Using the NIAZAB system to estimate the amount of water consumed by the eggplant plant using the method of inverse solution of the production function in the conditions of interaction of deficit irrigation and nitrogen fertilizer

Document Type : Original Article

Authors

1 On-Farm Water Management Department, Soil and Water Research Institute, Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran.

2 Assistant professor, Department of irrigation and soil physics, Soil and Water Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran

3 Associated professor, Department of Irrigation and soil physics, Soil and Water Research Institute, Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran

Abstract

Abstract
Introduction: Deficit low irrigation is of particular importance as a valuable strategy for areas where water is the limiting factor in crop cultivation. The ability to estimate in determining the water requirement, the amount of water consumed and Irrigation scheduling one of the most effective factors in the irrigated cultivation of agricultural products. Therefore, this research was conducted in order to investigate the NIAZAB system in determining the actual amount of irrigation water and eggplant yield based on the inverse solution of the production function under water stress conditions in Guilan province.

Material and methods: In this research, irrigation management included no irrigation and providing 60, 80, and 100% of the plant's water needs as the main factor and secondary factors nitrogen fertilizer amounts (from the urea fertilizer source) included two levels of zero and 120 kg/ha. The experiment was carried out in the form of split plots in the form of a randomized complete block design in three replications in the years 2020 - 2022. In terms of climate, the region was one of the temperate and humid regions. The Soil and Water Research Institute of the country presented a system called "NIAZAB System" which is used to determine the water requirement of agricultural crops. This system has the ability to estimate and determine water Requirements, water consumption and plant irrigation planning at the level of the region, city, watershed and plain. One of the important points of this system is its location-based nature, and the user can extract the needs of the desired area by referring to the system and estimate the water consumption for the cultivation pattern under different options.

Results and discussion: The results showed that the highest amounts of evapotranspiration in the studied years occurred in the irrigation conditions of 100% of the water requirement and the consumption of 120 kg N fertilizer. In the measured conditions and the methods of Tafteh, Pasquale and Reas, the amount of evapotranspiration in 2020 were 341, 332, 333 and 333 mm respectively and in 2021 it were 358, 346, 359 and 346 mm respectively and in 2022 were 620, 576, 615 and 577 mm respectively. The average relative error in the mentioned methods in the first year were 2.6%, 2.3% and 2.3% respectively and in the second year were 3.4%, -0.3% and 3.4% respectively, and in the third year, were 7.1%, 0.8% and 6.9% respectively. The root mean square error (RMSE) for evapospiration in Tafteh, Pasquale and Reas methods were 18.6, 79.3 and 18.3 mm/day, respectively, and the root mean square normal error (RMSEn) was 0.059, 0.251 and 0.058% respectively. The Index of agreement (d) in the Tafteh, Pasquale and Reas methods were 0.976, 0.595 and 0.977%, respectively. The coefficients of efficiency (EF) of the models were 0.915, -0.536 and 0.918 percent respectively, and the coefficients of determination (R2) were 0.92, 0.35 and 0.92% respectively.

Conclusions: In general, the statistical results between field data and NIAZAB System showed that Tafteh and Reas methods are a suitable method for making decisions and estimating the water consumption of eggplant plants in the study area.

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