Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 8, 1999
Publication Date: N/A
Technical Abstract: Soil crusts are thin, dense, surface layers that form as raindrops detach particles from and/or disperse soil aggregates. Emerging crops must penetrate or lift the crust, thus reducing seedling emergence and vigor. Our objectives were to quantify effects of forming a hill (cap) 25 mm high x 50 mm wide above the seed on crust formation and strength, and seedling emergence. Sieved (<12 mm) Pullman soil (fine, mixed, thermic Torrertic Paleustoll) was packed into columns (0.30 x 0.45 x 0.15 m) and planted with sorghum [Sorghum bicolor (L.) Moench], corn (Zea mays L.), soybean (Glycine max L.) and wheat (Triticum aestivum L.) in rows beneath a flat surface or soil cap. Rain was simulated using reverse osmosis water applied for 1 h at 50 mm h**-1. Columns were either bare or covered with an energy absorbing barrier. Analysis of variance comparisons show drop impact was needed to form soil crusts sufficiently strong to reduce seedling emergence. Surface caps reduced crust penetration resistance as much as 30%, but emergence was unaffected.