Urine As A Fertilizer
Our cultural perceptions are very apparent in response to the recycling of human wastes. The advantages of humanure are pointed out in the humanure article and are completely covered in Humanure by Joseph Jenkins. This book is revolutionary in a sense that it has the ability to effect cultural change dramatically and is a must for anyone thinking about composting their own wastes. In Jenkin's book urine and feces are composted along with a carbon source such as sawdust. The urine provides a nitrogen boost to enhance the thermophylic composting process. In subsequent years I've used green plant matter to heat the pile without adding urine freeing up the urine, which is sterile, for more direct use as a fertilizer. Urine is rich in nitrogen, phosphorus and potassium, three elements that are essential for not only plant growth, but for all life. By using the urine locally throughput is once again dramatically reduced having far reaching implications, the most obvious advantage being the reduction of resources needed to treat the urine.
To get a full picture of the other advantages of utilizing urine it is necessary to have a brief summary (it is advantageous to get a more in depth view of the cycles and processes pertaining these three elements) of the three elements mentioned above, nitrogen, phosphorus and potassium. All three are necessary for plant life to exist. We as humans obtain these elements when we consume the plants or other animals. Nitrogen is found in chlorophyl, DNA, RNA, and proteins. Although the atmosphere is made up of 78% nitrogen, plants cannot use the atmospheric form. Plants can only utilize nitrogen in the form of ammonium ion (NH4+) or nitrates.(NO3-) Generally nitrogen fixing bacteria living on the roots of certain plants (legumes such as peas, beans, clover, etc.) change the atmospheric nitrogen (N2) into nitrates. Phosphorus is used in energy storage. Energy is used to form Adenosine triphosphate (ATP) by combining a phosphate (PO4 3-) with adenosine diphosphate. Plants use sunlight as their energy source for this process whereas animals must use food for their energy source. After ATP is formed, energy can be released when needed by the reverse chemical reaction (ATP -----> ADP + Phosphate). In our system of agriculture phosphate is mined and is a limited resource (investigate peak phosphate and the implications to our food supply). Potassium is different from nitrogen and phosphorus in that it is not utilized in the chemical structure of life but is used in the osmotic activity of the cells. Potassium ions enter the cell and cause an osmotic gradient that results in the movement of fluids and other minerals in and out of the cells.
Both nitrogen and phosphorous become major problems when they enter the waterway because they stimulate algae growth in lakes downstream and in our oceans. When algal growth occurs it takes resources to remedy the situation and removing these nutrients at a sewage treatment plant is complicated and costly using up even more resources.
It just so happens that urine contains these three elements (nitrogen, phosphorous and potassium) in forms that plants can take up and metabolize. Urine is safe to use as a fertilizer so instead of using limited resources to remove these compounds they can reduce the amount of fertilizer produced and shipped. To optimize the use of urine, a holistic process should be considered. The life in the soil all needs carbon compounds to exist since life itself is carbon based. In a sense carbon compounds are the foods of soil lifeforms. It is the soil lifeforms that mineralize or change or store certain compounds such as nitrogen or phosphorus compounds that then can be utilized by plants. If there is not enough carbon to support the diverse soil life then the nitrogen and phosphorous will not be utilized and will enter our waterways. In the building article it was shown that instead of draining excess water away from the house, by building up the carbon base (also the gardens and areas surrounding the house) the water is retained. In other words, the flow of water is slowed down and since phosphorus and nitrogen are carried by the water the amount entering the waterways is reduced. The flow of water can be reduced further by collecting the rain water for household uses. The carbon base in the area surrounding the dwelling becomes the environment needed for the soil's microbial growth and, since the water flow is reduced, the microbes have a greater ability to metabolize the nitrogen, phosphorus and potassium.
One more piece of the puzzle is biochar. Biochar is made through pyrolysis, a process which involves heating organic material with very little oxygen present. It has a high content of carbon that is filled with tiny pores in which microbes can inhabit.
For the pyrolysis process we used a large propane tank for the outside container with with the top cut off and holes cut in the sides for oxygen to enter so the combustable material (dry wood) can burn. A smaller propane tank, also with the top cut off, is filled with pieces of wood and placed upside down inside the larger tank, This smaller tank has no holes in it so that oxygen can not enter this container.
To get a full picture of the other advantages of utilizing urine it is necessary to have a brief summary (it is advantageous to get a more in depth view of the cycles and processes pertaining these three elements) of the three elements mentioned above, nitrogen, phosphorus and potassium. All three are necessary for plant life to exist. We as humans obtain these elements when we consume the plants or other animals. Nitrogen is found in chlorophyl, DNA, RNA, and proteins. Although the atmosphere is made up of 78% nitrogen, plants cannot use the atmospheric form. Plants can only utilize nitrogen in the form of ammonium ion (NH4+) or nitrates.(NO3-) Generally nitrogen fixing bacteria living on the roots of certain plants (legumes such as peas, beans, clover, etc.) change the atmospheric nitrogen (N2) into nitrates. Phosphorus is used in energy storage. Energy is used to form Adenosine triphosphate (ATP) by combining a phosphate (PO4 3-) with adenosine diphosphate. Plants use sunlight as their energy source for this process whereas animals must use food for their energy source. After ATP is formed, energy can be released when needed by the reverse chemical reaction (ATP -----> ADP + Phosphate). In our system of agriculture phosphate is mined and is a limited resource (investigate peak phosphate and the implications to our food supply). Potassium is different from nitrogen and phosphorus in that it is not utilized in the chemical structure of life but is used in the osmotic activity of the cells. Potassium ions enter the cell and cause an osmotic gradient that results in the movement of fluids and other minerals in and out of the cells.
Both nitrogen and phosphorous become major problems when they enter the waterway because they stimulate algae growth in lakes downstream and in our oceans. When algal growth occurs it takes resources to remedy the situation and removing these nutrients at a sewage treatment plant is complicated and costly using up even more resources.
It just so happens that urine contains these three elements (nitrogen, phosphorous and potassium) in forms that plants can take up and metabolize. Urine is safe to use as a fertilizer so instead of using limited resources to remove these compounds they can reduce the amount of fertilizer produced and shipped. To optimize the use of urine, a holistic process should be considered. The life in the soil all needs carbon compounds to exist since life itself is carbon based. In a sense carbon compounds are the foods of soil lifeforms. It is the soil lifeforms that mineralize or change or store certain compounds such as nitrogen or phosphorus compounds that then can be utilized by plants. If there is not enough carbon to support the diverse soil life then the nitrogen and phosphorous will not be utilized and will enter our waterways. In the building article it was shown that instead of draining excess water away from the house, by building up the carbon base (also the gardens and areas surrounding the house) the water is retained. In other words, the flow of water is slowed down and since phosphorus and nitrogen are carried by the water the amount entering the waterways is reduced. The flow of water can be reduced further by collecting the rain water for household uses. The carbon base in the area surrounding the dwelling becomes the environment needed for the soil's microbial growth and, since the water flow is reduced, the microbes have a greater ability to metabolize the nitrogen, phosphorus and potassium.
One more piece of the puzzle is biochar. Biochar is made through pyrolysis, a process which involves heating organic material with very little oxygen present. It has a high content of carbon that is filled with tiny pores in which microbes can inhabit.
For the pyrolysis process we used a large propane tank for the outside container with with the top cut off and holes cut in the sides for oxygen to enter so the combustable material (dry wood) can burn. A smaller propane tank, also with the top cut off, is filled with pieces of wood and placed upside down inside the larger tank, This smaller tank has no holes in it so that oxygen can not enter this container.
The cut off top of the larger propane tank is placed on top with a stove pipe fitted for draft. Also, since the open end of the smaller tank only rests on the bottom of the larger tank the gasses produced inside when heated can escape through the crack and travel upward in the cavity between the smaller tank and larger tank. These gases are then ignited and you can see the flames shooting out of the stove pipe.
After the burn the tanks are turned over and the biochar in the smaller tank is removed.
This high carbon substance is very stable and does not break down easily so the carbon is sequestered, or trapped, and therefore can remain in the soil for long periods of time instead of entering the atmosphere as a greenhouse gas. The presence of biochar increases the life of the soil thus utilizing excess nitrogen and phosphorus. This can be a problem if the soil does not have sufficient nitrogen and phosphorus because the increased soil life will use up most of these nutrients leaving little for the plants.
To utilize urine as a soil enhancement the biochar can be crushed to increase its surface area then placed in a five gallon bucket which is used to catch the urine.
The biochar is light and floats on top of the urine which cuts the smell. The smell is further reduced because the char is very porous and absorbs the odors.
The final smell elimination is through closing the lid.
Since the char is so porous the nitrogen, phosphorus, potassium and other micronutrients penetrate making the biochar ready to stimulate the growth of soil life. If this mixture of urine and biochar is added to compost there is time to incorporate the nutrients and char into a highly diversified living soil to be added to the garden. Caution should be used when adding directly to the garden because the biochar is alkaline and can raise the pH while urine is acidic and high in nutrients. One can over fertilize and change the pH of the soil. It is beneficial to have a soil testing kit that includes pH, nitrogen, phosphorus and potassium. Everyone who has gardened knows there is a great amount of experimentation in growing plants. It is no wonder that everyone has there own opinion on how things should be done when gardening is concerned. Experimenting with carbon, biochar, ashes and urine can only increase the lively discussions we've all had over the years.