By Lauren Riensche, Farm Journal Intern
What is the point of fertilizer? According to Robert Mullen, director of agronomy at PotashCorp, the simple answer is, farmers use fertilizer to remove a yield-limiting factor. When it comes to the nitty gritty, fertilizer use is quite complicated. Several factors come into play: soil type; is land owned or rented; and fertilizer type, price and availability.
"When we look to increase yields, we must first look at the soil," Mullen advises. A soil test will help determine how much fertilizer is needed.
"Soil testing is not perfect, but it is our best tool," he says, adding that increased fertilizer application should lead to higher yield.
Land ownership also plays a role in determining how much fertilizer to apply. If a farmer owns the field, he is more willing to put down the cash to improve nutrient levels than if he rents it.
The type of fertilizer doesn’t matter all that much, Mullen notes. A nutrient source is a nutrient source, regardless of whether it comes in the form of manure or a commercial variety. The only thing a plant cares about is that the fertilizer can be dissolved and absorbed through the roots. What does matter is how much fertilizer is applied.
Mullen also cautions farmers that even in a drought year like 2012, it’s crucial for growers to maintain fertilizer levels. This summer, soybean yields are likely to be low. Without the correct amount of nutrients, those low yields can incur up to an additional 10% yield loss.
Cost is a significant factor, especially since fertilizer prices have continued to increase during the past few years. Price and availability are tied to the fact that a new potash mine has not been dug in more than 20 years.