Soil acidity can greatly reduce nodule growth and activity. This can cause nitrogen deficiency issues that negatively impacts grain yield and quality. Additionally, when soil pH is less than 5.5, aluminum toxicity can occur which greatly hinders root development. This can reduce growth even more in a dry environment. Soil acidity is becoming more widespread in the western third of North Dakota where long-term notill is common. Nitrogen fertilizers acidify the soil and the lack of tillage prevents the mixing of acidic soil layers with the more alkaline subsoil layers. This project will look at the impacts of surface applied beet lime to acidic no-till soil and how that improves soybean yield and quality. This data will be used to generate guidelines for liming acidic soils in North Dakota.

Observe impacts of beet lime application from the previous growing season to the yield and quality of soybean grain. Use data to produce liming acidic North Dakota soils recommendations.

Amending acidic no-till soil guidelines.

Update:
Liming Impacts on Soybean Yield and Quality Mid-year Report
Chris Augustin, Director, Dickinson Research Extension Center
Chris.augustin@ndsu.edu, 701-456-1103
Objectives of the research
1. Observe impacts of beet lime application from a previous growing season on the yield and quality of soybean grain.
2. Use data to produce liming acidic North Dakota soils recommendations.
Completed work
The experimental research plots were grown, harvested, analyzed for quality/yield, soil was collected and results have been analyzed.
Preliminary results
Experimental plots were treated with 0 (check), two, four, and eight tons of sugarbeet waste lime (beet lime) by hand application in 2018. Beet lime was soil incorporated shortly after the application with a field cultivator. Beet lime is a by-product of the sugarbeet refining process. As such, beet lime is made up of more than just the acid neutralizing calcium carbonate (lime), but there is nitrogen, phosphorus, various micro-nutrients, and organic matter. The beet lime used for this project contained 73% calcium carbonate so the actual amount of calcium carbonate applied was 0, 1.5, 2.9, and 5.8 tons/ac. Lime was incorporated by a field cultivator after hand applications.
Each beet lime treatment increased soil pH (Figure 1) and decreased extractable aluminum (Figure 2). Aluminum toxicity becomes an issue when the soil pH is less than 5.5 and extractable aluminum is greater than 25 ppm. Aluminum toxic plant root growth tends to be malformed and reduced.
Aluminum toxicity was possible with the beet lime applications of zero and two tons/ac. However, aluminum toxic symptoms were not observed. The beet lime applications of four and eight tons reduced soil extractable levels to less than two ppm (Figure 2). Soil pH was greater at the eight tons/ac beet lime treatment than the four tons/ac beet lime (Figure 1). However, the data suggests that beet lime applications of four and eight tons/ac reduced soil extractable aluminum to similar levels.

(Beet Lime and pH attachment)
Figure 1. The relationship of hand applied and incorporated beet lime on soil pH at the 0-6 inch depth. *Different letters indicate statistical differences at the 0.05 level.

(Beet Lime and Aluminum attachment)
Figure 2. The relationship of hand applied and incorporated beet lime on soil extrable aluminum at the 0-6 inch depth. *Different letters indicate statistical differences at the 0.05 level.

Beet lime applications improved soil pH and soil extractable aluminum. However, lime did not impact growth or quality of soybean grain. The analysis of variance determined that the average soybean yield was 22.5 bu/ac with a variance of 87.5 and a P-value of 0.586. Beet lime treatments did not impact soybean oil or protein content at the 0.05 level.
The average soil calcium carbonate content was 0.29% and similar across all lime treatments (p-value 0.556). This indicates that within two years, the lime treatments reacted with the soil acidity. Nitrogen fertilizer will likely re-acidify the lime applied soil. This study site will be monitored annually to gather important information on the frequency of re-liming.
Work to be completed
Due to the COVID-19 pandemic, ureide content was not measured. This data will be shared with producers through workshops and annual field reports. An Extension circular on acid soil management is in the works and this project will help supplement the publication.

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View uploaded report 2

Update:
Research has been conducted and shared through various outreach activities that include three producer/crop consultant meetings, two podcasts, and the North Central Research Extension Center 2020 Annual Report. An Extension publication is being developed to guide soybean producers on how to determine lime applications. Similar projects have been funded for corn, wheat, and soybean production. All that data is being combined to develop the lime recommendations.

View uploaded report

Liming Impacts of Soybean Yield and Quality Executive Report
Chris Augustin, Brian Jenks, Gary Willoughby, Tiffany Walter

Research conducted
Sugar beet waste lime is a byproduct of the sugar refining process. The calcium carbonate (lime) can neutralize soil acid and improve soil health. Lime was applied at 0, 1.5, 2.9, and 5.8 tons/acre in 2018. The research plot was tilled after application. Peas (2018 growing season) and wheat (2019 growing season) were raised prior to the study. In 2020, soybean was grown.

Why the research is important to North Dakota Soybean Farmers
Soil pH greatly influences many soil factors that impact crop growth and yields for all crops. Soil factors include nutrient availability, biological activity, and soil extractable aluminum. Nutrients are most available when the soil pH is approximately 5.5 to 7.5. Soil bacteria activity reduces when the soil pH is less than 5.5. Soil bacteria greatly help soybeans fulfill their nitrogen needs. Soil extractable aluminum levels greater than 25 parts per million can reduce plant root development. If nutrients are not available, biological activity reduced, or extractable aluminum is too high, yields will likely suffer.

Final Findings of the research
All lime treatments statistically improved soil pH and soil extractable aluminum (Table 1) at the 0-6 inch depth. However, soybean yield and grain quality were not impacted by the lime treatments. This work was done during a drought which likely prevented an impact from the lime treatments.
Benefits/Recommendations to North Dakota soybean farmers and industry
Soil pH is very important for soil health and crop production. Soybean yield and quality was not influenced by lime applications. However, 2.9 tons of lime/acre was the most effective lime application for improving soil pH and extractable aluminum.

Soybean Farmers: No-till soybean farmers will better understand how to manage acidic soils which will improve their bottom line.