From the time a pasture becomes properly established its production gradually declines and often the feed quality also reduces. Commonly there is a loss of high quality pasture species over time, often due to pest attack.
There are many reasons for renovating a pasture such as:
- To take advantage of a new advance in pastures (such as novel endophytes)
- To replace a poor producing or poor quality
- To re-establish a pasture species lost to pests (such as white clover lost to clover root weevil)
- To provide an opportunity to alleviate or remedy soil damage such as pugging
- To address a serious weed and/or pest problem
Benefits of regressing
Assuming the only benefit of regrassing was increased pasture production, regrassing is still very much economically viable. Assuming the new pasture produced just 3000 kgDM more than the one it replaced, this is worth $450, recovering most of the cost within a year and returning a profit within two years.
Sowing a new cultivar should also greatly improve feed quality, so animals perform better and the return becomes even greater. Replacing a pasture particularly in the case of using a new species, should also improve feed quality and the amount of energy produced by the pasture per hectare.
The reason for regrassing is that there are potentially massive performance gains and profit increases to be had from replacing old pasture with new high performing cultivars.