Peter Andrews, sometimes called the weed grower developed a system called Natural Sequence Farming. He looked at how Australian landscape used to re-hydrate itself and maintain fertility before we began to disturb it. He used history, his experience as a horse race breeder and his ability to read the land to develop a regenerative farming system based on slowing down water and vegetation succession. Here is Peter Andrews Natural Sequence Farming system website. The ABC also made a good documentary on Australian Story about Peter Andrews’ technique. I summarised some of his thought in this article. Though Peter Andrews’ book, “back from the brink” goes into more details and explores solution for salinity problems and looks at the debate on willows and native trees in Australia.
“Since the Australian landscape functioned perfectly well on its own for million’s of year, we ought to be able to solve the landscape’s current problems by somehow reinstating whatever it was that enabled the landscape to work so efficiently then.”
Andrew’s first objective was to investigate if farming could be commercially viable long term. He quickly realised how the cost of fertiliser and herbicide could eat a farm’s profit and investigates nature’s way of managing fertility and water.
Australian’s landscape History
Australia slowly broke away from Antarctica 160 millions years ago, letting plants and animals adapt to the changing climate and the land, which was becoming increasingly flat and dry. They learned how to survive without rivers as most of Australian water once flowed from the mountains of Antarctica. The environment evolved to survive on rain only, by storing water in the most efficient way, in the ground.
How the Australian landscape used to work
Rivers and creeks were very shallows and were made out of a series of ponds. Whenever there was enough water, it would spread across the plains on both sides.
“These flood were what really soaked the floodplains, the rain didn’t soak them – there wasn’t enough rain to do that.”
Rainwater also entered the ground through sandy patches called recharge area and was stored there, slowly recharging the ground. In grassland the Australian landscape worked differently. It formed deep cracks in the clay when dry which would fill up and close up during the rain so the water slowly sipped sideways underground.
“Now, the formation of the floodplain step or ponds was an automatic process which in each case would have been triggered by some chance occurrence in the landscape. A pile of logs may have blocked the stream, building up water behind it and allowing reeds and other plants to turn it gradually into a wetland. The plants would filter the clay out of the water and sediment would be dropped there, too, both of which would eventually result in the formation of the bank that separated one step from the next.”
The Australian landscape would have been full of ponds and floodplains, the water was slowly moving downstream not in rivers but by spreading across the entire floodplain. This system kept salt undisturbed underground, retained fertility from being washed up in creek and enabled the soil to absorb water slowly.
Basically, we removed the vegetation. The water was now rushing downstream, leaching out fertility and eroding creeks. The rivers got deeper and deeper so the floodplain stopped flooding in period of rain. To aggravate the situation, multitude government policies were and still are today centered on draining the water from the land and into the creek to stop floods. If we continue Australia will eventually become a desert.
Plants are the solution to everything
Peter Andrews believes that if we made it illegal to kill plants the land would start regenerate. He believes that the amount of plants, grasses and weeds that grow on the land represent the productivity of the environment.
“The thing to understand is that plants make soil. Soil is sand and clay with plant material added. Whatever there is in the soil that makes it fertile has been put there by plants.”
Weeds are the most cost efficient way to add fertility. If you’d leave a bare soil undisturbed, it would eventually be covered with forest through vegetation succession. The first plant that would grow on a degraded land is an aggressive weed that grows fast and adds organic matter and which is inedible to grazing animals so that it can do his job of regenerating the soil. Weeds accumulate fertility in the soil until the conditions are right again for grasses, shrubs and then trees to grow.
“Grasses extract carbon from the soil, assuming it gets eaten. It’s a debtor, as far as fertility is concerned. Weeds add carbon to the soil they’re donors in term of fertility. Weeds are the plants that repair the environment, so if they were edible how would the environment ever get repaired?”
Biodiversity is a kind of collective strength, which helps the environment cope in periods of stress. Part of this biodiversity is edible and non-edible plant. Weeds and grasses should cohabit in pastures.
“Biodiversity is good for the animals (health) that feed on the plants and it’s good for the plants themselves. It’s no coincidence that Australia, the continent with the greatest extremes of climate, was particularly rich in biodiversity.”
“The topsoil is the environment’s recycling factory, alive with bacteria breaking down and recycling the residue of the previous crop or whatever other organic matter was there. To plough up the soil is like putting a bulldozer through your factory.”
Mulch reduces evaporation and stores water. If you add 1 tone of dry mulch at the top of the hill, you’ll have 5 tonnes of water stored there next time it rains. This water will then be slowly released into the land around it. Mulch also add fertility, if you add 1 tone of mulch at the top of the hill, weeds will start growing and multiply their bulk by 3. If you slash it you will end up with 3 tonnes of mulch so you have now 15 tonnes of water stored at the top of the hill.
Adding fertility is one thing but unless you manage the flow of water, weeds might only be accumulating enough fertility to compensate for the loss. So the succession mechanism, which replaces weeds by grasses, cannot happen. Managing water to keep fertility from leaching out is another essential component as fertility always runs downhill carried by water. So how do you manage water on your land?
Peter Andrews experimented on his property at Tarwyn Park. He ran a series of channels across the land from the creeks, by digging banks along contour lines. Instead of running down the eroded creek bed, the rainwater was being redirected away from the river and spread across the land. A lot of neighbouring farmers downstream were worry that they’d get less water. Though soon they got more, cause the water didn’t rushed down anymore and instead trickled all year round.
Peter Andrews Advice to farmers
Weeds and fertility
“Don’t kill your weeds. Allowing weeds to grow is the single most effective step farmers can take to make their land more productive.”
The first advice he gives to farmers with paddocks full of weeds like thistle for example is to let them grow and flower. It is the most cost and labour efficient way of adding fertility to eventually replace the thistle with edible grasses through the succession cycle. He adds that thistle once slashed is edible so one way of regenerating a paddock that is full of thistle while feeding cattle is too slash it in summer and let the cows graze it.
He also advises to leave some weeds because they add diversity and are a necessary neighbour of grasses. 10% of thistle in a paddock is ideal to maintain fertility level to support grasses. The thistle will not compete with grasses for two reasons: First, weeds and grasses have different root depths, weeds being deep and grasses shallow so they never compete for nutrients. Secondly, in poor soil, weeds grow faster than crops but in fertile soil weeds grow slower than crops. So the thistle will not take over healthy pastures, only renew lost fertility.
Managing water and fertility
The main objective for managing water in Australian landscape is to slow down its flow so the fertility doesn’t leach into creeks. A design example would be to dig two channels along contour lines a few metres away from each other at the top of the hill starting from the creek or the gully. Place your dams away from the gully on the contour channels, this way the water from the creek will flow across the contour lines and into the dams. In addition, dig pits on the lower channel, a few metres apart and dump organic waste. The added fertility from the pits will then spread as the water flow through the channels an across the pastures. He also advises to identify recharge areas on your land, spots of sandy soil which will absorb the rain and make sure you channels run trough them so you make the most out of the rain. Finally, plant deciduous trees between the channels and on the bank of the lower channel to add even more fertility and slow down water further.
Peter Andrews advises to divide your land into three. Keep 1/3 for agriculture, 1/3 for grassland and weeds and 1/3 occupied by forest. The forest at the top of the hill will accumulate fertility, the crop or animals will exploit the fertility and the 1/3 of land at the bottom will serve as a recovery area. The grassland at the bottom will trap the excess fertility, which can be return at the top in a number of ways. Birds and insects will naturally to the job. Though cattle can also do it, dropping their dung near the trees when they go up to find shade in the forested area. Another way of returning the fertility at the top of the hill would be to slash the grass and feed them to the cattle at the top of the hill or use it as mulch. It all depends on your design and need.