Effects of Seeding Rate and Cutting Interval on Dry Matter Yield and Nutritive Values of Reduced Lignin, Roundup Ready and Conventional Alfalfa.

Lignin concentration increases as forage plants mature and lignin makes cell walls recalcitrant to digestibility for ruminant animals. Reduction of lignin levels in the forage legume alfalfa by molecular biotechnology results in strongly increased digestibility. For conventional alfalfa varieties, the best time to harvest alfalfa for hay production is generally at 10% bloom stage. However, extending a peak harvest date by up to 10 days (i.e., every 38-day harvesting) using reduced lignin alfalfa, rather than every 28-day harvesting, might benefit alfalfa growers by avoiding undesirable weather conditions such as rain damage and extending harvesting window. By doing this, alfalfa growers might be able to increase dry matter yield while maintaining nutritive values of alfalfa. The objective of this research was to test effects of the seeding rate and cutting interval on dry matter yield and nutritive values of three different cultivars of alfalfa (reduced lignin, roundup ready, and conventional). The field trial was established at Ashland Bottoms, Kansas in April 2015 with three alfalfa varieties: Hi-Gest 360 (reduced lignin cultivar), Gunner (conventional cultivar) and RR Tonnica (roundup ready cultivar). The experimental design was a randomized complete block in a split-split plot arrangement with four replicates (main plots: two cutting intervals, sub plots: three seeding rates, sub-sub plots: three varieties). The harvesting was performed 3 cm high from soil level by a flail type forage harvester. Dried alfalfa samples were ground through a 1 mm Wiley mill and analyzed for crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF).