Correct Methods for Using Organic Fertilizer in Vegetable Growing
How do you use organic fertilizer when growing vegetables? Please explain how applying organic fertilizer in vegetable production serves multiple important functions: it continuously supplies the various nutrient needs of the crop root zone, gradually raises the organic matter content and buffering capacity of vegetable garden soil, and reduces soil-borne diseases and continuous cropping obstacles. Therefore, vegetable...
How do you use organic fertilizer when growing vegetables? Please explain
In vegetable production, applying organic fertilizer serves multiple important functions: it continuously supplies the various nutrient needs of the crop root zone, gradually raises the organic matter content and buffering capacity of vegetable garden soil, and reduces soil-borne diseases and continuous cropping obstacles. Therefore, vegetable production has always valued the application of organic fertilizer. However, in the development of the modern intensive, high-yield, high-efficiency, high-quality vegetable industry, in addition to continued organic fertilizer inputs, there are also large inputs of chemical fertilizers and the interactive input of heavy water and heavy fertilizer. For the sustainable development of vegetable production, it is necessary to make a new assessment of the problems and scientific strategies of organic fertilizer application under the new situation.
Problems in current organic fertilizer application in vegetable gardens. First, the application rate is large and nutrient inputs are excessive, especially excessive nitrogen and phosphorus inputs, which have already caused environmental problems in some areas. For example, because organic fertilizers such as manure and urine types and food processing residue types have the characteristic of high salt content, excessive application of organic fertilizer may lead to soil salt accumulation.
Second, the types of organic fertilizer are monotonous, mostly livestock and poultry manure and urine types such as chicken manure and pig manure. Taking chicken manure as an example, it contains relatively more nitrogen and phosphorus nutrients but has a very low carbon-to-nitrogen ratio, so its function in regulating soil structure is insufficient.
Third, the safety of application. For example, organic fertilizers of the garbage type often contain pollutants such as heavy metals and radioactive substances; organic fertilizers of the animal manure and urine type also contain a certain amount of heavy metals such as zinc, copper and arsenic due to residues of feed additives; in addition, organic fertilizers of the straw type often contain certain pathogenic microorganisms, such as harmful bacteria and insect eggs. Market surveys have also found that some vendors add alkali to manure and urine fertilizers in order to make the organic fertilizer swell in volume, and such organic fertilizers with excessive alkalinity affect vegetable growth. Once these problematic organic fertilizers are applied to vegetable gardens, they may cause harmful components in vegetable products to exceed standards, posing a threat to food and environmental safety.
Rational application strategies for organic fertilizer in vegetable fields. First, the fertilization strategy in vegetable production should follow the principle of combining organic and inorganic fertilizers. The application rate of organic fertilizer should be reasonable rather than the more the better. First, understand the nutrient content of the organic fertilizer applied and fully estimate the amount of nitrogen, phosphorus and potassium nutrients it supplies to the crop. After deducting the nutrient amount that the organic fertilizer can provide, the shortfall should be supplemented with chemical fertilizers. However, in current production practice, vegetable growers often count only chemical fertilizer nutrients and not organic fertilizer nutrients, which leads to the widespread problem of excessive fertilization.
Regarding the appropriate ratio of organic to inorganic: taking the supply of nitrogen needed by vegetable crops over the year as an example, some countries propose that the proportion of nitrogen from organic fertilizer should be 50%-60%. The Food and Agriculture Organization of the United Nations once recommended a ratio of organic nitrogen to inorganic nitrogen of 1:(0.4-1), and determining the application rates of organic fertilizer and chemical fertilizer on this basis.
Second, select different types of organic fertilizer according to the quality characteristics of the vegetable garden soil. New vegetable fields should use fermented organic fertilizers with high chemical nutrient content and fast action, such as manure and urine, green manure, and cake fertilizer; old vegetable fields should use slow-release organic fertilizers rich in straw that have undergone composting and fermentation. Some old vegetable fields with severe continuous cropping obstacles achieve very good results by adopting straw bio-reactor technology, which uses straw to improve soil physical properties and also supplements sufficient carbon sources. Among the types of organic fertilizer, choosing compost products including manure and urine, straw, and solid garbage can improve vegetable crop resistance and root-promoting effects, improve soil pH and soil structure, increase the amount of soil organic matter, passivate the activity of heavy metals in vegetable fields, and reduce the risk of heavy metal pollution.
Third, the timing of organic fertilizer application. The general principle is that, given the slow-release nature of organic fertilizer, it should be applied as a base fertilizer or bottom fertilizer before sowing or transplanting. It should not be used as a topdressing; chemical fertilizer should be used for topdressing.
For this reason, a reasonable ratio of base fertilizer to topdressing should be established. For high-yield fruit vegetables, appropriately reduce the base fertilizer application rate and increase the topdressing application rate.
Finally, control fertilizer and water inputs in order to reduce the accumulation, leaching and runoff loss of nitrogen and phosphorus nutrients in vegetable fields and to reduce non-point source pollution.
In short, in current vegetable production, it is necessary to vigorously promote knowledge of scientific organic fertilizer application and popularize the concept of quantitative fertilization; promote composting and fermentation technology for organic materials to help vegetable growers use organic fertilizer safely and well, so as to achieve high yield, high quality and safety in vegetable production.
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