Foliar Potassium Fertilizer Additives Affect Soybean Response and Weed Control with Glyphosate

Figure 2

Soybean grain yield response to K-fertilizer additives (%N-%P₂O₅-%K₂O-%S) of 3-18-18-0 (𝑦=−1.4832𝑥²−10.738𝑥+3203, 𝑅²=0.92), 0-0-25-17 (𝑦=−0.8783𝑥²+15.749𝑥+3203, 𝑅²=0.99), 5-0-20-13 (𝑦=1.3693𝑥²−7.9878𝑥+3203, 𝑅²=0.94), or 0-0-62-0 (𝑦=8.0129𝑥²−13.635𝑥+3203, 𝑅²=0.80) applied alone to weed-free plots (a) and with glyphosate to weedy plots (b) for 3-18-18-0 (𝑦=2.4953𝑥²−21.474𝑥+2860, 𝑅²=0.99), 0-0-25-17 (𝑦=8.0594𝑥²−87.005𝑥+2860, 𝑅²=0.98), 5-0-20-13 (𝑦=10.901𝑥²−15.061𝑥+2860, 𝑅²=0.85), and 0-0-62-0 (𝑦=4.8315𝑥²−21.957𝑥+2860, 𝑅²=0.94) at Novelty in 2005. The nontreated, weed-free, and glyphosate plus nonionic surfactant plus diammonium sulfate grain yields were 1070, 3200, and 2750 kg ha⁻¹, respectively. Comparisons between figures are valid. The LSD (𝑃=0.01) was 320 kg ha⁻¹.

(a)

(b)