Nowadays, when people talk about a low-carbon economy, they talk more about industry, more about cities, less about rural areas, and less about agriculture, but in fact, there is great potential for developing low-carbon agriculture.
Climate change and the end of the fossil fuel era are creating new challenges for agriculture and human development. Water scarcity and fuel fluctuations** caused by climate change will have a direct impact on the stability of food production. Promoting energy conservation and carbon reduction in the agricultural sector is conducive to promoting the green development of agriculture.
Where to start with low-carbon agriculture?The application of low-carbon economy in agriculture can be explained from the four aspects of the 4R principle of circular economy, namely "reduce, reuse, recycle, and rethink".
The application of the principle of reduction - the implementation of "nine sections and one reduction". In rural areas, it is necessary to have the concept of "systematic economy," which can be concretized as "nine sections and one reduction." "Nine festivals", that is, saving land, water, fertilizer, medicine, seeds, electricity, fuel, firewood (coal), grain;"One reduction" means reducing the number of peasants engaged in the primary industry, and training the surplus rural labor force to work in the cities and towns to engage in business and engage in the tertiary industry.
Doing a good job of "nine sections and one reduction" can not only reduce the cost of agricultural production, increase farmers' income, effectively control agricultural non-point source pollution, protect the agricultural ecological environment, but also enhance the carbon sequestration capacity of the soil, greatly reduce greenhouse gas emissions, and is an important starting point and effective form of developing a green and low-carbon economy in the vast rural areas, transforming the mode of agricultural growth, resolving agricultural risks, developing circular agriculture and low-carbon agriculture, responding to climate change, and comprehensively promoting rural revitalization.
Application of the principle of reuse - strengthening the processing industry. The first is the deep processing of agricultural products. The second is to turn the by-products and organic wastes of various agricultural products into benefits and waste into treasures, and carry out series development and in-depth processing. Sometimes the resulting benefits will exceed the benefits of the main product, which not only saves energy resources, but also solves the pollution of the ecological environment, and can effectively control greenhouse gas emissions.
Application of the principle of recycling – the development of the microbial industry. The transition from traditional agriculture to low-carbon agriculture is not enough to rely on water and land resources, which requires a new way out.
One of the new ways out is to vigorously develop agricultural microorganisms. It is to extend the utilization of animal and plant resources in traditional agriculture to the utilization of microbial resources, and create a modern agriculture centered on the microbial industry. At present, biogas is the most widely used and effective use of microorganisms in rural areas. Biogas residue - biogas slurry can replace pesticides, biogas residue can replace chemical fertilizers, is an indispensable and important condition for the development of safe and high-quality agricultural products in rural areas. The second way out is to turn all kinds of rural wastes into benefits, waste into treasure, recycling and in-depth utilization. The third way out is to make full use of solar energy and smart alternative to chemical energy.
These three new ways out are the focus of the development of low-carbon agriculture in the vast rural areas, which can effectively reduce greenhouse gas emissions and cope with climate change.
Rethink the application of principles. The first is to operate the ecological environment, the second is to develop safe and high-quality agricultural products, and the third is to adjust, optimize and upgrade the rural industrial structure. These three points, especially the second point of "development of safe and high-quality agricultural products", organic agricultural products do not use any chemical synthetic substances, green agricultural products are strictly prohibited from applying high-toxicity and high-residue chemical fertilizers and pesticides, less chemical synthetics, more organic fertilizers. This is conducive to fundamentally solving the problem of large consumption of fossil fuels in the agricultural production process and greatly reducing greenhouse gas emissions, which is an important way to deal with climate change.
Practice has shown that the development of organic agriculture can almost achieve carbon neutrality in this field. Reducing greenhouse gas emissions and enhancing carbon sequestration in the production process also provides benefits in terms of biodiversity and other ecological services. Organic agriculture has many advantages and can make a significant contribution to the fight against climate change.
Previously, some experts put forward the idea of "turning one material (straw) into four materials (fertilizer, raw materials, feed, fuel)", which is also an important countermeasure for the development of low-carbon agriculture and climate change.
Use straw as fertilizer. The traditional practice is to turn the straw deep into the soil to rot as base fertilizer, some of the straw is crushed and mixed with livestock and poultry manure to ferment to make biomass organic fertilizer, and the straw can also be quickly rotted and returned to the field, which can reduce the use of high-carbon fertilizers such as chemical fertilizers.
On the other hand, returning straw as fertilizer can not only increase soil organic matter and improve the quality of cultivated land, but also fix the carbon in the straw in the soil, which can greatly reduce the release of carbon dioxide compared with open burning of straw.
The red line of cultivated land in China is 1.8 billion mu, and the average bulk density is 1A 1% increase in soil organic matter at 2 tonnes of cubic metres is equivalent to a net absorption of 30.6 billion tonnes of carbon dioxide from the air. Even if we take 30 years to complete this growth process, about 1 billion tons of carbon dioxide will be sequestered in arable land every year. It can be seen that the use of straw as fertilizer can also play an important role in soil carbon sequestration, and it is relatively easy to operate technically.
Straw is used as raw material. Some use straw to make various types of fiberboard, wood-plastic profiles, such as wheat straw as raw material through extrusion for the directional structure of wheat straw board, can be widely used as the bottom lining board of walls, roofs and floors, is one of the most used materials in frame structure buildings, not only heat insulation, sound insulation and moisture-proof, but also increase the space volume of the house, can greatly reduce the use of high energy consumption of steel, cement, bricks and tiles, and can also reduce the cutting of forests. Some use straw to burn activated carbon, such as Funan County, Anhui Province, which uses local abundant red hemp and other crop straw to burn activated carbon, which can save 500,000 cubic meters of wood every year, reducing the damage to ecology and environmental pollution. Some use crop straw and cow dung as a medium to cultivate various edible fungi, and some use the straw after pretreatment and anaerobic fermentation as raw materials for biogas, which solves the problem of insufficient biogas raw materials.
Use straw as feed. The corn straw silage ammoniation feeding cattle has a good effect, and the corn straw can also be cut off, kneaded and fermented and packaged to make breadgrass to feed cattle, with high nutritional value, long storage time, and reduced transportation costs.
Cattle are stomach animals, there are four stomachs (rumen, net stomach, valve stomach, true stomach), after the cow eats the grass, it is first decomposed and digested in the rumen, and then sent to the real stomach to be decomposed, digested, absorbed and utilized. According to this principle, the "artificial rumen" fermentation technology can be used as feed for monogastric animal pigs after fermenting straw. Raising a fattening pig with this feed can save 100-150 kg of grain, and breeding sows can save four-fifths of their grain per head per year. "Artificial rumen" is an improvement on the basis of human beings imitating the rumen mechanism of cattle and other compound stomach animals, and it is a great progress in raising single-stomach livestock and poultry with straw as the main material.
Use straw as fuel. There have been many experts and professors from colleges and universities, scientific research units and many important achievements in the research on the comprehensive utilization of straw. In the past, straw was used as biomass energy, and there were two main types: direct-fired and pyrolysis gasification. The direct-fired type uses crop straw to directly burn to generate heat, but its thermal efficiency is only one-third of gasification, and the investment is largePyrolysis gasification type volatilizes a variety of organic compounds and tar at the same time in the pyrolysis gasification process, if it is not utilized, it will cause environmental pollution, and only a single combustible gas is used, with low resource utilization rate and poor economic benefits. In view of the above problems, Academician Zhang Qisheng of Nanjing Forestry University has researched and developed the comprehensive utilization technology of biomass energy polygeneration, which burns biomass materials under the condition of limiting oxygen supply in the gasifier, and a series of combustion reactions occur, and the gas, liquid, carbon and hot water produced at the same time. The gas produced by pyrolysis mainly contains flammable gases such as methane, ethylene, carbon monoxide, hydrogen, etc., which can be fed into a gas turbine to generate electricity or directly supplied to usersThe liquid produced contains acids, alcohols, esters, aldehydes, ketones, phenols and other chemical components, which can be used as disinfection and sterilization liquid, deodorant or for pesticides, additives, foliar fertilizer to promote crop growth, and the effect of application in organic crops is obviousThe solid biochar produced can be used as industrial charcoal, domestic charcoal, organic compound fertilizer, fertilizer corrosion inhibitor, etcThe hot water generated by the cooling furnace can be used in industrial or civil use. This is a breakthrough achievement.
In short, in the vast number of rural production, all aspects of life can develop a circular economy and a low-carbon economy, everyone can use their strength, everyone must contribute, this is our magic weapon to win. As long as we persist in doing so, we can achieve harmonious development between man and nature, and embark on a new path of developing low-carbon agriculture with Chinese characteristics and addressing climate change.