Dynamic critical potassium concentrations in soybean leaves and petioles for monitoring potassium nutrition

Document Type

Article

Publication Date

11-1-2021

Abstract

Soybean [Glycine max (L.) Merr.] critical tissue-K concentrations associated with the bloom to early pod set growth stages have been used to diagnose K deficiency for decades. The ability to interpret tissue concentrations beyond the R2 stage would strengthen soybean tissue monitoring programs. Our objective was to develop continuous critical-K concentrations for the trifoliolate leaf and petiole of irrigated soybean. Trifoliolate leaf- and petiole-K concentration data were collected during soybean reproductive growth from 10 research trials. Multiple regression was performed to predict relative soybean yield as a function of tissue-K concentrations and days after R1 development (DAR1). The 10 research trials provided >1,400 leaf- and petiole-K concentration observations from the R1–R6 stages of soybean cultivars from the 4.4–5.5 relative maturity groups. Among the 10 trials, soybean receiving no fertilizer-K produced 59.2–83.2% of the maximum yield produced by soybean receiving fertilizer-K. The sufficient leaf-K concentrations associated with 95% relative yield were 20.2 g K kg–1 at 1 DAR1, 18.5 g K kg–1 at 20 DAR1, 15.5 g K kg–1 at 40 DAR1, and 11.2 g K kg–1 at 60 DAR1, which occur at the R1, R2, and R3-R4, and R5-R6 growth stages, respectively. Compared with leaf-K concentration, the sufficient petiole-K concentrations associated with 95% relative yield were 2.5 times greater at R1 but similar at 70 DAR1 (R6). Agricultural analytical laboratories can use these sufficiency equations for soybean leaf- or petiole-K concentrations, with planting date and maturity group information, to interpret soybean K sufficiency.

Publication Source (Journal or Book title)

Agronomy Journal

First Page

5472

Last Page

5482

This document is currently not available here.

Share

COinS