Observations on the Boron-Manganese Relationships in Soybean and Corn Plants

Abstract

The possibilities of ameliorating manganese-induced chlorosis with boron applications were studied under greenhouse conditions using soybean and corn as indicator plants. Five levels of boron with six manganese concentrations were used in the soybean experiment. Boron and manganese were used at five levels each in the corn experiment. Observations were made as to the development of toxicity symptoms. Boron, manganese, and iron were determined in the top leaves of the corn plants. Measurements of dry-matter production were made for both crops. Five parts per million of manganese was toxic to soybean plants and reduced yields, but toxicity was lessened by increasing the boron in the nutrient solution up to 0.5 p.p.m. Boron was toxic also at levels above 0.5 p.p.m. No definite manganese-toxicity symptoms developed in the corn plants. In general, high boron (2, 5 p.p.m.) reduced corn yields regardless of the manganese level. Chemical analyses of the corn leaves suggests the possibility that manganese accumulation may be modified to some extent by boron concentrations.