What are the sources of organic fertilizers?

In the wave of modern agriculture and ecological agriculture, Organic Fertilizers are gradually replacing some chemical fertilizers and becoming an important pillar of sustainable agriculture due to their advantages of improving soil structure, enhancing crop quality, and reducing environmental pollution. So, what exactly is organic fertilizer? What are its sources? This article will provide you with a detailed overview of the diverse sources and classifications of organic fertilizers.
1、 What is organic fertilizer?
Organic fertilizer (referred to as "organic fertilizer") refers to carbon containing materials formed from animal and plant residues, excreta, or their metabolites after harmless treatment such as microbial fermentation and composting. It is rich in organic matter, nitrogen, phosphorus, potassium, and various trace elements. It not only provides the nutrients needed by plants, but also activates soil microorganisms and enhances soil water and fertilizer retention capacity. It is a key material for building a healthy soil ecosystem.
2、 Classification of the main sources of organic fertilizers
According to different sources of raw materials, organic fertilizers can be divided into the following categories: 1 Animal based sources are currently the most core category of raw materials in large-scale organic fertilizer production, mainly including:
Livestock and poultry manure such as chicken manure, pig manure, cow manure, sheep manure, etc. These types of raw materials have high nitrogen content and moderate carbon to nitrogen ratio, and can provide abundant quick acting and slow acting nutrients after fermentation.
Human manure is an important component of traditional farmyard manure, with a high nitrogen content, but it must undergo sufficient fermentation and sterilization before use.
Animal processing by-products such as bone meal, blood meal, fish meal, feather meal, silkworm excrement, earthworm castings, etc. These substances have high protein content and release a large amount of nitrogen and trace elements after decomposition.
Aquatic waste includes fish offal, shellfish shells, seaweed, kelp residue, etc., which are rich in calcium, magnesium, and trace elements from marine sources.

2. There are various types of plant-based organic fertilizers that are widely present in agricultural production and daily life
Crop straw such as corn stalks, wheat stalks, rice straw, and soybean stalks are rich in cellulose and an important carbon source For Composting.
Green manure crops such as purple clover, alfalfa, field lily, arrow pea, etc. are directly plowed into the soil after planting to increase soil organic matter and fix nitrogen.
The residue from oil extraction of oilseed crops such as soybean cake, rapeseed cake, peanut cake, sesame cake, cottonseed cake, etc., is nutritious and has long-lasting fertilizer effects.
Garden and forestry waste such as fallen leaves, branches, sawdust, and grass shavings can be crushed and fermented to produce high-quality substrates or coverings.
The discarded mushroom sticks after cultivating mushrooms, shiitake mushrooms, etc. with edible mushroom residue contain a large amount of mycelium and incompletely decomposed organic matter.

3. With the development of circular economy, many Organic Wastes that were originally considered as "garbage" have also been included in the organic fertilizer raw material system:
Food processing by-products include distiller's grains, vinegar grains, soy sauce grains, monosodium glutamate residue, molasses residue, fruit residue, potato residue, corn residue, etc.
After evaluation, plant derived medicinal residues from traditional Chinese medicine can be used as safe raw materials.
Kitchen waste, after classification, decontamination, and aging treatment, is an important source of urban organic fertilizer.
Domestic sludge generated by sludge and sludge wastewater treatment plants (requiring strict harmless treatment), and sludge and slurry fermented in biogas digesters.
Other industrial organic wastes such as furfural residue, yeast residue, leather waste (requiring special treatment), etc.

4. Although natural minerals and biochar (auxiliary type) are not typical "organic" sources, they are often used as additives or conditioners in organic fertilizer production:
Peat, peat, and brown coal are rich in humic acid, which can enhance the stability and water retention of organic fertilizers.
Biochar is produced by high-temperature pyrolysis of biomass and has strong adsorption properties and long-term soil improvement functions.

3、 National policies and standard specifications
In China, the industry standard "NY/T 525-2021 Organic Fertilizer" issued by the Ministry of Agriculture and Rural Affairs clearly classifies organic fertilizer raw materials: applicable raw materials such as straw, livestock manure, cake, rice husk, peat, etc. can be directly used for production. Evaluation materials such as kitchen waste, Chinese medicine residue, fish offal, sludge, etc. must undergo safety evaluation to confirm that there are no risks of heavy metals, pathogens, antibiotic residues, etc. before they can be used.
In addition, since 2008, the country has implemented a tax exemption policy for bio organic fertilizers, greatly promoting the standardization and scale development of the industry.
4、 Conclusion: Turning Waste into Treasure, Green Circulation
The sources of organic fertilizers almost cover all biodegradable organic waste. From straw and livestock manure in the fields, to leftover food in urban kitchens, to distiller's grains and medicinal residues in factories - they are no longer burdens, but valuable resources. Through scientific fermentation and safe treatment, these "wastes" are transformed into "gold" that nourishes the land, not only reducing environmental pollution, but also building an ecological loop of "planting breeding processing returning to the field".
In the future development of agriculture, in-depth exploration and utilization of various organic waste resources will be an important path to achieve the goals of improving farmland quality, ensuring food security, and carbon neutrality. Let's work together to promote the widespread application of organic fertilizers, making the land healthier, food safer, and the earth more sustainable.
This article is compiled based on the latest industry data and national standards from 2025 to 2026, and is suitable for reference by agricultural practitioners, environmentalists, and the public concerned about sustainable development.