Greenhouses create a suitable growing environment for crops, but they also bring unique challenges such as soil salinization, continuous cropping obstacles, and the accumulation of pests and diseases. The scientific application of organic fertilizer is not only an effective means of solving these problems, but also key to achieving high yields and quality in facility agriculture. This article summarizes practical techniques for applying organic fertilizer in greenhouses.
Greenhouse Environment Places Higher Requirements on Organic Fertilizer Application
Greenhouses are relatively enclosed environments with limited ventilation, slow soil moisture evaporation, and a tendency for pests and diseases to accumulate. Applying organic fertilizer in this environment carries several special risks that need to be considered. First, ammonia hazards—uncomposted or improperly applied organic fertilizer will release ammonia in high temperature and humidity, leading to leaf scorch and stunted growth. Second, pest and disease transmission—if organic fertilizer carries pathogens or insect eggs, the warm and humid conditions in the greenhouse will accelerate their reproduction and spread. Third, soil salinity accumulation—excessive application of organic fertilizer, especially insufficiently composted fertilizer, will increase soil salinity and affect root growth.
Therefore, applying organic fertilizer in greenhouses requires higher standards for fertilizer composting and application methods.
First choice: Fully decomposed, high-quality organic fertilizer.
Greenhouses must use fully decomposed commercial organic fertilizer or qualified self-fermented organic fertilizer. Thoroughly decomposed organic fertilizer is dark brown, odorless, and loose in texture, and will not undergo secondary fermentation after being applied to the soil. Judging the degree of decomposition is simple: take a handful of organic fertilizer and hold it in your hand; if it is not hot to the touch, not sticky, and smells of fresh earth, it is generally considered properly decomposed.
It is recommended to choose organic fertilizers made from cow manure, sheep manure, soybean meal, and straw. These fertilizers are mild in nature and have relatively low salt content, making them more suitable for greenhouse use. While chicken manure and pig manure have high nutrient content, they also pose a relatively high risk of salt and heavy metal contamination. If used, choose professionally processed and tested finished products.
Scientific control of dosage and application methods. The amount of fertilizer used in greenhouses needs to be carefully calculated. The amount of base fertilizer is generally 500-800 kg per acre, adjusted according to soil fertility and target yield. When applying organic fertilizer, spread it evenly on the soil surface and till it to a depth of 15-20 cm to ensure thorough mixing. Avoid concentrating the fertilizer in the planting hole to prevent direct contact between the roots and high-concentration fertilizer.
Topdressing should be applied flexibly according to the crop’s growth. Leafy vegetables have a short growing season and may not require topdressing if sufficient base fertilizer is available. Fruiting vegetables require a large amount of fertilizer during flowering and fruiting; liquid organic fertilizer can be applied in conjunction with drip irrigation at a rate of 100-200 kg per acre each time. Liquid organic fertilizer is fast-acting, easily absorbed, and does not increase soil salinity, making it suitable for precision fertilization in greenhouses.
Control humidity and avoid odors. Excessive humidity in greenhouses can induce diseases, and improper application of organic fertilizer may also produce unpleasant odors. Several practical tips can help solve these problems: Cover the organic fertilizer with soil promptly after application to reduce ammonia volatilization and odor diffusion; seal the greenhouse for 7-10 days after applying base fertilizer to kill potential pathogens and insect eggs with high temperatures, while promoting the integration of organic fertilizer with the soil; use drip irrigation instead of flood irrigation to maintain alternating soil moisture levels, meeting crop water needs while avoiding excessive humidity; place sulfur fumigators or hang yellow sticky insect traps in the greenhouse to assist in pest and disease control.
Scientific Combination of Organic and Chemical Fertilizers: In greenhouse production, the combined use of organic and chemical fertilizers yields the best results. Organic fertilizer should be applied as a base fertilizer in one application, providing long-lasting nutrients and improving soil function; chemical fertilizers should be applied in stages according to different crop growth stages to meet the needs of readily available nutrients. It is generally recommended that organic fertilizer provide 50%-60% of the nitrogen in the base fertilizer, with the remainder supplemented by chemical fertilizers. This “organic-based, chemical-based” model ensures yield, improves quality, and reduces soil salinization.
Combining Crop Rotation with Soil Disinfection
In facility agriculture, continuous cropping obstacles are a common problem. It is recommended to combine crop rotation and soil disinfection measures while applying organic fertilizer. During the high-temperature summer season, after applying organic fertilizer, deep plow and turn the soil, then cover with mulch for 15-20 days of high-temperature fumigation. This effectively kills soil-borne pathogens and insect eggs, while accelerating the decomposition and transformation of organic fertilizer. When arranging crop rotations in winter and spring, try to rotate solanaceous crops, cucurbits, and leafy vegetables to reduce the risk of diseases caused by continuous cropping of the same family of crops.
Greenhouses are an important carrier of modern agriculture. Using organic fertilizer scientifically and effectively will make the soil healthier, the crops higher quality, and the yield more substantial. Starting with selecting fully decomposed organic fertilizer and precisely controlling the dosage and method, your greenhouse will surely grow better and better.
Organic Fertilizer Application in Greenhouses
To meet the high standards required for greenhouse application, producing your own organic fertilizer demands a reliable bio organic fertilizer production line. After the material is composted and granulated, it must undergo precise post-processing to ensure it is stable, safe, and ready for the controlled greenhouse environment. A rotary drum screening machine classifies the granules, ensuring uniform size for even application. A fertilizer dryer machine then reduces the moisture content to the optimal level, preventing mold growth in the humid greenhouse. A fertilizer cooler machine brings the product to ambient temperature, crucial for storage stability. Finally, a fertilizer packing machine seals the finished, high-quality organic fertilizer, ready for use as a safe and effective base or top dressing. This integrated system empowers growers to produce the fully decomposed, low-salt, and pathogen-free organic fertilizer that is the foundation for overcoming the unique challenges of greenhouse agriculture and achieving high yields and premium quality.
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