2011) in the A2 scenario. Also, evapotranspiration values for the period 2080-2099 will increase compared to the period 2020-2039 in all three scenarios. Among the crops of investigate, wheat will have the greatest changes (12%) in evapotranspiration in the future periods compared to the base period, while changes of maize will be only 3%. However, the average daily evapotranspiration of maize during the growing season (about 12 mm/day) will be more than the other crops.
A haghayeghi moghadam; m farzamniya
Abstract
Access to fresh groundwater plays an important role in stable crop production and secure livelihood of people living in the Neyshabour plain. Decline in groundwater table and annual aquifer abstraction of more than 200 million cubic meters are the most important challenges in this plain, where about ...
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Access to fresh groundwater plays an important role in stable crop production and secure livelihood of people living in the Neyshabour plain. Decline in groundwater table and annual aquifer abstraction of more than 200 million cubic meters are the most important challenges in this plain, where about 110,000 ha of agricultural land are cultivated annually and 96% of groundwater resources are used in the agricultural sector. In this study, Soil-Water-Atmosphere-Plant (SWAP) model was calibrated and validated using measured data from six different fields located in the Neyshabour plain. For this purpose, field information and other SWAP required data were collected in the six farm conditions. Calibrated and validated SWAP model was then used to quantify the effects of existing irrigation practices on water balance components and different water productivity indicators and to determine improved irrigation schedules for wheat, barley, sugar beet, cotton, silage corn, and tomato. Estimation of the net water saving as a result of improved irrigation schedules is also discussed. The results showed that under the current irrigation practices, soil evaporation reduced WPET (Yact/ETact) over WPT (Yact/Tact) by 24%, 26%, 27%, 21%, 8% and 16% for wheat, barley, sugar beet, cotton, silage corn and tomato, respectively. The reduction in WPETQ (Yact/ETact+qbot) over WPET because of deep percolation was even higher: 50%, 44%, 33%, 37%, 14% and 56% for wheat, barley, sugar beet, cotton, silage corn and tomato, respectively. The substantial differences in WP values emphasized the need to control non-beneficial soil evaporation and deep percolation losses, and change traditional irrigation system by a more efficient one. Model simulations by improved irrigation schedule revealed that a seasonal irrigation amount of 520 mm for wheat, 440 mm for barley, 1010 mm for sugar beet, 930 mm for cotton, 870 mm for silage corn and 1050 mm for tomato would be enough to get the maximum yields. The optimized irrigation schedule uses 26% less irrigation water as compared to current irrigation practices and increases WPI (Yact/Irrig) by a factor of 1.2 for wheat, 0.7 for barley, 1.6 for sugar beet, 6.7 for silage corn and 8.3 for tomato because of reduced soil evaporation and moisture storage in the root zone. Considering the total area of cultivation of the six studied crops in the Neyshabour plain (80000 ha), it is estimated that adoption of optimal irrigation schedules can save up to 165 million m3 of water.