Soil quality improvement through conversion to sprinkler irrigation

Authors: IPPOLITO, JAMES - Colorado State University; Bjorneberg, David - Dave; Stott, Diane; Karlen, Douglas

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2017
Publication Date: 1/4/2018
Publication URL: https://handle.nal.usda.gov/10113/5927806
Citation: Ippolito, J.A., Bjorneberg, D.L., Stott, D.E., Karlen, D.L. 2018. Soil quality improvement through conversion to sprinkler irrigation. Soil Science Society of America Journal. 81:1505-1516.

Interpretive Summary: Converting from furrow irrigation to sprinkler irrigation is a recommended conservation practice to improve irrigation efficiency and reduce soil erosion. Changing the type of irrigation can potentially change soil quality indicators, too. Several soil quality indicators were measured in the Upper Snake Rock Conservation Effects Assessment Project (CEAP) watershed on four farms where producers had grown barley (Hordecum vulgare L.) using both irrigation practices. Climate, soil type, and management were similar between sites on a farm. Soil samples were collected from the upper (inflow) and lower ends of furrow irrigated fields. Fields converted to sprinkler irrigation were sampled where the upper and lower ends were when the field was furrow irrigated. Soil quality indices (physical, chemical, biological, nutrient, and overall) were computed using the Soil Management Assessment Framework (SMAF). Furrow irrigated field bottoms had higher soil quality index scores than field tops due to long-term erosion on the top end and sediment deposition on the bottom end. Within sprinkler irrigated fields, soil quality indices for field tops and bottoms showed minimal differences. Overall, when all sampling locations were combined, soil quality was similar for both irrigation methods. However, as compared to furrow irrigation, sprinkler irrigation had greater soil quality indices in the field tops, suggesting that sprinkler irrigation improved soil quality by eliminating the continual erosion on the top end of furrow irrigated fields.

Technical Abstract: Conversion from furrow to sprinkler irrigation is a recommended conservation practice for improved water use efficiency (and/or erosion control), but effects on soil quality indicators were unknown. Several soil quality indicators were therefore quantified within a northwestern U.S. Conservation Effects Assessment Project (CEAP) watershed after changing from long-term furrow to sprinkler irrigation. Four on-farm sites were identified where producers were growing irrigated barley (Hordecum vulgare L.) using both irrigation practices. Climate, soil type, and management were similar between sites. Soil samples were collected from the upper and lower ends of furrow irrigated fields at three in-field positions (bed, shoulder, and furrow); fields converted to sprinkler irrigation were sampled where the upper and lower ends were when the field was furrow irrigated. Soil quality indices (physical, chemical, biological, nutrient, and overall) were computed using the Soil Management Assessment Framework (SMAF). Regardless of in-field position, furrow irrigated field bottoms had higher soil quality index scores than field tops due to long-term erosional deposition. Within sprinkler irrigated fields, soil quality indices for field tops and bottoms showed minimal differences. Overall, when all sampling locations and in-field positions were combined, soil quality was similar for both irrigation methods. However, as compared to furrow irrigation, sprinkler irrigation had greater soil quality indices in the field tops, suggesting that sprinkler irrigation improved soil quality of historically eroded furrow irrigated fields.