Cool Soil Temperatures in Direct Seeding Reduces Crop Stress and Improves Yield

Cool Soil Temperatures in Direct Seeding Reduces Crop Stress and Improves Yield
Author: Mirza N. Baig, Tom Goddard and Peter Gamache
Date Created: January 25, 2008
Last Reviewed: January 25, 2008
No-till or direct seeding is a conservation practice and it is economical (saving on fuel, farm machinery-life and reduced labor costs. while maintaining or improving crop yields) and is well known to be environmentally friendly (increased soil-organic matter, improved soil tilth, improved moisture conservation and use efficiency, and reduced soil erosion). Direct seeding also has the potential to sequester atmospheric carbon dioxide – an important factor in the mitigation of green house gas emissions. A characteristic of no-till or direct seeding is that it retains most of the crop residues on the soil surface. This crop residue acts as insulation and impedes the rate at which thermal energy is exchanged between the soil and the atmosphere, affecting soil microclimate through reducing the wind speed near the soil surface and the heat transfer through evaporation and heat flow. This often keeps the soil temperature 1 – 2 C cooler in zero-tilled fields than in conventionally tilled fields. Crop residues also help to trap and hold the snow, enhance moisture absorption during summer rains, and results in increased soil moisture availability at seeding time and throughout the growing season. Growers in the Black Soil Zones of Alberta have often raised concerns about cooler soil temperatures at seeding time under no-till systems, and this is often one of the reasons cited for using conventional tillage. The extent to which these cooler soil temperatures influence crop emergence and establishment and its subsequent growth in the Black Soil zones of Alberta is not fully understood. Therefore, the focus of this fact-sheet is to summarize all the current information on the effect of cool soil temperature on crop emergence, establishment, growth and yield in direct seeding systems. Click on the pdf for the complete 7 page factsheet.