Field evaluation of agronomic effectiveness of multi-nutrient fertilizer briquettes for upland crop production

Low nutrient recovery in upland crop production systems has prompted studies to improve the current nutrient management practices to increase fertilizer efficiency. Field studies were conducted in two growing seasons (2012 and 2013) under two land management systems (till and no-till) to evaluate agronomic effectiveness of a multi-nutrient fertilizer briquette (fertilizer briquettes) for upland crop production, using corn as test crop. The fertilizer briquettes were produced through a simple physical compaction of ordinary granular fertilizers with a final nutrient composition of 23.9% N, 19.2% P₂O₅, 19.1% K₂O, 0.9% Zn, and 2.5% S. The agronomic efficiency of the fertilizer briquettes were compared with commercial N sources, urea and ammonium sulfate supplied separately with phosphorus (P), potassium (K), zinc (Zn), and sulfur (S; for urea alone). During the wetter (2013) weather conditions, the fertilizer briquette treatment consistently produced the highest yields in both locations. At Ames Plantation, the fertilizer briquette treatment increased grain yields by ~ 16 and ~ 23% over the treatments having ammonium sulfate and urea granular fertilizers, respectively, and, in Jackson, by 16 and 34% respectively. Nutrient recovery efficiency was also greatest with the fertilizer briquettes treatment. However, during the drier weather conditions (2012), the fertilizer briquettes treatment was the least effective among the three treatments in terms of biomass and grain yields, and nutrient recovery efficiency. We conclude, with adequate rainfall conditions, the fertilizer briquettes could be an efficient fertilizer for upland crop production. However, under drier weather conditions where soil moisture is limited, the fertilizer briquettes may not be an ideal fertilizer source for upland crop production.     

Urea rate and placement for maize production on a calcareous Vertisol

A study of urea N rate and placement for irrigated maize (Zea mays L) grown in Somalia was conducted to investigate this most promising and rather easily adopted cultural practice, in order to sharply increase present low yields. This work was done at the Afgoi station of the Agricultural Research Institute on a calcareous Vertisol. Six different levels of N (0, 20, 40, 80, 160 and 320 kg N ha^?1) as urea were used as main-plot treatments with four different placements as subplot treatments. Three of the placements consisted of broadcast-incorporated, broadcast-not incorporated, and sidedress on or in dry soil while the fourth placement was broadcast on wet soil. The grain yield response to added N was very highly significant and the regression analysis predicted a maximum yield of 7.6 t ha^?1 from 210 kg N ha^?1. A consistent yield depression occurred at the 320 kg N ha^?1 rate in all placement treatments. Placement of urea on or in dry soil gave significantly higher yields than did placement on the wet soil. The data indicate that substantial N losses occurred on this soil when urea was broadcast on a wet surface. The economic analysis to determine the feasibility of applying N to maize grown under improved crop production practices showed that fertilization with N can be very profitable. At the existing price for urea and value of maize, the economic optimum occurred at 164 kg N ha^?1 which gave a 2.1 t ha^?1 grain yield increase. This increased yield from N fertilization produced a profit of 1010 Somali shillings (US $162) ha^?1.     

我国尿素生产技术进展及展望

论述了目前国内生产尿素的几种工艺技术:CO2汽提法、氨汽提法、TOYO公司的ACES工艺和水溶液全循环及其他工艺,针对尿素生产中中压蒸汽消耗高、污染物排放高的主要问题提出了应对措施和推进思路。     

MTBE深度脱硫技术的应用

为生产满足京Ⅴ汽油含硫标准的甲基叔丁基醚(MTBE)产品,探讨了MTBE深度脱硫原理,利用MTBE脱硫体系的热力学基础数据,采用化工流程模拟与分析的方法,对MTBE脱硫过程进行了全面系统的模拟研究。通过对工艺条件的综合分析,明确了单塔、双塔两种脱硫工艺的利弊,提出了适于不同工况的可行的MTBE深度脱硫技术方案。在MTBE装置改造中取得了良好的应用效果,MTBE产品的硫含量不高于3 mg/kg。     

硫酸脲复合肥生产技术综论

阐述了硫酸脲复合肥生产过程、生产设备、主辅装置操作控制,并结合多套装置生产实践经验从造粒率、产量、质量、开车率、成本控制、防结块性能、安全环保、节能降耗、生产品种覆盖性等方面对硫酸脲工艺进行了综述,最后与现在主流的氨酸法生产工艺进行了对比。     

尿素法水合肼生产工艺的优化

介绍对尿素法水合肼合成工艺、冷冻法水合肼提纯工艺进行的优化,和对丙酮汽提法提纯水合肼进行的尝试。     

尿素-过磷酸钙系复混肥料生产的一种新工艺

采用尿素与包裹后的磷钾粒肥直接掺混 ,避免和解决了尿素过磷酸钙系复混肥生产中存在的一系列问题 ,减少了氮素的损失 ,提高了产品的市场销售属性 ,增大了企业经济效益。     

熔融尿液联产复合肥的生产工艺

介绍熔融尿液联产复合肥的生产技术:利用氯化钾溶于尿液中可形成低熔化合物,采用喷浆圆盘造粒、无干燥工艺流程,生产各种规格高浓度尿基复合肥,该工艺生产尿基复合肥不用干燥产品水分可达标,大大降低了投资和生产成本,技术与经济优势明显。     

发展尿素增值技术 促进尿素产品技术升级

评述了普通尿素产品存在的主要问题和改性增效的意义;分析了尿素改性增效的途径,定义了增值尿素的概念和范畴;对增值尿素的增产效果、增效机制、施用技术等进行了讨论。加强增值尿素产品质量标准建设,是推动尿素增值技术在我国健康发展的重要环节。     

长效尿素对玉米的肥效试验

玉米作物每公顷施氮达到 45 0～ 60 0 kg,氮利用率低 ,环境污染日趋严重 [1]。在尿素生产中 ,加入脲酶抑制剂——氢醌 ,制成长效尿素[2 ] ,减缓尿素水解进程 ,减少氮的损失 ,提高氮的利用率 ,达到增产节肥目的 ,现将长效尿素肥效试验介绍如下。1　材料方法试验设置在甘肃张掖地区农科所的水浇地上。土壤为灌漠土 ,0～ 2 0 cm土层含碱解氮 65 .8mg/kg,指示作物春玉米 ,保苗 75 0 0 0株 /hm2 。施氮水平设 :1 CK;2 N150 ;3 N2 2 5;4N3 0 0 ;5 N3 75;6 N450 ;氮肥品种设等氮量水平的普通尿素 ( U) ;长效尿素( MU) ,共 1 1个处理。重复 3次 …     

Agronomic performance of urea briquette applicator in transplanted rice

Field trials were conducted in the Philippines and India during 1989 and 1990 seasons to study comparative yield responses of transplanted rice (Oryza sativa L.) to pillow-shaped urea briquettes (UB) deep placed by an applicator (prototype developed by IFDC) and by hand immediately after transplanting. The applicator-placed UB consistently increased grain yields over the split-applied prilled urea, and the additional yields ranged from 0.23 to 1.48t ha^–1 (5 to 83%) for 25 to 63 kg N ha^–1. Agronomic responses of transplanted rice to the UB placed by the applicator and by hand were statistically equal. Modified rice hill spacing may be considered as a requirement for efficient use of the applicator. The results demonstrate that with the UB applicator it is possible to deep place UB mechanically and achieve the agronomic efficiency that is achieved by hand deep placement of the UB.     

Nitrous oxide and nitric oxide fluxes from an upland field in Japan: effect of urea type, placement, and crop residues

Fertilizer type and application mode may influence nitrous oxide(N₂O) and nitric oxide (NO) emissions as well as crop yield. Using astatic chamber method, fluxes of both gases from a Chinese cabbage field inJapan were measured in situ following the application of easily decomposableurea by broadcasting (U-BC) and banding (U-B) and coated urea by banding(CU-B),respectively, at an application rate of 250 kg Nha^–1. The measurements were made throughout the growingseason and continued 3 more months after harvest to determine the effect ofcropresidues on the emissions. Large N₂O fluxes from U-BC occurredwithinabout 2 weeks after the application of the N fertilizer, while that from bothU-B and CU-B was prolonged by about 2 weeks, and significant emissions lasted alonger time but with a smaller emission size. Substantial N₂O fluxesderived from crop residues were observed in the late growing season (especiallyfollowing rainfall) as well as after harvest, at all treatments including thecontrol plots (CK). Large NO fluxes occurred only at U-BC within the first 2weeks through the measurements. Total emissions were estimated to be 38.1,78.3,77.8, and 100.4 mg N₂O-N m^–2 and 0.7,194.9, 8.5, and 11.4 mg NO-N m^–2 at CK, U-BC,U-B,and CU-B, respectively. Statistical analyses indicate that neither the bandmodenor the coated urea was able to significantly reduce the total N₂Oemission through the season, but the band mode substantially reduced the NOemission. However, the application of urea by the band mode presented a 22.8%increase in crop yield as compared with urea applied by broadcasting.Therefore,by improving fertilizer use efficiency to decrease the amount of N needed tobetter meet the crop growing demand, the band mode may be a good agriculturalpractice to also reduce N₂O emission. In addition, the experimentdemonstrated that crop residue is a large source of N₂O emission.     

微粉流化床干燥技术在脲醛缓释肥生产中的应用

将微粉流化床干燥技术用于脲醛缓释肥生产,介绍了微粉流化床干燥系统的工艺流程及主要设备工作原理,对各工艺参数进行优化,并详细论证了关键工艺参数的设计依据,选择出最佳参数。     

尿素增值技术及应用

根据我国尿素的生产与施用现状,介绍了主要尿素增值技术,分析增值尿素的推广与应用情况,并对尿素增值技术未来的发展提出了建议。     

串联中压技术在二氧化碳气提法尿素生产中的应用

分析了原CO_2气提法尿素生产装置存在的问题,主要包括气提效率低、精馏塔出液温度低、氨水槽中氨水浓度超出设计值、单位产品综合能耗较高等。针对存在的问题,在原有CO_2气提生产装置的基础上,采用绝热闪蒸技术,串联了中压系统。改造后,单套装置平均产能提高,超过原设计产能;装置综合能耗降低,平均为105 kg/t(折算成标准煤);生产1 t尿素产品成本比改造前降低约17.21元;产品中缩二脲质量分数降低,产品质量提高;氨水槽的氨水质量分数维持在3.8%以下,远低于改造前,使设备腐蚀得到缓解。生产运行实践表明,串联中压系统的改造给生产提供了更便利的操作条件,增加了产品的市场竞争力。     

尿素解吸塔技改小结

改造前解吸塔简况。改造前，我公司尿素一车间解吸塔共有15块塔板，塔底为直接蒸汽加热，用蒸汽量的大小来控制解吸塔底部温度，保持解吸压力下的水的沸点温度，使塔底排出的废液氨含量尽可能小。通过解吸给料泵将碳铵液从碳液槽送到解吸塔，解吸塔的进料分冷流和热流两路，热流量的大小根据解吸塔的能力与碳液槽的液位高低进行调节，     

控失尿素在夏玉米上的应用效果研究

通过田间试验,研究了控失尿素在夏玉米上的应用效果。结果表明,控失尿素追施处理比习惯施肥处理667 m2增产68.03 kg,增产率13.7%;控失尿素种肥同播处理比习惯施肥处理667 m2增产48.98 kg,增产率9.9%;控失尿素减量20%不会造成玉米产量下降;施用控失尿素可显著提高氮肥利用率。     

尿素生产经验总结

0　前　言近年来小尿素发展很快 ,生产能力基本赶上了中型尿素装置 ,但中小尿素装置在高负荷运行中会出现一些问题。笔者根据积累的生产经验及对其进行理化分析 ,将一些常见的问题浅述如下 ,供同行参考。1　合成系统高负荷生产中 ,因尿塔生产强度提高 ,CO2 转化率会有所下降 ,为此应对合成系统进行优化操作。1 .1　尿塔温度的选择合成反应分两步进行。2 NH3 +CO2 NH4 COONH2 +Q1( 1 )NH4 COONH2 CO( NH2 ) 2 +H2 O-Q2( 2 )( 1 )式为放热反应 ,在 1 43～ 1 82℃之间 ,反应平衡常数 K随温度的升高而减小。 ( 2 )式为吸热反应 ,K值…     

控释尿素与普通尿素配施比例对玉米产量及效益的影响

为推广缓控释肥在玉米上的应用,进行了控释尿素和普通尿素不同掺混比例的复混肥对玉米肥效的试验。结果表明,玉米施用控释氮比例为40%的控释氮肥时,玉米产量及其构成因素、叶面积、种植效益较高。