vrijdag 24 januari 2014

This hay is a great stuff for composting

2012 July : Hendrik collects the remnants of hay on the land,  
where that summer the sheep have been grazing.
This hay is a great stuff for composting. There is a lot of it. It has volume. And it contains a large amount of organic material. But it is not easy to compost. It is not soft and accessible. So we have to make it accessible. We can make it wet. But that is not enough. More has to happen to turn this hay into compost.


We use manure from cows or sheep as a compost starter. Each manure from a 'grass eater - vegetarian' can serve. The manure must be processed first before it can be used as a starter. To begin we add water. Then also leachate coming from the composting process. But we add that later. What we gain then is grafting fluid with which we graft the hay.
For this we use a barrel. An 'immersion barrel', a 'grafting barrel', name it as you like. A barrel where the materials are immersed, grafted. Half the barrel we fill up with grafting fluid and extra water from the bore hole. In here we put the hay for one day or two. This way of working basically imitates the stomach of a cow... The hay is predigested. 


We like cow dung because it is easy to find. A cow actually is a super vegetarian with 4 stomachs. So she can digest grass and hay. In fact, a cow digests the bacteria soup, which she makes of what she eats. She does not digest the grass itself. But the soup she makes of all that grass and hay.
The manure, which remains, we can use very well as a bacterial carrier. Something we can always fall back on. We have discovered that this is the best way to conquer grasses. We use the bacteria that a cow makes for us. This way of working prevents the bacterial process going in the wrong direction... so it does not turn into butyric acid. In what direction the process goes one can tell by the smell and the pH. The smell of butyric acid is penetrant and aggressive, and has a pH of less than 5, about 4.


Where to find

Here the cows graze in the mountains by a shepherd with dogs. They are kept for meat and graze where it is possible. The land often has different owners and is mostly free accessible. For example, for us, to collect dung. The dung dries by sun and wind and is quickly turned into cardboard. Here it is usually pretty hot and the sun is relentless. So this happens fast. The bacteria in the wet manure have been passed into something we call 'endospore'. These are the same bacteria, but in a dry form. The bacteria go to sleep, as it were. And they come back to life if we make the manure wet again. We collect and store it until it is needed for making grafting fluid.

Dry grasses

The grasses and herbs, we compost, we prefer to fully grow into 'hay on stem'. Which means that the crops dry while they are still on the land, with the roots in the soil. This is only possible in dry summers, in warm areas like here in the Alentejo. This hay is pretty great for composting.

Grafting fluid

When the hay crop dries, the moisture disappears from the crop down to about 10%. This makes it easily accessible, to immerse it with grafting fluid. Fresh crop contains certainly about 70%-80% water, if not more. One could, at first glance, think that this would make composting easier. But we found out that the opposite is true. Compost of wet grasses and herbs is very sticky and it contains less separating structure, or loose texture. This makes it more difficult to use. It is a sticky soil improvar. The distinction between compost out of hay and compost from grass lies in the structure mainly. But there is more.

Not to clean

The normal moisture in fresh crop is not the proper moisture we need for composting. For composting it is basically to clean, to sterile. What we want in the crop, to compost, is moisture that is saturated with bacterial life. The decomposition of a dry crop progresses more quickly, when grafted with the right bacteria in the grafting fluid we prepare.
Our garden and kitchen waste we let dry for the same reasons. In dried form it is able to absorb the grafting fluid better. Usually we compost this materials together with the grasses.

Crush into packets

A plant protects itself with a layer of wax. So that moisture, mold, and bacteria can not penetrate into the plant. A dry plant looses its wax easier. Although we have to break the harvested hay or crush it. Because the Alentejo crop is stiff, hard and full of thorns.
To process the hay into manageable packets Hendrik bruises it. This makes small openings in the wax layer and the skin of the stems. Plus, the packages are easier to transport and to handle in the composting process.


Letting the hay grow, into hay on stem, has more advantages. There are many annuals in the crop. They than have the time to spread for the next year. This benefits the diversion of the land, plant- and animal life. And eventually also for us.

In general

Here we should note that, whatever the moisture content in the plant, a coarse and woody crop yields a 'separating bounce' compost, more than a soft and pliable crop, which yields a more 'sticky and compact' compost. 

Proteins and carbohydrates

A plant also must contain sufficient proteins and carbohydrates, to heat properly. In average grass has a C/N quotient of 19 or 20... C/N 19/1 or C/N 20/1. Which means that there is enough nitrogen (in proportion with the carbon, C) in the grass for heating; 1 carbon (C) and 19 or 20 nitrogen (N).

In connection with this we need to add sufficient moisture (with bacteria) to the process. 'For optimal heating the optimal moisture content of a mass composting material is 30%', the books say. Here we mean the moisture added, not the natural moisture inside the plant.

To see if the books are right Hendrik set up a small test:

Hendrik: "I wanted to know how much grafting fluid I needed to graft hay. I also wanted to know how much moisture hay can hold after all the moist was drained. For the measurement, I used the small packets of hay I usually make. Here are the numbers:

A single package dry hay weighed 850 grams
After 48 hours draining, the wet package weighed 2425 grams
The difference is: 1575 grams
This represents a near tripling
 of its own weight (2425 : 850 = 2,86).

Then the same test set up with 12 packets of hay:

The weight of the 12 packets of dry hay together: 11.200 grams
After 48 hours draining, this wet packets weighed: 38.000 grams
The difference is: 26.800 grams
In this case, the wet weight of the hay was more than triple (38.000 : 11.200 = 3,40).

It looks that the amount of hay has a favorable effect on the fluid retention. In this case you might say: "The more hay, the more mass, the more moist it can contain."

This shows that hay is able to absorb enough moisture (penetrate) and can also adsorb (cling), in order to be able to compost it. The moisture is thus everywhere, in the plant and to the plant. Incidentally, I was quite surprised about the amount of retained moisture. If I am busy with it, it does not seem so be so much. However, I had the idea to take measurements, because the packets felt so heavy when I lift them out of the immersion barrel. For further composting I have only experienced advantage of all this. My conclusion? My conclusion is that the material it selves shows me how much moisture it needs to compost. Grass and hay are not concerned with numbers... We make the numbers. Nature doesn't"

Guitar in this video: Tatyana Ryzhkova with a part of the piece
'Un dia de Noviembre' by Leo Brouwer.



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