Hi All,
I wanted to wait until I visited the clients farm on Friday to see fist hand
their irrigated and dryland pastures. Irrigation appeared to be well managed
and we were observing the 1st leaf at ~8 days and at day 20 when the
pastures were being grazed we were seeing 2 and a bit leaves. Looking back
at old reports for February and this is consistent for what we had seen in
other years. So my conclusion was that leaf emergence was 8-10 days and
seemingly consistent enough not to change rotations for a little while yet.
Interestingly in the same paddock where the irrigation (Van Den Bosch type)
had only partly watered leaf emergence had slipped out to at least ~12 days
and on the dryland, growth rates had nearly stopped again and while there
was still pasture available it was drying out very quickly, hence the aim to
graze what was available quickly and then wait for the autumn break.
I agree Frank, that counting one leaf can be a bit tricky and really what is
a 1/2 leaf? Is a leaf that is half way through emergence 1/2 its final size?
I suspect (guessing) that it will be well below 1/2 its final size (ie
sigmoid growth curve). More to the point my reason for trying to get a
handle on latest leaf emergence versus average LAR for the past rotation is
as follows. If leaf emergence has gone from
Leaf 1 - 20 days
Leaf 2 - 15 days
Leaf 3 - 10 days
Then the average leaf emergence is 15 days. If the conditions that prevailed
for the leaf 3rd are to continue (or improve) then 45 days (if we're aiming
for 3 leaves at grazing) will be at least 15 days too slow. I find this
strategy particularly useful coming out of summer and winter as growth rates
start to kick in.
I joke with clients that the beauty of leaf emergence is that you can
usually find what you're after to back up your argument on LAR if you look
hard enough. A bit like condition scoring cows, but I try to avoid tillers
that have not been left with a large partly grazed residual - these just add
a complication to something that wasn't meant to be too complicated!!
To finish off, a question for Rick Jordan - what are LAR's under "best
practice" pivots in the Mt Gambier district?
Cheers, Neil.
-----Original Message-----
From: Frank Tyndall [mailto:ftyndall@ozemail.com.au]
Sent: Wednesday, 22 February 2006 11:58 AM
To: vicdairy-l@unimelb.edu.au
Subject: LAR in gippsland areas
Dear all,
I have four ryegrass plots, watered reasonably well but not perfectly. I
have a tensiometer in one, so I don't let them get too dry, about the same
as a typically irrigated paddock. They are at Inverloch which I am sure is
a bit cooler than say Maffra.
1: Dys since grazed: 60 Leaf stage: 4.1 Avge leaf
appearance: 14.6
2: Dys since grazed: 49 Leaf stage: 3.6 Avge leaf
appearance: 13.6
3: Dys since grazed: 32 Leaf stage: 2.2 Avge leaf
appearance: 14.5
4: Dys since grazed: 22 Leaf stage: 1.5 Avge leaf
appearance: 14.7
Yesterday I checked leaves on a irrigated paddock at Newry (near Maffra):
2.3 leaves, 27 days since grazing: average LAR 12 days.
I reckon trying to pick one leaf after grazing is tricky. How much are you
allocating to the remnant leaf? What about the bit of variation you find
in the one clump? After 10 days it is a bit tricky to say you have 0.7 of
a leaf (i.e. 14.3 day leaf appearance) or 1.3 leaves (i.e. 7.7 day leaf
appearance)? And remember not to count tillers that are seeding, or
counting poa. At one leaf I think it is pretty easy to find whatever you
want to find. And it is the leaf stage when the cows actually arrive at a
paddock to be grazed that matters. I doubt there would be a paddock in
irrigated Gippsland that is sitting at three leaves right now that was
grazed less than 30 days ago, and for dryland 40 days plus.
Some 30 day rotation paddocks I have seen recently were great: huge amount
of feed and quality still ok. Others had a bit too much decay underneath
and some with too much paspalum to warrant going to 30 days.
Danny, what is the go with summer rain on dryland? You get green growth
again but hot dry weather is still likely. Is it best to hold some sort of
rotation (it will go dry) or eat it all off as quick as possible while
still green?
Recently there has been some good discussion about the profitability of
dairyfarming. Mostly external factors were mentioned. I think grazing
rotation is a very important profit driver that a farmer has total control
over. It drives pasture consumption which drives the cost of feed.
Happy rotation length setting
Frank Tyndall
This archive was generated by hypermail 2b29 : Tue Aug 08 2006 - 02:38:30 EST