Friday, 4 September 2009

Replacing fertilizers with human Urine and Feaces

Do you know that Nigeria is ranked 20th on the Global Hunger Index? What this means is that about 65percent of Nigerians are food insecure and vulnerable to hunger and ill-health. Though a coterie of factors is involved in food cultivation, but the role of fertilizer (organic or inorganic) is great. Sadly findings have shown that fertilizer application is still dismal amongst farmers. Nigeria is said to require about 3.7million metric tones of fertilizer per annum but only one-third is used in the farms.

Nigeria’s rate of application of NPK is reported to be 13kg per hectare. The ugly implication is the heavy post harvest losses calculated at 50per cent for fruits and vegetables and 30per cent for root crops and tubers. The number of those using compost or inorganic manure is grossly unknown, yet the potential for human waste to complement or replace the chemical fertilizers are not really considered.
Interestingly, Nigeria’s policy guideline on excreta and sewage management (2005) prescribes amongst others for the promotion and adaptation of the by-products of sewage treatment in productive uses. This if practiced will benefit the population in many ways.
First, food security and poverty alleviation .In parts of Nigeria, particularly in rural Nigeria, rural people suffer from periodic famine due to drought, small plot size, soil erosion, poverty (inability to purchase sufficient food) and political factors. In urban areas, poor people also suffer from under nutrition due to poverty, although urban agriculture is a growing phenomenon. However, growing food for the immediate family within confined spaces is a challenge.
Human urine and feaces can be used in rural and urban areas to increase food security for all households, particularly the poor. These products can be used directly at the homestead level, in backyard gardens. Researchers have shown that about 1.5litres of undiluted urine can be used to fertilize 1 square meter of soil. 1.5 liters is the amount produced by one adult in one day.
People could collect their own urine and use it on backyard gardens to increase yields. However, the fertilizing effect of urine is said to work best in soil with high organic matter content and this can be increased by adding the humus from eco-toilets and garden composts.
In urban areas, the sanitized urine and feaces from eco-toilets can be used as a rich nutritious soil for planting in pots, and the urine can be used to fertilize the soil before planting and for continued fertilization of plants during growth. Vegetable and fruit crops grown using urine fertilization produces 2-10 times the amount of crop by weight as those grown in unfertilized, poor soil. If people use urine to grow vegetables and fruits, the increased production results in greater food security at virtually no cost. Instances abound in Burkina Faso.
Soil enriched with humus from human waste (faeces) holds water longer than soils not enriched with it. Research has also shown that plants grown in soils enriched with large amounts of humus require less watering and survive droughts better than plants grown in ordinary soils without this humus.
In times of drought as was recently experience in Yobe and Jigawa states in northern Nigeria, when whole fields of grain may die, backyard crops grown on humus may well survive and produce enough vegetables to help a family through a difficult period. If over time, families can collect enough humus from their eco-toilets, they may be able to enrich larger and larger areas, leading to increasing food security.
Second, cost saving for Nigerian farmers is another benefit. This is true because the formulation of nutrients in urine is similar but not exactly the same as that in commercial fertilizers. But urine and commercial fertilizers give similar results in boosting plant growth. Urine is high in nitrogen and lower in phosphorus and potassium. Some top-up of phosphorus and potassium is often needed to get the best possible use of nitrogen. As faeces and ash are high in phosphorus and potassium, farmers can replace commercial fertilizers with urine and top-up with sanitized faeces from eco-toilets at little or no extra cost.
A study in China calculated the cost savings of using urine and dried faecal humus from eco-toilets as a fertilizer in a 3000 square meter greenhouse owned by one farmer in Jilin Province of northern China. The farmer not only used the dried faeces from his household but also purchased additional dried faeces from other homes with eco-toilets and was given their urine free of charge.
He did not calculate the cost of transport of dried faeces (which was transported by tractor) or the cost of transporting urine, which was carried in buckets on shoulder poles. He used to buy 350-400kg commercial fertilizer per year, but now this has been replaced by the free urine. The farmer calculated his cost savings per year to be the equivalent of CNY 740 (USD90) per 1000 square meters.
Such calculations could become even more important at the community level, especially where farmers are struggling to make a living. A city of 100,000 people would produce about 500,000kg of elemental nitrogen, phosphorus and potassium (NPK) per year in excreta. While the cost of commercial fertilizer varies between countries, as does its content of elemental NPK, it is possible to make a rough cost comparison of buying elemental products or collecting and transporting locally produced urine and faeces.
Third; preventing nitrogen pollution of drinking water in our communities is another benefit. Pit toilets as well as sewers are frequently a source of ground water pollution, especially in areas where the water table is high such as Port Harcourt, Calabar and Lagos etc.
Urine is rich in nitrogen and up to 50% of the nitrogen leaches out of the pit toilet pass through the soil and reaches the groundwater. Water with NO3 concentrations higher than 50mg/liter is considered to be unfit for human consumption. It is not unusual to find such high concentrations of nitrogen in wells in communities with pit toilets.
Recommendations as those in Nigeria’s policy guidelines on excreta and sewage management (2005) that toilets be sited at least 30meters from wells are meant to protect well water from pollution, but plenty experience shows that soil conditions vary considerably and both pathogens and nitrogen pollution can still result.
Finally, restoring lost top soils could also be another great benefit. This is true because according to FAO, the Earth is losing 25billion tones of topsoil per year because of erosion. Chemical fertilizers, while boosting plant growth, cannot replace topsoil. Topsoil contains humus formed from decayed plant and animal matter, and is rich in carbon compounds and micro-organisms necessary for healthy plant growth, which are not found in chemical fertilizers.The addition of humus is therefore necessary to maintain and renew the topsoil. With the loss of topsoil comes the loss of human food security. In many parts of the world, people are experiencing reduced productivity on their lands due to loss of top soils.

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