Investigating the volume of applied irrigation water and water productivity in cherry Orchards of Razavi Khorasan province, Iran

Razavi Khorasan province is one of Khorasan provinces in northeastern of 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, 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 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 water productivity in agricultural activities. Reviewing the sources indicated that the volume of water used in the cherry orchards varied in different regions and with different irrigation systems. This research aims to measure the volume of applied water, the yield, and the productivity of cherry under the management of farmers in three plains: Mashhad - Chenaran, Torghabe - Shandiz, and Nyshabor, and to compare the volume of applied water with the volume of water requirement of cherry mentioned in the national document and calculated by Penman- Monteith method using meteorological data.

This project was carried out in the field in order to determine the optimum water requirement of cherry in the orchards under the management of farmers during one cropping season (2021). Three plains: Mashhad - Chenaran, Torghabe – Shandiz, and Nyshabor were selected in Razavi Khorasan province, these plains have the largest area under cherry cultivation in the province. Based on the data required to implement the project, a questionnaire containing necessary information and logical conclusion was prepared. The required data of the selected farms in each plain were either measured or gained through interviews with the farmer or were calculated and completed according to the data obtained. The measurements were carried out in type of water source, irrigation network, irrigation method, and water source discharge. The field and area under cultivation of cherry, variety, planting arrangement, planting date, soil texture, electrical conductivity of irrigation water and soil saturation extract, date of first irrigation, irrigation cycle, different irrigation methods, etc. The volume of applied water were compared with the net irrigation water requirement estimated by the Penman- Monteith method using the last 10 years meteorological data (2011 to 2021) 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).

In Razavi Khorasan province, underground water sources are facing with deficit. Therefore, efforts towards better use water and reducing exploitation of underground water resources are inevitable. In this project, the water given by the farmers for cherry production during one cropping season was measured in three plains of Mashhad - Chenaran, Torghabe – Shandiz, and Nyshabor, without interfering farmer’s irrigation schedule; these plains had the largest area under cherry cultivation in Razavi Khorasan province. The method of irrigation of the fields was surface and drip irrigation.  The results showed that the volume of applied water in Mashhad - Chenaran, Torghabe - Shandiz and Nyshabor plains were 7760, 7590 and 7740 m3/ha, respectively. The average amount of applied water, the amount of cherry yield and the water productivity in those plains were 7799 m3/ha, 7049 kg/ha and 0.907 kg/m3, respectively. Also, the average volume of irrigation water, yield, and productivity of water in the surface irrigation method were 8029 m3/ha, 6489 kg/ha, and 0.8013 kg/m3 respectively; for drip irrigation method the figures were 7638 m3/ha, 8439 kg/ha, and 0.972 kg/m3 respectively. 

The results showed that the average volume of water, yield and water productivity in three plains were 7799 m3/ha, 7049 kg/ha, and 0.907 kg/m3 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 to surface irrigation method, the volume of applied water was 5% less (7638 cubic meters per hectare versus 8029 cubic meters per hectare), the yield was 14% higher (7439 kg/ha versus 6489 kg/ha) and the water productivity was about 20% higher (0.972 kg/cubic meter of water versus 0.813 kg/cubic meter of water).