Interseeding and Pitting on a Sandy Range Site in Eastern Montana

Abstract

A study of the effects of interseeding and pitting on herbage yield, species composition, soil water content, and nitrogen uptake was conducted on a sandy range site in eastern Montana from 1967 to 1972. Over these 6 years, interseeding with a lister and rotary tiller increased perennial grass yields 30 and 24%, respectively. Pitting increased the yield of sedges (Carex spp.) over most of the 6 years, but increased total grass yield only in 1969. The yield increase from interseeding was due to increased growth of native western wheatgrass (Agropyron smithii) and interseeded species. An interseeded mixture of western wheatgrass, bluebunch wheatgrass (A. spicatum), green needlegrass (Stipa viridula), and little bluestem (Andropogon scoparius) produced two to three times more than any individual species. Interseeding by lister and rotary tiller increased perennial grass yields in the sixth year after treatment by 58 and 41%, respectively, indicating potential long-term benefits from interseeding. Of the treatments, only lister interseeding showed evidence of increasing soil water recharge on this sandy range site. Tillage associated with the interseeding and pitting treatments increased the uptake of nitrogen by plants for at least 2 years after treatment.