Correct application methods and precautions for slow-release nitrogen fertilizer
Traditional nitrogen fertilizer management for strong-gluten wheat is generally divided into two applications. The first is a portion of nitrogen fertilizer applied before wheat sowing in conjunction with plowing, accounting for 60%-70% of the total nitrogen application; the second is a topdressing applied from the spring green-up stage to the stem elongation stage of wheat in conjunction with watering, accounting for 30%-40% of the total fertilizer application. Some apply it before wheat overwintering...
Slow-release nitrogen fertilizer, also known as coated nitrogen fertilizer, is a nitrogen fertilizer coated with a coating material. Its coating is formed by spraying a solution of a small amount of nutrients such as nitrogen, potassium, magnesium, manganese, zinc, iron and boron. After coating, the nitrogen fertilizer does not change its original properties. Compared with ordinary nitrogen fertilizer, slow-release nitrogen fertilizer has the characteristics of good physical properties, slow nitrogen release, long fertilizer effect and high nitrogen use efficiency. Slow-release nitrogen fertilizer has a slow-release effect and is suitable for the nitrogen needs of crops throughout the entire growth process from the seedling stage to the growth stage, without the shortcomings of excessive supply in the early stage and insufficient supply after the period. Promoting slow-release nitrogen fertilizer can not only save energy and labor costs but also improve the effective utilization rate of nitrogen fertilizer and alleviate the contradiction of nitrogen fertilizer supply falling short of demand. Therefore, vigorously promoting and rationally using slow-release nitrogen fertilizer is an important means of improving the yield and quality of agricultural products.
Slow-release nitrogen fertilizer is suitable for various crops and various soil conditions. At present, two main varieties of slow-release nitrogen fertilizer are promoted and used in China: slow-release urea and slow-release ammonium bicarbonate, and their application methods are basically the same as those of urea and ammonium bicarbonate. The specific application points are as follows:
(1) The nitrogen release of slow-release nitrogen fertilizer is relatively slow, and the peak release period is about 5 d later than that of urea, so it should be applied earlier than the conventional application period of urea. Generally, 5-6 d earlier in early spring and 3-4 d earlier in summer is appropriate.
(2) Slow-release nitrogen fertilizer has a relatively strong nitrogen retention capacity in the soil and a relatively high utilization rate. Therefore, its dosage should be slightly less than that of general nitrogen fertilizer. Usually it should be reduced by 10%-15% compared with the conventional amount.
(3) Due to different soil textures, the absorption and retention capacity of slow-release nitrogen fertilizer in the soil also differs noticeably. Clay soil has a relatively strong absorption and retention capacity, so a larger single application amount may be used; for sandy soil, small amounts applied multiple times are appropriate.
(4) Slow-release nitrogen fertilizer should be applied scientifically according to the different oxygen absorption characteristics of crops.