Soilification of humanure

Soilification manual

Summary

One of the greatest challenges for humanity is to secure soil fertility for generations to come. This manual presents an easy and cheap method to optimize soil fertility by soilification of i.a human manure, household waste, garden waste, and fine-cut biomass. The method can be used for the introduction of 100% organic farming.

Introduction

Commercial mineral fertilizers are not very suitable for eroded tropical soils as most soluble nutrients leach to the ground water resulting in low fertilizing efficiency and ecological damage. Moreover, commercial mineral fertilizers constitute a substantial expense for poor farmers and their production is energy-intensive and contributes to climate change. If correctly prepared and applied, organic fertilizers are not only more environmentally friendly but they can also be dosed much easier and they can be prepared almost for free on a household level.

The main part of the nutrients are found in the urine, see Table 1.

Table 1. Urine nutrient content in human manure (Humanure)

Urine separation will facilitate the recycling of humanure since it will be possible to optimize the C/N ratio by optimizing the working conditions for soil bacteria and will play a key role in system solutions involving the substitution of chemical fertilizer with biofertilizer, thus paving the way for the introduction of full-scale organic farming.

Securing of soil fertility involving organic waste can be improved by soilification since it creates a deep root system, resistant to rough draught periods. The soilification method for making black fertile soil of humanure and biomass has been developed by the Swedish small-scale organic farmer and innovator Borje Gustavsson, who has the European record in organic pumpkin cultivation with a 550 kg pumpkin. See amazing pictures at www.skurupsborren.se

The method involves the drilling of a hole with the Skurup drill, innovated by Borje. The drill makes it extremely easy to drill deep holes in soft soil. We now have a Kenyan version of the Skurup drill made in Nairobi.

Soilification

For soilification of humanure, you can separate the excreta from the urine by using two dry toilets with two buckets with a volume of 30 liters each with a sitting cover.

If you have a flushing toilet, you can convert it to a source-separating toilet with a cutting pump and two outputs connected to different storage tanks, one for urine and one for faeces. You can dimension the storage tanks for emptying intervals for your own convenience concerning time for soilification.

After using the dry toilet for faeces, you add some soil and dry or green leaves as a top cover which gives a pleasant smell for the next visitor and optimizes the C/N ratio for optimal decomposition rate by the soil bacteria. The urine toilet is filled with biomass like dry grass, leaves, or branches cut into small pieces. When it’s full of urine it’s replaced by a new bucket primed with fine-cut biomass. The full urine bucket is covered with a tight lid and stored for two weeks before soilification.

If you use a mobile dry toilet made from bamboo or papyrus you will only need one bucket for the urine. Instead of using the bucket for the faeces you drill a hole around 1 meter deep with a diameter of around 25 cm. The bottom of the hole should end at least one meter above ground water level..

This will now be the start of soilification of faeces. When the hole is filled to about 60 cm with faeces, you mix it with another 30 cm of remaining soil. The top 10 cm you just cover with unmixed soil.  Then you drill a new hole for faeces inside the mobile toilet or move it to a new place.

During the soilification of urine mixed with the fine-cut biomass, you drill the same type of hole, but you can add any organic household waste or garden waste in the bottom of the hole. Mix the biomass soaked in urine with soil and fill the hole to 10 30 cm from the top. Fill the remaining surface layer with soil, and plant the seedlings for your trees or bushes.

Groundwater level varies across the country, but on average, it goes to a depth of between 30-40 m during the dry season and up to between 15-20m during the rainy season. Thus there is no risk of infiltration of contaminants into the groundwater due to soilification even if the depth of the hole goes up to 4m depending on the locations and type of soil within the zone, therefore the .claims of underground water contamination are unfounded.

The decomposition time for humanure is between 2-3 months depending on soil fertility. and the time for biomass to be soaked in urine, is around 2 weeks.

Soilification for trees in areas with long time severe draughts or even deserts can be made by drilling new deeper holes in circles around the tree After drilling and filling some circles you can repeat the drilling from the inner circle but with each circle a little bit deeper. In this way, the root profile can reach a depth of 5-6 meters and thus securing the survival of the plant even in deserts

Introduction of soilification toilets will be the end of the pit latrine era introduced during the colonial time. The method will improve soil fertility and crop yields to even higher levels than conventional farming. It can easily be scaled up to metropolitan areas by the introduction of urine-separating flushing toilets in combination with source separation of blackwater and greywater.