Applying base fertilizer to greenhouse vegetables is crucial, and growers should pay attention to it

Greenhouse vegetables have a high multiple-cropping index, high yields and large fertilizer requirements, and base fertilizer has a great influence on vegetable yield, quality and soil properties. It is the most basic step in fertilization and is crucial to vegetable growth and development. Therefore, base fertilizer must be applied rationally, and the following issues should be noted when applying base fertilizer:

1. Determine the fertilization amount according to the target yield of the vegetables. To determine the amount of base fertilizer applied in a greenhouse, the soil fertility level and the fertilizer requirement of the vegetables must be considered. Generally, 30% of the total nitrogen fertilizer, 80% of the total phosphorus fertilizer and 50% of the total potassium fertilizer are used as base fertilizer, while biological fertilizer and micro-fertilizer should all be applied as base fertilizer at one time if possible. For example, the yield of autumn tomatoes is roughly 8000-9000 kg. Within this yield range, every 1000 kg of tomatoes produced requires the absorption of 4.4 kg of nitrogen, 1.1 kg of phosphorus pentoxide and 4.8 kg of potassium oxide, with a nitrogen, phosphorus and potassium ratio of 1:0.25:1.1, and also requires more calcium, boron and so on. Among these, a high-phosphorus fertilizer should be selected as the base fertilizer, and a low-phosphorus fertilizer should be selected for topdressing. The base fertilizer amount is suitably 40-50 kg, with an approximate nitrogen, phosphorus and potassium ratio of 1:1:0.75; the topdressing amount is 75-85 kg, with a nitrogen, phosphorus and potassium ratio of 1:0.2:0.85. 2. Ensure sufficient organic fertilizer amount

Organic fertilizer (including farmyard manure, barnyard manure and cake fertilizer) is most suitable for application as base fertilizer, and for older greenhouses with relatively high soil fertility, more bio-organic fertilizer should be applied as base fertilizer. To keep the soil fertility and organic matter in the greenhouse from declining or slightly increasing, organic fertilizer must be supplemented to the greenhouse soil. According to the change pattern of soil organic matter in greenhouses and the principle that the highest yield is obtained when the ratio of organic nitrogen to inorganic nitrogen is 1:0.4-1, it is calculated that to maintain greenhouse soil organic matter above 2% so as to ensure a relatively high yield, no less than 2000 kg/mu of organic fertilizer with an organic matter content of 30% should be applied each year.

3. Determine the base fertilizer application method according to the weather and growth characteristics

In terms of application method, base fertilizer should generally be applied throughout the entire plow layer, that is, to a depth of 15-30 cm. For organic fertilizer, nitrogen fertilizer, potassium fertilizer and so on, they can be mixed and evenly spread on the surface, then immediately plowed into the soil, so that the fertilizer is evenly mixed with the soil of the entire plow layer, which helps the different root layers of the vegetables absorb and utilize the nutrients. Because phosphorus fertilizer has poor mobility, it should be applied in a concentrated way under the ridge (or bed), so that the phosphorus fertilizer can be evenly distributed in the dense root layer.

Biological bacterial fertilizer stimulates vegetable growth through the activity or metabolites of live bacteria. If it is mixed with fungicides, the live bacteria are easily killed and the effect is reduced. For example, many bacterial fertilizers currently are mainly based on actinomycetes, and they should be used alone during application, with special attention that they must not be mixed with bactericidal agents (DT, streptomycin, etc.). In addition, environmental conditions unfavorable to the survival of beneficial bacteria, such as overly dry soil, excessively strong light and too high salinity, should also be avoided.

Gucheng County Agriculture Bureau Li Chunzhen