Carbon Neutrality Focus | What is Ecological Agriculture? What are the classic models of "ecological circular agriculture?"

Ecological agriculture is an important trend and direction for the future development of agriculture. Adopting a sustainable development path is a common choice for agriculture in all countries around the world. We should actively learn from successful experiences at home and abroad and vigorously develop ecological circular agriculture in our country.
 

2025 is a key year for ecological circular agriculture. The "Notice on Issuing the Guiding Opinions on Regional Ecological Circular Agriculture Projects of Comprehensive Agricultural Development" mentions that the country will build around 300 regional ecological circular agriculture projects, actively promoting the development of resource-saving, environmentally friendly, and ecologically conservation-oriented agriculture, and improving the quality and safety of agricultural products, the level of standardized production, and the level of sustainable agricultural development.

Ecological circular agriculture generally refers to ecological agriculture. It requires combining the development of food and various cash crops, the development of field planting with forestry, animal husbandry, sideline production, and fisheries, and the integration of large-scale agriculture with the secondary and tertiary industries, utilizing the essence of traditional agriculture and the achievements of modern science and technology, Through the artificial design of ecological engineering, coordinating the contradictions between development and the environment, and between resource utilization and protection, forming a virtuous cycle in both ecological and economic terms, and achieving the unification of economic, ecological, and social benefits.

Ecological agriculture first emerged in Europe in 1924, and developed in Switzerland, Britain, and Japan in the 1930s and 1940s; in the 1960s, many farms in Europe turned to ecological cultivation, and in the late 1970s, the Southeast Asian region began to discuss ecological agriculture, with sustainable development becoming a common choice for agriculture in all countries around the world.

Three Major Models of Ecological Circular Agriculture

# 01

Reduction Model

According to the specific conditions of each operational unit in the field, precisely manage the soil and various crops, maximizing the optimization of agricultural inputs (such as chemical fertilizers, pesticides, water, seeds, etc.) to obtain the highest yield and economic benefits, reduce the use of chemicals, and protect the agricultural ecological environment. The pursuit of high-quality, high-yield, and high-efficiency with minimal input is the circular agriculture of the "reduction" model, also known as "precision agriculture".

[Case Study]

Precision agriculture in the United States. The United States is one of the earliest countries in the world to implement precision agriculture. After 1990, the United States applied GPS system technology to the field of agricultural production. Farms in Minnesota conducted precision agriculture technology experiments, and the crop yield using GPS-guided fertilization was about 30% higher than that of traditional balanced fertilization.

After the successful experiment, precision agriculture technology began to be applied to the production management of wheat, corn, soybeans, and other crops. In the mid-1990s, the development speed of precision agriculture in the United States was quite rapid. By 1996, the number of harvesters equipped with yield monitors had increased to 9,000.

Water-saving agriculture in Israel. Israel's circular agriculture is prominently reflected in its perfect water-saving agricultural system. Spray irrigation, drip irrigation, micro-spray irrigation, and micro-drip irrigation technologies are widely used in Israel, with over 80% of farmland irrigation using drip irrigation, 10% using micro-spray, and 5% using mobile spray irrigation, completely replacing the traditional furrow irrigation method.

The most effective is agricultural drip irrigation technology: First, water can be directly delivered to the roots of crops, saving 20% of water compared to spray irrigation; second, the use of drip irrigation on sloped farmland will not exacerbate soil erosion; third, the use of purified water after wastewater treatment (with a higher salt concentration than freshwater) for drip irrigation will not cause soil salinization.

Drip irrigation technology saves more than 30% of water and fertilizer compared to traditional irrigation methods, and is conducive to the recycling of wastewater. To develop water sources, Israel has increased investment in wastewater treatment and recycling.

Israel plans to use all recycled water after wastewater treatment for agricultural irrigation. Currently, 80% of urban wastewater has been treated and recycled, mainly used for agricultural production, accounting for 20% of agricultural water use. The treated wastewater is also re-injected into the aquifer in addition to being used for agricultural irrigation.

# 02

Ecological Industrial Park Model

The scale of circular agriculture has three levels: departmental, regional, and social. The departmental level mainly refers to a single enterprise or farmer as a circular unit; the social level implies a "circular rural area"; the regional scale is based on ecological principles, through the integration of matter, energy, and information between enterprises, forming an ecological industrial park with a leading enterprise as the driving force and several small and medium-sized enterprises and farmers within the park.

[Case Study]

Maya Farm in the Philippines. Initially just a flour mill, it developed into a virtuous cycle ecological system of agriculture, forestry, animal husbandry, sideline production, and fisheries after 10 years of construction starting in the 1970s.

The flour mill produces a large amount of bran. To avoid wasting the bran, a breeding farm and fish ponds were established; to increase income, meat processing and canning factories were also established to process livestock and aquatic products.

By 1981, the farm had 36 hectares of paddy fields and economic forests, raising 25,000 pigs, 70 cattle, and 10,000 ducks. To control livestock and poultry manure pollution and recycle waste from processing plants, the farm established more than a dozen biogas workshops, producing tens of thousands of cubic meters of biogas daily, which can meet the energy needs of farm production and family life.

Some livestock feed can also be recovered from the biogas residue after gas production, and the rest is used as organic fertilizer. The biogas liquid after gas production is treated and sent to ponds to raise fish and ducks, and finally the pond water and pond mud are used to fertilize the fields.

The grain produced in the fields is then sent to the flour mill for processing, entering the next cycle. Maya Farm does not need to purchase raw materials, fuel, and fertilizers from outside, yet it maintains high profits and has no pollution from waste gas, wastewater, and waste residue, fully realizing the recycling of materials.

# 03

Waste Recycling Model

 

Through multi-level recycling of agricultural waste, the waste or by-products of the previous industry are used as raw materials for the next industry. For example, the utilization of biogas and animal manure.

Comprehensive utilization of biogas. Using biogas as a link, livestock and poultry manure, crop straw, and rural domestic sewage are treated as biogas substrates. The biogas produced is used as fuel, and the biogas slurry and residue are used as organic fertilizers. Combined with soil testing and formula fertilization, standard farmland soil improvement, high-quality agricultural product base construction, and pollution-free agricultural products, the "one gas, two biogas" integrated utilization model is explored. Research and demonstration promotion of biogas residue and biogas slurry ecological cycle utilization technology are carried out, and "pig-biogas-fruit (vegetable, grain, mulberry, forest)" and other circular models are promoted to form a new ecological circular agricultural pattern connecting animal husbandry and planting industries.

Livestock manure collection, treatment, and organic fertilizer processing and utilization. A well-equipped livestock manure collection and processing center, with standardized operation and a collection mechanism of household collection, village transportation, and regional collection, increases the livestock manure collection rate and comprehensive utilization rate to over 95%.

Circular model using straw as a link. This model can achieve stepwise utilization of straw resources and zero emission of pollutants, making reasonable and effective use of straw waste resources, solving the environmental pollution and resource waste problems caused by the arbitrary discarding and burning of straw, while obtaining organic fertilizers, clean energy, and bio-based materials.

For example, building industrial chains such as "straw-substrate-edible fungi", "straw-formed fuel-fuel-farmers", and "straw-silage-animal husbandry" around the comprehensive utilization of straw as feed, fuel, and substrate.

[Case Study]

Japanese circular agriculture. In the Aido town area, rapeseed is produced. On the one hand, the oil residue left after rapeseed utilization can be processed into high-quality organic fertilizers or feed through composting or feed processing; on the other hand, waste cooking oil is recycled and reprocessed into biofuel.

Hizashi town in Japan is an area that has developed circular agriculture earlier and more successfully. In 1988, the town passed the "Regulations on the Development of Natural Agriculture," stipulating that the use of pesticides, chemical fertilizers, and other non-organic fertilizers is prohibited in agricultural production, and the agricultural products produced must be organic agricultural products without chemical fertilizer, pesticide residue, and pollution.

Hizashi town uses small-scale sewage sludge, poultry manure, and organic waste from enterprises as raw materials for fermentation equipment. The methane gas produced is used for power generation, and the remaining semi-solid waste residue is subjected to solid-liquid separation. The solid components are used for composting and drying, and the liquid components are treated for reuse or discharge (discharge is basically harmless to the environment), achieving high resource utilization and harmlessness of waste.

In addition, Hizashi town collects and processes kitchen waste to produce organic fertilizer.

Germany's "green energy" agriculture. In the early 1990s, German scientists discovered that mineral energy and chemical raw material substitutes can be extracted from some agricultural products to achieve the recycling of agricultural products. These biomass energy and raw materials are green and pollution-free, and the German federal government began to pay attention to the development of such economic crops.

German scientists have carried out directional breeding of sugar beet, potato, rapeseed, and corn, from which ethanol and methane are extracted, successfully developing green energy; alcohol is extracted from Jerusalem artichoke plants; and alkaloids are extracted from broad beans. Rapeseed is currently the most important energy crop in Germany, not only can it be used as a chemical raw material, but it can also be refined into vegetable diesel, replacing mineral diesel as a power fuel.

UK "permanent agriculture". "Permanent agriculture" is an important form of waste resource utilization in the circular economy. Its characteristic is to maximize the beneficial relationship through the effective allocation of elements on the basis of saving resources and not damaging the environment.

Growers recycle various resources and save energy. For example, using cigarette butts to collect rainwater, turning feces into organic fertilizer, and returning straw to the field. "Permanent agriculture" seeks to use land resources as economically as possible, emphasizing the use of perennial plants; encouraging the use of self-regulating systems. When cultivating land, land is maintained through diversified planting and green cover technologies, local environments are monitored, and green development plans are built.

"Permanent agriculture" does not use artificial chemical fertilizers and pesticides. It prevents pests by planting a variety of plants and encouraging carnivores to enter the ecosystem. For example, alfalfa, a legume, releases nitrogen, which can cause pests to lose their way.

China's ecological agriculture. Deqingyuan uses world-leading agricultural waste biogas power generation technology to successfully convert 100,000 tons of chicken manure per year into 14 million kilowatt-hours of green electricity and 160,000 tons of organic fertilizer, supplying biomass energy such as electricity and heat to surrounding farmers, achieving an annual reduction of 84,000 tons of carbon dioxide emissions. In addition to the income from egg sales, Deqingyuan's ecological agriculture has also generated over 100 million yuan in economic benefits annually.

Producing organic fertilizer. Deqingyuan invested in the construction of four 3000-cubic-meter biogas fermentation tanks. Chicken manure and sewage are transported to the pulping hydrolysis pool for preliminary treatment through underground pipelines and conveyors, and then enter the primary fermentation tank, secondary fermentation tank, and post-fermentation-slurry storage tank in sequence. Finally, the biogas slurry comes out of the slurry storage tank and enters the biogas slurry pool, becoming a very good organic fertilizer.

Giving back to animal husbandry and planting. The power plant has achieved maximum utilization of chicken manure and biogas, collecting the remaining biogas residue and providing organic fertilizer for farmers to plant corn and Deqingyuan's organic plantation, ensuring that the corn planted by farmers is truly organic corn, in turn providing organic feed for Deqingyuan's egg-laying chickens, which is an ideal fully circular ecological cycle farming.

Using chicken manure and sewage to generate electricity and produce biogas. The biogas produced by the biogas fermentation tank, after desulfurization through the primary and secondary biological desulfurization towers, enters the 2150-cubic-meter double-membrane dry gas storage tank. Then, three pipelines are drawn from the gas storage tank: one pipeline leads to the new village to provide domestic gas for the villagers in the south; one leads to the boilers and heating equipment of the entire park. Another pipeline's biogas, after being pressurized by a biogas booster fan, enters the assembly...