RESULTS ON THE ESTABLISHMENT OF NAMED VARIETIES OF EASTERN BLACK WALNUTS ON UPLAND SITE IN THE OUACHITA REGION OF ARKANSAS

Authors: Brauer, David; JONES, JIM - CTR ADV. AMER BLK WALNUT

Submitted to: Northern Nut Growers Annual Report
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2003
Publication Date: 10/11/2004
Citation: Brauer, D.K., Jones, J. 2004. Results on the establishment of named varieties of eastern black walnuts on upland site in the Ouachita region of Arkansas. Northern Nut Growers Annual Report. 94:133-145.

Interpretive Summary: Agroforestry systems that include eastern black walnut trees grown for nut production are a viable option for landowners in western Arkansas, and the use of named varieties selected for high nut quality will be an important component of viable systems. Currently, there is little information regarding which named varieties would grow better in the Ouachita region of Arkansas. This report describes data from the establishment phase of a variety trial of eastern black walnuts planted on an upland site near Booneville AR: trees with Ogdaw and Surprise scions tended to survive and grow poorly while trees with Sauber, Thomas and Kwik Krop had higher survival and greater height. These results are of interest to landowners, natural resource professionals, and extension agents who are planning to plant walnut trees in the Ouachita/Ozark region or assist landowners with tree plantings.

Technical Abstract: Agroforestry systems that include eastern black walnut trees grown for nut production are a viable option for landowners in western Arkansas, and the use of named varieties selected for high nut quality will be an important component of viable systems. Currently, there is little information regarding which named varieties would grow better in the Ouachita region of Arkansas. This report describes data from the establishment phase of a variety trial of eastern black walnuts planted on an upland site near Booneville, AR. Grafted seedling trees consisting of 8 combinations of two year-old rootstocks and one year-old scions were planted in early December 1999. Rows were 40 feet apart with trees spaced 25 feet apart within rows. Supplemental water was provided by drip irrigation. Experimental design was completely randomized block with 7 replication s and 8 scion-rootstock combinations. Data were collected on tree and scion survival, bud break in the spring, rate of leaf loss in the fall, presence of a terminal bud, degree of branching, and tree height. Data on presence of flowers and nut production were gathered in the third growing season (2002). Overall survival after tree growing seasons was about 60%. Overall survival may have been greater if not for the negative effects of one of the two irrigation treatments in the first growing season. In 1999, each replication was assigned to one of two irrigation regimes, 6 or 12 hours of supplemental water at 1 gallon per hour every 5 days without rain or irrigation. Early leaf drop was noted for the trees in the high irrigation treatment in late August. Despite the topsoil being dry, soil moisture measurements identified water-logged soil conditions 20 to 30 inches below the surface. Irrigation treatments were ended at that point for 2000 growing season. Trees under the high irrigation regime had greater instances of mortality from the remainder of that growing season and the next. Overall survival at the end of the third growing season for trees in the low irrigation treatment in 1999 averaged 85%. Trees with Ogdaw as the scion had the lowest survival while trees with Thomas, Sauber, and HPC 148 scions had the highest percentage of survival. Trees with Ogdaw and Surprise scions tended to be the shortest while trees with Sauber, Thomas, and Kwik Krop scions tended to be the tallest. Nut production by trees with Sauber scions tended to be superior to all others in 2002.