Organic fertilizer
This can have an adverse effect on plants as the ammonia can burn the roots and microbes from the animal’s gut can harm the microorganisms in the soil, killing them, or contaminate produce, such as E. coli and salmonella.
This type of chicken litter should not be spread on crops, and can pose a risk to grazing livestock due to botulism, a disease caused by bacteria within decaying birds.
[13] Horse manure contains the perfect balance of Carbon to Nitrogen for composting (30:1) and is a traditional garden soil amendment.
However, careful organic sourcing is critical because feed (and bedding materials) from fields treated with the picolinic acid family of herbicides including aminopyralid, clopyralid, and picloram (marketed in the US as Milestone and Grazon-) can pass through a horse’s digestive tract, remaining unchanged in manure and compost piles for long periods.
These chemicals commonly affect potatoes, tomatoes, and beans, causing deformed plants and poor or non-existent yields.
Guano typically contains about 10% nitrogen, which helps plants keep a healthy and vibrant green color and promotes rapid growth.
Guano is also rich in bio-remediation microbes which helps to clean unnatural toxins from the soil that can prevent plant growth and cause rapid decay.
However, there are ongoing studies that have shown that aging urine in closed containers for 12–16 months eliminates 99% of harmful bacteria, due to increasing urea content and therefore pH.
[27] When initially spread they can cause an increase in ammonia within the soil and burn seeds, it is recommended to use these after plants have developed, to ensure crop success.
Other ARS studies have found that algae used to capture nitrogen and phosphorus runoff from agricultural fields can not only prevent water contamination of these nutrients, but also can be used as an organic fertilizer.
ARS scientists originally developed the "algal turf scrubber" to reduce nutrient runoff and increase quality of water flowing into streams, rivers, and lakes.
They found that this nutrient-rich algae, once dried, can be applied to cucumber and corn seedlings and result in growth comparable to that seen using synthetic fertilizers.
Use of bio-solids in agricultural production is less common, and the National Organic Program of the USDA (NOP) has ruled that biosolids are not permitted in organic food production in the U.S.; while biologic in origin (vs mineral), sludge is unacceptable due to toxic metal accumulation, pharmaceuticals, hormones, and other factors.
Fertilizer trees aid organic farming by bringing nutrients from the depths of the soil, and by assisting in the regulation of water usage.
By their nature, organic fertilizers increase physical and biological nutrient storage mechanisms in soils, mitigating risks of over-fertilization.
[38][39] A University of North Carolina study found that potential mineralizable nitrogen (PMN) in the soil was 182–285% higher in organic mulched systems than in the synthetics control.
