Comparing the amount of sugar beet irrigation water using the NIAZAB system and field measurement

Estimating the amount of irrigation water for plants is one of the important indicators of the planning of the agricultural sector, and the NIAZAB system was created to estimate the water requirement of agricultural and garden plants and has the ability to check the changes in the irrigation and irrigation water requirements of different agricultural and garden plants in the country. The purpose of this study was to compare the results of field measurement of the amount of irrigation water and sugar beet yield in field conditions with the estimation of NIAZAB system in 117 points, 16 cities in 2016. The results of comparing the field measurement results with the estimation of the NIAZAB system showed that the average amount of sugarbeet irrigation water in the field measurement method and the NIAZAB system is equal to 13088 and 13856 cubic meters per hectare, respectively, and the average yield of sugarbeet tubers in the measurement of the farm and the NIAZAB system was 71846 and 64206 kg per hectare, respectively.The average water productivity of sugar beet in field measurement method and NIAZAB system was equal to 5.8 and 4.9 kg/m3, respectively.The comparison results of the statistical analysis showed that the NIAZAB system estimates the amount of sugar beet irrigation water in the city division scale with the root mean normal error of 21% and the agreement coefficient of 0.89 compared to the field measurement and also, it estimates the yield of sugar beet tuber with a root mean normal error of 0.27% and a coefficient of agreement of 0.81 and the water productivity of sugar beet tuber with a root mean normal error of 0.34%. The efficiency coefficients of the model showed that the NIAZAB system provides acceptable results in determining the amount of irrigation water and the productivity of sugar beet water in the fields of the country. It can be concluded that the NIAZAB system has the ability to provide the amount of irrigation water required by the sugar beet plant in the whole country as well as in the agricultural field.Most of the regions of Iran are located in arid and semi-arid climates, the characteristic of this climate is dry and long seasons without rain. In these areas, the lack of water is one of the most important factors limiting the production of agricultural products, in such a situation, the competition for water is increasing with the increase in population, urbanization and industrialization, and on the other hand, the lack of water is aggravated by improper irrigation management in agriculture (Moravejalahkam et al. al., 2022). In the dry climatic conditions of the country, it will not be possible to provide water easily. Therefore, in these conditions, one of the basic solutions for the proportionality between agricultural water resources and uses, considering the economic and social importance of domestic cultivation of strategic crops, which is included in legal documents, including the Law on Increasing the Productivity of the Agricultural Sector and Natural Resources, approved by the Islamic Council of 2010 was also emphasized (APERDRI, 2016). Optimum use of water resources and management of water consumption is of particular importance for sustainable agriculture and increasing the efficiency of water consumption, and the requirement for optimal use of water resources is to know the amount of water needed to produce an economic product. Sugar beet (Beta-rulgaris) is one of the important economic products and supplies 40% of the world's sugar production (Doorenbos et al, 1979). The benefits of sugar beet cultivation are very important in the national economy and in temperate regions where most of the sugar factories are built. Currently, there are suitable conditions for sugar beet growth in many parts of the country, and the cultivation of this plant is done on a relatively large scale. According to the official statistics of Iran's Ministry of Jihad and Agriculture, the area under sugar beet cultivation in 2016 was equal to 142,821 hectares, and the average yield of sugar beet tubers in Iran was reported as 48.8 tons per hectare (Statistics of the Ministry of Jihad and Agriculture, 2016). Sugar beet is the most important source of sugar production in Iran, and sugarcane is in second place. But sugarcane is cultivated only in Khuzestan province due to special weather conditions (Rahimian and Asadi, 2019). Sugar beet is one of the crops that is cultivated on a large scale in the form of irrigation, and the supply of water required by the plant is one of the necessary factors of production (Mountonnet, 2002). The water requirement of the sugar beet plant is different based on different varieties and different regions (Kochaki, 1996). So that it is reported between 250 and 2700 mm in different regions of the world (Ebrahimi Pak 2019).The results of field measurements in 116 farms in 16 cities and eight provinces of the country with different irrigation methods and different irrigation water sources showed that the average irrigation water of sugar beet plant from the measurement method in the fields and the estimated water demand system is equal to 13088 and it was 13856 cubic meters per hectare. The results of the weighted average of sugar beet irrigation water which was estimated by the system equal to 13817.9 cubic meters per hectare and directly measured from the fields equaled 12805 cubic meters per hectare, and it can be concluded for the surface of 140 thousand hectares of sugar beet irrigated lands. The volume of irrigation water estimated by the water requirement system was 1.94 billion cubic meters and the volume of irrigation water measured in the field was equal to 1.79 billion cubic meters. The comparison of the results of the two methods showed that there is a difference of about 7.7% in the country.