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 th