Good morning, and welcome to the next edition of our monthly newsletter, Reading Landscapes.

Here’s what we’ve got for you today:

• What are recharge areas?

• Siam Weed, a plant with many potential uses

• How things could have started in Australia

• What we’ve been learning

🔎 Looking at the Landscape

Like us to discuss a photo of your landscape? Share it with us here. 

Thanks Donna for asking about recharge areas in our landscape.

Recharge Areas - What are they? And what do they do?

Put simply, a recharge area is an area of land where water intake happens more readily. Typically, these areas will have different soil types compared to the surrounding area, which is comprised of sandy, gravelly soils that readily allow water to infiltrate into the underlying layers of soil, where the water can then be stored. Recharge areas are located on the high parts of a landscape - on the ridges. But not only the ridges you think of when you first hear the word ridge.

Ridges are also present on a floodplain; they are simply the higher parts of the landscape. It’s as simple as that; we don’t want to overthink it.

Recharge areas are everywhere in our landscapes as they form a crucial part of the hydrological process - they are responsible for getting water back into our soil where it is protected from evaporation, slowed down and stored in a way that makes it readily available for plants.

This is why we focus on building contours (and why that is one of the biggest things we teach in our courses) - as they have the ability to connect lower, wet areas where there is excess water to the higher, dry areas that are our recharge areas. This would have once happened naturally, but since our flow paths have become eroded, the ability to get that water out and across the landscape has been lost - the role of the contour is to get that process started again.

🌳 Learning from Plants

Have a plant you’d like to discuss? Share it with us here.

Siam Weed

Common Names: Siam Weed, Jack in the Bush, Triffid Weed, Bitter Bush

Scientific Name: Chromolaena odorata

Where in the Succession: Early Succession Accumulator

Thanks to Simon for sending in this month’s plant species Siam Weed.

Siam Weed is a perennial shrub native to tropical America. It grows to 1.5 to 3 metres in height. It has been introduced and is now found in most subtropical and tropical areas worldwide.

What is it telling me about my landscape?

Siam weed is an early successional accumulator species.

Where will I find Siam Weed growing, and why is it growing there?

It is most often found growing in disturbed environments;

• Roadsides and forest margins

• Cleared forest

• Cropping land, plantations and cleared pastures

Its ability to create an allelopathic effect on the plants around it and provide low palatability and high nitrate levels provides it with the very best attributes to fill the role as an early pioneer species in landscapes.

Landscapes where Siam Weed is found growing often show some of the following characteristics;

• Low organic matter

• Cleared forest landscapes

• Acidic soils

• Overgrazed areas

• Lack of ground cover/paddocks in fallow

How can we manage Siam Weed?

🚜 Mechanical Intervention. One method of managing growth is slashing. However, it should be completed regularly, as the plant will readily regrow from cutback material and propagate from cuttings. One report found that in operations that didn’t undertake tillage, slashing carried out 4-5 times over a 4-6 week period in the summer growing season effectively suppressed the growth of Siam Weed¹ .

In many areas worldwide, there are alternating views on its role as a weed or a fallow species. One study looked into research papers on the role of Siam Weed as a weed or a fallow plant, and interestingly, there is a large body of research on the role of the plant as a fallow species in cropping systems. These studies found² ;

• That it can better handle acidic soils

• Has a fast decomposition rate after being slashed

• Capable of providing a regular source of organic matter and nutrients after slashing for crops and

• Weeds were less rampant in paddocks following a Siam dominated fallow

🌿 Incorporate other plant species. At the same time, as we manage the Siam Weed, we should be looking to incorporate other more preferred species to take over its role in the environment. A good option would be legume species, which can take on the role of the siam weed whilst having the hardiness and growth ability to compete with it.

⬆️ Increase soil fertility and organic matter. Siam Weed is often found colonising landscapes that were once forested but have been cleared. Its role is to start the successional process back to a forest, and a big part of that is increasing soil fertility—building up elements like carbon and nitrogen. One study found that areas with a severe invasion built carbon and nitrogen back up closer to levels observed in restored native forest plots³ .

Siam Weed can also contribute to this, thanks to the incredible volume of biomass it can produce—up to 18.7 tonnes/ha in fresh form⁴ —which can then be left to break down or composted into a more available form of fertility. In this particular study, Siam weed compost resulted in higher available nitrogen, phosphorus, and potassium than the traditional NPK treatment⁴ .

🌲 Reincorporate forest species. Many landscapes where Siam weed grows were once forested, and Siam weed is becoming an early successional forest species to start the shift back to forest. Knowing this, we can incorporate more trees and shrubs into that landscape to promote diversity while also increasing the fungal balance in our soils and evening out the relationship between bacteria and fungi.

🪰 Biological control. C. connexa is being researched as an insect management method for the plant, with it first being released in 2019 in Northern Queensland⁵ .

How to make the most of your Lantana

🪨 As a Soil Indicator: Low organic matter levels, bacteria-dominated soils, acidic soils, low nitrogen, low phosphorus, presence of heavy metals - as it holds the ability to remediate such levels⁶.

🐮 Livestock: The plant has high nitrate levels, which indicate its desire to be left alone and complete its task. Interestingly, the high nitrate levels are the most potent at its young growth stage, when it needs the most protection. 

Despite this, numerous studies have been conducted on its use as a food source for livestock. Thanks to its high protein content, it has the potential to be a more affordable protein source than traditional products in more deprived economies.

Studies have shown that once adequately processed, nitrate levels are reduced to acceptable levels for consumption, and nutritional quality is high. In one study, protein levels were recorded up to 24%.

💊 Medicinal: Siam weed has a long history in traditional medicine and is being actively researched for use in modern medicine. The plant's most common use is for wound healing. It also exhibits anti-inflammatory, analgesic, and anti-microbial properties⁸.

🍽️ Consumption: Very little evidence of Siam weed being used in cooking.

🙋 Answering your Questions

Ask the Team! Share your question here, and we’ll answer it in a future newsletter.

I want to share this question from Peter’s book Back from the Brink for this month's edition.

💬 Asks:

If you’d been in charge of the colony when the first white settlers arrived, what would you have done to prevent the floodplain systems from being ruined?

🎙️ Peter’s Answer:

I’d have made the farmers manage their hard-footed animals. Precisely how they went about it is something I’d have to have spent time working out, but the basic aim would have been to prevent erosion, which would certainly have entailed keeping the wetlands at the bottom of the floodplains intact. Eventually, this may have involved fencing off the wetlands, but to begin with (this was the 1800s, remember) we’d definitely have needed orderly grazing routines. This could have been handled successfully by the shepherds who were employed in large numbers on sheep stations in the 1800s. The shepherds stayed with the stock all day and moved them around as needed. It was the random destruction of the environment by vast numbers of animals that did the damage.

A fellow I went to school with in Adelaide has told me he’d been digging into the records of his family’s sheep property in South Australia and discovered that 100 000 lambs were marked there one year. At least 150 000 ewes would have been needed to produce those lambs, so you would have had a quarter of a million sheep running around in huge mobs without any fences to restrain them. And this was on just one property. It isn’t hard to imagine how all the sensitive areas of the Australian landscape were wiped out in fifty years.

Our floodplains were enormously productive when farmers first occupied them. They not only carried five times as many sheep and cattle as today, but those sheep and cattle were also virtually free of disease and worms because of the biodiversity in their diet. If we’d prevented erosion and allowed the floodplain systems to continue operating, the land would be carrying just as many stock today, and they’d be just as healthy. In fact, the floodplains would probably be more productive now than then.

Our floodplain systems were the most efficient nature ever devised. If they’d been preserved, the Australian landscape would have to be better than ever, considering we now have the benefits of modern technology. But they weren’t preserved. The thought of preserving them didn’t even enter our heads.

📚 What We’ve Been Learning

A quick list of our favourite things we’ve been watching, reading, listening, and writing.

How Joel Salatin Develops Leaders Ready to Thrive at Polyface Farms (WCP 400): A great chat with Joel about how they are creating the next generation of leaders and farmers at Polyface Farms.

Total Grazing: I spent the first weekend of March at a two-day Total Grazing school with Jaime Elizondo at Mellow Farm. Having already completed his online program, Real Wealth Ranching, this was a great follow-up. The school covers four key areas - Total Grazing Program, Adapted Genetics and Selection, Nutrition, and Optimal Calving Season. I highly recommend watching Jim’s YouTube channel to learn more.

Will Winter on The A to Z of Apple Cider Vinegar: An interesting episode covering the unique benefits of Apple Cider Vinegar as a supplement for livestock in increasing on-farm production and health of livestock.

1  Chromolaena odorata invasion in Nigeria: A case for coordinated biological control

2  Chromolaena odorata in different ecosystems: Weed or fallow plant?

3  Invasion effects of Chromolaena odorata on soil carbon and nitrogen fractions in a tropical savanna

4  Effects of Chromolaena Odorata Compost on Soil and Nutrient Uptake of Lettuce (Lactuca sativa)

5  First release and establishment of the biological control agent Cecidochares

6  Rhizospheric soil chemical properties and microbial response to a gradient of Chromolaena odorata(L) invasion in the Mount Cameroon Region

7  Utilization of Chromolaena odorata leaf meal as a supplement in broiler chickens' diet

8  Chromolaena odorata: A neglected weed with a wide spectrum of pharmacological activities (Review)

9  Deteriorating soil health: ‘A teaspoon of soil contains more life than there are humans on earth’