According to relevant statistics, as a large agricultural country, China can produce more than 700 million tons of straw every year, which is “not very useful” but must be disposed of as “waste”.
In recent years, crop straw has become a new source of non-point source pollution in rural areas. Every summer harvest and autumn and winter, a large number of wheat, corn and other straws are burned in the field, resulting in a large amount of smoke, which not only becomes the bottleneck problem of rural environmental protection, but also the main culprit of endangering the urban environment.
Facing these seemingly useless straws, farmers usually accumulate them and burn them centrally.
However, straw burning can cause haze weather, and produce a large number of toxic and harmful substances, which pose a threat to human and other biological health.
Every year in the wheat and maize harvest season, because a large amount of straw cannot be treated in a short period of time, farmers often burn in situ, which saves labor, but the smoke of burning will affect the environment and transportation and soil moisture. In addition, with the increase of crop yield, the amount of straw is also increasing every year. The excessive amount of straw returned to the field, insufficient soil moisture and inappropriate tillage measures will affect the emergence and growth of crops, resulting in the increase of pests and diseases, and the imbalance of soil carbon-nitrogen ratio.
Crop straw is a very valuable biomass energy resource in agricultural ecosystem. The comprehensive utilization of crop straw resources is of great significance to increase farmers ‘income, environmental protection, resource saving and sustainable development of agricultural economy.
Mechanized straw returning includes straw smashing, stubble smashing, whole-pole burying, whole-pole braiding and so on. It has the advantages of convenience, rapidity, low cost, large-area Fertility Cultivation and is a mature technology. The main characteristic of Mechanized Straw Returning is that the harvested crop straw is crushed and buried by machinery or buried by whole straw or braided by whole rod. It can complete many working procedures at one time. Compared with the human work industry, the work efficiency has increased by 40-120 times. It not only competes for agricultural time, but also reduces environmental pollution, enhances soil fertility and increases grain production.
Returning is to treat straw through silage, micro-storage, ammoniation, thermal spraying and other technologies, which can effectively change the structure of straw and make straw easy to digest and taste good feed for livestock.
After digestion and absorption of some nutrients, such as carbohydrates, proteins, cellulose and other nutrients in the abdomen of animals, the rest become feces, applied to the soil, fertilize the soil, without side effects. The nutrient part of straw absorbed by animals is effectively transformed into meat and milk, which is eaten by people and improves the utilization rate. This way is scientific and ecological, and should be promoted.
When the straw is crushed and used scientifically as the base material of edible fungi cultivation, edible fungi such as agaric, mushroom and Tremella can be cultivated, which can effectively solve the contradiction between the rapid development of edible fungi production and the insufficient supply of cottonseed hulls in recent years. After treatment, the basal material can still be used as livestock feed or fertilizer to return to the field.
Cultivation of Edible Fungi Using Straw Material
Crop straw can be used as raw material for papermaking, as well as for pressing fibre wood. It can make up for the shortage of timber resources, reduce the amount of timber felled, improve forest coverage, and make the ecological environment develop benignly.
A series of chemical reactions were carried out with additives in the reactor after ultra-fine crushing of straw, which made the fibers in straw thermoplastic. This material can be used in the manufacture of film, sheet and injection grade products. It can replace petroleum-based products (plastics) and has complete biodegradability (weight loss rate of 90% after 180 days). It is a kind of healthy environmental protection material.
Biomass power generation
Direct incineration of straw and mixed incineration of straw and garbage can also generate electricity by vaporization. Straw is a good clean and renewable energy. The calorific value of every two tons of straw is equivalent to one ton of standard coal, and its average sulfur content is only 3.8. In the process of coal’s average sulfur content is about 1% of biomass’s renewable utilization, the emission of carbon dioxide and the absorption of carbon dioxide during biomass regeneration reach carbon balance, which has the function of zero emission of carbon dioxide. It will mitigate and ultimately solve the problem of greenhouse effect. It has made important contributions.
The comprehensive utilization of straw has broad prospects, especially in developed countries. Through scientific and technological progress and innovation, it has found many uses for the comprehensive development and utilization of crop straw. In addition to traditional straw crushing and returning to the field as organic fertilizer, it has also found new ways such as straw feed, straw vaporization, straw power generation, straw ethanol, straw building materials and so on, which has greatly improved the utilization value and utilization of straw. Rate is worth learning from.