Title: Plant-water relationships and growth of black walnut in a walnut-forage multicropping regime

Author: Dey, Daniel C.; Conway, M. R.; Garrett, H. E.; Hinckley, T. S.; Cox, G. S.

Year: 1987

Publication: Forest Science. Volume 33 Number. 1. 1987. pp. 70-80.

Abstract: Eastern black walnut seedlings were planted on a 1.5 ? 1.5m spacing in the spring of 1976 and irrigated throughout the growing season. During the spring of 1977, forage plots consisting of Kentucky 31 tall fescue, orchard grass, or Kobe lespedeza measuring 1 m wide and 10.2 m long and centered on a row of trees, were established with and without irrigation. Soil-water relationships measured throughout the 1977 growing season demonstrated lower on the average in irrigated than in nonirrigated plots during drought periods. Differences were attributed to the greater physiological vigor, thus greater transpiration, of forages growing under irrigated conditions. At the 45 cm depth dropped to a low during August of -3.0 MPa with irrigation and only -0.8 MPa without. Predawn xylem pressure potentials of walnut seedlings however, were consistently lower on forage plots without irrigation. Significant decreases in dry weights of walnut grown with forages were associated with reductions in and increases in anthracaose infection.