Document Type : Original Article
Authors
1 Member of scientefic board, Agriculture Research Center of Khorasan Razavi
2 Assistant Professor and Professor of Irrigation and Drainage Engineering Department, Agricultural Engineering Research Institute (AERI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
Abstract
Extended Abstract
Introduction
Razavi Khorasan province is one of Khorasan provinces in northeastern Iran, the center of this province is Mashhad. The area of this province is 118854 square kilometers. Due to having high evaporation potential and low rainfall, which is mostly associated with inappropriate distribution, this region is among the dry and semi-arid regions of our country, so that water is considered the most important factor limiting the growth and development of agriculture. Nowadays, limitations in water resources has made it necessary to create ways to increase water productivity. This is a proof of the importance of careful planning and finding the use of different irrigation methods to increase the water productivity of agricultural activities. By examining the sources, it was found that the volume of water used in the cotton crop varies in different regions and with different irrigation systems. This research aims to measure the volume of applied water, the yield and productivity of cotton under the management of farmers in Razavi Khorasan province (Bardaskan, Nyshabor, Sabzevar, Khaf, Roshtkhar and Sarakhs cities) and compare the amount of applied water with the water requirement of cotton in these six plains (city) with the national document and It was also calculated by Penman-Monteith method with meteorological data.
Methodology
This project was carried out in the field in order to determine the useful water of cotton in the fields under the management of farmers during one cropping season (2018). Six cities of Bardaskan, Nyshabor, Sabzevar, Khaf, Roshtkhar and Sarakhs were selected in Razavi Khorasan province, which have the largest area under cotton cultivation. At first, based on the data required by the project, a questionnaire containing necessary information for investigation and logical conclusion was prepared. The required data of the selected farms in each city were either measured or through face-to-face interviews with the farmer or were calculated and completed according to the data of the previous two stages. The measurements were carried out in type of water source, irrigation network and method and water source discharge, total level The field and area under cultivation of cotton crop, variety, planting arrangement, planting date, soil texture, electrical conductivity of irrigation water and soil saturation extract, date of first irrigation, irrigation cycle and different irrigation methods, etc. The Measured Applied water were compared with the net irrigation water requirement estimated by the Penman-Monteith method using the last 10 years meteorological data (2009 to 2018) and also with the national water document values. Crop yield was recorded at the end of the growing season and water productivity was calculated as the ratio of yield to total water (irrigation applied water and effective rainfall).
Results and Discussion
The results showed that the volume of applied water, the amount of cotton yield and the water productivity in Bardaskan region were 7369 m3/ha, 4583 kg/ha and 0.638 kg/m3, respectively. The amount of applied water, the amount of cotton yield and the water productivity in Nysahabor region were determined as 9773 m3/ha, 3554 kg/ha and 0.528 kg/m3, respectively. The amount of applied water, the amount of cotton yield and the water productivity in Sabzevar region were 9173 m3/ha, 3033 kg/ha and 0.225 kg/m3, respectively. In Khaf region the amount of applied water, the amount of cotton yield and the water productivity were 14791 m3/ha, 2821 kg/ha and 0.194 kg/m3, respectively. The amount of applied water, the amount of cotton yield and the water productivity in Roshtkhar region were 11281 m3/ha, 3466 kg/ha and 0.327 kg/m3, respectively, The amount of applied water, the amount of Cotton yield and the water productivity in Sarakhs region were determined as 9004 m3/ha, 2113 kg/ha and 0.265 kg/m3, respectively. The average amount of applied water, the amount of cotton yield and the water productivity in above six regions were 9830 m3/ha, 3078 kg/ha and 0.357 kg/m3, respectively. Also, the average volume of irrigation water, yield and productivity of water in the surface irrigation method were 10175 m3/ha, 2892 kg/ha and 0.318 kg/m3 respectively, and in the drip irrigation method 7242 m3/ha 4470 kg/ha and 0.649 kg/m3 were obtained.
Conclusions
In Razavi Khorasan province, underground water sources are facing a reservoir deficit. Therefore, efforts towards better use of extracted water and reducing exploitation of underground water resources are inevitable. In this project, the water given by the farmers for cotton production during one cropping season was measured in the six plains of Bardaskan, Nyshabor, Sabzevar, Khaf, Roshtkhar and Sarakhs cities, without interfering farmer’s irrigation schedule ; these plains had the largest area under cotton cultivation in Razavi Khorasan province. The method of irrigation of the fields was surface and drip irrigation (tape). The results showed that the average volume of water, yield and water productivity in these planes were 9830 cubic meters per hectare, 3078 kg per hectare and 0.357 kg per cubic meter of water, respectively. The difference between the volume of applied water, performance and water efficiency in two methods of surface and drip irrigation was significant. Under the drip irrigation system, comparing surface irrigation method, the volume of applied water was 30% less (7242 cubic meters per hectare versus 10175 cubic meters per hectare), the yield was 55% higher (4470 kg/hectare versus 2892 kg/hectare) and the water productivity was about 104% higher (0.649 kg/cubic meter of water vs. 0/318 kg/cubic meter of water.
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Main Subjects
of Irrigation and Drainage Engineering Research, 17 (67), 113-128. (In Persian).
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