Soil Carbon Storage in Wheat-Based Cropping Systems

At 3:30 p.m., Upendra Sainju, Northern Plains Agriculture Research Laboratory research scientist will be discussing soil carbon storage under dryland wheat-based cropping systems at the Wheat Show, Feb. 9.

Sainju will discuss long-term research in eastern Montana, involving 10-36 years of experiments. He will also touch on the effects of tillage, crop rotation, and nitrogen fertilization on soil organic carbon to a depth of 4 ft.

Since 2004, Sainju has been working at the USDA-ARS, researching carbon sequestration, nitrogen cycling, greenhouse gas emissions, and crop production in dryland and irrigated cropping systems. He studies soil organic and inorganic carbon levels at the surface and subsurface soil layers using various management practices, such as tillage, cover crops, crop rotation, nitrogen fertilization, irrigation, and sheep grazing.

"Our research shows that conventional tillage/wheat-fallow rotation has not only reduced soil health by increasing soil erosion and salinization and reducing organic matter, but also reduced annualized crop yield due to the absence of crops during the summer fallow period," explained Sainju.

He also says that their results show how soil carbon level can be enhanced by using no-tillage crop rotation with recommended nitrogen fertilization rate by eliminating summer fallow and how spring wheat yield can be enhanced with this practice. Improved soil carbon storage also enhances soil health by increasing soil water content, aggregation, microbial activities, and nutrient levels.

Sainju says producers can enhance farm income by increasing carbon sequestration in carbon credit markets using improved management strategies.

"Increased soil carbon levels also can enhance spring wheat yield by increasing soil fertility. This is a win-win situation for producers, as increasing soil carbon storage also reduces greenhouse gas emissions that enhance global warming and the potentials for additional income through carbon credit markets and increased crop yields," said Sainju.

Although soil carbon is shown to increase yields, it is a slow process. It takes more than 10 years to enhance soil carbon sequestration using improved management techniques in dryland cropping systems.

"However, indirect effects of improving soil health, such as increased soil water content, aggregation, and microbial activities, are readily observed by increasing carbon sequestration. More than ever, there is a need to mitigate climate change by reducing greenhouse gases, such as carbon dioxide, by enhancing soil carbon sequestration using improved agricultural practices."


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