Cow Peas

Our deal with our children is they can watch as many movies as they like, as long as they she’ll peas at the same time!

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Here are the results:

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We planted about one hectare of cow peas this year, and they did quite nicely with all of the rain. We are harvesting enough peas to keep us in bean soups and so on through the winter.

Our boer goats will eat the rest probably next month, before the plants dry too much. It will make a good, high protein green feed before they lamb in July.

We will also combine the peas with our tomato crop and make ‘baked beans’ as a preserve.

Winter. Endings and beginnings..

Our summer garden has come to an end. All of the tomatoes and aubergines, pumpkins and squashes, broccoli and cauliflower have been eaten, preserved or given away.

Some of our boer goat ewes are heavily pregnant and so the task of clearing the leftovers falls to them. Here they are making short work of some cauliflower plants.

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It’s now a few weeks since I took that pic. It is now midwinter and they are now eating their way through the lucerne and sericea I baled. The grey is last year’s mulch, and the yellow, this year’s contribution. The goats sort through the bale and eat all of the tasty bits, and spit out the stems and other unpalatable bits. I estimate about a quarter of the bale is turned to mulch, but that is simply a function of the amount of grass growing in the lucerne field when baled.mulchgoats

I will soon start making seedlings again for spring, and hopefully we should be producing abundant tomatoes again before long like last season.

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Some new lambs for the new season:

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So this completes a cycle where goats, lucerne, vegetables and the by products of all of them, add to the fertility of the soil, the goats, and us humans even get some benefit!

Boiling a Kettle with Goat Poop!

I would like to use biogas for cooking in the house, so I built a pilot project to check if and how it works. We have the feedstock, being goat manure so I decided to give it a try.

I wasn’t going to spend any money on the project, so I built a crude digester out of junk lying around on the farm. It comprises a 220 litre drum filled with goat manure slurry, a 100 litre drum upended in the larger drum with a valve and a rock on top, and a piece of gas pipe, wedged into the valve with a plastic bag. Behold its precision engineered glory!

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I filled the big drum about one third full with goat manure, topped up the drum with water and mixed it up into a nice slurry. I then put the small drum upside down inside, covered it with black plastic and waited.

For a week nothing happened.

In the next week the smaller drum started to lift a little, but the gas produced did not ignite.

In the following week a foul stench was noted.

And after about 3 weeks the contraption was producing gas every day, and I could make flares of gas flame out of the pipe.

Apparently the bacteria first ferment the mixture to produce CO2, then H2S is produced and finally methane production commences as the methane producing bugs establish themselves.

The next test was to see if anything useful could be done with the gas, so I connected up a camping gas cooker, but it wouldn’t light. It took a lot more google research to figure out that biogas (being mainly methane and carbon dioxide), behaves quite differently to your normal propane or butane gas that you buy in cylinders.

An important difference is that propane and butane liquify under pressure, so they occupy a lot less space as a liquid than as a gas. You can’t compress methane into a liquid, so you need relatively large storage volumes. Methane’s burning characteristics are different so you can’t just use a normal gas burner, it needs some tweaking.

I then bought a small one ring cooker that I could modify. What needs to be done is the jet needs to be opened up to much larger than for normal gas, and the amount of air restricted. I opened up the jet in the stove from about 0.5mm to 1.5mm, and blocked up the air intake with a piece of plastic with one 6mm hole drilled in it.

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So, I opened up the gas, applied a match and hey presto! It works!

Next thing is to boil a kettle, which I duly did (OK, only 1cm of water in it, but it boiled nonetheless). You can’t see the flame or the steam in the pic, but it is boiling, trust me….

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So I’m quite pleased that the experiment worked. The digester is probably making about 30 litres of gas per day, probably quite a lot is lost due to the small drum not filling nicely in the big drum.

My next step will be to make a 1000 liter digester so that we can use the single ring burner in the kitchen to make a cup of coffee in the morning. I am going to use the design from this website and see how it goes : Solar Cities IBC Digester

I will keep this digester bubbling as the bacteria are established in this system, so you can take this material to quick start the new system, without waiting for the whole process to establish from scratch again. Seeing as IBCs are fairly cheap, I will probably be able to get a small working system going for less than $50, hopefully enough to do some of our cooking on, but we’ll keep our normal gas stove as well. Based on the experience of this pilot system I would anticipate about 100 litres of gas per day from the 1000 liter system.

There are many variables that dictate how much gas a biogas system will produce, like type of feedstock, ambient temperature, water hardness and so on, which is why I wanted to see it work on a small scale first, but I am very pleased with the results!

I found these websites quite helpful in this process :

ATTRA – Sustainable Agriculture

DIY Methane Generator

Biogas Plant in a Plastic Drum

Biogas Start Up

Backyard Biogas

Biogas from Kitchen Waste

Modifying a Gas burner for Biogas

 

 

Goat Fodder from Sweet Thorn Trees

Do goats like trees? Of course they do! And in particular they like Sweet Thorn (acacia karroo). Fresh leaves contain 12% protein and a lot of calcium and phosphorus, and the pods are even more protein rich.

I am establishing Sweet Thorn all over the farm as part of my Silvopasture project. The pictures below are of goats devouring the leaves from branches pruned from Sweet Thorn trees growing in our garden.

I prune off all of the bottom branches so the trees grow tall and spread to become shady, and the cuttings are fed to the goats.The tree below is about 5 years old. If the goats were allowed to graze the trees, they would clean off the bottom branches without my help, but there are fruit trees in the same area which would be equally pruned. The trees are full of pods after the drought a few months earlier, so I will have plenty of seeds to make seedlings from.

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The pruned branches cause a feeding frenzy amongst the adults. How they manage to nibble between the thorns is quite a talent.

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And the kids nibble off everything that is left.

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Once the branches are dry I will use them for firewood, or use them to keep chickens out of vegetables (the thorns help).

More Information

Acacia Karroo – A sweet and thorny thing

Sweet Thorn Leaves Nutritional Value

Sprout selection and performance of goats fed Acacia karroo coppices in the False Thornveld of the Eastern Cape, South Africa

Long-Term Impacts of Goat Browsing on Bush-Clump Dynamics in a Semi-Arid Subtropical Savanna

Boergoat Kids Two Weeks Old

Some pictures of our new boergoat kids. We have 22 in total so far, with just one or two ewes left to kid. Two thirds of them are male which we suspect has something to do with the drought conditions that prevailed during the pregnancies.

The kids all stay close to their shed during the day while the adults walk to another field to graze.

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Slangbos Control Using Goats

Slangbos (snake bush, bankrupt bush) is a small shrub that invades grazing land. In cattle farming operations it can completely invade grass land and push out the grass entirely. This mainly occurs as it is not palatable for cattle so they don’t eat it, but they do remove the competing grasses.

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A bad infestation:

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Some people promote the use of poisons again Slangbos : Chemicals: the best weapon against slangbos. Goats, however, find Slangbos very tasty and readily graze the growing tips of the plant. So while they don’t eradicate the plant completely, as the stem is very woody, they do keep it under control so that grasses and other plants grow amongst the slangbos. I don’t see many new plants establishing, so I would imagine that after some time the goats may graze the plant so that very few remain. The area below was quite choked at a stage, and almost completely covered over but the goats have grazed it back and grasses are regrowing in between.

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If you break the plant and smell it it is quite aromatic so I would think that it is probably quite nutritious and likely has medicinal properties.

More Information

Slang Bos

Grassland.org

AgriSA

Silvopasture and land reclamation

I am fairly sure that Silvopasture is the correct term for what we are doing, but it could also be termed land reclamation, or agroforestry perhaps? There were two stages to the process, firstly getting rid of the invasive alien trees on the farm, and then re-establishing the natural trees to improve the grazing potential.

Invasive Tree Removal

When we moved to this farm there was a lot of black wattle and blue gum (eucalytus) trees which are invasive in South Africa. They have a use in that they provide firewood and wood for other purposes like fence poles etc, but the ground underneath is degraded and the grazing quality severely depleted. Blue gums transpire a huge amount of water and depress the water table around them, drying out the ground, and black wattles form dense stands with almost no vegetation growth underneath.

Many years were spend cutting out the invasive species (providing a lot of warm winter fires in the process), and eventually the farm was clear of them. It is a long and laborious process to remove the trees, and a good chainsaw is essential.

For blue gums the trees need to be cut down and the stumps poisoned. Fortunately the seeds only seem to last in the soil for about two seasons, so the trees stop regrowing from seeds after a while. It stands to reason then, if you are trying to remove these trees, to get rid of the large, seed producing trees first, and then tackle the smaller ones.

Black wattles are more difficult. It is not generally necessary to poison the stumps of the larger trees, as they die when they are cut down. Small saplings are very resilient though and will regrow unless they are poisoned. Once a stand of wattles has been cut down, the sunlight on the ground causes all of the seeds on the ground to germinate like a carpet. I also noticed that after a grass fire it also induced the seeds to germinate en masse. To get rid of these, I applied a number of approaches.

  1. Wait until it has rained and the ground is soft and then pull them out by hand.
  2. Spray them with a poison
  3. Graze them

The third option works in winter, as the wattles are one of the few plants that are still green so our goats eat them quite readily. In summer though they find more palatable food as the wattles are quite high in tannin.

Ultimately it was the continual application of all 3 methods over a few years that eventually eradicated them.  The picture below is of the last few that I cut out last year, with the wattle saplings coming up again amongst some taaibos and wild asparagus (katbos). These will unfortunately have to be poisoned as this is right next to our lucerne field, so there is no way we will persuade our goats to chew on tannin filled wattle rather than sweet lucerne!

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This picture is across our fence line. In the foreground you can see the cleared land with the stumps of the cut out trees. In the background is our neighbours land which is still infested with the invasives. It is a bit irksome as they continue to drop seeds over the fence which I have to keep under control.

When I stood under that big blue gum in the picture, I had no idea which way it would fall when cut, so I ring barked it rather than being squashed by a 30m tree!

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Planting of Beneficial Trees

Once the invasive tree species were removed, the land was still degraded, and very poor for grazing. Also all of the stumps made it impossible to get in with the tractor to plough it and plant pasture. Some research on the internet brought me to the concept of silvopasture where trees and livestock are farmed together.

But which trees to plant? The answer was actually quite obvious when I noticed that indigenous acacia karroo (sweet thorn) trees were starting to come up where the invasive trees had been removed.

Sweet thorn has a number of benefits:

  1. It is a pioneer plant that readily establishes itself in degraded areas, needing no watering or any attention at all really.
  2. It is nitrogen fixing and improves the soil around it.
  3. They shade the ground and allow grasses and other plants to grow.
  4. The leaves and pods are nutritious and high in protein and are readily grazed by goats.
  5. It has thorns so it is not grazed to destruction by goats.
  6. It is part of the natural succession of trees in this area, so once the acacias are established, white stinkwoods, wait a bit trees, wild olives and other trees start to grow as well as seeds are brought by birds from nearby.

We have some areas of natural bush which act as seed banks for a great variety of indigenous trees. Below are white stinkwoods and wild olives.

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From observing the natural areas on and around the farm, it seemed to me that a tree spacing of about 10 meters was about optimal spacing for the acacias. At that spacing they don’t shade the ground too densely and allow other plants to thrive beneath them. Wider spaced than that and you don’t see the benefit of ground shading, and closer than that they start to form a thicket and inhibit plant growth.

Below is a winter picture of about 2 year old acacias starting to establish themselves amongst the blue gum stumps.

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This is the same tree one year later in summer:

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Eventually the idea is to end up with this. Large trees, grazed up to as far as the goat can reach, as well as nutritious grasses and other plants underneath. This is also a winter picture so the grass and other vegetation has been grazed short.

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Transplanting of Trees

During summer the acacia karroo seedlings come up underneath the larger trees in great numbers so all you need to do is dig out the small ones, and re plant them. Note that they have a very deep taproot which grows very quickly, so once the seedling has more than two or three compound leaves, the root will be too deep and you will likely snap it off and kill the tree. The seedling below is probably about as big as you can transplant. Here are the steps:

Find and dig out the seeding, this one actually came up in our vegetable patch, then dig a small hole, loosening up the soil to as deep as possible so the roots can establish, and replant the tree. A bit of shade around the seedling helps, but otherwise it is as easy as that!

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After about 4 years the trees should be about 2-3 metres high.

Acacia Karroo as an invasive species

In some areas, acacia karroo is itself considered an invasive species. This is generally in cattle areas as it is not grazed by cattle, but goats love it, so bush encroachment will not occur. Goats can actually be used to clean up areas suffering from bush encroachment.

Some more info on Acacias:

Acacia Karroo in the Karoo

Acacia Karroo

Boergoat Lambing Season

Our boer goats are lambing currently, the picture below is a new born being cleaned by her mother. A healthy kid should be up and standing within 10 minutes, and drinking on its mother within 30-60 minutes.

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A one day old kid with its mother.

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So far about two thirds of the kids have been born male, we were speculating whether that had something to do with the severe drought that has affected us, which only broke about three weeks ago.