Composting with limited resources in land rehabilitation

It may be frustrating sometime to read articles describing the different methods of composting. The gathering of such materials as cow manure, horse manure, chicken manure, duck manure, lawn cuttings, kitchen scraps, seaweed, fine straw, etc… may be difficult to perform at affordable price or to transport when it comes to make 1 m3 of compost, the minimum size for successful hot composting.

When doing land rehabilitation with financial constraints each of the materials indicated as being part of composting may represents a scarce resource.

For example;

Manure may exist only if animals exist which themselves are introduced taking into account the capability to be fed with adequate and local food. Humanure is a solution but requires time to be produced.

Brown matter is maybe the easiest material to find. However it is often a hard to break material having been able to resist harsh conditions (drought and poor soil imposing slow growing).

Green material is usually rough and does not easily degrade to provide with nitrogen, sugar and carbohydrates.

Here are some tips and strategies to obtain these composting materials in a difficult context.

Obtaining animal manure

Animals digestive system participate in an up-cycling process of food production. Animals can eat and process certain food not edible by human then produce manure that can be used to create compost to help grow human edible and more delicate plants.

Animal introduction requires to identify the plants or other edible organisms, assess the capacity of production of such food and determine the number of animals the farm can afford to host. Usually the first phases of implementation use small animals easy to shelter and to monitor in term of quantity.

Chicken for example eat a lot of insects which are themselves able to process even harder basic material in this up-cycling process. They can go errand and feed on plants and seeds including weeds.

Another animal of choice is the guinea pig. They are happy eating forage easy to grow in poor soil, for example elephant grass. Their diet can be balanced by kitchen scraps. Their size and their reproduction speed ease their monitoring.

The issue having small manure production capacity is that manure needs to be used fresh when doing composting. Therefore by stocking the weekly increments of animal production a large part of nitrogen will transform to gas and reduce the nitrogen proportion of your manure. The outcome is a higher C/N ratio with the necessity to add more manure than described in documentation.

A quick solution is to get manure from a farm. Making a pile of 1 m3 of compost, assuming that you already have your local production will require only few buckets more. If no farms can be found on the surrounding then you may look for places where horse are used to go and gather dung, the fresher the better.

Once you get the quantity you need then the compost should be done as soon as possible.

Since this source of nitrogen may be difficult to obtain it is important to get a larger quantity of fresh green manure to compensate the low nitrogen ratio.

Certainly the most convenient way to gather nitrogen is to store human urine in closed container. Urine contains more nitrogen than solid excreta and is usually sterile unless the person has some specific disease (e.g. urinary tract infections or fecal contamination). By storing urine (not diluted) in a close recipient the pathogens are killed (1 to 2 months in the tropics, 4 to 6 months in cooler climates).

Using urine as a direct fertilizer (diluted 5 times) is feeding the plant more than feeding the soil ecosystem although experience show that long term effects are positive on soil fertility. Urine lacks carbon to sustain plant growth on the long term. Urine may be high in salts depending on human diet and it requires an active microbiological substrate to recycle these salt, usually associated with dense vegetation and good humidity and drainage. Studies show that human urine performs better when used in combination with compost which help among other things to reduce salts accumulation.

When applied on carbon based material (to make compost) then urine plays the role of humidification and nitrogen addition (+ phosphorus + potassium). Human urine as all excreta from omnivores is very high in nitrogen and easy to gather for example in dry toilets with urine diversion or in urinal. Urine usage as nitrogen source (or as main nitrogen material) resolves the issue of compost planning constrained by fresh manure availability. Storing this liquid resource in closed containers is easy and prevent nitrogen evaporation.

Urine, which contains urea has better fertilizing capabilities than urea alone. Two of urine properties (there are others) when used in compost are nitrogen loss reduction and increased availability of organic carbon in the soil.

Obtaining green manure

Improving the availability of green material requires spending time to observe the ecosystem of the farm and identify adequate plants. They should have fine texture and have a high ratio of soft leaves. They should be propagated in locations which suit them and be harvested when their leaves are the most tender and green. You may plan the compost making when the rain season has produced enough of soft and green manure.

The oasis of humidity or fertility can be used as well to be stretched in order to propagate plants having a high productivity of green and soft biomass.

A third solution for obtaining green manure is to plant pioneer perennials leguminous like leucaena which have fine leaves rich in nitrogen which can be chopped, or leguminous cover crops resistant to drought like arachis pintoi. This latter plant does not impact perennials and grows high when competing for light against weeds. The combination of high grass and arachis is easily harvested providing with a fine green material.

If you have a pond or open tanks you may use aquatic plants which usually propagate very fast. Growing azola (leguminous aquatic plant generating a high ratio of nitrogen) is a perfect solution to get a material rich in nitrogen.

You may as well use Moringa (perennial) leaves high in many different minerals. Moringa is a tree well adapted to the tropics.

Obtaining brown material

This can be obtained fairly easily as long as you have trees in or beside your garden. Leaves can be used and should have a fine texture to be able to degrade easily. Planting giant bamboo is a good solution since it produce a lot of biomass and provide with fine leaves with plenty of silicate.

Another source of brown material is the bedding of animals which is partly mixed with animal manure. Leaves are used as well in compost toilets mixed with humanure. Using this material will influence the nitrogen ration by being mixed with manure.

Fungus are an important part of your compost and gathering small degraded branches in the surrounding forests will provide with beneficial diversity. Compost is a soil inoculum which requires soil ecosystem biodiversity.

Spreading compost

Compost is an inoculum meaning that it should not be used as a substratum to grow plant but as a material added on the soil or injected in the soil to increase its fertility. Injection can be done by first making compost tea which gives a soluble material. Many recipes can be found on Internet on the way to make compost tea.


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