Weather is the worst enemy
LARGE variations in grass growth rates (20-70kg DM/ha/day) are apparent, depending on rainfall and temperatures, writes BGS consultant Paul Bird. Grass quality is poor on many farms and must be improved by the end of September.
Producers aiming to extend their grazing season should apply N in late August and September. Most farms require growth rates of at least 45-50kg DM/ha/day to achieve sufficient grass covers in October for extended grazing.
To illustrate how grass growth in September is important, a farm visited recently was stocked at 2.5 cows/ha (1/acre), with each cow consuming 14kg of grass DM through grazing – 2.5 cows x 14kg grass/cow = 35kg grass DM eaten/ha/day. Grass growth was also 35kg DM/ha/day resulting in a constant grass cover. Average grass cover on the farm was 2300 kg DM/ha on Aug 17. Target grass cover on October 1 is 2700kg DM/ha which is going to be grazed to late November.
To increase grass cover from 2300kg DM/ha to 2700kg DM/ha in about 40 days (late August to Oct 1) will require an average grass growth rate of 45kg DM/ha/day or 10kg above stock requirements – 10kg x 40 days = 400kg DM/ha increase in average cover. *
Grass growth – previous 7 days (kg DM/ha a day)
Pembrokeshire – Richard John 50
Staffordshire – Steve Brandon 62