Evaluation of Nutritional Status and Priority of Nutrients Requirement of Tomato by Compositional Nutrient Diagnosis Method in Bushehr Province

Tomato is one of the most important crops in Bushehr Province and its out-of-season cultivation has doubled its importance. Achieving optimal performance is possible by balancing the nutrients. Nutritional indicators are used to diagnose nutritional disorders and the subsequent optimal use of chemical fertilizers. This research was conducted by selecting 79 tomato farms from different parts of the province with different yields in two years (2018-2020). Soil samples of selected fields were taken from a depth of 0 to 30 cm and leaf samples were taken at the beginning of fruiting. The average yield of each field was measured at the end of harvest and laboratory analysis of samples was performed by standard methods. The experimental data were fitted with compositional nutrient diagnosis model (CND). The studied farms were divided into two groups, low and high yields, with a cut-off yield of 86.7 tons per hectare, based on the highest yield and calculations according to the CND method. Reference numbers of leaf nutrient concentrations were calculated as 2.79±0.202, 0.460±0.174, 2.62±0.143, 2.57±0.195, 2.08±0.225, -2.20±0.134, -3.10±0.134, -3.74±0.200, -4.34±0.250, and -3.25±0.173 for N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, and B, respectively. Also, the optimal leaf nutrient concentrations range for 86.7 tons per hectare of yield were N: 3.38±0.94, P: 0.324±0.074, K: 2.77±0.397, Ca: 2.63±0.423, Mg: 1.64±0.394 percent, and for Fe: 221±24.6, Mn: 90.9±14.8, Zn: 48.3±11.1, Cu: 27.3±8.40, and B: 79.3±17.5 mg.kg-1. Potassium, N, and Zn deficiency as well as excess amount of Mg, Ca, and Mn were identified as the imbalanced nutrients in tomato production in Bushehr Province. This can be due to the calcareous nature of the soil and unbalanced use of chemical fertilizers.