Determination of Critical Concentrations of Boron in Soils and Leaves of Tomato (Lycopersicon esculentum L.) using Polynomial Equation

Tomato (Lycopersicon esculentum L.) is a sensitive crop to B deficiency, but information on critical concentrations of the element in plant tissues and soils for the crop is scarce. An experiment was, therefore, undertaken to assess available B content in the Gangetic alluvial soils (Entisols and Inceptisols) for tomato and to determine critical limits of B in soils and leaves of tomato involving second order polynomial curve fitting. Soils and tomato leaves were collected from 94 tomato growing fields. Soils were analysed for hot-calcium chloride (HCC), potassium dihydrogen phosphate (PDP), tartaric acid (TA) and hydrochloric acid (HCl) extractable B and tomato leaves for B concentration. Among the four extractants, HCl extracted the highest amount of B followed by HCC > TA > PDP. Extractability of the extractants for B was explained mechanistically with soil properties. Hot-CaCl2 showed stronger relationships with soil properties, tomato fruit weight and leaf B concentration, and thus proved to be the superior over other extractants for assessing available B status in soil for tomato. Critical limits of HCC extractable B were 0.51 and 0.52 mg kg(-1) and of mature tomato leaf B concentration were 40.5 and 37.5 mg kg(-1) in Entisols and Inceptisols, respectively. The method of determining critical concentrations of B in soils and plants involving polynomial equations with non-destructive on-field samples was efficient for delineation of B deficiency in both Entisols and Inceptisols. Multi-criteria based novel approach established HCC as the best extractant for assessment of available B in soils.

Automated summary

This study aimed to establish critical limits of boron (B) in soils and leaves of tomato crops. The experiment analyzed soil and tomato leaf samples from 94 fields and found that hot-calcium chloride (HCC) was the most effective extractant for B assessment. The study provided insights into addressing B deficiency in tomato cultivation.