I read Peter Andrews' books "Back from the Brink" and "Beyond the Brink" a couple of years ago and I decided to read them again recently to refresh my memory. I'm so glad I did, because I had forgotten so much and I found that some of the things that didn't make sense the first time really clicked into place this time. There's no way I can summarise all the ideas here, if you are interested in improving the fertility and water-holding capacity of your land, as well as reducing your input costs (fertiliser and irrigation), you really need to read the books carefully yourself. However, I can summerise the ideas that we are applying on our property.
Farms don't need expensive inputs
Peter has developed a system based on his expectation and experience that farms should be viable without expensive inputs of fertiliser and herbicides. Interestingly he's not actually pro-organic farming, he just wants to save money.
8 Acres Application: farming on a small scale means that we're not trying to make a profit, just feed ourselves, so of course we'd prefer to use cheap or free inputs (especially as we miss out on all the tax benefits that larger farmers can access). We also prefer systems that don't use much of our time and labour (spreading fertiliser and spraying weeds is hard work!) and we support organic systems in general, as we want to eat chemical-free food.
Weeds are good
Weeds have deep tap roots compared to grasses, so can bring water and minerals to the surface that would have been out of reach of the grass roots. This means that weeds are valuable in the landscape and should not be poisoned. Also more advantages of weeds are described here.
8 Acres Application: we do still dig out and control weeds that we believe are detrimental to our cattle (honestly, we have seen them munching on lantana and we'd rather they didn't have the opportunity, this is what we've been doing), however all other weeds are allowed to live and we slash regularly to create weed mulch. We never use burning to control vegetation on our property. Obviously this is much easier on a small property than on a larger one, and I suppose that's one of the advantages we have here. On a larger property it would help to use mob-stocking, where cattle trample what they don't eat.
Plants maintain soil pH
Plants alter the soil pH in order to access certain minerals. If minerals are lacking, the soil will become acidic. Modifying the soil pH using lime or dolomite will not correct the underlying imbalance so is not a long-term solution. Its better to let various weeds grow to rebalance the soil minerals.
8 Acres Application: Our soil test revealed that our soil was acidic and required copious amounts of lime and other minerals to correct the deficiencies. We haven't rushed into spreading around the lime, and I'm glad now that we took our time. It looks like we're better to focus on improving the fertility in general and letting the plants correct the pH and mineral balance over time. However, the soil test wasn't a waste of money, this allows us to make sure that we are feeding the cattle mineral supplements for the minerals that they're not getting from the plants in our paddocks. Eventually the minerals in their manure will contribute to the soil too.
Green surface area is important
Green surface area is the total amount of green in the paddock, including grass, weeds and trees. Trees can create far greater green surface area than grass for the same land area because they occupy more vertical space. Green surface area builds the fertility in the soil by dropping leaves that build top soil AND attracting birds and animals (= manure), so the more green surface area the more fertility. Peter suggests that approximately one third of a farm should be treed, one third cropped and one third grazed. The trees should be planted on the high ground so that the fertility is transported downhill to the other two thirds by water/gravity. The thirds don't have to be solid blocks, but can be spread out over the farm.
8 Acres Application: We don't have the water for cropping, so our property will only need trees and grazing area. We probably don't need one third of the area in trees as grazing using less fertility than cropping. We have a steep property divided into 4 paddocks, and large gum trees remain in each paddock for shade. We wouldn't want to plant all of the top of the property with trees and potentially lose the use of part of that top paddock, however we could increase the number of trees by planting more trees at the top of each paddock instead. This would contribute to the shade available as well as the green surface area. I would like to plant frost hardy fodder trees (eg pigeon pea and tree lucerne) , so that we have some green matter for the cattle to eat over winter. Need to investigate this further......
Salinity is caused by badly sited dams and removal of trees
This is one of the more confusing concepts in Peter's work and I didn't really get it until the second reading. He says that salinity in the groundwater is controlled by a layer of freshwater sitting above the denser saline water underground. Trees help to maintain this layer by exerting a vacuum on the freshwater, holding it in place. Rather than trees consuming all the water (one reason that they have been cut down in the past) they actually hold the water near the surface. However, bare ground allows the rainwater to enter the ground too quickly and can cause the fresh and salty water to mix. In addition, dams on the surface will exert a positive pressure and push the fresh water into the salty water. Salinity travels horizontally in the ground until it reaches the surface of a slope and appears as a salt outbreak, it does not travel upwards, as commonly thought.
8 Acres Application: unfortunately we have seen this concept at work around our creek area/small dam, but we have no control over it as its the neighbours' large dams and clearing activities that are causing the problem. All we can do it maintain the trees and vegetation around that area to try to control the water table on our property. This is when small scale farming is difficult, you rely on your neighbours also taking an interest in maintain soil fertility and for the most part, ours aren't doing anything to help.
We don't plough any of our land and as I said above, we are letting the weeds grow, this has to help prevent increasing salinity.
Build contours across slopes to distribute water and fertility
Creating banks along contour lines to catch freshwater and backfilling some of these with organic matter which will spread fertility is an efficient method to distribute water and fertility across a hillside. This is similar, but not identical, to using swales in permaculture design. Swales are usually dug into the bank and may hold water for some time, this is not ideal for preventing salinity, as discussed above, so Peter recommends creating mounds so that water sits on the surface for a short time only.
8 Acres Application: we recently did a permaculture course and were thinking about building swales. We haven't decided how and where to build them so that we can still slash the paddocks. I think we will end up building something closer to contours anyway, as that will be easier on the tractor!
Climate change is caused by loss of vegetation cover
Peter Andrews proposes that climate change is not caused by carbon dioxide, rather from the loss of the cooling effect of all the trees that have been cut down all over the world. I have to say that it kind of makes sense, even if its not the only cause, surely it has to be a contributing factor.
Plant more trees, let the weeds grow and be careful how you store and distribute water!
Have you read Peter Andrews' books? Have you applied his principles on your property?
You may also be interested in One Straw Revolution. See more sustainable farming books here.