|Black, A - RETIRED USDA-ARS|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 15, 1996
Publication Date: N/A
Technical Abstract: Drought accelerates wind erosion. Soil science literature says little about effects of multiyear wet-dry weather cycles on soil-plant factors of wind erodibility. We measured these factors in biennial spring wheat-fallow for 8 yr in central North Dakota on Pachic and Typic Haploborolls soil: dry aggregate size distribution by rotary sieve; soil surface roughness by pin meter and chain; standing residue profile and residue coverage photographically. Four tillages ( less than 15 cm deep) ranged from low- residue (LR) to no-till (NT). Tillage affected ASD inconsistently, and much less than climate. The erodible fraction (less than 0.84 mm diam.) of ASD was 45 to 55% in droughty 1989-1990 vs. 15 to 25% in wet 1993-1994. Low wheat growth in 1988 greatly reduced residue in spring 1990. Application of the Revised Wind Erosion Equation (RWEQ) model indicated that wind erosion hazard (WEH) was 10 to 250+ times greater in spring 1990 than in spring 1993/94. Calculated WEH for spring 1990 was 5+ times greater in LR than i NT; low WEH for spring 1993/94 was 40+ times greater in LR than NT. Results indicate biennial small grain-fallow is non-sustainable in long- term without extensive soil conservation inputs.