The need for use of boron (B) for alfalfa production has been recognized for many years in Kentucky and is presently recommended for general use as an annual topdressing on alfalfa fields. Use of B is also recommended in Kentucky for red clover fields which are to be harvested for seed. In recent years, there has been interest in use of fertilizer B for good corn production in Kentucky. Plant available B is greatly affected by soil pH and decreases with increasing soil pH. Because of this, some states recommend use of B on corn grown on soils with a pH of 6.1 or higher. Also, some commercial soil testing laboratories serving Kentucky routinely test for B, and often recommend its use for corn. This has resulted in many corn growers in Kentucky asking if they need to use B on corn.
Murdock, Lloyd W.; Wells, Kenneth L.; and MIiller, H. F., "Boron Fertilization of Corn in Kentucky" (1977). Agronomy Notes. 112.