Comparison of enhanced, tame Italian ryegrass (Lolium multiflorum L.), long established and naturally reseeded, versus an annual ryegrass crop in the flood plain of Río Salado, Argentina: Winter forage production under grazing

摘要: Effective operation of grazing production systems requires controlling forage availability at the farm level. A nine-year-old stand enhanced native ryegrass (Lolium multiflorum L.) (RGE) and an annual crop Italian L. cv Tama) (RGT) were monitored to test hypotheses that: (1) herbage biomass in such pastures can be assessed by Ration Calculation methodology as accurately more exhaustive procedures, (2) enhancement increases quantity quality winter supply. Enhancement includes fertilization with NH4NO3 (NH4)2HPO4, weed control Glyphosate. The method estimates available dry matter assuming that «one ration» is equal one cow equivalent (CE), consisting 10 kg DM day-1 77.57 MJ ME. Herbage samples taken from each paddock, representing harvestable biomass. Grazing harvest efficiency intake (HDMI) estimated through difference between initial (IHA) final (FHA) (kg ha-1), before after grazing, corrected for losses due grazing. Eight cycles RGE produced annually 16 041 DM/ha, (2 001 ± 79.3 rations/ha) while ration calculation 9 775 DM/ha. RGT allowed seven cycles, yielded 12 269 DM/ha or 1 144 87.1 rations/ha compared 8 688 calculating rations. latter did not assess cumulative produced. technology improved tame winter.