Urea is a kind of high concentration nitrogen fertilizer, a kind of neutral and quick acting fertilizer, which can also be used to produce various compound fertilizers. There is no harmful substance left in the soil, and there is no adverse effect after long-term application. Animal husbandry can be used as feed for ruminants. After urea, soil urease, hydrolyzed ammonium carbonate and ammonium bicarbonate can be absorbed and utilized by crops. Therefore, urea of crops can be fertilized 4-8 days ago. Below, Hengyi chemical will explain how to apply urea and precautions for use in detail, let's have a look!

　　1. 平衡施肥

　　1. Balanced fertilization

　　尿素是純氮肥，不含磷、鉀等作物生長所必需的大量元素，因此，在進行追肥時應在土壤試驗的基礎上，采用配方施肥技術，平衡施入氮、磷、鉀。，將作物整個生育期所需的全部磷、鉀肥和部分(約30%)氮肥進行組合整地。剩余70%左右的氮肥(尿素)作為追肥，其中肥料需求的關鍵期和作物的率期約為60%，后期約為10%。只有氮、磷、鉀三種肥料合理配合，科學施用，才能使追肥尿素的利用率提高。

　　Urea is a pure nitrogen fertilizer, which does not contain a large number of elements necessary for crop growth, such as phosphorus and potassium. Therefore, formula fertilization technology should be used to balance the application of nitrogen, phosphorus and potassium on the basis of soil test. First of all, all P, K and part (about 30%) of nitrogen fertilizer needed for the whole growth period of crops are combined for land preparation. The remaining 70% of nitrogen fertilizer (urea) is used as top dressing, of which the critical period of fertilizer demand and the highest efficiency period of crops are about 60% and the latter period is about 10%. Only when the three fertilizers of nitrogen, phosphorus and potassium are combined reasonably and applied scientifically can the utilization rate of top dressing urea be increased.

　　2. 及時跟進

　　2. Follow up in time

　　在農(nóng)業(yè)生產(chǎn)中，經(jīng)常會出現(xiàn)一些不合理的施肥現(xiàn)象:每年春小麥青綠期開始后，農(nóng)民都趁機灌溉綠水尿素或沖進麥田;在玉米的苗期，農(nóng)民在雨前把尿素撒到地里。尿素灌溉配合大白菜苗期生長;番茄在苗期澆水時，澆尿素等。這樣的施肥尿素，雖然使用了化肥，但浪費現(xiàn)象嚴重(氨氣揮發(fā)，尿素顆粒流失)，還會導致營養(yǎng)生長過于旺盛，小麥、玉米后期倒伏，番茄“吹花”，卷心菜包心延遲等不良現(xiàn)象發(fā)生。

　　In agricultural production, there are often some unreasonable fertilization phenomena: every year after the green period of spring wheat begins, farmers take the opportunity to irrigate the green water urea or rush into the wheat field; in the seedling period of corn, farmers sprinkle the urea into the field before the rain. Urea irrigation is combined with the growth of Chinese cabbage at seedling stage, and urea is applied to tomato at seedling stage. This kind of fertilizer urea, although the use of chemical fertilizer, but serious waste (ammonia volatilization, urea particles loss), will lead to the growth of nutrition is too strong, wheat, corn later lodging, tomato "blow flowers", cabbage Baoxin delay and other adverse phenomena.

　　每一種作物都有一個特定的吸收氮、磷和鉀的關鍵時期。這一時期缺肥(氮、磷、鉀)，作物產(chǎn)量下降，品質(zhì)下降，影響是巨大的，即使下次施肥充足，對作物產(chǎn)量的影響，品質(zhì)也是不可逆轉(zhuǎn)的。此外，還有一個的增效期，即作物的施肥可以獲得較高的產(chǎn)量，作物的施肥效率。從以上分析可以看出，只有在作物營養(yǎng)和效率的關鍵時期，施肥才能提高肥料的利用率，從而達到高產(chǎn)的目的。

　　Each crop has a specific critical period of absorption of nitrogen, phosphorus and potassium. During this period, the yield and quality of crops decreased due to the lack of fertilizer (n, P, K). Even if the next fertilization is sufficient, the quality will be irreversible. In addition, there is also a maximum efficiency period, that is, the fertilization of crops can obtain higher yield, and the fertilization efficiency of crops is the highest. From the above analysis, we can see that only in the critical period of the highest nutrition and efficiency of crops, fertilization can improve the utilization rate of fertilizer, so as to achieve the purpose of high yield and high quality.

　　施用尿素作為追肥時，應在作物臨界需氮期和率期的前一周施用。不同作物的需肥關鍵期和肥效是不同的。例如，小麥、玉米等禾本科作物的氮素需求關鍵期處于分蘗期、穗分化期、棉花處于結(jié)鈴期。小麥拔節(jié)孕穗期、水稻分蘗期拔節(jié)期、玉米大角口期、番茄果實期、甘藍蓮座期、向日葵花蕾期、大豆早花期等是氮素效率的時期。

　　When applying urea as topdressing, it should be applied in the week before the critical nitrogen requirement period and the highest efficiency period. The critical period and the maximum fertilizer efficiency of different crops are different. For example, the key period of nitrogen demand for Gramineae crops such as wheat and maize is in tillering stage, ear differentiation stage, and cotton is in Bolling stage. From jointing to booting stage of wheat, from tillering stage to jointing stage of rice, from bighorn mouth stage of corn, from tomato fruit stage, from lotus seed stage of cabbage, from flower bud stage of sunflower to early flowering stage of soybean, the nitrogen efficiency is the highest.

　　3.及時表面處治

　　3. Timely surface treatment

　　氨基脲作為肥料,需要轉(zhuǎn)化為碳酸銨土壤膠體吸附,反過來,被作物吸收,這個過程需要6 ~ 7天,這里的尿素是個土壤水分融化,慢慢轉(zhuǎn)化為碳酸銨后,因此,尿素做肥料的應用,應該是氮的關鍵時期的農(nóng)作物和肥料效率階段耕地前1周,不是太早或太遲。

　　As fertilizer, semicarbazide needs to be converted into ammonium carbonate soil colloid for adsorption. In turn, it needs to be absorbed by crops. This process takes 6-7 days. Urea here is the first soil water to melt, after slowly converting into ammonium carbonate. Therefore, the application of urea as fertilizer should be the first week before the most important crop and fertilizer efficiency stage of nitrogen, not too early or too late.

　　4. 應用土壤深度

　　4. Applied soil depth

　　使用方法不當很容易造成尿素失水、氨揮發(fā)等氮素流失現(xiàn)象，造成肥料浪費、勞動力成本增加，同時也大大降低了尿素的利用率。

　　Improper use of urea can easily lead to water loss, ammonia volatilization and other nitrogen loss, resulting in fertilizer waste, labor cost increase, and greatly reduce the utilization rate of urea.

　　正確的使用方法是:玉米、小麥、番茄、白菜和其他作物的應用程序,應該在作物20厘米的距離,挖深孔15 ~ 20厘米,土壤中的肥料后土壤覆蓋,不是太干后7天澆水。當土壤干旱嚴重確實需要澆水時，應小澆1次，不要漫灌，以防止尿素隨水分流失。

　　The right way to use it is: for the application of corn, wheat, tomato, cabbage and other crops, it is necessary to dig 15-20cm deep holes at a distance of 20cm from the crops, and cover the soil with fertilizer in the soil, not water it for 7 days after it is too dry. When the soil drought is serious and it really needs to be watered, it should be watered once in a small way, and do not be flooded, so as to prevent the loss of urea with water.