FARMVIEW Episode 3.3 transcript
Episode 3.3 - Use mulch to retain moisture
They have actually been planting cover crops in the mid rows of grapevines and citrus trees for a long time. Initially why they started doing that I am not sure, other than weight suppression and ultimately that was one of the things we started doing it for, because the cover crop will actually drown out any competitive weeds in that windless period. We just took it to the next stage via trial and to cut it under the bank and seeing what benefits we could get and the benefits were huge really.
The biggest benefits we get is moisture retention in the soil, it improve the soil quality. The vineyard is a lot cooler in the hotter season that the grass actually holds the temperature better than dirt reflects it. In the 2008 heat wave where a lot of guys lost up to 30% and 40% of their crop, we probably had losses of maybe 1% or 2% and that was just because the soil did not reflect heat as bad as what they did in other vineyards and mate that is a big saving. If you are not spraying out weeds all the time you are saving your mid row as well with compaction and things like that.
This is actually barley and we have been using barley over oats and rye corn because it gives a better storking feature. Once it has been cut, it actually goes from one blade to three or four blades and storks out, so you get a bigger bulk and once it gets up to sort of a foot and a half two feet high, we cut it and then it will actually re-shoot and grow again and it will do that six or seven times, whereas oats are not as good at it and rye corn, you are probably only get one or two cuts and it is gone. We have actually got a slasher with the sides removed, it is a twin bladed slasher and we cut it down at about probably four or five inches off the ground and the slasher, the way the blades are set up, it throws the grass out onto the west side bank and actually just lies there in a straight row and then we come back probably four, five weeks later, when it is warming up and cut it again and that will go on top of that and by the end of sort of November after our last few cuts, we will have a mulch bed, sort of that high and that will stay there right up as you have seen, there is a little bit of it left now and that is just what is left that the organisms have not eaten and what has not been turned into organic carbon.
What we are looking at here is the remainder of our barley crop that was sown four weeks ago. That has actually been decimated by grasshoppers as you see it would have been a lot thicker than this and a lot higher and all the way to the other end of the patch. We will probably sow this again in the next week or so and it will be a bit later start, but it probably will not make a lot of difference. By mid July it will be probably at the height, two and a half foot high and will be, we will commence the cutting and throwing it onto the banks and probably after that as the weather warms up into spring, we will cut it maybe every two and a half weeks, right through till when we think we have got enough mulch on the banks to get us through the summer and then we can burn the cover crop off with a Round-up or Glove soap of some sort and we have got our mulch. The dead stalks will remain in the mid row and they will give a good hold on the soil and open the soil up for water penetration which is everything we are after really.
This is what is pretty much left of our cow manure, which is our base that the barley was thrown on top of through the growing seasons through the spring of last year and this looks like a bacteria and organisms in the soil there that help turn fertilisers into an uptakeable form for the plant and that is really important. You also get worms and all sorts of little goodies in there that help aerate the soil and improve it, which is all for a function from the mulch that you throw on top of it. Fantastic, looking good,. You can actually see the left over stubble and this is already been worked in from last year and that actually aerates the soil as well, like all the fibrous roots off the bottom one. This opens the soil up and lets the water penetrate much easier throughout the ground season, even though it has been killed off. It just cools the soil and opens up the pores of it.
Growing your own mulch in the mid row and slashing it on is probably the cheapest form of mulch that you can get of any mulch. It is cheaper than composted cow manure and you have got no spreading cost, although you have cutting costs with your slashing, but to buy hay to do what we are doing every year would be phenomenal. Probably 10 to 15 times the cost of what it costs us now, which is big savings. Probably on a hectare basis you are probably saving $500/hectare.
I do not think you can do it in every situation, because we have under vine sprinkler systems here, we are not relying on rainfall completely, whereas with the lot of drip irrigated vineyards now and there is a lot of them around, it is a big cost to put it in if it does not grow and it is a lot of time waisted, so look if you had overhead sprays or under vine sprinklers, I think you would be mad not to trial it and just see the benefits for yourself. Whereas maybe a cow manure or you would have to buy straw for your drippers, knowing you would get a guaranteed result.
Well moving forward I do not think we can afford not to do it. I think we have to keep putting it in. It is a pretty minimal cost at a not such a busy time of the year, so for the few weeks of the year we run through and drop our seed in at a pretty minimal cost and we get the benefits for the whole year.
If you want to know more about this programme, contact your industry grower association or the DEPI customer service line - 136 186.