Ethanol-Soluble Carbohydrates of Cool-Season Grasses: Prediction of Concentration by Near-Infrared Reflectance Spectroscopy (NIRS) and Evaluation of Effects of Cultivar and Management.

The study involved the analysis of cool-season grasses and how their Ethanol-Soluble Carbohydrates (ESCs) concentrations can be accurately predicted using Near-Infrared Reflectance Spectroscopy (NIRS). This method was found to be over 95% accurate and revealed that ESC concentrations rise in the afternoon and are unaffected by nitrogen application to plots.

Research Methodology

• The research involved analyzing the ESCs of four cool-season grass species – orchardgrass, Kentucky bluegrass, tall fescue, and perennial ryegrass. The grass samples were collected from 10 different cultivars in central Kentucky, during both the morning and afternoon, over two separate growing seasons.
• A calibration for predicting ESC concentration was developed using NIRS. This calibration drew data from 323 samples taken from the first growing season.
• In the second growing season, this calibration was used to predict the ESC concentrations of 1,532 samples.

Prediction Score and Observations

• The accuracy of the calibration was found to be over 95%, suggesting that NIRS is an extremely efficient and precise tool for predicting the ESC concentrations in cool-season grass species.
• The data showed that the ESC concentrations increased in the afternoon compared to the morning across all cultivars, irrespective of the type of cool-season grass species.
• The application of nitrogen to the plots did not significantly affect the concentration of ESCs in the majority of samples, indicating that this element does not play a critical role in ESC concentration.

Implication of the Study

• The use of NIRS has been proven to be effective in predicting and reading the ESC concentration levels in cool-season grass species.
• This research provides valuable information that can guide land management practices in relation to cool-season grass pastures, including determining the ideal time of day to harvest grass to manage ESC levels.
• The results also suggest further study is needed to understand why nitrogen application does not significantly affect the concentration of ESCs, which contradicts conventional assumptions about nitrogen’s role in carbohydrate production.