Base fertilizer is the most important part of fertilization, and it is very important for the growth and development of crops. The application of base fertilizer is generally considered from the aspects of base fertilizer type, quantity, fertilizer type and depth of application.
From the perspective of species, organic fertilizers (including farmyard manure, manure, green manure, and cake manure) are most suitable for base fertilizer application. In addition, nitrogen, phosphorus, potassium, and trace fertilizers are also suitable as base fertilizers.
To determine the amount of base fertilizer application, especially the amount of chemical fertilizer, the soil fertility must be considered, and soil with organic matter below 1.2% should be applied with organic fertilizer of 3 cubic meters per mu or more. When the available nitrogen, phosphorus, potassium, and trace elements in the soil are lower than the effective threshold for crop fertilization, these fertilizers should be selected first, especially when the crop needs more phosphate in the early stage.
The specific amount of various fertilizers used as base fertilizer can be determined with reference to the local comprehensive results of field fertilizer effect test results and target yield. Generally, about 30% of the total amount of nitrogen fertilizer is applied to high-fertility soils, and 50% to 70% for medium and low-fertility soils. % of nitrogen fertilizer is used as the base fertilizer, while phosphorus, potassium fertilizer and micro fertilizer are all applied at one time as much as possible.
From the perspective of fertilizer varieties, ammonium bicarbonate, ammonium phosphate, phosphate, diammonium, calcium magnesium phosphate fertilizer, potassium phosphate, potassium sulfate, potassium sulfate, grass ash, zinc fertilizer in fertilizer, manganese fertilizer, etc. Both are suitable as base fertilizers.
In terms of depth, the base fertilizer should generally be applied to the entire plough layer, ie a depth of 15 to 20 cm. For organic fertilizers, nitrogen fertilizers, potash fertilizers, and trace fertilizers, they can be mixed evenly on the surface of the ground and then ploughed into the soil so that the fertilizer can be evenly mixed with the entire plough layer to facilitate the absorption and utilization of nutrients by different root layers of the crop. Phosphorus fertilizer is poor in mobility, and is easily fixed after being applied to the soil and loses its effectiveness. Therefore, it should be applied in two layers at the end of the application, that is, the depth of 15-20 cm in the lower layer and the depth of about 5 cm in the upper layer. The upper layer mainly meets the demand for phosphorus at the seedling stage of crops, and the lower layer supplies the phosphorus nutrition during the middle and later stages of crop growth.