Effects of boron sources and rates on grain yield, yield components, nutritional status, and changes in the soil chemical attributes of soybean

Abstract

Boron (B) deficiency has been demonstrated as a frequent problem in soybean crops, as soybean exhibits a large sensitivity to this nutrient, regardless of its uptake efficiency in the soil. The objective of this study was to evaluate the effects of B sources and rates on the yield, yield components, nutritional status, and changes in the chemical attributes of soil cultivated with soybean. The experimental design was completely randomized in a 2 × 5 factorial design with four replicates. The treatments consisted of two sources (H₃BO₃ and ulexite) and five B rates (0, 2, 4, 8, and 16 mg kg⁻¹). The grain yield (GY), yield components, nutritional status, and soil chemical attributes were evaluated. B sources–rates interactions (S × R) were significant for most variables evaluated. The B (H₃BO₃) application resulted in higher B levels in the leaves and the soil cultivated with soybean than those obtained with ulexite. GY was highest with a B application of 4 mg kg⁻¹, exhibiting a toxic effect in H₃BO₃ at 8 and 16 mg kg⁻¹. The application of B increased N, S, Fe, and B concentrations while decreasing P and K in the leaves. The shoot dry weight yield, number of pods, grains per pot, and 100-grains weight were also influenced by the B rates. The highest GY ranged from 0.3- to 0.8 mg kg⁻¹ in the soil and 50- to 100 mg kg⁻¹ in the soybean diagnostic leaf.

Keywords:

• Glycine max
• foliar B
• available B
• H₃BO₃
• ulexite

Acknowledgments

The experiment was supported by the Soil Fertility and Microbiology team for the experiment carried out in Londrina (Paraná State) and National Council for Scientific and Tecnological Development (CNPq) for financial support.

Disclosure statement

No potential conflict of interest was reported by the authors.