Comparison Between Fodder Cropping Rotations Carried with or without Meadow in the Intensive Farming System of the Po Valley Plain (Italy)

Pour fodder cropping rotations were compared at different degrees of crop intensification: (RI) a I-year continuous monoculture of Italian ryegrass (Loll111n multij/orum Lam.) +silage maize (Zea mays L.); (R3) a 3-year rotation of Italian ryegrass+silage maize - barley (Hordeum vulgare L.)+silage mai1:e - grain maize; (R6) a 6-year rotation of Italian ryegrass+silage maize for 3 years followed by meadow for 3 years (Trifolium repe11s L. + Festuca ari111di11acea Schreb,): (PM) a monoculture of permanent meadow. The most efficient rotation for dairy cattle feeding, on sandy-loam soils, was the I-year rotation of Italian ryegrass, followed by silage maize, with 22 9S0 milk feed units (MPU)lha, The 3-year rotation without meadow, ranked second, with 18 "ISO MPU/ha. On soils with higher clay content, the 6-year rotation with meadow, in spite of the lower yield (15 9S0 MPU/ha), deserves careful consideration. The permanent meadow, the less intensive rotation, yielded only 16S0 MPU/ha. The experiment indicates that 6.9, S.6, 4.8 and 2.3 adult cattle/ha can be fed with rotations Rl, R3, R6 and PM respectively.