Broiler chicken litter application timing effect on Coastal bermudagrass in southeastern U.S.

Presently, more than 85% of the broiler chicken (Gallus gallus domesticus) litter (BCL) is being applied to pasture lands year-round. This practice results in nutrient losses and potentially unfavorable environmental impacts particularly during the wet winter months. A field plot experiment was initiated in 2001 on a Ruston silt loam in Mize, MS to identify the proper BCL application timing that enhances BCL nutrient uptake by crops while minimizing undesirable nutrient buildup in soil. Seven treatments (BCL application timings) were employed on previously established “Coastal” hybrid bermudagrass Cynodon dactylon (L.) Pers.] plots. For each treatment, the quantity of broiler chicken litter (a mixture of chicken manure plus bedding materials) needed for each plot was calculated based on the BCL total N content to provide 400 kg N ha⁻¹ for top bermudagrass yield (18 Mg ha⁻¹) and applied either as a single, two-way split, or three-way split at different dates as follow: May; May/June; April/May/June; May/June/July; June/July/August; July/August/September; and August/September/October. Bermudagrass was harvested 5 times each year for dry matter (DM) and nutrient uptake determination. Significant differences in DM yield were observed in each year among application timings. The greatest DM yield was 18.6 Mg ha⁻¹ for the single application in May and lowest at 15.0 Mg ha⁻¹ for Aug/Sep/Oct application dates in 2001 and followed by the same trend in 2002. The N and P uptake by bermudagrass ranged from 270 to 381, and 53 to 63 kg ha⁻¹ respectively, in 2001. Similar trend, but lower values for nutrient uptake were observed in 2002. Significant differences were observed among BCL application timings in regard to soil residual of total carbon (TC), total nitogen (TN), Mehlich 3 extracted P (M3-P), NO₃–N, Cu, and Fe elements at the end of the study. In general, summer and early fall BCL applications resulted in greater buildup of most of these elements. Based on the results of this study, there is a wide window (May–July) for BCL application timing on bermudagrass considering the criteria of producing high yield and low soil residual nutrient. However, the best BCL application timing should be in spring (late April–June) when minimum temperatures exceed those required (24–27°C) for bermudagrass growth.