By Peter Callan, Extension Agent, Culpeper County, Agriculture & Natural Resources, Farm Business Management, Culpeper, Virginia
Over the past 10 years increasing numbers of cattle producers have started to intensively graze pastures to maximize pasture as a source of feed. Rotational grazing is a management intensive system that concentrates animals within a relatively small area (paddock) for a short period of time e.g. 1-3 days for beef cattle. A pasture may be divided into multiple paddocks. The animals are then moved to another paddock while the other paddocks are allowed to recover and regrow. Animals are moved according to a flexible schedule based on herd size, the amount of land available, quality of forages in the paddock and forage consumption.(1) Continuous grazing is use of one pasture. The type of grazing system implemented on a farm has major implications regarding pasture fertility.
Missouri researchers estimated that grazing animals recycle 75-85% of forage nutrients consumed. An even distribution of manure throughout a paddock is required for productive plant and animal growth. Intensity of grazing rotations affects the manure coverage in paddocks. In a rotational grazing system there is an even distribution of manure because the animals are forced to consume forage in the paddock before being moved to another paddock. The Missouri researchers calculated that under continuous grazing practices, 27 years would be needed to obtain one manure pile per every square yard within a pasture. Conversely, the pasture was divided into paddocks and a two day rotation was used. Then two years would be needed to achieve an even distribution of manure within the paddock.(2)
The location of hay feeding areas will impact the distribution of nutrients within a field. Manure will be deposited near the feeding areas. Depending on weather conditions and the potential for creating mud and ruts in the pasture, feeding areas may be moved throughout the pasture to insure a more even distribution of nutrients. Whenever hay is baled, nutrients are removed from the field and exported to the feeding area. Kentucky researchers have estimated that a ton of grass hay (fescue, orchard grass) removes the following nutrients from the soil: 12 lbs. of phosphate and 50 lbs. of potash.(3) If these nutrients are not replaced; soil reserves will be depleted over time. Consequently, there will be a reduction in crop yields. Soil testing determines the amount of fertilizer that needs to be applied to maintain hay yields.
Cooperative extension agents can assist producers in the design of rotational grazing systems for their farms. Virginia Tech livestock budgets have shown that the implementation of rotational system can maximize profitability for cow/calf producers. There are Virginia livestock producers who have increased net profits by $200 per head due to the implementation of rotational grazing systems on their farms. Rotational grazing systems can maximize farm profitability by recycling nutrients which results in a major reduction of purchased fertilizer inputs.
Source:osu.edu