Lime Microdosing: A new liming strategy for increased productivity in acid soils

Authors: Agyin-Birikorang, Sampson; ADU-GYAMFI, RAPHAEL - University For Development Studies; KADYAMPAKENI, DAVIE - University Of Florida; Chambers, Rachel; TINDJINA, IGNATIUS - International Fertilizer Development Center (IFDC); DAUDA, HARUNA - International Fertilizer Development Center (IFDC)

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2023
Publication Date: 12/26/2023
Citation: Agyin-Birikorang, S., Adu-Gyamfi, R., Kadyampakeni, D.M., Chambers, R.A., Tindjina, I., Dauda, H.W. 2023. Lime Microdosing: A new liming strategy for increased productivity in acid soils. Soil Science Society of America Journal. 88:136-151. https://doi.org/10.1002/saj2.20610.
DOI: https://doi.org/10.1002/saj2.20610

Interpretive Summary: For several decades, mitigation of the negative effects of soil acidity has been application of tons of agricultural lime per hectare. With increasing production costs, such an approach is no longer sustainable and new strategies are required. In a three-year study at four locations across three countries (one in USA, two in Ghana, and one in Burkina Faso) we evaluated the effectiveness of the microdosing technique for lime application to alleviate the issues of soil acidity on crop production using corn as the study crop. Lime microdosing at five lime application rates were compared to the traditionally calculated lime-requitement rate (LR), which included: (i) 75% of LR (0.75_LR), (ii) 50% of LR (0.50_LR), (iii) 25% of LR (0.25_LR), (iv) 10% of LR (0.10_LR), and (v) 5% of LR (0.05_LR), and a control where no lime was applied. Averaged across all experimental sites and for the three growing seasons, treatment effects on corn yield followed the order: LR = 0.75_LR = 0.5_LR = 0.25_LR > 0.10_LR > 0.05_LR > control. Lime microdosing with 0.25_LR resulted in similar N, P, and K uptake as higher lime application rates, up to LR. Similarly, post-harvest rhizosphere Al saturation percentage followed the order: control > 0.5_LR > 0.1_LR > 0.25_LR = 0.5_LR = 0.75_LR = LR, but the extent of pH change resulting from the treatment in the bulk soil was the highest with LR, and lowest with rates < 0.5LR. The combined results suggest that lime microdosing with as little lime material as 25% of the traditionally-calculated lime application rates could mitigate the negative impacts of Al toxicity associated with soil acidity on crop production.

Technical Abstract: Soil acidity is a major production-limiting factor for crop production globally. For several decades, mitigation of the negative effects of soil acidity on crop production has been the application of tons of agricultural lime per hectare, depending on the intensity of soil acidity and the desired pH level. With increasing production costs in recent times, such an approach is no longer sustainable and a new method to mitigate soil acidity for enhanced productivity is required. In a three-year study (2020-2022) in acid soils at four locations across three countries (one in USA, two in Ghana, and one in Burkina Faso) we determined the effectiveness of the microdosing technique for lime application to minimize the quantities of lime required to increase crop productivity in acid soils. Lime microdosing at five lime application rates were compared to the traditionally calculated lime-requitement rate (LR), including: (i) 75% of LR (0.75LR), (ii) 50% of LR (0.50LR), (iii) 25% of LR (0.25LR), (iv) 10% of LR (0.10LR), and (v) 5% of LR (0.05LR), and a control where no lime was applied. Averaged across all experimental sites and for the three growing seasons, treatment effects on corn yield followed the order: LR = 0.50LR > LR = 0.25LR > 0.75LR > 0.10LR > 0.05LR > control. Lime microdosing with 0.25LR resulted in similar N, P, and K uptake as higher lime application rates, up to LR. Similarly, post-harvest rhizosphere Al saturation percentage followed the order: control > 0.05LR > 0.10LR > 0.25LR = 0.50LR = 0.75LR = LR, but the extent of pH change resulting from the treatment in the bulk soil was the highest with LR, and lowest with rates < 0.5LR. The combined results suggest that lime microdosing could be an efficient liming technique, and as little lime material as 25% of the traditionally-calculated lime application rates could be used to mitigate the negative impacts of Al toxicity associated with soil acidity on field crop production.