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(zhǎng)所必需的大量元素，因此，在進(jìn)行追肥時(shí)應(yīng)在土壤試驗(yàn)的基礎(chǔ)上，采用配方施肥技術(shù)，平衡施入氮、磷、鉀。，將作物整個(gè)生育期所需的全部磷、鉀肥和部分(約30%)氮肥進(jìn)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(guān)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(xué)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(shí)跟進(jìn)

　　2. Follow up in time

　　在農(nóng)業(yè)生產(chǎn)中，經(jīng)常會(huì)出現(xiàn)一些不合理的施肥現(xiàn)象:每年春小麥青綠期開(kāi)始后，農(nóng)民都趁機(jī)灌溉綠水尿素或沖進(jìn)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(zhǎng);番茄在苗期澆水時(shí)，澆尿素等。這樣的施肥尿素，雖然使用了化肥，但浪費(fèi)現(xiàn)象嚴(yán)重(氨氣揮發(fā)，尿素顆粒流失)，還會(huì)導(dǎo)致?tīng)I(yíng)養(yǎng)生長(zhǎng)過(guò)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(gè)特定的吸收氮、磷和鉀的關(guān)鍵時(shí)期。這一時(shí)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(duì)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(gè)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(yíng)養(yǎng)和效率的關(guān)鍵時(shí)期，施肥才能提高肥料的利用率，從而達(dá)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(shí)，應(yīng)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(guān)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(guān)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(shí)期、甘藍(lán)蓮座期、向日葵花蕾期、大豆早花期等是氮素效率的時(shí)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(shí)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(guò)來(lái),被作物吸收,這個(gè)過(guò)程需要6 ~ 7天,這里的尿素是個(gè)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(yīng)用,應(yīng)該是氮的關(guān)鍵時(shí)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(yīng)用土壤深度

　　4. Applied soil depth

　　使用方法不當(dāng)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(fèi)、勞動(dòng)力成本增加，同時(shí)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(yīng)用程序,應(yīng)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(dāng)土壤干旱嚴(yán)重確實(shí)需要澆水時(shí)，應(yīng)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.