Northwest Columbia Plateau PM10 Project Objective 2: Measurement and Prediction of Wind Erosion and Dust Emissions Title: Tillage Tool Modifications for Reducing the Emission of Windblown Dust from Agricultural Soils Personnel: Principal Investigator: Brenton Sharratt, USDA-ARS; Co-investigator:

of Research Findings Alternative tillage and cropping systems are sought for reducing dust emissions and improving air quality in the Pacific Northwest dryland cropping region. The purpose of this study was to modifiy the conventional rodweeder that would facilitate the armouring of the soil surface with straw and large aggregates otherwise buried below the soil surface. Several modifications were tested in the laboratory; these modifications included attaching a rake or plate-rake apparatus behind the rodweeder bar. These modifications largely resulted in pushing the soil ahead of the apparatus as opposed to sieving the soil through the rake or plate-rake apparatus. These modifications were tested on a conventional rodweeder in the field. Similar results were obtained – the modifications pushed the soil ahead of the apparatus without sieving the soil. Improvements to these modifications are required that will facilitate moving (through the use of rollers or moving components) the soil from the rodweeder bar to the rake where straw and large aggregates can be separated from the finer soil material. Objectives Conservation tillage and cropping systems are sought in the low precipitation zone of the Columbia Plateau that will reduce windblown dust and PM10 emissions from agricultural soils. Past studies related to tillage in the region have primarily focused on agronomic characteristics (e.g. yield, crop cover) of contrasting tillage systems and on emission characteristics of conventional tillage systems. In addition, the undercutter has been shown to be an effective primary tillage tool for reducing dust emissions during the subsequent summer fallow period. Although the undercutter represents one tool for reducing soil erodibility and dust emissions, other tillage tools are sought that can reduce dust emissions during conventional summer fallow. Therefore, the design of tillage equipment must be given some consideration in maintaining summer fallow but yet reducing soil erodibility and emissions during summer fallow. The objectives of this research were to: 1. Modify the rodweeder, which is conventionally used to control weeds during the summer fallow phase of a winter wheat – summer fallow rotation, that will enable