Soilless cultivation

Soilless cultivation:

It refers to the method of cultivating crops without or partially without natural soil, but using nutrient solution or solid matrix plus nutrient solution to directly provide plants with the nutrients necessary for growth and development

Soilless cultivation mainly includes hydroponics, mist cultivation and matrix cultivation, among which matrix cultivation is the main form of soilless cultivation. Matrix cultivation is solid matrix cultivation, which can be divided into inorganic matrix, organic matrix and organic-inorganic mixed matrix (referred to as composite matrix).

Organic matrix cultivation refers to the use of organic matter such as crop straw, mushroom residue, peat, sawdust, livestock and poultry manure, etc., after fermentation or high-temperature treatment, mixed in a certain proportion to form a relatively stable and buffering full-nutrition cultivation matrix raw material.

In order to improve the physical and chemical properties of the cultivation matrix, inorganic substances such as river sand, coal slag, vermiculite, perlite, etc. can be mixed with it in a certain proportion to form an organic and inorganic cultivation matrix.

Organic cultivation uses agricultural waste as the main matrix raw material and is an emerging and efficient soilless cultivation method. The utilization of organic waste has become a major development direction for substrate selection. There are many research reports on the selection of sawdust, cottonseed hulls, edible fungus substrate waste, rice husk ash, straw and xylose residue as soilless seedling substrates. The utilization of organic waste has greatly reduced the cost of cultivation and reduced pollution to the environment.

1.Coconut fiber

Coconut fiber, also known as coconut shell fiber or coconut bran, is a by-product of the coconut processing industry. Compared with peat, coconut fiber contains more lignin and cellulose, is loose and porous, and has good water retention and ventilation properties. The pH is acidic and can be used to adjust the substrate or soil with too high pH. The content of P and K is high, but the content of N, Ca and Mg is low, so N must be supplemented during use, and the application amount of K can be appropriately reduced.

2.Bark

Different tree species vary greatly. The most commonly used barks as substrates are pine bark and fir bark. Bark contains inorganic elements but poor water retention, and contains inhibitory substances such as resin, tannin, and phenols, which need to be fully fermented to degrade. Liu Hujun found that pine bark substrate is beneficial to the dry matter accumulation and tillering of the nutritional organs of pineapple strawberry. Fan Shuangxi's research shows that when the ratio of decomposed bark: peat is 7:3, it is most beneficial to the growth of lettuce. Shbata et al. in the United States developed artificial soil made of rotten bark or peat as an important component. This type of soil has good drainage, water retention and fertilizer retention. It is not only a suitable substrate for soilless cultivation of flowers, but also particularly suitable for lawn soil in the green area of ​​golf courses.

3.Bagasse

Bagasse is a by-product of the sugar industry. The main component is cellulose, followed by hemicellulose and lignin. Fresh sugarcane bagasse has a high CN ratio, and it is difficult for plant roots to grow normally in it without treatment, so it must be composted before use. Under natural conditions, its composting effect is poor. It needs to be added with nitrogen fertilizer and composted before it can become a good soilless cultivation substrate with the same effect as peat planting.

Yu Wenjin's research shows that after adding NH4NO3, puffed chicken and compost fast-acting fungus to bagasse and then composting, the obtained matrix can be used for the cultivation of cucumbers, tomatoes and cauliflower, all of which meet the requirements of pollution-free vegetable products. Long Minghua et al. added compost fast-acting fungus, urea and chicken manure and then composted, and the produced matrix was used for soilless cultivation of watermelon and melon with good results. The bagasse resources in Guangdong and Guangxi are rich in my country, and its potential for use as a matrix is ​​huge.

4.Rice husk

Rice husk is a by-product of rice processing. It has good permeability, is not easy to rot, and has average water holding capacity. It can be used in combination with other matrix materials and is generally used as a cutting matrix for flowers. The usual method of use is to carbonize it through dark fire smoldering to form carbonized rice husks, namely rice husks. Pan Kai showed through indoor physical and chemical shape analysis and greenhouse vegetable crop cultivation experiments that it is feasible to use raw rice husks as the main formula of organic ecological soilless cultivation matrix, which can meet the normal growth and development needs of tomato crops.

5.Sawdust

The best sawdust is from yellow fir and hemlock. Some sawdust from arborvitae is poisonous and cannot be used. Coarse sawdust mixed with 25% rice husk can improve the water retention and air permeability of the substrate. In addition, sawdust contains a large number of bacteria and pathogenic microorganisms, and needs to be properly treated and fermented before it can be used. It has a high carbon content, and after fermentation and decomposition, a certain amount of nitrogen source needs to be added to facilitate carbon degradation. It has achieved good results in cultivating tomatoes, peppers, etc.

Commonly used inorganic substrates include vermiculite, perlite, rock wool, sand, polyurethane, etc.; organic substrates include peat, rice husk charcoal, bark, etc. Therefore, substrate cultivation is divided into rock wool cultivation, sand cultivation, etc.