The Use of Woodchips and Nitrogen Fertilizer in Seeding Scab Ridges

Abstract

A depleted scab ridge in northeastern Oregon was treated with woodchips and nitrogen, and seeded with a mixture of hard fescue, timothy, and pubescent wheatgrass. On the deeper soils, plots receiving 1 inch woodchips disked in plus 300 lb N averaged 2,457 lb air-dry herbage/acre over a 7-year period. Control plots average 1,973 lb/acre and those receiving woodchips, but no N 1,434 lb/acre. On the shallow soils similar treatments yielded 1,193, 688, and 528 lb/acre, respectively. At 1 inch chips and 300 lb N/acre, whether the chips were disked into the soil was relatively unimportant. At 0.5 inch chips and 150 lb N/acre disking lowered yields from 1,288 lb/acre (not disked in) to 673. With time, pubescent wheatgrass increased on the deeper soils and remained constant on the shallower. Hard fescue increased and timothy decreased markedly on both soils.