DuPont Pioneer Agronomy experts say fields tested in drought-stricken areas may have plenty of nutrients waiting to move back into the soil – despite some soil tests showing low potassium levels. DuPont Pioneer Agronomy Research Manager Andy Heggenstaller says potassium is quite safe in plant residues – so growers shouldn’t be alarmed if soil test levels of the nutrient are lower than expected – but he warns more nutrients will be released into the soil with precipitation. Since there was little rain during the 2012 season – potassium absorbed by corn plants during that time hasn’t been released into the soil from deteriorating corn stalks – and in a drought – the nutrient can get stuck between clay layers and until water moves through the soil.
Heggenstaller says some growers may think it’s best to wait and sample soil in the spring – but he cautions against spring sampling unless farmers normally do so because they would be comparing apples and oranges. He say farmers can count on crop removal rates and previous years’ soil tests as a guide to estimate their potassium needs for the coming year – multiplying the field’s harvested bushels by point-three-pounds of potassium removed per bushel of corn or 1.5-pounds removed per bushel of soybean. Still – Heggenstaller recommends producers test soils this year to help in determining future fertilizer needs.