Pasture conservation management effects on soil surface infiltration in hay and grazed systems

Authors: Adams, Taylor; Ashworth, Amanda; Owens, Phillip; Moore, Philip; POPP, MICHAEL - University Of Arkansas; PENNINGTON, JOHN - University Of Arkansas

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/22/2021
Publication Date: 8/20/2021
Citation: Adams, T.C., Ashworth, A.J., Owens, P.R., Moore Jr, P.A., Popp, M., Pennington, J. 2021. Pasture conservation management effects on soil surface infiltration in hay and grazed systems. Journal of Soil and Water Conservation. 77(1):59-66. https://doi.org/10.2489/jswc.2022.00182.
DOI: https://doi.org/10.2489/jswc.2022.00182

Interpretive Summary: With the abundance of poultry production in the southeastern US, fertilizing with poultry litter is an economical practice for cattle producers in the region. However, applying poultry manure without proper management can poorly affect downstream water quality if the litter does not enter the soil. Therefore, using farm implements that aerate the soil or apply the litter beneath the surface in bands may have beneficial effects on litter nutrient availability to crops and are examples of best management practices (BMPs). Researchers evaluated these BMPs at different times throughout the year in hay and grazed pastures and measured water infiltration in the soil immediately after using BMPs and one and three months thereafter. Pasture yields in the hay system were also measured twice per year. Researchers found that using the aerator in June provides the greatest infiltration over time compared to all tested BMPs. Two application rates of gypsum were included in the hay system and did not affect infiltration or yield. Infiltration rates were similar between hay and grazed pastures, indicating cattle hooves and subsequent compaction did not negatively affect infiltration. Yields in the hay system were greater during the second harvest period (May-July), likely due to warm-season forage peak growth, but were unaffected by any BMPs. Therefore, researchers recommend pasture aeration in June following poultry litter applications for reducing nutrient runoff and improving available soil water in pastures, regardless of management (hay or grazing) compared to poultry litter surface-broadcasting.

Technical Abstract: Diminished water quality in the mid-southern US is often resultant from poor poultry litter management in pastures. Grassland best management practices (BMPs) need to be identified that soil-water increase infiltration. Therefore, the objective of this research was to evaluate infiltration rates based on pasture BMPs (aeration timing, subsurface banded litter, and gypsum) in hay and grazed systems from 2018-2019. Twenty-min falling-head infiltration measurements were conducted at zero, one, and three months following management implementation in hay (Experiment 1) and grazed (Experiment 2) systems. Management effects on forage quality and yield were also measured in the hay system. In Experiment 1, infiltration differed across treatment and by month following BMP implementation. Averaged across months (Experiment 1), the greatest infiltration rate occurred for June aeration, which was the only month when aeration increased infiltration compared to the control under hay conditions. In Experiment 1, averaged across treatments, greatest infiltration occurred three months following treatment implementation. Gypsum had no effect (P > 0.05) on infiltration rates. Under grazed conditions (Experiment 2), infiltration rates differed by treatment and month and were greatest one and three months following the June aeration, three months following the April aeration, and three months following the subsurface banded litter treatment. February aeration and subsurface litter applications resulted in lower (P < 0.05) infiltration rates than the control in grazed systems. Across months for the grazed experiment, June aeration had the greatest (P > 0.05) infiltration rates. Among all BMPs temporally, June aeration improved soil-water infiltration under both hay and grazed systems. Therefore, pasture aeration implemented in June following broiler litter applications can likely reduce nutrients in surface runoff in grassland systems, regardless of management (hay or grazing) compared to traditional surface-broadcast practices.