Studies from the United States Department of Agriculture have shown ‘no-till’ farming, a method which reduces soil erosion and increases the amount of nutrients and water in the soil, will help reduce crop losses caused by drought and climate change.

The researchers’ timing is especially convenient given that the country’s worst drought in 50 years has caused widespread damage to US farmers’ major export crops of maize and soy in the Midwest. Researchers said that adoption of the technique, particularly in the central Great Plains region could conserve water, resources of which are stressed in some of the US’ main arable land, and reduce losses caused by climate change.

Whereas conventional tillage has damaging effects, including soil compaction, loss of organic matter, disrubtion of microbial activity, damaging effects on other organisms including earthworms, and soil erosion, no-till avoids this. The method requires very different management than conventional systems.

Research leader Laj Ahuja, from the Agricultural Research Service (ARS), where the studies were carried out, used computer modelling to compare current agricultural practices with ‘no-till’ methods. Ahuja superimposed climate projections onto 15 to 17 years of field data to see how future crop yields might be affected.

In the central Great Plains region, climate change is expected to result in a higher level of atmospheric carbon dioxide (levels are expected to increase from 380 parts per million by volume in 2005 to 550 ppmv in 2050), a 5-degree Fahrenheit increase in summer temperatures and more erratic weather patterns.

Ahuja’s team of researchers, based in Akron, Colorado, looked at crop rotations of wheat-fallow, wheat-maize-fallow, and wheat-maize-millet to investigate how yields might be affected in the future. They ran the model with the projected climate for each of the 15 to 17 years of field crop data for each cropping system.

Whereas the team’s tests showed yields for the three rotation patterns would drop over time under conventional management, with declines in maize and millet being most significant, only switching to ‘climate smart’ methods had any remedial effect on yields.   

Ahuja simulated earlier planting dates in an effort to boost yields, but only no-till management was seen to reduce the projected losses. In the wheat-fallow rotation with no tillage, wheat yields were higher than with conventional tillage.

However, although the approach was shown to provide benefits up until 2050, in long term modelling, its efficacy decreased. After 2075, when modelling showed a summer temperature increase of 8oC, its effectiveness decreased and by 2100 even the no-till yield advantage was lost.

No-till is an agricultural method widely promoted by conservation, research and development groups. Advocates of the approach claim more widespread implementation will ensure food security, biodiversity and water conservation.

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