From dust bowl to carbon sink: the potential of conservation agriculture

Two new videos exploring conservation agriculture were recently shared. The first looks back to the US dust bowl in the 1930s that motivated the development of no-till farming and conservation agriculture. The second looking at how conservation agriculture can help in practice and how we can prevent the next dust bowl in the Russian Steppes through sustainable land management strategies.

Changing an Age-Old Practice Helps New Generation of Farmers, is the title of a new video created by the World Bank. Tilling of soil is done to prepare the seed bed, release nutrients and control weeds but tilling can also lead to soil erosion, causing the loss of top soil that degrades farmland and causes sedimentation in waterways. In the lower Mississippi River removal of sediment costs over $100 million each year. In the Great Plains of the US around the 1930s the dust bowl winds eroded top soil from 65 million hectares of land and led to an unprecedented environmental disaster. Soil degradation globally is increasing due to climate change whereby more frequent storms and floods erode vulnerable soils. The disturbance of these soils releases greenhouse gas emissions, contributing to climate change.

Conservation agriculture is proposed as a solution, which comprises no tillage of the soil or minimum disturbance of the soil; the maintenance of crop residue in the field; and crop rotations and species diversity. These practices help to reduce soil erosion, allow recovery of the soil structure, reduce pests and diseases, conserve water and build up nutrient stores. Such practices are also said to be more labour and cost efficient. Breaking the centuries old tradition of tilling the soil is not easy however, and requires the development of new herbicides, new equipment and farmer education. But the benefits conservation agriculture can bring, such as relatively inexpensive climate change adaptation and mitigation and sustainable farms into the future, far outweigh the costs.

How to prevent the next “Global Dust Bowl”? – Ecological and Economic Strategies for Sustainable Land Management in the Russian Steppes: A Potential Solution to Climate Change was produced by Kulunda, an interdisciplinary project on sustainable land management. The Kulunda Steppe in Siberia close to the border with Kazakhstan has dry continental climate conditions. In the 1950s about 420,000km² of natural grassland were converted to farming. In recent decades crop yields have been continually declining as a result of low soil fertility and carbon, wind erosion and drought, and today some 50% of these lands are degraded. Because of the arid climate the soil neither stores water nor nutrients well and conventional agricultural methods are failing leading to the out-migration of young people.

Extreme Weather Events on the Rise

Can scientists now say with a fair amount of confidence that extreme weather events such as the Texas heat wave last year, the Russian heat wave of 2010 and the European heat wave of 2003 are directly linked to global warming caused by humans?

In a new paper entitled ‘Perception of Climate Change’ NASA scientist James Hansen and two colleagues describe how climate change has increased the occurrence of unusually warm weather events in the past 30 years. There is only a small chance that the shift towards both higher temperatures and increased weather extremes would have happened in the absence of climate change.  Periods of extreme summertime temperatures have increased in geographic scope from less than 1% of the land’s surface in the base period of 1951 to 1980 to covering 13% in recent years.