Planting Date Effects on Fall Forage Production of Oat Cultivars in Wisconsin

Abstract

Previous research has shown that cereal‐grains, such as oat ( Avena sativa L.), that undergo stem elongation following late‐summer establishment will likely exhibit a 2:1 advantage in forage dry matter (DM) yield before winter compared to other cereals that remain vegetative until spring. Our objectives for this project were to assess the effects of planting date on the fall forage growth of one forage‐ and three grain‐type oat cultivars. Over a 3‐yr trial, oat cultivars were planted on three target dates (15 July, 1 August, and 15 August), and subsequently evaluated over five harvest dates (15 September, 1 October, 15 October, 1 November, and 15 November) each year. For the 15 July planting date, a late‐maturing forage cultivar (ForagePlus) produced maximum annual yields ranging from 4501 to 8100 kg ha −1 , and these responses were explained generally by linear ( P < 0.01) and quadratic ( P ≤ 0.03) effects of time. Accumulation of DM was superior to grain‐type cultivars because ForagePlus matured slowly, and was better able to respond to sometimes erratic late‐summer precipitation. With a 1 August planting date, maximum forage yields generally were similar to those observed with a mid‐July planting date, but peak yield often was delayed by approximately 2 wk. For the 15 August planting date, maximum yields of forage DM were only 42.3, 79.9, and 20.5% of those observed following planting dates on 1 August of 2007, 2008, and 2009, respectively. Under these circumstances, the late‐maturity characteristics of ForagePlus were less advantageous, often resulting in poorer yields throughout early harvest dates compared to grain‐type cultivars.