Emergency Pasture Renovation
pe...@swep.com.au
years of drought, many farmers urgently need to establish new grass -
right now! Of course, we all know that 'haste makes waste', so moving
too quickly could spell disaster. So what shortcuts are available and
what is needed to ensure a reliable result?
In an ideal World, preparations for renovating pasture would begin 6
to 12 months before actually sowing the new seed. This is because most
of the problems people experience in trying to establish new grass
relate to aspects of the physical condition of soil. For example, the
soil may be compacted, or form a surface crust after wetting. These
kinds of problems are quite treatable, but it takes time for the soil
condition to improve.
Generally, the advice would be to soil test and use the results to
work out appropriate applications of materials such as Lime, Dolomite
or Gypsum. These would be applied in Autumn for a Spring planting, or
in Spring for an Autumn planting. In this way, the seed and fertiliser
have the best possible conditions in which to perform.
However, there are a few things you can do to shorten this process.
The results may not be quite as good, but they should be good enough -
good enough to quickly generate much needed fodder and good enough to
ensure persistence of the new grass until things can be improved
further. So here are some strategies that should take account of most
conditions you could presently be facing.
Firstly, you need to assess the state of your paddocks and teat each
one on its merits. It may be that most look dry and brown, but walk
through each one and take a closer look.
Do you have many paddocks with a fairly good cover of grass clumps
that could grow back quickly once there is moisture in the soil? For
these paddocks, where the aim will be just to quickly fill in the bare-
patches, the rule is: "Avoid cultivation and over-sow the old grass".
Paddocks like this should need no more than a light harrowing in
preparation for sowing. The more lightly you harrow, the more benefit
you will get from the grass that is already there. Hopefully, you have
at least a few paddocks like this, as they will be the quickest to
produce feed for you. Over-sow with seed and fertiliser and leave soil
testing until Spring. By then you should have good cover and paddocks
that will respond well to improvements in soil condition.
Next are paddocks in which the cover is getting a bit sparse - more
bare-patches and dead grass than surviving old grass clumps. Some of
these could be treated in the same way, but at some point you will
find it is just not worth saving the old grass that remains and so
full renovation becomes the best option. Since this can be costly, you
will hopeful only have one or two paddocks needing this treatment.
This strategy must start with a soil test. Since you will be
cultivating to prepare a seedbed, you can at least make a start on
improving soil condition. The important aspect to keep in mind is soil
depth. The standard depth for soil testing of pastures is 10cm, so the
recommendations you get for any Lime, Dolomite or Gypsum will be
designed to treat the soil to that depth. However, renovating pasture
usually requires cultivation to only about 5cm. In this case only
apply half the recommendation and leave the rest until later - say,
early next Spring. This approach will have implications for what
fertiliser you use, but usually nothing too drastic.
The soil test you took at the start will also give you recommendations
for proper nutrition of the pasture and you will need to provide some
of this to ensure strong establishment and good early growth. However,
you should post-pone the application of any trace elements until
Spring as these may be tied up by whatever Lime, Dolomite or Gypsum
you applied. Minimising any interaction with the base fertiliser can
be achieved by broadcasting it with the seed and finish with a light
roller to press both into the soil.
Some people prefer to drill rather than broadcast and this is fine, so
long as any mixing of seed and fertiliser only occurs immediately
before sowing (although it is always best avoided if possible).
Drilling may even be preferred if there are indications of another
mild Winter, since having seed sown a bit deeper will help protect
them from being dried in the early stages of germination. However,
even when drilling, it is still wise to roll the paddock lightly
afterwards.
Lastly, there may be a paddock or two that has been totally 'trashed'.
Here the keyword may well be 'sacrifice'.
In drought conditions, the most important thing is to feed your
livestock, but not many people realise how many nutrients they can
bring on to the property with this feed. The trick is to make the best
use of this, so sacrifice paddocks can be used as a good cheap
renovation strategy. Ideally, there should be enough shelter available
that stock can be continuously housed in these paddocks without undue
stress. If not, you should start looking for places to move them for
short periods now and then, as soon as growth permits.
The rule that underlies this strategy is that 'Fences Grow Grass', so
the time you keep stock in a sacrifice paddock is time the other
paddocks have in which to recover.
Again, it is advisable to start with a soil test. Since it will be a
while before re-sowing these paddocks, you can apply any required
Lime, Dolomite or Gypsum and let the stock work it in with their
hooves. This will also lead to increased microbial activity in the
soil and quicker breakdown of the manure they leave behind.
The important things to remember with sacrifice paddocks are:
- Don't just spread feed in the same place all the time; work your way
around the paddock to ensure complete coverage.
- Every now and then drag a set of light harrows around (or even just
an old steel gate) to help break up the manure. This is important as
it ensures good exposure to sunlight that will kill any parasites that
could otherwise build up in the paddock.
- When you have finished and want to re-sow, lightly cultivate and sow
without fertiliser (there should be enough nutrient from all that
manure to get things going), but repeat the soil test three to six
months after sowing to see if anything is needed to keep everything
going strong. Again, roll the paddock after sowing.
With any renovation it is also important not to leave it too long
before the first grazing. A simple way to check when it is ready is to
grab some grass between your thumb and forefinger, the sharply tug
upwards. If you pull up roots, then wait a bit longer. If not, it is
ready for its first, quick, Light grazing. Afterwards, let it
completely re-grow before grazing again.