As wheat plants move into the ‘construction’ development phase there will be high demand for most nutrients as rapid growth occurs. Deficiency of potassium, manganese or copper during stem extension will lead to weaker stems and increase the risk of lodging later in the season.
As stem extension takes place it s important to avoid deficiencies of those nutrients which contribute to straw strength particularly potash, manganese and copper. Each of these nutrients has a role in maintaining stem strength and therefore reducing lodging susceptibility.
Pay particular attention to: potash, manganese and copper
Potassium is required for water regulation in the plant, being held in the cell vacuoles which hold most of the plant water, maintaining the plants strength. Low levels of potassium reduces water movement into cells, reducing their strength and increasing the likelihood of wilting and increasing the potential for lodging. The demand for potash may be in excess of 10-12kg/ha/day (depending on the crop) with a total requirement of 250-300kg by the end of flowering. Potassium is also potentially mobile in soils following high rainfall (depending on the clay content) so most seasons this could also be particularly important for potash applications.
It should be remembered however, that high rates of potassium can lead to a reduction in the availability of magnesium, an essential part of the chlorophyll molecule, important for efficient photosynthesis.
The roles of manganese and copper in reducing the potential for lodging comes from the requirement by enzymes that catalyse the production of lignin. Lignin is important in cell walls of plants which are key in stem strength and as a barrier to pathogenic infections.
YaraMila compounds such as provide a balance of major nutrients most including sulphur for spring application to cereals, whilst YaraVita micronutrients supply the important micronutrients for cereals in spring.
The following fertilisers are particularly useful for spring application to wheat crops to improve straw strength