Impact of dairy housing practices on lagoon effluent characteristics: Implications for nitrogen dynamics and salt accumulation

Increasing emphasis on maintaining environmental integrity by dairy operations warrants examination of management influence on waste characteristics. Complete profiles of anaerobic dairy lagoons for eleven operations in central Texas, distinguished by use of dry-lot and hybrid (i.e., facilities comprised of free stalls with smaller dry-lot areas) management systems, were analyzed for 15 physicochemical parameters. Although solids, pH and TKN values were similar between housing type, statistical differences in NH4-N, P, K, Mg, Na, Mn, Cu and electrical conductivity (EC) were observed. The discrepancies were attributed to dissimilar cattle activity, where cows spend more time near flush alleys in hybrid systems than dry-lot systems, which facilitates waste transport to anaerobic lagoons. These results suggest a possible difference in N dynamics between lagoon types, which in turn would have implications for NH3 volatilization. Potential salt-stress impact on both lagoon effectiveness and pastures receiving land-applied lagoon effluent may also be enhanced by hybrid systems. This study not only contributes data on anaerobic lagoon characteristics, but also provides additional considerations for dairy producers striving to meet more rigorous regulations while attempting to protect soil resources for crop production.