Evaluation of Nutrient Supply, Kinetics, and Prediction of Iron (Fe) Uptake in Iron-deficient Soil using a Mechanistic Model

A pot culture experiment in the factorial completely randomized design (FRCD) was formulated with the three levels of iron (Fe) @ 0, 20 and 40 mg kg-1 in the iron-deficient Typic Ustochrept sandy loam soil at Anand Agricultural University, Gujarat, India to evaluate and predict the iron uptake, nutrient efficiency and its depletion of in the rhizosphere of efficient and in-efficient chick pea cultivars using mechanistic model NST 3.0. The current investigation was carried out with the four chickpea cultivars namely, Fe-efficient (GG-1 and GAG-735) and Fe-inefficient (ICCC-4 and GJG-305). Plant observations were recorded during three different growth stages viz., 20 DAG, 40 DAG and maturity, respectively. The shoot weight and shoot length of Fe-inefficient varieties (ICCC-4 and GJG-305) well responded to the application of Fe as compared to Fe-efficient varieties (GG-1 and GAG-735) with 20 mg Fe Kg-1 application through FeSO4. Lower dose of 20 mg Fe kg-1 was found equally effective in increasing root length and root radius. Root radius (ro) and initial soil solution concentration of Fe (CLi) were found most sensitive parameters influencing Fe uptake, which was followed by maximum net influx (Imax). In no Fe treatment, increasing r0, CLi by a factor of 2.0 times individually caused increase in Fe uptake by 1.60, 1.45 times, 1.36, 1.53 times, 1.16, 1.15 times and 1.05, 1.25 times, respectively in GG-1, GAG-735, ICCC-4 and GJG-305 varieties of chickpea. While, increasing Imax and Km separately by a factor of 2.0 Fe uptake altered in proportions by 1.03, 0.57 times, 0.93, 0.57 times, 0.73, 0.54 times and 0.69 and 0.48 times, respectively in GG-1, GAG-735, ICCC-4 and GJG-305 varieties of chickpea. The ICCC-4 instead of GG-1 and GAG-735 could be rational choice to grow on Fe deficient soil to get with dense Fe content. On the other hand, Fe-Inefficient varieties had 2 times of higher mean Fe-influx at 40 mg Fe kg-1 application than Fe-Efficient varieties.