Harvest frequency effects on white clover forage biomass, quality, and theoretical ethanol yield

Understanding the growth of white clover (Trifolium repens L.) under varying management regimes and weather conditions will aid producers in making sound decisions on the utilization of this crop. The objectives of this study were to determine the effect of harvest frequencies on white clover forage biomass potential, theoretical ethanol yield, crude protein (CP) concentration, and in vitro digestible organic matter (IVDOM). Frequency of forage removal (treatment), year, and treatment × year interactions significantly affected forage quantity and quality. This 4-year study indicated that forage dry matter (DM) yield, theoretical ethanol yield, CP concentration, and IVDOM with four harvests (15 May, 1 and 15 June, and 1 July) or two harvests (15 May, and 15 June) were consistently better than the other one, two, or three harvest systems. Four harvests yielded on average 2380 ± 80 kg ha−1 (a theoretical ethanol yield of 570 ± 20 L ha−1) with 540 kg ha−1 of CP and 1780 kg ha−1 of digestible DM. Forage removed with two harvests (15 May and 15 June) yielded on average 2200 ± 80 kg ha−1 (a theoretical ethanol yield of 530 ± 20 L ha−1) with 490 kg ha−1 of CP and 1640 kg ha−1 of digestible DM. A two harvest system would reduce harvest costs over that of a four harvest system and would allow for two haying or grazing rotations (each with 28-30 day rest) before a decline of white clover DM production in mid-summer.