Assessment of soil aggregate stability methodologies in calcareous silt loams

Authors: Krecker-Yost, Jenifer; KRUGER, KEVIN - University Of Idaho; Bjorneberg, David - Dave; Dungan, Robert - Rob; Leytem, April; MOORE, AMBER - Oregon State University; SCHOTT, LINDA - University Of Idaho

Submitted to: Journal of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2024
Publication Date: 7/3/2024
Citation: Yost, J.L., Kruger, K., Bjorneberg, D.L., Dungan, R.S., Leytem, A.B., Moore, A.D., Schott, L.R. 2024. Assessment of soil aggregate stability methodologies in calcareous silt loams. Journal of the ASABE. 67(4):879-887. https://doi.org/10.13031/ja.15650.
DOI: https://doi.org/10.13031/ja.15650

Interpretive Summary: Idaho is a top producer of dairy, potato, barley, hay, sugarbeet, corn silage, and dry beans. Irrigation is necessary to grow crops in the Magic Valley which can cause soil erosion and runoff to occur. The overall goals of this project were to identify the best method for the assessment of soil aggregate stability (an indirect indicator of soil erosion) and to determine which agricultural management practices help mitigate soil erosion. Three long-term agricultural research study sites in Southern Idaho were used for this study. It was found that soil aggregate stability was more sensitive under simulated rainfall compared to traditional wet sieving in irrigated croplands. The results can help producers reduce soil erosion on their fields and improve crop production.

Technical Abstract: Idaho ranks in the top 10 in the United States for dairy, potato, barley, hay, sugarbeet, corn silage, and dry bean production. The highest producing areas in the state for these commodities are in the Magic Valley where irrigation is necessary. To measure progress in producer efforts for reducing erosion and runoff, appropriate methods need to be identified. The soils in this region are prone to crusting, have low organic matter, and are high in calcium carbonates making these soils unique to the western United States. Thus, the overall goal of this project was to identify the best method for the assessment of soil aggregate stability. The three study sites were located on the USDA-ARS Northwest Irrigation and Soils Research Laboratory in Kimberly, Idaho, and were established in 2012 (LT-Manure and GRACEnet) and 2015 (Cover Crop). Each study was set up using common cropping rotations and agricultural management practices for the region using a variety of nutrient sources, tillage types, and cover cropping. Three methods were used to measure soil aggregate stability: wet sieving, simulated rainfall using a Cornell Sprinkle Infiltrometer (operational height: 30, 90, and 150 cm), and the SLAKES mobile application. No differences in soil aggregate stability were found when the wet sieving or SLAKES methods were used at the three study sites. No treatment differences were found at LT-Manure or GRACEnet when using the Cornell Sprinkle Infiltrometer, however differences were observed at the Cover Crop study site (30 and 90 cm operational height). At 30 cm, the average mean weight diameter was the highest when cover crops and dairy manure were applied (3.73 mm) and lowest in the control (3.12 mm). At 90 cm, the average mean weight diameter was the highest when cover crops and dairy manure were applied (3.54 mm) and lowest in the cover crop only treatment (2.46 mm). These results not only have implications on which methods are best for assessing progress, but also what management practices can be utilized to decrease water erosion from irrigated cropland. Under these soil conditions, the Cornell Sprinkle Infiltrometer was more sensitive to the treatments than the traditional wet sieving method and better captures and assesses typical erosion processes occurring in irrigated crop land.