3KAPUINEN P.Deep litter system for beef cattle housed in unin-sulated barns, part 2:temperatures and nutrients[J].Journal of Agricultural Engineering Research, 2001, 80(1):87-97.
4DEININGER A, TAMM M, KRAUSE R, et al.Penetration resistance and water holding capacity of dierently conditioned straw for deep litter housing systems[J].Journal of Agricultural Engineering Research, 2000, 77(3):335-342.
5GREENESTEIN C M, VAN FAASSEN H G.Volatilization of ammonia, nitrous oxide and nitric oxide in deep-liter systems for fatening pigs[J].Agric Engng Res, 1996, 65:269-274.