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Improving Air Quality with No-Till Cropping

By Ann Perry

July 5, 2012

Studies by U.S. Department of Agriculture (USDA) scientists show some no-till management systems can lower atmospheric levels of PM10—soil particles and other material 10 microns or less in diameter that degrade air quality—that are eroded from crop fields via the wind. These findings could help Pacific Northwest farmers reduce erosion from their fields and assist communities in complying with federal air quality regulations.

Agricultural Research Service (ARS) research leader Brenton Sharratt and ARS agronomist Frank Young conducted this research, which supports the USDA priorities of promoting international food security and responding to climate change. ARS is USDA's chief scientific research agency. Both scientists work at the ARS Land Management and Water Conservation Research Unit in Pullman, Wash.

Farmers in the inland Pacific Northwest favor winter wheat-summer fallow production systems so that crops can germinate and grow during late summer and fall. But controlling weeds and conserving soil water during the summer can require up to eight tillage passes. This produces a dry, loose layer of fine soil particles that can be easily eroded by strong summer winds.

Sharratt and Young conducted an 11-year study that evaluated whether no-till spring cereal rotations could help mitigate wind erosion. The systems they studied included typical winter wheat/summer fallow rotations, no-till spring barley/spring wheat rotations, and no-till spring wheat/chemical fallow rotations.

The scientists found that in the spring, soils in spring barley and spring wheat rotations were wetter than soils in traditional winter wheat systems. In late summer, the spring barley rotation also had more standing stubble than the other two rotations. The stubble helped keep soil on the ground and out of the air. Spring wheat/spring barley rotations also resulted in soils that had larger and more continuous pore space, higher water infiltration rates, higher saturated hydraulic conductivity, and higher drainage rates.

Sharratt and Young concluded that annual no-till spring cereal crops could significantly improve water infiltration and retention and help retain crop surface residue in the late summer—results that improve soil quality and reduce soil losses from wind erosion.

Findings from this work were published in the Journal of Soil and Water Conservation and Soil & Tillage Research in 2011.

Read more about this research in the July 2012 issue of Agricultural Research magazine.