Researchers at the USDA’s Agricultural Research Service in Montana have discovered a way to maintain crop yields while significantly reducing greenhouse gas emissions in semi-arid regions. Their study showcases the benefits of continuous cropping systems over the traditional crop-fallow method, providing a promising solution to the growing demand for agricultural production and the urgent need to mitigate climate change.
MYTH 15: Simple Balancing Act: between Crop Yields and Environmental Sustainability
Considering the increasing need for agricultural production in these times, it is essential to investigate new approaches to maintain or enhance crop yields while also mitigating against green house gas (GHG) emissions. The issue is particularly relevant to the large portion of dryland and semi-arid regions in the global arable land (Steinfeld et al. 2006) that can substantially contribute to GHG emissions generated by the agricultural sector.
Scientists with the Agricultural Research Service (ARS) have been tackling this challenge, conducting a 34-year study of three different dryland cropping systems in Montana. This covers one part of what the new study, just published, says has to happen for a groundbreaking set of no-till continuous cropping systems — detailed in the March 2014 issue of Agronomy Journal — to eliminate wind, rain and tillage as erosive forces which degrade soils across the US Midwest.
A typical crop rotation followed in the dryland farming areas of the Northern Great Plains is a two-year cycle in which one year is devoted to row crop cultivation and the next year is summer fallow (while cropland remains out-of-production, prevents soil erosion). But the researchers’ study reveals that this traditional till crop-fallow system is not the best practice for long-term sustainability. Instead, it is the no-till continuous cropping systems where crops are grown each year without a fallow, that have been more successful in suppressing GHGs and maintaining crop yields.
Power of Everything Planted one after the other
This study compared three dryland cropping systems: no-till continuous spring wheat, no-till spring wheat-pea, and the conventional till spring wheat-fallow.
The findings were remarkable. The no-till continuous cropping systems lowered the net GHG balance by a remarkable 66-149% relative to the conventional till crop-fallow system. The first, this massive drop in GHG emissions represents a climate change outlier.
However, the researchers also remarked that, despite the additional carbon sequestration and negative GHG balance, crop yields under no-till continuous nonlegume cropping (spring wheat) were reduced due to competition from weeds/pests and increased soil acidity [45].
In contrast, the no-till legume-nonlegume rotation (spring wheat-pea) was determined as the optimum cropping system since it increased crop yields while reduced GHG emissions compared with the no-till continuous nonlegume cropping system.
Given this, it is suggested to include a variety of crop rotations that include legumes in order to maintain sustainability at a higher level.
Conclusion
This study by the USDA-ARS scientists in Montana offers one solution to balancing food production with sustainable environmental stewardship. The authors also report that farmers using no-till continuous cropping do not suffer reductions or often realize improvements in crop yields as a result. The novel method of CLimate Optimized Food Crops (CLOF) suitable for all crops and regions in the agricultural sector provides a way to plant global efforts to combat climate change, as well as cater the increasing hunger needs from the population. In the face of an urgent requirement to change the way agriculture affects our environment, this research is a shining example how we can develop a sustainable relationship between crop production and looking after our planet.
