Forages underseeded in barley for residue management for potatoes

Abstract

Producers have attempted to increase soil organic matter content in a 2-yr rotation of barley-potato by underseeding barley with forage grasses and legumes. A study beginning in 1996 was initiated to evaluate the effect of this practice on barley yields, root biomass, soil organic matter content, ease of post-harvest tillage as measured by a soil penetrometer and surface plant residue levels for the first year of a 2-yr rotation of barley-potato. Barley seeded alone, barley underseeded with berseem clover, barley underseeded with timothy/red clover, barley underseeded with timothy/red clover fall chisel plowed and barley underseeded with Italian ryegrass were evaluated with and without a fall application of glyphosate on a well-drained, fine sandy loam, Orthic Humo-Ferric Podzol soil. Barley yields were not affected by underseeding. Despite an increase in root biomass for some of the underseeded crops, soil organic matter content was not affected. Potato producers attempting to increase soil organic matter content in a 2-yr rotation of barley-potato by underseeding barley with a forage crop are advised to consider using annual forages such as berseem clover or other solutions such as residue management. Underseeding barley with red clover/timothy will require either a fall application of glyphosate or extra spring tillage to eliminate living plants. By underseeding barley, producers are incurring additional costs and eliminating the option of practising residue management, a soil conservation practice, unless they use glyphosate at an additional cost. Key words: Soil organic matter, glyphosate, root biomass, Italian ryegrass, red clover, berseem clover