Increasing levels of phosphate in farmland soil

Jan 24, 2011 by Astrid Smit

Phosphate levels in arable farmland have risen over the past thirty years, despite the restrictive policy on manure. This is the conclusion of Alterra (part of Wageningen UR) researchers in the journal Soil Use & Management.

The researchers analyzed data covering the past seventy years. A striking feature is the large regional differences that have arisen since the 1930s: phosphate levels can be twice as high in some regions compared with others. There is a clear link with the availability of manure in the surrounding area and with the market value of the crops grown. The more manure there was available, the more phosphate got into the soil. A high market value for the crops also led to more phosphate in the soil.

Average levels of phosphate in farmland soil have increased over the past seventy years. Levels in arable land grew by as much as 33 to 40 per cent in the past thirty years. However, phosphate levels in grassland have remained the same since the 1970s.

The introduction of the policy on in 1984 has clearly not had an effect on phosphate levels in arable soil. Arjan Reijneveld from Alterra is not surprised. 'On average more phosphate was being added to the land than was being taken from it during the period we studied. This surplus may gradually have been getting smaller over time but there was still constantly more phosphate entering the than there was being extracted via crops.'

However, he does find it strange that phosphate levels in grassland have remained constant. 'The phosphate surplus must have gone somewhere', says Reijneveld. 'Perhaps it is deposited in deeper layers, but unfortunately we don't have any data for them.' Reijneveld and his colleagues expect phosphate levels in arable land to remain relatively high in the decades to come. That means there will still be a risk of phosphate getting into the surface water for some time to come.

Explore further: Global warming blamed for Pacific coral bleaching

Provided by Wageningen University

5 /5 (1 vote)
add to favorites email to friend print save as pdf

Related Stories

Household cleaners effectively remove lead-laden dust

Dec 15, 2005

All-purpose detergents remove lead-contaminated dust from household surfaces just as effectively as high phosphate detergents and lead-specific cleaning products, according to new research scheduled for publication in the ...

Recommended for you

Rising anger as Nicaragua canal to break ground

18 hours ago

As a conscripted soldier during the Contra War of the 1980s, Esteban Ruiz used to flee from battles because he didn't want to have to kill anyone. But now, as the 47-year-old farmer prepares to fight for ...

Hopes, fears, doubts surround Cuba's oil future

Dec 20, 2014

One of the most prolific oil and gas basins on the planet sits just off Cuba's northwest coast, and the thaw in relations with the United States is giving rise to hopes that Cuba can now get in on the action.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.