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
CropLife 100The Andersons Starts Venture Capital Subsidiary
January 26, 2015
The Andersons has established Maumee Ventures, a venture capital subsidiary designed to foster promising innovations that strategically align with the company’s core businesses. Read More
CropLife 100CHS Partners With Northern Partners Coop On Fertilizer Warehouse
January 21, 2015
In addition, the two companies will form a joint venture to build and operate a grain barge loading facility that will handle corn, soybeans and wheat for export through the CHS terminal at Myrtle Grove, LA. Read More
CropLife 100Wilbur-Ellis Move To Colorado Complete
January 20, 2015
Wilbur-Ellis Co. announces the opening of its new Agribusiness Division location in the Denver, CO, Metro Area. The new facility will host key personnel as the company shifts the base of its Agribusiness operations from California to Colorado. Read More
CropLife 100United Suppliers, McGregor Co., Five Others To Form Aligned Ag Distributors
January 20, 2015
These companies will continue to operate as independently owned and operated businesses, however, their crop protection divisions will now be formally aligned under the umbrella of Aligned Ag Distributors. Read More
CropLife 100Bozeman Named SEEDWAY Chief Operating Officer
January 16, 2015
He succeeds Donald Wertman, who will retire at the end of August 2015 after 40 years with the GROWMARK subsidiary. Read More
CropLife 100Wilbur-Ellis’ Craig Bair Honored For Safety Contributions To Ag Aviation
January 14, 2015
The William O. Marsh Safety Award recognizes significant achievements in safety, safety education or an outstanding operational safety program. Read More
Latest News
FertilizerThe Fertilizer Institute President Jahn Testifies Befor…
January 28, 2015
The committee hearing, "Freight Rail Transportation: Enhancing Safety, Efficiency, and Commerce," looked at challenges facing our nation's freight rail network created by higher demand, rules and regulations and infrastructure needs. Read More
HerbicidesPurdue University Acquires Technology For Herbicide Mol…
January 28, 2015
Protea's LAESI DP-1000 Instrument System will be used in Purdue's College of Agriculture, the Department of Botany and Plant Pathology, for the molecular imaging of herbicide active ingredients and other related compounds to optimize herbicide applications and improve weed management.  Read More
FertilizerH.J. Baker Hires New Crop Peformance Marketing Manager
January 27, 2015
As Marketing Manager for the Crop Performance division, Usman Khalid will work out of H.J. Baker’s global headquarters in Westport, CT, and will drive new initiatives for the division. Read More
CropLife 100The Andersons Starts Venture Capital Subsidiary
January 26, 2015
The Andersons has established Maumee Ventures, a venture capital subsidiary designed to foster promising innovations that strategically align with the company’s core businesses. Read More
Exclusive state-of-the art Stueve Construction designed “Vista View” Elevated Control Room.
Eric Sfiligoj2015 Agricultural Market Read: Mixed
January 26, 2015
The agricultural market could look radically different this year, profit-wise, depending upon which segment you do business in. Read More
Edward Chell Biosafe
Crop InputsBioSafe Systems Names Ed Chell California Territory Man…
January 26, 2015
BioSafe Systems has announced the recent addition of Ed Chell as California Territory Manager for the agrichemical division, supporting the crop protection, water treatment and food safety business segments. Read More
InsecticidesBayer CropScience Introduces Sivanto Insecticide
January 26, 2015
Sivanto precisely targets key damaging pests at multiple insect life stages to prevent damage to plants and help minimize the spread of diseases from insect carriers. Read More
ManagementRetail Collaboration, Communicating Agriculture’s Good …
January 23, 2015
Editors Paul Schrimpf and Eric Sfiligoj discuss the recent creation of Aligned Ag Distributors, and the US Farmers and Ranchers Read More
FertilizerOSU Expert: Toledo Water Crisis A Turning Point For Ohi…
January 23, 2015
The August 2014 water crisis in Toledo, OH, impacted Ohioans’ views of Lake Erie algae problems by increasing the attribution of blame of algae growth on agriculture. Read More
FertilizerH.J. Baker Launching TIGER XP
January 22, 2015
Tiger-Sul introduces this next generation sulphur-bentonite product with a proprietary activator – ensuring farmers have a well-balanced nutrient replacement program. Read More
Crop InputsH.J. Baker Expands China Sales Force
January 21, 2015
Global Agricultural firm H.J. Baker announced that sales veteran Shi Dongshen has joined their Shanghai office in China. This newest hire follows the recent opening of their Lianyungang Sulphur Bentonite Plant. Read More
CropLife 100CHS Partners With Northern Partners Coop On Fertilizer …
January 21, 2015
In addition, the two companies will form a joint venture to build and operate a grain barge loading facility that will handle corn, soybeans and wheat for export through the CHS terminal at Myrtle Grove, LA. Read More
Matt Hopkins5 Bold Predictions For Ag Retail In 2015
January 21, 2015
This past year was filled with ups and downs for the nation’s top ag retailers, but what will 2015 have in store? Read More
SoftwareDeere Launches App Center
January 20, 2015
The John Deere App Center provides users the ability to search and find apps most useful to their business or operations. Read More
Crop InputsNew Syngenta Herbicide Approved In Soybeans, Sunflowers
January 20, 2015
Syngenta will sell BroadAxe XC herbicide in 2015 for use on soybeans, sunflowers and dry peas Read More
CropLife 100Wilbur-Ellis Move To Colorado Complete
January 20, 2015
Wilbur-Ellis Co. announces the opening of its new Agribusiness Division location in the Denver, CO, Metro Area. The new facility will host key personnel as the company shifts the base of its Agribusiness operations from California to Colorado. Read More
Crop InputsNovozymes Sales Figures Up For 2014
January 20, 2015
Novozymes announces its sales growth in 2014 was in line with expectations as sales grew by 7% compared with 2013. Read More
CropLife 100United Suppliers, McGregor Co., Five Others To Form Ali…
January 20, 2015
These companies will continue to operate as independently owned and operated businesses, however, their crop protection divisions will now be formally aligned under the umbrella of Aligned Ag Distributors. Read More