How To Minimize Phosphorus Losses In Runoff

Phosphorus losses from agricultural fields can be divided into three categories:

  • Flash losses of soluble phosphorus soon after application of fertilizer or manure.
  • Slow leak losses of soluble phosphorus.
  • Erosion events.

Flash Losses Of Soluble Phosphorus

Manure, like fertilizer, has a vastly higher concentration of soluble phosphorus than soil does. If a rainfall runoff occurs soon after a surface application, the concentration of soluble phosphorus in the runoff can be more than 100 times higher than normal in the runoff.

Over time, highly soluble manure and fertilizer phosphorus on the soil surface will react with the soil, reducing soluble phosphorus in runoff back to initial levels. Normal levels return over the course of a month in warm soils, longer in cold soils. Manure and fertilizer application is not recommended on frozen or snow-covered soils because phosphorus never has a chance to react with the soil before runoff occurs.

Research from Arkansas on poultry litter and swine manure applied to pastures shows that soluble phosphorus concentrations increase in direct proportion to increasing application rate in these flash phosphorus loss events.

Flash losses of soluble phosphorus have high concentrations of phosphorus in a form that is readily available to aquatic organisms. These events occur only if rainfall runoff occurs soon after a surface phosphorus application or when phosphorus is surface applied to frozen or snow-covered fields. However, one ill-timed application can contribute more phosphorus to surface water than is lost by all other processes over the course of a year or more.

To minimize flash losses of soluble phosphorus:

  • Apply phosphorus sources below the soil surface in a manner that does not increase soil erosion.
  • Surface-apply phosphorus sources during periods of the year when runoff is unlikely.
  • Surface-apply phosphorus sources only on fields with a low potential for runoff.
  • Do not surface-apply phosphorus sources to frozen or snow-covered soils.
  • Maintain low-phosphorus buffer strips around water resources.
  • Add alum or a similar treatment to manure to reduce the availability of phosphorus.

Slow Leak Losses Of Soluble Phosphorus

All soils naturally release some soluble phosphorus into surface runoff. The concentration of soluble phosphorus in runoff is affected by the soil test phosphorus level of the soil.

Soil tests for phosphorus were developed to help estimate phosphorus fertilizer requirements for crops. Research on soils from other states indicates that soils near optimum soil test levels for growing crops typically support soluble phosphorus concentrations of 0.5 ppm or less.

There is substantial evidence that soluble phosphorus concentration in runoff will increase linearly with increasing soil test phosphorus levels. This linear relationship changes from soil to soil. Tripling soil test phosphorus above the high soil test category may increase soluble phosphorus in runoff to 0.5-2.5 ppm.

Slow leak phosphorus losses are important because they occur in every runoff event. Because of the cumulative effect of multiple runoff events, this mechanism can be the most important source of phosphorus loss. To minimize slow leak losses:

  • Apply phosphorus only to fields that have an agronomic need for phosphorus.
  • Reduce the amount of annual runoff from agricultural fields through crop selection and soil conservation practices.
  • Maintain buffer strips where no phosphorus is applied around water resources.

Erosion Losses

When runoff water gains sufficient energy to cause soil erosion, the amount of phosphorus lost from the field increases dramatically. Controlling erosion losses by reducing or eliminating tillage on corn or wheat can reduce total phosphorus losses by 50 percent or more.

In soil, the total phosphorus is much higher than the soluble phosphorus content. Soil particles have a tremendous capacity to fix soluble phosphorus, allowing only a small proportion of the plant-available phosphorus to exist in the soluble form.

The sorting of soil particles that naturally takes place during erosion results in the soil particles with the highest phosphorus concentration being carried with runoff. Soils with higher soil test phosphorus levels will have higher phosphorus content in eroded particles. To minimize erosion losses of P:

  • Adopt soil conservation practices to minimize soil erosion.
  • Maintain buffer strips around water resources where no phosphorus is applied.

Source: University of Missouri Extension

Leave a Reply

One comment on “How To Minimize Phosphorus Losses In Runoff

  1. A typical comment from CropLife – Not a single comment regarding the all important role microorganisms play in making phosphorus available to plants thus reducing the amount of P needed. There is a limited amount of P on the planet. One country controls 60 % of the know source of P. Five years ago the price increased 800 percent. Most countries that have P deposits have increased their export fees. So what does Crop Life talk about ? Erosion loss And slow leak .

Fertilizer Stories
FertilizerFall Fertility 2014: Forecasting Fertilizer Use
September 7, 2014
Great crops this year have tapped the soil, and fall work is definitely called for, but how challenging will that get? Read More
Aerial view of the West Fertilizer explosion site
FertilizerFertilizer Companies Blame City For West, TX, Explosion
August 6, 2014
El Dorado Chemical Co. and CF Industries contend the city failed to properly train the first responders and had insufficient protocols in place to battle the April 17, 2013, blaze at West Fertilizer Co. that triggered the explosion. Read More
FertilizerThe Fertilizer Institute: New President, Renewed Energy
February 3, 2014
Chris Jahn relishes the opportunity to lead the organization through the challenging times ahead. Read More
FertilizerA New Cycle For Fertilizer Demand
January 2, 2014
Changes in the corn market could have a major impact on the crop nutrients sector in 2014, say experts. Read More
Top 100 Articles
Milan Kucerak, president/CEO, West Central
CropLife 100West Central Cooperative And Its New President Are A Match Made In Deviation
June 29, 2015
To appreciate just how unique West Central Cooperative is in the world of ag retail, an observer need only consider Read More
Winter Wheat
CropLife 100South Dakota Co-op Member Owners Vote No On Unification
June 26, 2015
The Boards of Directors for North Central Farmers Elevator (NCFE) and Wheat Growers (WG) have announced that member-owners have voted Read More
CropLife 100The Andersons Acquires South Dakota Plant Nutrient Manufacturer Kay-Flo
May 20, 2015
The Andersons, Inc., ranked No. 22 on the CropLife 100, has purchased Kay Flo Industries of North Sioux City, SD. “This Read More
CropLife 100AgGateway’s Barcoding Initiative Progressing Nicely
May 8, 2015
According to legend (or Wikipedia), the first step towards modern bar codes came back in 1948, when Bernard Silver, a Read More
CropLife 100Pinnacle Agriculture Acquires Minnesota Retailer
April 14, 2015
Pinnacle Agriculture Holdings, LLC, ranked No. 6 on the CropLife 100,  has successfully acquired Liebl Ag, LLC in Ada, MN.  Read More
CropLife 100CHS, Aurora Cooperative Complete Fertilizer Storage, Grain Shuttle Loading Facility
April 13, 2015
CHS Inc., the nation’s leading cooperative and ranked No. 5 on the CropLife 100, and Aurora Cooperative (ranked No. 21) Read More
Latest News
Measuring Bulk Tanks
ManagementBulk Pesticide Compliance: Top 10 Areas Of Improvement …
July 1, 2015
  In honor of the 33-year run of David Letterman’s Late Show, the American Agronomic Stewardship Alliance (AASA) is happy Read More
Industry NewsArysta North America Hires Midwest Sales Manager
July 1, 2015
Arysta LifeScience North America recently announced the hiring of Brian Battles as the Senior Technical Sales Manager for the Midwest Read More
Farmer on tablet
Eric SfiligojThe Never-Ending Battle Against Modern Agriculture
July 1, 2015
In the world of comic books, the character of Superman often refers to the fight to save the world as Read More
Retail FacilitiesBuilding Up Ag Retail
July 1, 2015
In the oftentimes unpredictable world we live in, it’s nice to know some things can be reliably countered on to Read More
Retail FacilitiesMaple River Grain And Agronomy Phases In Site Developme…
July 1, 2015
Marcus Construction helped Maple River Grain and Agronomy in Casselton, ND, with the design-build of its dry fertilizer, liquid chemical/seed Read More
Retail FacilitiesA&B Welding Builds A New Liquid Terminal Hub For Br…
July 1, 2015
To build its new hub facility, Briggs Crop Nutrients enlisted the help of A&B Welding. The result, an efficient facility Read More
Edon Farmers Co-op
Retail FacilitiesNew Marcus Facility At Edon Farmers Co-op Provides More…
July 1, 2015
Edon Farmers Co-Op in Edon, OH, needed a new facility to consolidate outdated locations. Marcus Construction was able to design Read More
Retail FacilitiesKinder Morgan Expands Its Storage With A New Dome Barre…
July 1, 2015
Kinder Morgan wanted additional covered storage at its Dakota Bulk Terminal on the Mississippi River in St. Paul, MN. With Read More
Retail FacilitiesHeartland Tank Protects Fertilizer From Extreme Cold At…
July 1, 2015
The Arthur Companies in Harvey, ND, enlisted the help of Heartland Tank Companies to develop a new liquid fertilizer facility Read More
The McGregor Co. fertilizer loadout
Retail FacilitiesThe McGregor Co. Partners With Kahler Automation To Cre…
June 30, 2015
Kahler Automation helped The McGregor Co. expand its Clarkston, WA, operation with unstaffed loadout technology that enables customers to pick Read More
Dry and Liquid Plant
Retail FacilitiesKahler Automation Helps CHS Dakota Ag Cooperative Build…
June 30, 2015
CHS Dakota Ag Cooperative in Mooreton, ND, wanted a liquid/dry blender system that could meet the needs of its customers Read More
Crop InputsLand O’Lakes, United Suppliers To Merge Crop Inpu…
June 29, 2015
Land O’Lakes, Inc. and United Suppliers, Inc. of Ames, IA, today announced their intent to merge their crop inputs businesses. Read More
FungicidesHelena To Distribute Unique Summit Agro Fungicide
June 29, 2015
RANMAN 400 SC fungicide, the only fungicide with a FRAC group 21 designation, is now part of the innovative Summit Read More
Eric SfiligojIARC Targets 2,4-D In Latest Report
June 29, 2015
The International Agency for Research on Cancer (IARC) has struck again. Earlier this year in March, this agency of the Read More
Milan Kucerak, president/CEO, West Central
CropLife 100West Central Cooperative And Its New President Are A Ma…
June 29, 2015
To appreciate just how unique West Central Cooperative is in the world of ag retail, an observer need only consider Read More
EquipmentCase IH Launches New Precision Air 5 Series Carts
June 29, 2015
Case IH recently introduced its new Precision Air 5 series air carts, developed to get the most from every plant’s Read More
InsecticidesVestaron Biopesticide Approved In California
June 29, 2015
Vestaron Corporation, a developer of insect control products derived from naturally occurring peptides, today announced that its VST-006330-EP biopesticide has received Read More
InsecticidesValent’s Zeal SC Miticide Receives EPA Approval
June 29, 2015
Valent U.S.A. Corporation announced today that Zeal SC Miticide has been registered by EPA with a new liquid formulation that Read More