Soil Fertility

Last updated on February 23, 2014

Fertilizing for High Wheat Yields

First step - soil test

Build levels of P and K to the medium-high to high levels

Once medium high to high levels of P and K are attained, growers add MAINTENANCE amounts.

A maintenance amount is the estimated amount that a crop will remove

If both grain and straw are harvested, plants will remove about 0.8 lb of P₂O₅ and 1.9 lb of K₂O per bushel of grain

If only grain is harvested, about 0.6 lb of P₂O₅ and .4 lb of K₂O are removed per bushel of grain yield

In Wisconsin, ICM wheat growers are commonly adding 80 to 100 lbs N/a to wheat

When large amounts of N are used, applications should be split

Winter wheat N applications: 1/3 in fall (pre plant) 1/3 applied during spring greenup 1/3 applied during early stem elongation

How much N should be applied?

• Recommendations vary according to YIELD GOAL, % OM, and SEASONAL EFFECTS (Amount of rainfall, etc)
• Spring wheat N applications: 1/2 pre-plant,1/2 early stem elongation (Zadoks 31)

Split applications of N have several advantages

• Avoid excess N during vegetative growth
• Adequate N available throughout growth cycle
• Flexibility