Changes in Soil Properties Under Annual Applications of Feedlot Manure and Different Tillage Practices

A long‐term manure study was set up in which cattle feedlot manure was applied annually at four rates to nonirrigated and irrigated land and was incorporated into the soil by plow, rototiller, or cultivator. The soil is a Dark Brown Chernozem (Typic Haploborolls) at the Lethbridge Research Station. The effects of the manure, incorporated by different methods, on the physical properties and organic matter content of the soil were determined. On both nonirrigated and irrigated land, the soil organic matter content of the surface 0 to 15 cm increased with increasing rates of manure application. Spring‐time soil temperatures, at 8‐cm depth, were coldest where the highest rate of manure had been incorporated. Drawbar draft decreased with increasing rates of manure application. Similarly, bulk density of the surface 0 to 15 cm of soil decreased with increasing rates of manure application, the greatest effect being where the manure had been incorporated by cultivator on irrigated land. But, at 15 to 30‐cm depth, the smallest bulk density was where the manure had been incorporated by plow. Increasing rates of manure on irrigated land tended to decrease the amount of aggregates < 1 mm and increase the amount > 1 mm in size, at the 15 to 30‐cm depth. These results indicate that manure, applied at the relatively low rates that are currently recommended, can maintain and increase the organic matter content of the soil and ameliorate the physical condition of southern Alberta soils.