Crops responded positively to future levels of atmospheric carbon dioxide (CO2), but soil tillage practices had little effect on this response, according to a U.S. Department of Agriculture (USDA) study.
http://www.physorg.com/news203852397.html
Raised carbon dioxide improves crop yields
The first long-term study comparing tillage practices under high CO2 levels showed that elevated CO2 caused soybean and sorghum plants to increase photosynthesis while reducing transpiration-the amount of water the plants release. This resulted in increased water use efficiency, whether the crops were grown with no-till or conventional tillage, according to researchers with USDA’s Agricultural Research Service (ARS).
Plant physiologist Steve Prior, plant pathologist Brett Runion, and their colleagues at the ARS National Soil Dynamics Laboratory in Auburn, Ala., found that water use efficiency response to high CO2 was much greater for soybeans than for sorghum over the 6-year study. The scientists also compared current ambient CO2 levels—about 370 parts per million (ppm)—with levels of 720 ppm. With the higher level of CO2, regardless of tillage method, soybean photosynthesis increased by about 50 percent, while sorghum photosynthesis rose by only 15 percent. This was expected because crops like soybean, which have a C3 photosynthetic pathway, are known to respond better to high CO2 levels than crops like sorghum and corn that have a C4 photosynthetic pathway. Most plants worldwide are C3 plants.
Carbon dioxide concentration and Photosynthesis
Although no-till didn’t make a difference as far as crops responding to high CO2, it can greatly reduce soil erosion, conserve soil water, and increase carbon storage, among its many benefits.
The results of this research were published earlier this year in the Journal of Environmental Quality.
Tags: Agriculture, carbon dioxide, Field Crops, Tillage
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