|Sauer, Thomas - Tom|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2004
Publication Date: 11/20/2004
Citation: Scarbrough, D.A., Coblentz, W.K., Humphry, J.B., Coffey, K.P., Sauer, T.J., Jennings, J.A., Daniel, T.C., Turney, J.E., Kellogg, D.W. 2004. Estimating losses of dry matter in response to simulated rainfall for bermudagrass and orchardgrass forages using plant cell wall components as internal markers. Agronomy Journal. 96:1680-1687. Interpretive Summary: Grass is often cut, dried, and baled to be used as animal feed during the winter when there is not enough grass growing in pastures. Growers try to schedule grass mowing to avoid rainfall as rain slows the drying time of the cut grass and also reduces the quality of the hay as animal feed. In this study, samples of two grasses (bermudagrass and orchardgrass) were collected from bales in storage and subjected to simulated rainfall. Samples of the forages were then analyzed to determine the effects of rainfall on the amount of dry matter in the grasses. The results showed that analyzing for the loss of different types of fiber in the hay samples was a good method for predicting how much total dry matter was lost during rainfall. This research is important to forage growers as it shows the importance of getting hay baled and into storage before rainfall to protect the quality of the hay as animal feed.
Technical Abstract: Previous methodologies to measure losses of dry matter (DM) in wilting hays subjected to natural or simulated rainfall have generally relied upon gravimetric techniques, resulting in variable and questionable estimates of DM loss. The objective of this study was to evaluate the use of fiber components and acid detergent insoluble ash (ADIA) as internal plant markers for accurately predicting losses of DM in bermudagrass [Cynodon dactylon (L.) Pers.] and orchardgrass, (Dactylis glomerata L.) forages that were damaged by simulated rainfall. For both forages, concentrations of neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HEMI), cellulose (CELL), and lignin generally increased with the amount of simulated rainfall in primarily linear patterns. Recoveries of fiber components were high (982 g kg-1), and did not change in response to artificial rainfall for orchardgrass (P 0.115). A quadratic tendency (P 0.063) towards reduced recovery was observed for NDF in bermudagrass forage, but there were no observed effects for any other fiber component (P 0.180). Predicted losses of DM increased in primarily linear patterns with simulated rainfall for both forages when concentrations of NDF, ADF, HEMI, and CELL were used as an internal marker. Linear regressions of predicted losses of DM on gravimetrically determined values were good (r2 0.727; P 0.031) when concentrations of any fiber constituent or ADIA were used to calculate losses of DM; however, NDF was especially effective (Y = 1.12 X 5; r2 = 0.971; P < 0.0001).