Spinach is a leafy vegetable with a short growth period. It can be said for sure that when the seedlings grow to a certain extent, they should be watered in time. The leafy vegetables are mainly long stems and leaves, so nitrogen fertilizer is the main fertilizer. Because the cultivation of spinach is divided into spring spinach, autumn spinach and overwintering spinach, their fertilization techniques are not the same. In order to better master the fertilization techniques of spinach, we will talk about the correct fertilization techniques of spinach in different sowing dates according to the law of spinach's fertilizer demand. After understanding the fertilization techniques of spinach, it will be clear at a glance whether it is necessary to fertilize the seedlings.

First, the law of fertilizer demand of spinach

Spinach is a fast-growing vegetable, with fast growth and high yield, and the corresponding fertilizer requirement is also large. Through years of production practice, it is shown that:

Every production1000kg of spinach needs to absorb 2.48kg of pure nitrogen, 0.86kg of phosphorus pentoxide (P2O5) and 5.6kg of potassium oxide (K2O)5.6

It can be seen that spinach has the largest demand for potassium fertilizer, followed by nitrogen fertilizer and the least demand for phosphorus, which plays a guiding role in the application of base fertilizer. On the basis of adequate basal fertilizer application, the rapid growth period of foliage (from 3 leaves to pre-harvest 10 day) is the key period for fertilization, with quick-acting nitrogen fertilizer as the main fertilizer, supplemented by phosphorus and potassium fertilizer.

Second, the fertilization technology of spinach

Fertilization of spinach is divided into basic fertilizer and topdressing.

1. Application of base fertilizer

Base fertilizer is the basis of nutrient supply in the whole growth period of spinach. When applying fertilizer, it is necessary to combine organic and inorganic elements, combine a large amount with medium and small amounts, and apply fertilizer comprehensively.

Spring Spinach Base Fertilizer: Spring Spinach should be planted in neutral clay soil early, which can be about 3500 kg of decomposed organic fertilizer, 40 kg of calcium superphosphate, 0/0 kg of potassium sulfate/kloc, and 25 cm of deep ploughing. Base fertilizer for autumn spinach: combined with soil preparation, there are about 3500 kilograms of decomposed organic fertilizer and 30 kilograms of calcium superphosphate per mu, and the soil is about 25 centimeters deep, and the width of the border is 1~ 1.2 meters. Basic fertilizer for overwintering spinach: Applying 5,000 kilograms of decomposed organic fertilizer, 30 kilograms of calcium superphosphate and 0/5 kilograms of potassium sulfate/kloc per mu, and deeply ploughing the soil, so that the soil and fertilizer are evenly mixed, the soil is loose, and the basic fertilizer supply is sufficient, which is the basis for the healthy growth of spinach seedlings, and it is also the key to whether spinach seedlings can successfully overwinter. Spinach is a calcium-loving crop. Therefore, no matter which stubble spinach is, a certain amount of calcium fertilizer should be applied to the base fertilizer, generally 4 kg of calcium nitrate can be applied per mu.

2. Top dressing of spinach

Topdressing at the seedling stage of spinach is the premise of obtaining high yield, and the fertilization time at the seedling stage of spinach with different stubbles is also slightly different.

Top dressing of spring spinach: When the base fertilizer is sufficient, it is generally not necessary to fertilize and water before the seedlings reach 4 leaves. After five leaves, it enters the vigorous growth period, and the water demand for fertilizer is increased. At this time, ammonium bicarbonate 15 kg can be applied per mu. Topdressing of autumn spinach: When the seedlings grow 4-5 true leaves, topdressing with quick-acting nitrogen fertilizer twice can meet the needs of spinach growth. Combined with watering, applying urea 10 kg per mu can effectively increase the leaf thickness and yield, and then improve the quality of spinach. Topdressing of overwintering spinach: Overwintering spinach is dormant for a long time in winter, which requires certain nutrient consumption, so we should pay attention to fertilization. Before overwintering, when spinach seedlings grow to the height of 10 cm, it is necessary to apply overwintering fertilizer once, applying nitrogen fertilizer 10 kg and calcium superphosphate 10 kg per mu, and flexibly increasing or decreasing the amount of fertilizer according to the growth. In order to prevent the seedlings from growing in vain, there is no need to apply fertilizer before overwintering, but frozen water must be filled. After the spring of the following year, it is necessary to topdressing the green fertilizer in time, which can be about 25 kilograms of nitrogen fertilizer and 20 kilograms of phosphorus and potassium fertilizer per mu. After the spinach enters the vigorous growth period, it should be fertilized about twice according to the growth, with nitrogen fertilizer as the main fertilizer, delaying the premature bolting of spinach and improving the yield and quality. The above is the law of spinach fertilizer demand and the corresponding fertilization technology. After understanding this, I believe that you should have a clear idea of whether, when and what fertilizer to use for spinach seedlings.