Effect of Foliar Boron Fertilization of Fine Textured Soils on Corn Yields

Boron ( B) is an essential micronutrient needed for normal plant growth and development. To evaluate the response of corn to foliar B applications at V4- V6 ( 4- 6 leaves with visible collars) and VT ( tasseling) growth stages on fine textured soils, a field experiment was conducted at four sites from 2008 to 2010 in Northeast Missouri. The treatments included a non- treated control; V4- V6 applied B at 0.56, 1.12 and 2.24 kg . ha-1; and VT applied B at 0.28, 0.56 and 1.12 kg . ha-1. Foliar B, applied at V4- V6 at 2.24 kg . ha- 1, resulted in higher yields than VT applications. No significant differences in yield were found for B applications at different timings for concentrations of 0.56 and 1.12 kg . ha- 1. Boron applied at V4- V6 and 2.24 kg . ha- 1 increased yield 0.29 Mg . ha- 1 compared to the non- treated control. The B applications at VT increased ear leaf tissue B concentration compared to V4- V6 applications and non- treated control, but it had no significant effect on corn yields. No significant difference between B treatments was observed for grain oil, protein, starch or extractable starch concentration; severity of anthracnose stalk rot or common rust; and ear tip fill. The B application of 2.24 kg . ha- 1 at V4- V6 decreased the severity of gray leaf spot, but increased the severity of northern leaf blight compared to the non- treated control. Boron applied at V4- V6 at 2.24 kg . ha- 1 was the most beneficial timing and concentration evaluated in these fine textured soils.