The fertilization of lettuce field is different from that of cooked vegetable field.

One is to increase the application of a large amount of mature organic fertilizer. Especially for cooked vegetables, it is advisable to stop using chemical fertilizer and single nitrogen fertilizer.

The second is to adhere to the perennial application of plant straw, barnyard manure and human and animal manure and other organic fertilizers to improve the soil aggregate structure and make water, fertilizer, gas and heat obviously coordinated. For the transformation of acidified or alkalized soil, in addition to adding organic fertilizer, neutral fertilizer should also be applied appropriately. If the soil is acidic, it can be neutralized with lime or plant ash, the soil is alkaline, and it can be adjusted by ammonium sulfate or calcium superphosphate to improve the acidizing properties of vegetable soil.

The third is to implement the reasonable rotation of vegetables of different families, whether it is lettuce field or cooked vegetable field, it is not suitable to grow the same kind of vegetables in the same vegetable field for several consecutive crops. Crop rotation should be done frequently.

The fourth is to adhere to the scientific principle of fertilization. Keep 19 kg of pure nitrogen, 7 kg of available phosphorus and 30 kg of pure potassium per mu. Before fertilization, test the effective content in the soil, then calculate the variety and quantity that need to be replenished, and then determine the application method and quantity according to the variety and seedling condition. The general principle is: "lettuce fields" and vegetable fields with poor soil should be applied more, while "cooked vegetable fields" and vegetable fields with fertile soil should be applied less. The ratio of nitrogen, phosphorus and potassium is 2.5 ∶ 0.9 ∶ 5.5. Appropriate supplement of boron and zinc fertilizer, pay attention to the application of multi-element special fertilizer for vegetables. The seedlings damaged by fertilizer should be controlled in time, and the growth regulator should be sprayed outside the root. When salt or fertilizer damage occurs, water the vegetable field in time, cover the barren soil, press salt and buffer the nutrient concentration of the soil, so as to prevent vegetables from being "held up" by fertilizer.