Document Type

Article

Publication Date

1-1-2018

Abstract

Potassium fertilization research on soybean [Glycine max (L.) Merr.] double cropped with winter wheat (Triticum aestivum L.) is lacking. We characterized double-crop soybean response to fertilizer K across 22 Coastal Plain and Piedmont sites with and/or without wheat straw removal during 2013 to 2015. Mehlich-1 soil-K concentrations at 0- to 15- and 0- to 30-cm depths were better in explaining relative yield variability (r2 = 0.80), defining critical soil-K concentrations that ranged from 40 to 75 mg K kg–1 for 0- to 15-cm and 36 to 66 mg K kg–1 for 0- to 30-cm depths, and identifying K-deficient sites (100% accurate) than soil-K concentration at 0- to 60-cm depth (r2 = 0.48; 56% accurate). Critical soil-K concentration at 0- to 30-cm depth did not change with wheat straw management, but slightly increased at 0- to 15-cm depth when straw was removed. The R2 leaf-K concentration with a critical range of 20 to 23 g K kg–1 was better (75% accurate) in diagnosing K deficiency than V5 plant-K concentration (50% accurate) with a critical range of 17 to 23 g K kg–1. Double-crop soybean required 33 to 119% more fertilizer K than Virginia Cooperative Extension recommendations for ≤50 mg soil-K kg–1 at 0- to 15-cm depth, but 6 to 55% less fertilizer K for similar soil K concentration at 0- to 30-cm depth. Wheat straw management should not be an issue of concern for fertilizer-K recommendations based on soil-K concentration at 0- to 30-cm depth for double-crop soybean production on Coastal Plain and Piedmont soils.

Publication Source (Journal or Book title)

Agronomy Journal

First Page

399

Last Page

410

Download

Share

COinS