Determining the Water Requirement and Applied Water of Bell Pepper in the Greenhouse and Comparing It with the Results of the Water Requirement System

One of the important goals of the development of greenhouses in the country is to improve production efficiency and increase water and fertilizer efficiency. Bell pepper is also one of the most important greenhouse products around the world and has a high economic value. This research was carried out to provide irrigation and fert fertigation scheduling for greenhouse peppers through monitoring soil moisture and salinity in the root zone in 1400 in Alborz province, Chaharbagh city. The treatments include three irrigation treatments I1, I2 and I3 (100, 80 and 60% of the plant's water requirement) and three fertigation treatments F1, F2 and F3 (150, 100 and 50% of the plant's fertilizer requirement, respectively) in the form of a randomized complete block design in three replications. The total amount of irrigation measured for treatments I1, I2 and I3 was 397, 318 and 238 mm, respectively. The irrigation requirement values simulated by the irrigation requirement system of agricultural and garden plants were compared with the measured values, and the statistical indices RMSE, NRMSE, MBE, d and EF were calculated to be 38.55, 0.21, and -21.1, 0.99 and 0.95 respectively. The results showed that the effect of irrigation, fertigation and their mutual effect on the yield of greenhouse pepper was significant. The maximum yield of pepper in the I1F1 treatment was 114.38 tons/ha and the minimum in the I3F1 treatment was 40.96 tons/ha. Also, the maximum water productivity in the I2F2 treatment was 31.05 kg/m3 and the minimum in the I3F1 treatment was 17.19 kg/m3. Although the maximum yield was obtained in the I1F1 treatment, the maximum water productivity was obtained in the I2F2 treatment, and the product yield was not significantly different in these two treatments. The general conclusion shows that 20% deficit irrigation is recommended by monitoring the moisture of the root zone in greenhouse pepper production, but the fertilizer should be controlled by monitoring the salinity of the root zone.