Submitted to: American Society of Agronomy
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 1996
Publication Date: N/A
Technical Abstract: The cutting height of wheat harvest affects harves losses and residue distribution, and therefore soil and water conservation. We evaluated the effects of cutting height on harvest losses and on conservation of soil and water. Spike height frequency was determined for wheat under NT and CT crop culture with 0, 1, or 2 times normal residue loading rates, for two growing gseasons. Effects of flat and standing residue architecture on soil and water loss were quantified by the critical friction velocity ratio for an erodible soil and by a soil-residue energy balance simulation. Spike height frequency varied with crop culture treatments and between years. Expected soil and water protection from erosion and evaporation diminished with stem area indices exceeding 0.1 m2m-2 and flat residue loadings exceeding 3 Mg ha-1, corresponding to 80% soil cover. The significance of cutting height increased with sparse and short wheat stands, or for extended fallow periods where residue decomposition can reduce soil and water protection b decreasing residue cover and frequency of standing stems.