[permaculture-oceania] No till methods

Wed Sep 13 18:09:09 EST 2006

hi Terry

I had a bit of exposure to broadacre agriculture in Walgett, 5 years ago.  
i'm sure they have come a long way since then.  I am however no agronomist.

Hard pan in many cases is avoided through controlled traffic (or tramlining) 
- sacrificial tracks which all farm machinery follows avoiding compaction of 
adjacant plant beds.  This has allowed them to get smaller tractors as it 
requires less energy to drive over a compacted track and less energy to pull 
a plough through uncompacted earth hence using less fuel.  Chemical usage is 
also reduced as there is no overlap between runs.  spray units also follow 
the same tracks however I am not sure that the harvesters had the same wheel 
span and often chaser bins took a direct line between the gate and 
harvestor.  GPS technology is also widely used to effectively steer the 
tractor.  The GPS technology is also used to enable yield maps to be 
produced showing exactly which parts of the paddock had low yeilds and so 
limit fertiliser application where needed.

The minimum tillage methods meant minimum soil disturbance meaning less 
evaporation and more moisture for the following crop.  Retention of stubble 
also helps retain moisture.

They were also looking at spray rigs that could detect weeds and spray only 
the weeds, making huge savings on chemicals.  Crop rotations are also 
important to minimise crop specific diseases building up.  Chick peas and 
legumes were used in rotations to increase soil nitrogen.

The technology certainly is a big step forward however many are skeptical 
that broadacre farming is viable that far west, There is no room for paddock 
trees as they want nice straight lines.  This type of farming technology has 
made cropping "viable" (at least short term in good seasons) as far west as 
Bourke.  The farmers out west were generally more willing to adopt new 
technologies as farming was new to them and they didnt have the previous 
generations bad habits to follow.

It is arguably more sustainable to some organic farming which relies on 
ploughing to destroy weeds and leads to reduced soil structure and hard 
pans.  A few farmers were going "organic" on new country to take advantage 
of the premiums then switching to no till after a few years once the soils 
nutrients have been depleted.

type "conservation farming" into google and you will find heaps of 
information.  I think conservation refers to conserving soil moisture.

Regards
John

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>From: Terry Leahy <Terry.Leahy at newcastle.edu.au>
>Reply-To: permaculture-oceania <permaculture-oceania at lists.cat.org.au>
>To: permaculture-oceania <permaculture-oceania at lists.cat.org.au>
>Subject: [permaculture-oceania] No till methods
>Date: Tue, 12 Sep 2006 12:05:31 +1000
>
>Dear Permies,
>
>I note the recent discussion on glyphosate and it reminded me of
>something I wanted to ask this chatline about.  I recently presented
>some stuff on agriculture in my broader course on environment and
>society.  In this I showed some of the video Global Gardener where it
>starts with Bill talking about how plough agriculture is not suitable
>for the humid tropics because the nutrients get washed away and
>dissolved and also because of hard pan.  Earlier in the lecture I talked
>about problems with cereal crops that include soil erosion following
>ploughing and figures on this - now many kilos of topsoil we lose for
>every kilo of wheat.  In the class, one of my students said he found
>this a bit out of date really;  most Australian farmers now use
>"No-Till" or "Conservation" farming.  This means that the stubble is
>left rather than burned,  they let the weeds grow and knock them out
>with round up before sowing.  They do not turn the soil with a "plough"
>but rather use a disc  (?) which just puts in a small knife like slit in
>the soil to drop the seed in.  He also said that if they get a hard pan
>they use lime to break it up.
>
>None of this is entirely new to me; I have of course read about all
>this but I thought afterwards that the student is maybe right to an
>extent and I am unfairly bagging cereal crop production on the modern
>Australian farm.
>
>There are a number of issues that I would be interested in hearing
>about:
>
>Firstly, my understanding is that frog friendly round up is only used
>by home gardeners - commercial farmers just think the extra cost is not
>doing anything for their bottom line.  So this no-till tech actually
>intensifies environmental problems for frogs.
>
>Secondly, my understanding is that topsoil is usually the result of
>centuries of humus deposition by various kinds of trees and bushes.  No
>- till may prevent further erosion of this topsoil but it cannot build
>the topsoil very readily.  But again I know that with maize they can
>achieve a mimic of a forest humus production by putting in a cover crop
>and slashing it - for example velvet beans are very popular in Latin
>America.  Do no-till farmers in Australia do anything like this or are
>they essentially mining soils when they plant cereals?
>
>Thirdly, do these new "ploughing" techniques - it seems they do not
>like them referred to as "ploughing" which conveys the concept of
>turning over the soil - really stop soil erosion or not?
>
>What about hard pan?  Are there any problems with repeated applications
>of lime?  Does it actually work?  Doesn't the weight of agricultural
>machinery pack down the soil regardless?  This liming solution is
>probably too expensive for some cereal farmers, especially in developing
>countries.  Again, I would have thought that in the context of grain
>agriculture some kind of rotations and cover crops that were reasonably
>deep rooted combined with minimal ploughing would have solved these
>problems better than applications of lime but maybe I am wrong?
>
>What about the problems of dissolving soil minerals that Mollison talks
>about and which is often referred to especially in relation to former
>rainforest soils?  Does no-till stop this mineral leaching?
>
>Would be interested in any comments on this,
>
>Terry
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