Straw is a general term for the stem and leaf (spike) parts of mature crops, which has a variety of important uses and environmental values. The following is a detailed analysis of straw:
The composition and properties of straw
Composition: Straw is the product of crop photosynthesis, which is rich in nitrogen, phosphorus, potassium, calcium, magnesium and organic matter, etc. It is a renewable biological resource with multiple uses. Different kinds of straw contain different nutrients, such as leguminous straw contains more nitrogen, and graminaceous straw contains more potassium.
Properties: Straw has a high crude fibre content (30%-40%) and contains lignin, among other things. The decomposition and transformation of straw is affected by factors such as carbon and nitrogen ratio, lignin mass fraction, soil water content, temperature and soil texture.
The use of straw
Agricultural use: straw can be directly returned to the field, as a soil conditioner and organic fertiliser, to improve soil fertility. In addition, straw can also be used as feed for livestock, realising the effective use of resources.
Biomass energy: Straw can be used to produce biomass energy, such as diesel, liquefied petroleum gas (LPG) and natural gas, helping to reduce dependence on fossil energy.
Building materials: Straw can be used to make building materials such as structural columns, walls and roof panels, which have good environmental performance.
Paper products and fibres: Straw can be used to make paper products and fibres such as newspapers, magazines, cardboard boxes, paper cups, as well as cotton and hemp fibres.
Other uses: straw can also be used in many fields such as food, medicine, chemistry, automobile, electronic products, packaging, ceramics, furniture and daily necessities, etc., demonstrating its wide application value.
The environmental value of straw
Improve soil fertility: straw can increase soil organic matter content, improve soil structure, soil fertility and crop yield.
Reduce environmental pollution: the effective use of straw can reduce the pollution of air quality by straw burning, and at the same time reduce the dependence on fossil energy and reduce greenhouse gas emissions.
Promote sustainable development: as a renewable resource, the effective use of straw can help promote the sustainable development of agriculture and environmental protection industry.
Current situation and development trend of straw utilisation
Status quo: In recent years, with the development of agricultural production and the improvement of agricultural mechanisation, the quantity of straw has increased significantly. Straw return technology has been widely promoted and applied, and has become an important part of China’s Fertile Soil Project and Harvest Programme. Meanwhile, the application of straw in biomass energy, building materials and other fields is also gradually increasing.
Development trend: The use of straw will be more diversified and efficient in the future. On the one hand, with the improvement of environmental protection awareness and policy support, straw return technology will be further promoted and improved; on the other hand, the application of straw in biomass energy, building materials and other fields will be more extensive and in-depth. Meanwhile, with the progress of science and technology and the implementation of innovation-driven development strategy, the comprehensive utilisation of straw will present a broader development prospect.