Promoting potassium allocation to stalk enhances stalk bending resistance of maize (Zea mays L.)

Potassium (K) is an essential macronutrient for crop growth but it catches less attention than either nitrogen or phosphorus regarding their role in escalating crop yield. However, increasing evidences support the fact that K application enables crop to enhance resistance to lodging, but little is known about how maize resistance to lodging is affected by K distribution in shoot. We conducted a two-year field experiment including 6 levels of K application, monitored K uptake and distribution in different parts of shoot, and examined the effect of K application on stalk bending resistance of maize. K application significantly enhanced above-ground K uptake of maize. Across growing season, maize increased K uptake in the vegetative period while leveled off after anthesis. Stalk contained greater proportion of K than other parts, and stalk increased but ear rarely altered the K proportion with K application increase. K application significantly enhanced the bending resistant strength of maize stalk. The bending resistant strength was positively correlated with the diameter/length ratio, dry matter linear density and stalk K concentration, but those two internode morphological traits played more important role. We concluded that K application promoted K allocation to stalk and enhanced maize resistance to stalk lodging by modifying the internode traits. The study provides evidence for the importance of K application in maize production on soils with high stalk lodging risk.