Farmer Survey Reveals Inconsistencies in Phosphorus Practices

Minneapolis, MN (January 21, 2004) - A recent survey of croplands across the United States reveals that soil testing and fertilizer application practices are inconsistent with farmers’ stated understanding about phosphorus’ importance in helping maximize crop profits. Nearly 40 percent of farmers surveyed soil-test only half of their acreage on a regular basis to determine phosphorus application levels, despite 73 percent acknowledging the nutrient’s vital role in early crop development and generating higher yields. Phosphorus is one of three nutrients used to promote crop development, along with nitrogen and potassium.

Conducted by telephone between November 2003 and January 2004, the Phosphorus Utilization Survey interviewed 150 farmers growing corn, wheat, soybean, alfalfa and cotton. Fifty-one percent of the farmers believed that amending low phosphorus levels to recommended levels in their fields could increase crop yields up to 40 percent, while 65 percent conceded that depleted phosphorus levels could limit yields as much as shortages of nitrogen could.

According to Mike Brubaker, a 25-year practicing agronomist and long-standing member of the NAICC, “These practices leave a significant percentage of crop fields untested, and thus highly vulnerable. Farmers can’t assume that there is adequate phosphorus in the soil, and the only way to know how much phosphorus and other nutrients are in their fields is to engage in a regular soil-testing program.”

A regular soil-testing program can be defined as one that provides representative soil test information for each individual field, regardless of field size, every three to four years. Often times this testing will utilize either grid or management zone sampling.

Brubaker recommends that farmers contact their professional agronomist, local fertilizer dealer, or extension service office to determine the most effective soil-testing practice for their land.

The Phosphorus Utilization Survey was commissioned by a group of private- and public-sector agronomy experts from the National Alliance of Independent Crop Consultants (NAICC), the University of Minnesota Extension Service, Cargill Crop Nutrition and the Potash and Phosphate Institute (PPI). Last year the coalition launched the Phosphorus 101 (P101) Education Project, a long-term effort to educate and inform farmers of the benefits of phosphorus.

The study’s findings on phosphorus awareness and usage corroborate a major finding of the landmark 2001 Soil Test Levels in North America study by the Potash and Phosphate Institute, which revealed that 47 percent of North American farmland is at barely optimal or less-than-optimal phosphorus levels, despite advances in soil-testing methodology and application technology.

Add to that, publicity in recent years has focused more on ill-advised uses of phosphorus that contribute to algae growth in lakes and streams rather than its role as a vital crop nutrient.

“Phosphorus is like the crop’s battery – vital to root growth, seed formation, disease resistance and early maturity, but as this latest study shows, testing and application practices are not in sync with general awareness about the valuable function of phosphorus,” says Dr. Dan Froehlich, U.S. Manager of Agronomy for Cargill Crop Nutrition. “In addition, we are now learning that soil-testing levels are dropping into the medium or low range, and it will take many years to build soil nutrient levels back to where farmers can maximize this resource.

“We know that part of the issue with phosphorus application is habit,” added Froehlich. “Through efforts such as our P101 education campaign, we hope to work more closely with farmers, fertilizer dealers, crop consultants and others to promote responsible use of phosphorus through regular soil testing and approved application methods that will most benefit their soil.”

For more information about the Phosphorus 101 Education Project and a copy of the 2001 Soil Test Levels in North America, go to www.P101.org.

Contacts:
David Feider

(952) 742-6910

david_feider@cargill.com