Yield and forage quality of smooth brome in a black walnut alley-cropping practice

Abstract

In the central plains of the United States, there is a growing interest in establishing smooth brome (Bromus inermis Leyss.) as an alley crop. Field experiments were conducted near Manhattan, Kansas over a period of 18 years. Walnut (Juglans nigra L.) trees were originally planted in rows 12.2 m apart. During the first 15 years of the study, smooth brome yield averaged 5,800 kg/ha. Sixteen to eighteen years after establishment, forage yields average 286 g/m2 under tree canopies (2.4 from tree row) and 346 g/m2 in the center between the rows on a north to south orientation compared to 497 g/m2 in the open. Forage heights ranged from 39 to 120 cm depending on year and followed the same trends by location as dry matter yields. Although no differences were found in forage quality among locations, crude protein, acid detergent fiber, and neutral detergent fiber averaged 20.4, 31.3, and 57.1 %, respectively, for forages harvested in May 2012 and July 2011, compared to 13.9, 19.2, and 36.4 % respectively, for forages harvested in October 2010.