Surface Soil Salinity and Soluble Salts after 15 Applications of Composted or Stockpiled Manure with Straw or Wood-Chips

The influence of 15 annual applications of composted (CM) or stockpiled (SM) beef feedlot manure with straw (ST) or wood-chip (WD) bedding on electrical conductivity (EC), soluble cations and anions (Na, K, Ca, Mg, SO4-S, Cl), sodium adsorption ratio (SAR), potassium adsorption ratio (PAR), and pH of a clay loam soil (0–15 cm) in southern Alberta was examined in an irrigated barley silage cropping system. Manure type (CM versus SM) had a significant effect on certain soil salinity parameters. Calcium, Mg, Na, K, and SO4-S were significantly (p ≤ 0.05) greater for SM- than CM-amended soils for certain bedding materials and rates. Electrical conductivity, concentration of soluble cations and anions (Na, K, SO4-S, Cl), SAR, PAR, and pH in the surface soil were greater for ST than WD bedding. Two exceptions were Ca and Mg, where soil concentrations were generally greater for WD than ST. Salinity parameters were greater with increased application rate, and greater for amended than unamended soils. Overall, bedding had considerably more significant effects on soil salinity parameters compared to manure type. Wood-chip bedding may be a management tool for feedlots to lower EC, soluble cations and anions, and pH of surface soils.