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Corn and Soybean Tissue Potassium Content Responses to Potassium Fertilization and Relationships with Grain Yield
Author(s) -
Clover Matthew W.,
Mallarino Antonio P.
Publication year - 2013
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2012.0223
Subject(s) - potassium , human fertilization , agronomy , yield (engineering) , crop , chemistry , crop yield , dry weight , zea mays , zoology , biology , materials science , organic chemistry , metallurgy
Research on relationships between K fertilization, crop yield, and tissue K concentration is needed for modern corn ( Zea mays L.) hybrids and soybean ( Glycine max L. Merr.) varieties. Twenty 2‐yr trials with these crops in Iowa evaluated K effects on plant dry weight (DW), K concentration, and accumulation at the V5‐V6 stage; leaf K concentration (R1 stage in corn and R2 in soybean); and grain yield, K concentration, and K removal. Five K rates (0–168 kg K ha ‐1 ) were broadcast the first year (10 sites for each crop). Potassium increased corn or soybean yield at 16 site‐years, which had soil K ≤ 173 mg K kg ‐1 (15‐cm depth, CH 3 COONH 4 test). On average across first‐year responsive crops, 91 and 103 kg K ha ‐1 maximized corn and soybean yield, respectively, and across second‐year crops the response was linear. Potassium fertilization increased grain K concentration and K removal to a greater extent and more frequently in soybean than in corn (10 vs. 5 site‐years, respectively, for concentration and 11 vs. 3 site‐years, respectively, for removal). The magnitude and frequency of responses for both crops were greatest for vegetative tissue K concentration and smaller (in decreasing order) for grain yield and K removal, grain K concentration, and early DW. There was large luxury K accumulation in vegetative tissues. Critical tissue K concentration ranges defined by two models were 20.2 to 25.1, 10.2 to 11.0, and 17.6 to 20.0 g K kg ‐1 for corn plants, corn leaves, and soybean leaves, respectively, and could not be determined for soybean plants.