Dairying on heavy soils
DAIRY farming on heavy soils is challenging but the potential exists to increase cow production.However, stocking rates must be appropriate to reduce the reliance on bought in feed.
Early work at Kilmaley research farm in Clare, which was at the extremes of heavy land, indicates a profitable spring milk system should be based on a feed budget of 10 tons silage/cow over six months with 14 tons of grazed grass/cow and 0.5 tons of meals/cow. This should allow two cows/Ha on average using seven bags of nitrogen per acre, per year.
Most dairy farmers on heavy land have a lower S.R. (1.83 cows/Ha), low output (310 kgs milk solids/cow) with 374kgs meals fed/cow and grazing on average of 218 days.
A major study was conducted in Kilmaley to determine the efficiency of two different production systems on a high rainfall, heavy clay soil, based on differences in meals fed and stocking rate.
There were two treatments.
1. Blueprint Group: 30 Spring calving cows stocked at 2.18 cows/Ha fed 680Kgs meals with 6.5 bags nitrogen spread per acre.
2. High meals Group: 30 cows stocked at 2.87 cows/Ha fed 1.35 tons meal/cow with 7 bags nitrogen spread per acre.
The trial lasted four years (2006 - 2009) and separate 'farmlets', each with 19 paddocks were used. In both systems the target was to minimize the amount of silage fed during the summer months and have cows on grass only for the grazing season. The high meals group got the extra meal in early and late lactation.
1. Cows over the four years grazed on average of 180 days.
2. Milk solids were 378 Kgs/cow for the blueprint group and 402 Kgs/ cow for the high meals group. There was no difference in the percentages of fat and protein.
3. No difference in cow fertility.
4. High profit was got with the blueprint system at low, medium and high milk price because the high meals group was too reliant on bought-in feed.
The conclusion from this research was that dairying on heavy land can be profitable. Key components are moderate stocking rates with compact spring calving, high E.B.I. cows, moderate amounts of meal and good grass utilisation with high use of on/off grazing techniques.
The research also found that major emphasis must be placed on having good farm roadways and cow paths. Soil fertility, especially lime, phosphate and potash levels must be corrected. Drainage works must be carefully investigated and costed.