Cattle Manure Application Reduces Soil Compactibility and Increases Water Retention after 71 Years

Current interest in integrating livestock with crop production systems warrants further understanding of the impacts of manure application on soil physical processes and properties such as soil's susceptibility to compaction (compactibility) and water retention. We quantified the 71-yr cumulative impacts of beef (Bos Taurus L.) cattle manure (0 and 27 Mg ha−1 yr−1) and inorganic N fertilizer (0, 90, and 180 kg N ha−1 yr−1) application to conventionally tilled and irrigated corn (Zea mays L.) on soil compactibility, water retention, available water, and soil organic C (SOC) on a Tripp very fine sandy loam (coarse-silty, mixed, superactive, mesic Aridic Haplustoll) at the centennial Knorr-Holden plots of the University of Nebraska's Panhandle Research and Extension Center, Scottsbluff, NE. Manure application improved soil properties at the 0- to 30-cm depth, but inorganic fertilization had no effects. Across N levels, manure application reduced maximum Proctor bulk density by 6% and increased Proctor soil critical water content (water content at which maximum compactibility occurs) by about 17%, indicating that manured soils can be slightly less susceptible to compaction and trafficked at higher water content without being excessively compacted compared with nonmanured soils. Manured plots also retained 18% more soil water at −0.033 MPa and 21% more at −1.5 MPa potential, resulting in about 16% more plant available water compared with nonmanured plots. The SOC concentration increased two-fold with manure addition and was negatively correlated (r > −0.77) with soil compactibility and positively (r > 0.72) with water retention. Overall, 71-yr manure application reduced compactibility and increased water retention in this semiarid soil.