Modelling N mineralization from bovine manure and sewage sludge composts.
Nitrogen mineralization kinetics were compared in three different soils (pH values: 5.2, 7.1 and 8.6) when treated with bovine manure (BM) and sewage sludge (SS) composts. The soil-compost mixtures were kept at a controlled moisture content of 60% of their water holding capacity (WHC) and were incubated in the dark at 25 °C for 2 years. Five mathematical models were compared (simple exponential, double exponential, special model, hyperbolic and parabolic), using as experimental data the mineralized N accumulated during 360 and 720 days of incubation. The results showed that the best fit for describing the mineralization of organic N from the compost after 1 year of experimentation was obtained with the simple exponential model. However, the special model showed the best fit for data from 2 years of incubation and thus better reflected organic N mineralization over a longer time-span. This suggested that the organic N in the two composts was made up of two organic pools of different degrees of stability.
Gil
M V
MV
Chemical Engineering, Institute of Natural Resources, University of Leon, Avda. Portugal, 41, 24071 León, Spain.
Carballo
M T
MT
Calvo
L F
LF
D000818:Animals; D002417:Cattle; D008372:Manure / Q000032:analysis*; D008903:Minerals / Q000378:metabolism*; D008956:Models, Chemical; D009584:Nitrogen / Q000378:metabolism*; D012722:Sewage / Q000032:analysis*; D012987:Soil / Q000032:analysis*
D008372:Manure; D008903:Minerals; D012722:Sewage; D012987:Soil; D009584:Nitrogen