Long-acting nitrogen fertilizer is suitable for various crops and soil conditions. At present, there are two kinds of long-acting nitrogen fertilizers widely used in China: long-acting urea and long-acting ammonium bicarbonate, and the application methods are basically the same as urea and ammonium bicarbonate. The specific application points are as follows: (1) The nitrogen release of long-acting nitrogen fertilizer is relatively slow, and the peak release period is about 5 days later than that of urea, which should be earlier than the conventional application period of urea. Generally, 5-6 days in advance in early spring and 3-4 days in summer are appropriate. (2) Long-acting nitrogen fertilizer has strong nitrogen retention ability and high utilization rate in soil. Therefore, its dosage is slightly less than that of ordinary nitrogen fertilizer, usually less than the constant 10%- 15%. (3) Because of the different soil quality, the absorption and preservation ability of long-acting nitrogen fertilizer in soil are also obviously different. Clay has strong absorption and preservation ability and can be used for multiple purposes at one time; Sandy soil should be applied several times in small quantities. (4) Scientific application of long-acting nitrogen fertilizer should be based on different nitrogen absorption characteristics of crops.

1. The recommendation of suitable nitrogen application rate is mainly divided into two categories: (1) methods based on soil nitrogen supply prediction; (2) There is no need to predict soil nitrogen supply. At present, these two methods are only semi-quantitative. It should be emphasized that (1) the soil nitrogen supply (Ns) measured by the accumulated nitrogen of crops in nitrogen-free areas is closely related to crop characteristics and hydrothermal conditions during growth, and is also strongly influenced by non-soil nitrogen; (2) There is no clear relationship between the forms of soil organic nitrogen and its biodegradability, so the chemical index of soil organic nitrogen mineralization (Nm) is only empirical; (3) Therefore, theoretically, there is not necessarily a high correlation between Ns and Nm, unless the factors affecting the mineralization of soil organic nitrogen and the amount of non-soil nitrogen are similar between fields. The method of "average suitable nitrogen application rate" is beneficial to regional control of nitrogen application rate. The average suitable nitrogen application method refers to the suitable average value of each field obtained from the nitrogen application test network of the same crop in the same area. 2. Deep application This is a mature and effective technology, including deep application in paddy field, mixed application in waterless layer and irrigation after surface application in dry land. It is proved that the effect of deep application is mainly to reduce ammonia volatilization, and its effect depends on the amount of nitrogen fertilizer left in field water (paddy field) or soil surface layer (dry land) after nitrogen fertilizer application. 3. It is an effective way to reduce the loss of nitrogen fertilizer and improve the utilization rate of nitrogen fertilizer by using the competitive absorption of fertilizer nitrogen by crops during the application period, which has been confirmed by many field experiments. Therefore, in the distribution of nitrogen fertilizer application in different periods, the amount of nitrogen fertilizer application in the early growth stage should be reduced as much as possible on the premise of ensuring the early growth of crops, and the focus should be shifted to the middle growth stage. 4. A small amount of N2O escaped during nitrification. In addition, the formed nitrate nitrogen is easily lost due to denitrification and/or leaching. Therefore, the inhibition of nitrification has received extensive attention. 5. Urease inhibitors are mainly PPD and NBPT, which are used together. In China, the combination of hydroquinone and coated urea, urease inhibitor and nitrification inhibitor has also been studied. The results showed that there was a good correlation between the reduced ammonia volatilization after applying urease inhibitor and the ammonia volatilization without applying urease inhibitor in the control. However, reducing the total loss has nothing to do with controlling the total loss.

Be careful not to mix ammonium nitrogen fertilizer with alkali.

because

For example, (NH4) 2SO4+Ca (OH) 2 = = 2nh3 ↑+2h2o+caso4.

It will produce ammonia, pollute the atmosphere, and the effect is not good.

ionic equation

NH4+ + OH- = NH3 + H2O

Can I go to /notexists? word = % b5 % aa % B7 % ca % D7 % a2 % D2 % E2 % ca % C2 % cf % ee。