KEY FINDINGS

LAND IS RESTORED           rice fieldBio-agricultural farming improves soil fertility, biodiversity  and land regeneration, restoring degraded and desertified  soil, which now totals over 2 billion hectares worldwide. It reduces dryland-salinity, increases water retention (by 20%-50%)

A FIGHT AGAINST POVERTY AND HUNGER      land degradation2,000 million hectares, or 40% of the earth’s agricultural land, has been degraded through
unsustainable cultivation, overgrazing, deforestation, chemical pollution and aquifer degradation. The fight against desertification is fundamentally a fight against poverty and hunger.
 

Research at America’s longest running farm trials show that synthetic nitrogen fertilisers reduce soil carbon.

 

morrow plotsThe Morrow plots at the University of Illinois were started in 1876. At the time Illinois was famous for its deep, black soils well suited to corn production. Morrow and Miles – the founders of the Plots - wanted to find out whether this productivity could be sustained and how various cropping-systems would affect yield and soil properties.

Using results from over a hundred years of continuous field trials at the Morrow Plots as well as from other published research from around the world, University of Illinois soil scientists Saeed Khan, Richard Mulvaney, Tim Ellsworth, and Charlie Boast found that excessive application of synthetic nitrogen stimulates soil microbes which feed on organic matter. Over time, this enhanced microbial activity consumes carbon in the soil from crop residues. The net result being a reduction in soil carbon.
Their paper "The Myth of Nitrogen Fertilization for Soil Carbon Sequestration" was published in the November/December 2007 issue of the Journal of Environmental Quality. (see paper here)

From 1904 the plots had been fertilised with manure, limestone, and rock phosphate. In 1955 some plots were changed to synthetic nitrogen fertilisation – others were changed in 1967. Aboveground crop residues were originally removed from each plot but beginning in 1955 were incorporated in the soil.
Khan and his colleagues analyzed samples for organic carbon in the soil to identify changes that have occurred since the onset of synthetic nitrogen fertilization.

"What we learned," said Khan, "Is that after five decades of massive inputs of residue carbon ranging from 90 to 124 tons per acre, all of the residue carbon had disappeared, and there had been a net decrease in soil organic carbon that averaged 4.9 tons per acre. Regardless of the crop rotation, the decline became much greater with the higher nitrogen rate,"
Excessive application of synthetic fertilisers…“cuts profits and is bad for soils and the environment” said Ellsworth. “The loss of soil carbon has many adverse consequences for productivity, one of which is to decrease water storage. There are also adverse implications for air and water quality, since carbon dioxide will be released into the air, while excessive nitrogen contributes to the nitrate pollution problem."

 

 

land degradation

 

A century of changes in organic C concentrations    for the plow layer in The Morrow Plots

Open circles represent subplots with fertilizer and aboveground residue inputs beginning in 1955. Solid circles represent subplots with manure, limestone, and rock phosphate inputs before 1967, subsequently replaced by high NPK fertilization and aboveground residue return.