Potassium effects on stalk strength, premature death and lodging of maize (Zea mays L.)

Abstract

In a field trial with maize, applications of potassium (K) proved to have a highly significant effect on stalk strength, premature death, root lodging and stalk breakage. A week prior to harvest the percentage of lodged plants varied from 77% in plots which received 50 kg K ha⁻¹ to 47% in plots which received 200 kg K ha⁻¹. Although some stalk breakage of green plants and root lodging were evident, premature death was clearly the prime cause of lodging. Significantly, premature death and stalk breakage were lowest in plots which received no K fertilization. The virtual absence of ears precluded the establishment of the carbohydrate sink, considered to play an important role in predisposing plants to invasion by stalk-rot organisms. The marked effects of K observed in this study suggest that K stress could profitably be used as a selection aid in breeding programmes. It seems probable that discrimination in terms of standability will be reduced when crops are adequately fertilized with K.