With regard to soil aggregation and stability, microbial polysaccharides are important components of the organic soil chemistry. Certain microalgae are known producers of relatively large amounts of extracellular polysaccharides. Compaction data from 40, 1987 and 10, 1988, on-farm test sites was collected to estimate the effect that a microalgae soil inoculation or seeding would have on soil structure. Cotton yields were estimated for on-farm test sites from 30, 1987 and 11, 1988, sites where soils were seeded with microalgae. At the two and four inch depths the treatment effects averaged 34% and 21%, for 1987, and 28% and 14%, for 1988, less compaction respectively. Yield estimates on the cotton sites averaged 115.1 pounds for 1987 and 119.0 pounds for 1988 more lint cotton for the treatment.