Types and Sources of Organic Fertilizers
– Main organic fertilizers: peat, animal wastes, plant wastes from agriculture, treated sewage sludge
– Minerals sourced from fossils: greensand, some limestones, rock phosphates
– Other organic fertilizers: rock phosphate, raw Langbeinite, rockdust, unprocessed natural potassium sulfate
– Algal turf scrubber, ash from plant combustion, and biosolids are also used as organic fertilizers
Animal-Based Organic Fertilizers
– Animal manures and residues from animal slaughter are organic fertilizers
– Manure from dairy animals, poultry, meat animals, and sport animals is abundant
– Manure adds nitrogen, potassium, phosphorus, sulfur, magnesium, and calcium to crops
– Manure increases soil stability, water infiltration, and bacterial diversity
– Organic manure must come from organic livestock or certified organic growers
Human Waste as Organic Fertilizer
– Biosolids (sewage sludge) are used as a fertilizer on non-agricultural crops
– Biosolids are not permitted in organic food production due to toxic metal accumulation and other factors
– Human excreta can be used as a fertilizer
– Human borne pathogens are a concern with the use of human waste as fertilizer
Plant-Based Organic Fertilizers
– Processed organic fertilizers include compost, liquid plant manures, humic acid, grain meal, amino acids, seaweed extracts
– Compost increases soil stability and provides bio-available nutrients
– Grain meals made of corn gluten, alfalfa, cottonseed, or soybean provide nitrogen and potassium
– Decomposing crop residue from prior years is another source of fertility
Benefits and Comparison of Organic Fertilizers
– Organic fertilizers improve soil structure and fertility
– Enhance nutrient availability for plants
– Increase microbial activity in the soil
– Reduce the risk of nutrient runoff and water pollution
– Promote long-term soil health and sustainability
– Organic fertilizers have been shown to be at least as effective as chemical fertilizers over longer periods of use
– Organic fertilizers improve soil biodiversity and may act as a depository for excess carbon dioxide
– Organic nutrients reduce the need for external inputs of pesticides, energy, and fertilizer, but may result in decreased yield
– Organic fertilizers have environmental benefits such as reducing greenhouse gas emissions and protecting water quality
– Organic fertilizers should be applied following recommended rates and timing, incorporated into the soil, and considered in relation to crop nutrient requirements and soil test results Source: https://en.wikipedia.org/wiki/Organic_fertilizer
