Integrated assessment of yield,nitrogen use efficiency and ecosystem economic benefits of use of controlled-release and common urea in ratoon rice production

Controlled-release urea(CRU)is commonly used to improve the crop yield and nitrogen use efficiency(NUE).However,few studies have investigated the effects of CRU in the ratoon rice system.Ratoon rice is the practice of obtaining a second harvest from tillers originating from the stubble of the previously harvested main crop.In this study,a 2-year field experiment using a randomized complete block design was conducted to determine the effects of CRU on the yield,NUE,and economic benefits of ratoon rice,including the main crop,to provide a theoretical basis for fertilization of ratoon rice.The experiment included four treatments:(i)no N fertilizer(CK);(ii)traditional practice with 5 applications of urea applied at different crop growth stages by surface broadcasting(FFP);(iii)one-time basal application of CRU(BF1);and(iv)one-time basal application of CRU combined with common urea(BF2).The BF1 and BF2 treatments significantly increased the main crop yield by 17.47 and 15.99%in 2019,and by 17.91 and 16.44%in 2020,respectively,compared with FFP treatment.The BF2 treatment achieved similar yield of the ratoon crop to the FFP treatment,whereas the BF1 treatment significantly increased the yield of the ratoon crop by 14.81%in 2019 and 12.21%in 2020 compared with the FFP treatment.The BF1 and BF2 treatments significantly improved the 2-year apparent N recovery efficiency,agronomic NUE,and partial factor productivity of applied N by 11.47-16.66,27.31-44.49,and 9.23-15.60%,respectively,compared with FFP treatment.The BF1 and BF2 treatments reduced the chalky rice rate and chalkiness of main and ratoon crops relative to the FFP treatment.Furthermore,emergy analysis showed that the production efficiency of the BF treatments was higher than that of the FFP treatment.The BF treatments reduced labor input due to reduced fertilization times and improved the economic benefits of ratoon rice.Compared with the FFP treatment,the BF1 and BF2 treatments increased the net income by 14.21-16.87 and 23.76-25.96%,respectively.Overall,the one-time blending use of CRU and common urea should be encouraged to achieve high yield,high nitrogen use efficiency,and good quality of ratoon rice,which has low labor input and low apparent N loss.

超声监测结合BUN、UA水平预测PE并发FGR孕产妇不良结局价值

目的:探讨超声胎儿监测结合血尿素氮(BUN)和尿酸(UA)水平预测子痫前期(PE)并发胎儿生长受限(FGR)患者不良结局价值。方法:回顾性收集2020年1月-2023年5月本院就诊的PE患者,其中并发FGR 106例为观察组,未并发FGR患者106例为对照组,比较两组血BUN、UA水平,超声胎儿静脉导管收缩期峰值速度(PSV)、舒张期峰值速度(EDV)、平均时间最大血流速度(Vmax),统计新生儿及孕妇不良结局。结果:观察组血BUN(5.03±1.22mmol/L)、UA(435.54±52.13mmol/L)高于对照组(4.01±1.30 mmol/L、391.60±60.88 mmol/L),PSV(0.85±0.12cm/s)、EDV(0.78±0.11cm/s)、Vmax(0.81±0.13cm/s)低于对照组(0.89±0.11 cm/s、0.96±0.14 cm/s、0.98±0.12 cm/s),新生儿不良结局总发生率(67.9%)高于对照组(15.1%),孕妇不良妊娠结局总发生率(38.7%)高于对照组(20.8%);观察组发生新生儿不良结局患者血BUN、UA高于未发生新生儿不良结局患者,而超声胎儿静脉血流参数均低于未发生新生儿不良结局患者(均P<0.05)。血BUN、UA、PSV、EDV、Vmax及联合预测新生儿不良结局的曲线下面积分别为0.735、0.760、0.643、0.809、0.670和0.706,联合预测的灵敏性达到100.0%。结论:PE并发FGR患者BUN、UA水平异常升高,超声胎儿静脉血流参数异常降低,上述超声及血指标预测新生儿不良结局有一定临床指导价值。

格列美脲联合达格列净治疗2型糖尿病肾病的疗效及对BUN、CREA、ACR水平的影响

目的 探究格列美脲联合达格列净治疗2型糖尿病肾病的疗效及对尿素氮(BUN)、肌酐(CREA)、尿白蛋白/肌酐比值(ACR)水平的影响。方法 选取2021年3月至2023年3月120例临泉县人民医院内分泌科收治的2型糖尿病肾病患者为研究对象,依据治疗方式的不同分为达格列净治疗组(对照组)64例(给予达格列净治疗)与格列美脲联合达格列净治疗组(研究组)56例(给予格列美脲联合达格列净治疗)。对比两组临床疗效、血糖达标时间及胰岛素日用量间的差异,比较达格列净治疗组与格列美脲联合达格列净治疗组治疗前后的血糖指标及BUN、CREA、ACR水平。结果 格列美脲联合达格列净治疗组临床治疗总有效率96.43%显著高于达格列净治疗组82.81%,差异具有统计学意义(χ^(2)=2.006,P<0.05)。治疗12周后,与达格列净治疗组比较,格列美脲联合达格列净治疗组血糖达标时间明显缩短,胰岛素日用量也显著减少,差异均有统计学意义(t=4.449、9.958,P<0.05)。两组FPG、HbA1 c、BUN、CREA、ACR水平均下降,且格列美脲联合达格列净治疗组FPG、HbA1 c、BUN、CREA、ACR水平低于达格列净治疗组,差异有统计学意义(t=4.382、4.028、20.741、2.930、2.360,P<0.05)。结论 与单用达格列净治疗相比,采用格列美脲联合达格列净治疗可有效改善2型糖尿病肾病患者血糖控制情况,调节胰岛素抵抗状态,降低BUN、CREA、ACR水平。

妊娠期高血压产妇孕中期Scr、BUN及UA水平与急性肾损伤程度的相关性

目的 探讨妊娠期高血压(HDCP)产妇孕中期血清肌酐(Scr)、尿素氮(BUN)及尿酸(UA)水平与急性肾损伤(AKI)程度的相关性。方法 选取2018年2月—2022年1月青海大学附属医院收治的104例HDCP产妇,根据急性透析质量指导组(ADQI)推荐标准将其分为AKI组(36例)和非AKI组(68例),根据RIFLE标准将AKI组分为轻度AKI组(21例)和中重度AKI组(15例),另随机选取同期于本院行常规产检的52例健康妊娠女性纳入健康对照(HC)组。比较AKI组、非AKI组和HC组血清Scr、BUN及UA水平;比较不同AKI严重程度HDCP产妇血清Scr、BUN和UA水平。受试者操作特征曲线(ROC)检测血清Scr、BUN、UA水平对HDCP产妇并发AKI的诊断效能;Spearman相关性分析血清Scr、BUN、UA水平与HDCP产妇AKI严重程度的关系。结果 AKI组孕中期血清Scr、BUN和UA水平显著高于非AKI组和HC组(P<0.05)。ROC结果显示,孕中期血清Scr、BUN和UA诊断HDCP并发AKI的曲线下面积(AUC)分别为0.843、0.755和0.847,截断值分别为53.04μmol/L、4.81 mmol/L和349.35μmol/L,三者联合检测诊断HDCP并发AKI的AUC为0.876;中重度AKI组孕中期血清Scr、BUN和UA水平均明显高于轻度AKI组(P<0.05);Spearman相关性分析提示Scr、BUN、UA与HDCP产妇AKI程度呈正相关(P<0.05)。结论 HDCP并发AKI产妇孕中期血清Scr、BUN和UA水平升高与AKI病情严重程度呈正相关。

CHF患者CRP/Alb、PDGF、BUN/Cr水平变化及对预后的评估价值

目的 探讨慢性心力衰竭(CHF)患者C-反应蛋白与白蛋白比值(CRP/Alb)、血小板源性生长因子(PDGF)联合血尿素氮与肌酐比值(BUN/Cr)水平变化,并分析各指标预测心血管死亡和全因死亡的效能。方法 选取2020年1月至2022年3月收治的109例CHF患者,根据1年内心血管死亡和全因死亡情况分为死亡组(26例)和存活组(83例)。比较2组社会人口学资料和临床特征[美国纽约心脏病学会心功能分级(NYHA)、左心室射血分数、左心室舒张末期内径、左心室收缩末期内径、N-末端脑钠肽前体(NT-proBNP)、临床用药]、CRP/Alb、PDGF、BUN/Cr水平,分析CRP/Alb、PDGF、BUN/Cr水平的相关性,采用Cox回归分析CHF患者心血管死亡和全因死亡的相关影响因素,采用受试者工作特征曲线(ROC)分析预测价值,采用卡普兰-迈耶曲线(K-M)生存曲线分析不同CRP/Alb、PDGF、BUN/Cr水平患者的生存率。结果 死亡组NYHA心功能分级、左心室舒张末期内径、左心室收缩末期内径、NT-proBNP高于存活组,左心室射血分数低于存活组(P<0.05);死亡组CRP/Alb、PDGF、BUN/Cr高于存活组(P<0.05);CHF患者CRP/Alb与PDGF、BUN/Cr呈正相关,PDGF与BUN/Cr呈正相关(P<0.05);在校正了NYHA心功能分级等混杂因素后,CRP/Alb、PDGF、BUN/Cr仍是CHF患者心血管死亡和全因死亡的相关影响因素(P<0.05);CRP/Alb、PDGF、BUN/Cr预测心血管死亡和全因死亡的ROC下面积(AUC)分别为0.712、0.801、0.738,三者联合时的AUC为0.911(P<0.05);CRP/Alb、PDGF、BUN/Cr高水平患者生存率低于低水平患者(P<0.05)。结论 CRP/Alb、PDGF、BUN/Cr与CHF患者心血管死亡和全因死亡有关,联合检测可作为预测患者病情转归的一个方案,为临床评估预后、治疗等提供参考依据。

β_(2)-MG、BUN、CysC及SCr在肾功能损伤中的临床应用价值

目的分析肾功能损伤中各项指标的应用价值。方法回顾性选取巨野县人民医院于2021年12月—2022年12月收治的100例肾功能损伤患者的临床资料作为观察组,选取同时期100名健康体检者的临床资料作为对照组。对两组各项指标及观察组中不同类型肾功能损伤患者的各项指标进行对比。结果观察组β_(2)-微球蛋白(β_(2)-microglobulin,β_(2)-MG)水平为(5.61±0.47)mg/L、尿素氮(Blood Urea Nitrogen,BUN)水平为(12.67±2.50)mmol/L、血清胱抑素C(Cystatin C,Cys-C)水平为(2.29±0.27)mol/L、血清肌酐(Serum Creatinine,SCr)水平为(184.59±7.15)μmol/L,明显高于对照组的(2.29±0.59)mg/L,(5.26±1.32)mmol/L,(0.82±0.35)mol/L(89.67±9.28)μmol/L,差异有统计学意义(t=44.013、26.211、33.255、81.024,P均<0.05)。随着肾功能损伤程度的不断加深,不同类型肾功能损伤患者的β_(2)-MG、BUN、CysC、SCr检测水平明显增加,差异有统计学意义(r=0.564、0.338、0.451、0.875,P均<0.05)。结论肾功能损伤患者的β_(2)-MG、BUN、CysC及SCr水平会出现异常变化,且随着肾功能损伤程度的不断加深,β_(2)-MG、BUN、CysC及SCr水平也相应增加。

初诊糖尿病患者脂代谢指标及血BUN、UA检测的临床价值分析

目的:探究初诊糖尿病患者脂代谢指标及尿素氮(Blood urea nitrogen,BUN)、尿酸(Uric acid,UA)检测的临床价值分析。方法:回顾性分析2020年1月至2023年11月期间,本院收治的初诊糖尿病患者共计64例;与此同时,从医院体检中心选取50例健康体检人群作为对照组,通过查阅患者电子病历档案以及医院信息系统(Hospital information system,HIS)收集上述研究对象的基线资料、脂代谢水平、BUN以及UA水平;对两组研究对象的上述指标以及水平进行对比,并分析上述指标应用于初诊糖尿病患者对的临床价值。结果:初诊糖尿病组患者的甘油三酯(Triglyceride,TG)、总胆固醇(Total cholesterol,TC)以及低密度脂蛋白(Low density lipoprotein,LDL-C)水平显著高于健康对照组;高密度脂蛋白(High density lipoprotein,HDL-C)水平显著低于健康对照组,差异存在统计学意义(P<0.05);与此同时,初诊糖尿病组患者的BUN水平以及UA水平显著高于健康对照组,差异存在统计学意义(P<0.05);Logistic回归分析结果显示,研究对象的TG、TC、LDL-C、HDL-C、BUN以及UA水平同初诊糖尿病的发病之间存在一定的关联性(P<0.05)。结论:初诊糖尿病患者脂代谢指标及BUN、UA水平同健康对照组之间存在显著差异,对于糖尿病患者的早期诊断具有一定的评估价值,值得临床研究人员的借鉴应用。

A Comparative Study of Nitrogen Loss after Application of Biochar Coated Urea and Common Urea in Vegetable Soil at Chaihe Catchment of Dianchi Lake

[Objective] This study aimed to provide the basis for scientific and rea- sonable application of nitrogen fertilizer and control Of agricultural non-point source pollution in vegetable-growing area at Chaihe catchment of Dianchi Lake. [Method] A pot experiment was carried out to compare the loss of nitrogen via ammonia volatilization and nitrogen leaching after application of biochar coated urea （BCU） and common urea （Urea） with different nitrogen rates （0 mg N/kg soil, 400 mg N/kg soil, 320 mg N/kg soil and 280 mg N/kg soil）. [Result] The results indicated that the amount of nitrogen loss was proportional to nitrogen applied rate. Leaching nitrogen was higher than ammonia volatilization. Compare with Urea treatments, ammonia volatilization and nitrogen leaching losses were significantly lower in BCU treatments at the same nitrogen application rate. At the nitrogen application rate of 320 and 280 mg N/kg soil, nitrogen loss, ammonia volatilization and leaching nitrogen was 43.5%-45.5%, 3.7%-21.7% and 49.8%-52.1% lower in BCU treatments than in Ure- a treatments, respectively. [Conclusion] The application of BCU could minimize nitro- gen loss by reducing nitrate leaching loss. It can be concluded that the low nitrogen application rate combined with BCU have a practical influence on controlling the risk of nitrogen pollution in Dianchi Lake.

BUN、Cr、UA、β2-MG变化及血清CK-MB、cTnI、NT-proBNP水平与慢性高血压并发重度先兆子痫的相关性分析

目的:研究血清尿素氮(BUN)、肌酐(Cr)、尿酸(UA)、β2微球蛋白(β2-MG)水平变化及血清肌酸激酶同工酶(CK-MB)、肌钙蛋白I(cTnI)水平、血清N-端脑利钠肽前体(NT-proBNP)与慢性高血压并发重度先兆子痫的相关性。方法:将360例慢性高血压孕妇纳入研究,按照是否并发重度先兆子痫分作A组(并发重度先兆子痫)89例及B组(未并发重度先兆子痫)271例。另择同期正常孕妇100例作为C组,100例单纯先兆子痫病人作为D组。比较4组基线资料,血清BUN、Cr、UA、β2-MG以及CK-MB、cTnI、NT-proBNP水平,并以多因素logistic回归分析明确慢性高血压病人并发重度先兆子痫与各项影响因素的关系。并比较4组孕妇及新生儿不良妊娠结局发生情况。结果:A组年龄均高于B组、C组、D组,且B组、D组年龄高于C组(P<0.05~P<0.01);A组、D组先兆子痫史占比均高于B组、C组(P<0.01);A组高血压病程高于B组,差异有统计学意义(P<0.01)。A组、B组、D组血清BUN、Cr、UA、β2-MG以及CK-MB、cTnI、NT-proBNP水平以及新生儿低出生体质量、宫内发育迟缓、胎儿窘迫、胎儿窒息、巨大儿、先天性异常及胎儿死亡发生率、孕妇不良妊娠结局总发生率均高于C组,且A组上述各项指标水平均高于B组和D组(P<0.05)。多因素logistic回归分析发现,孕妇年龄、先兆子痫病史、高血压病程以及血清BUN、Cr、UA、β2-MG以及CK-MB、cTnI、NT-proBNP水平均是慢性高血压病人并发重度先兆子痫的危险因素(P<0.05~P<0.01)。Pearson相关分析发现,血清BUN、Cr、UA、β2-MG以及CK-MB、cTnI、NT-proBNP水平均与慢性高血压并发重度先兆子痫呈正相关关系(P<0.01)。结论:检测血清BUN、Cr、UA、β2-MG及CK-MB、cTnI、NT-proBNP水平能有效预测重度先兆子痫的发生。

Effect of Incorporation of Wheat Straw and Urea into Soil on Biomass Nitrogen and Nitrogen-Supplying Characteristics of Paddy Soil

Pot experiments were carried out to study the effect of incorporation of wheat straw and/ or urea into soil on biomass nitrogen and mineral nitrogen and its relation to the growth and yield of rice. The combined application of wheat straw and urea increased much more biomass nitrogen in soil than the application of wheat straw or urea alone and consequently increased the immobilization of urea nitrogen added and reduced the loss of urea nitrogen. An adequate nitrogen-supplying process to rice plant could be obtained if C / N ratio of the material added was about 20. The three yield components of rice were affected significantly by the status of nitrogen supplying. More than 30mg N / kg soil of mineral nitrogen at effective tillering stage, panicle initiation stage and filling stage should be maintained in order to get high rice yield, though the criteria varied with the different experimental conditions.

Patient characteristics with high or low blood urea nitrogen in upper gastrointestinal bleeding

AIM: To examine characteristics of patients with blood urea nitrogen(BUN) levels higher and lower than the normal limit.METHODS: Patient records between April 2011 and March 2014 were analyzed retrospectively. During this time, 3296 patients underwent upper endoscopy. In total, 50 male(69.2 ± 13.2 years) and 26 female(72.3 ± 10.2 years) patients were assessed. Patients were divided into two groups based on BUN levels: higher than the normal limit(21.0 mg/d L)(H) and lower thanthe normal limit(L). One-way analysis of variance was performed to reveal differences in the variables between the H and L groups. Fisher's exact test was used to compare the percentage of patients with gastric ulcer or gastric cancer in the H and L groups.RESULTS: White blood cell count was higher in the H group than in the L group(P = 0.0047). Hemoglobin level was lower in the H group than in the L group(P = 0.0307). Glycated hemoglobin was higher in the H group than in the L group(P = 0.0264). The percentage of patients with gastric ulcer was higher in the H group(P = 0.0002). The H group contained no patients with gastric cancer.CONCLUSION: Patients with BUN ≥ 21 mg/d L might have more severe upper gastrointestinal bleeding.

Increase in yield and nitrogen use efficiency of double rice with long-term application of controlled-release urea

Controlled-release urea(CRU)has better characteristics than conventional urea for synchronizing nitrogen(N)release with plant uptake.Understanding the effects of CRU on crop yield and N use efficiency(NUE)has long been the key to evaluate the performance of CRU.A long-term experiment over five consecutive years was conducted in Changsha,Hunan Province,China,to investigate the effects of polyethylene-coated urea with a 90-d release period on the yield and NUE of double rice(early and late crops are grown in the same year),the amount of residual soil mineral N and the soil–plant N balance,as well as on the economic benefits.Four N fertilizer treatments including CK(no N fertilizer),U(conventional urea),CRU1(polyethylene-coated urea with equal N application rate to U)and CRU2(20%reduction in N application rate of CRU1)were established.The results indicated that CRU1 application increased the yield and NUE of double rice by 11.0 and 13.5%,respectively,compared with U.Higher yield and NUE of late rice were found than in early rice in CRU treatments.Compared with conventional U,the yield and NUE of early rice in the CRU1 treatment were increased by 6.0 and 10.2%,respectively,and those of late rice were increased by 15.4 and 13.8%,respectively.There was no significant difference between CRU1 and CRU2 in double rice yield.Furthermore,CRU treatments(including CRU1 and CRU2)had higher apparent residual Nmin rate(ARNR)and apparent N recovery rate(ANRR),but lower apparent N loss(NS)than the conventional U treatment.Concentrations of NH_(4)^(+)-N and NO_(3)^(-)-N were greater in the surface soil(0–20 cm)and lower in the deeper soil layer(40–60 cm)with CRU treatments than in the U treatment after harvest.Moreover,CRU application produced a greater economic benefit than conventional U application.In general,CRU outperformed U fertilizer in terms of rice yield,NUE,soil–plant N balance,economic benefit,and CRU2 provided greater comprehensive benefits than CRU1.It is suggested that CRU application is beneficial for solving N management challenges in the production of rice.

Hybrid rice yield response to potted-seedling machine transplanting and slow-release nitrogen fertilizer application combined with urea topdressing

Machine transplanting and the application of slow-release nitrogen(N) fertilizer(SRNF) have played vital roles in the modernization of rice production. We aimed to determine the effects of potted-seedling transplanting—a new machine-transplanting method—and SRNF on hybrid rice yields. A 2-year splitplot experiment(2016–2017) was conducted in Meishan, Sichuan province, China, using two machinetransplanting methods(potted-seedling and blanket-seedling) and three N treatments. Total green leaf area, high-effective leaf area and its rate at heading, net photosynthetic rate of flag leaves 7 days after heading, glutamate synthase(GOGAT) and glutamine synthase(GS) activity after heading, dry matter production, and N accumulation at heading and maturity increased under the potted-seedling method or 70% SRNF as a base + 30% urea application at the panicle initiation stage(SBUP). Stem diameter and number of small and of all vascular bundles at the neck–panicle node in potted-seedling plants increased as a result of increasing numbers of effective panicles, secondary branches, and spikelets. In pottedseedling plants, treatment with SBUP increased the number of large and total vascular bundles at the panicle–neck internode and the number of differentiated and surviving secondary branches and spikelets and decreased the number of ineffective tillers and degenerated secondary branches and spikelets. We conclude that the potted-seedling machine transplanting method and SRNF combined with urea topdressing can strengthen the source–sink relationship in rice, resulting in higher yields.

Nitrogen vacancies enriched Ce-doped Ni_(3)N hierarchical nanosheets triggering highly-efficient urea oxidation reaction in urea-assisted energy-saving electrolysis

Urea oxidation reaction (UOR),which has favorable thermodynamic energy barriers compared with oxygen evolution reaction (OER),can provide more cost-effective electrons for the renewable energy systems,but is trapped by its sluggish UOR kinetics and intricate reaction intermediates formation/desorption process.Herein,we report a novel and effective electrocatalyst consisting of carbon cloth supported nitrogen vacancies-enriched Ce-doped Ni_(3)N hierarchical nanosheets (Ce-Ni_(3)N @CC) to optimize the flat-footed UOR kinetics,especially the stiff rate-determine CO_(2)desorption step of UOR.Upon the introduction of valance state variable Ce,the resultant nitrogen vacancies enriched Ce-Ni_(3)N @CC exhibits an enhanced UOR performance where the operation voltage requires only 1.31 V to deliver the current density of 10 mA cm^(-2),which is superior to that of Ni_(3)N @CC catalyst (1.36 V) and other counterparts.Density functional theory (DFT) results demonstrate that the incorporation of Ce in Ni_(3)N lowers the formation energy of nitrogen vacancies,resulting in rich nitrogen vacancies in Ce-Ni_(3)N @CC.Moreover,the nitrogen vacancies together with Ce doping optimize the local charge distribution around Ni sites,and balance the adsorption energy of CO_(2)in the rate-determining step (RDS),as well as affect the initial adsorption structure of urea,leading to the superior UOR catalytic performance of Ce-Ni_(3)N @CC.When integrating the Ce-Ni_(3)N catalyst in UOR//HER and UOR//CO_(2)R flow electrolyzer,both of them perform well with low operation voltage and robust long-term stability,proofing that the thermodynamically favorable UOR can act as a suitable substitute anodic reaction compared with that of OER.Our findings here not only provide a novel UOR catalyst but also offer a promising design strategy for the future development of energy-related devices.

Global Optimization of Norris Derivative Filtering with Application for Near-Infrared Analysis of Serum Urea Nitrogen

Near-infrared (NIR) spectroscopy combined with chemometrics methods was applied to the rapid and reagent-free analysis of serum urea nitrogen (SUN). The mul-partitions modeling was performed to achieve parameter stability. A large-scale parameter cyclic and global optimization platform for Norris derivative filter (NDF) of three parameters (the derivative order: d, the number of smoothing points: s and the number of differential gaps: g) was developed with PLS regression. Meantime, the parameters’ adaptive analysis of NDF algorithm was also given, and achieved a significantly better modeling effect than one without spectral pre-processing. After eliminating the interference wavebands of saturated absorption, the modeling performance was further improved. In validation, the root mean square error (SEP), correlation coefficient (RP) for prediction and the ratio of performance to deviation (RPD) were 1.66 mmol?L-1, 0.966 and 4.7, respectively. The results showed that the high-precision analysis of SUN was feasibility based on NIR spectroscopy and Norris-PLS. The global optimization method of NDF is also expected to be applied to other analysis objects.

Equidistant combination wavelength screening and step-by-step phase-out method for the near-infrared spectroscopic analysis of serum urea nitrogen

We applied near-infrared(NIR)spectroscopy with chemometrics for the rapid and reagent-fee analysis of serum urea nitrogen(SUN).The modeling is based on the average effect of multiple sample partitions to achieve parameter selection with stability.A multiparameter optimization platform with Norris derivative filter-partial least squares(Norris-PLS)was developed to select the most suitable mode(d=2,s=33,g=15).Using equidistant combination PLS(EC-PLS)with four parameters(initial wavelength I,number of wavelengths N,number of wavelength gaps G and latent variables LV),we performed wavelength screening after eliminating high-absorption wavebands.The optimal EC-PLS parameters were I=1228 nm,N=26,G=16 and LV=12.The root-mean square error(SEP),correlation coefficient(R_(p))for prediction and ratio of performance-to-deviation(RPD)for validation were 1.03 mmol L^(-1),0.992 and 7.6,respectively.We proposed the wavelength step-by-step phase-out PLS(WSP-PLS)to remove redun-dant wavelengths in the top 100 EC-PLS models with improved prediction performance.The combination of 19 wavelengths was identifed as the optimal model for SUN.The SEP,Rp and RPD in validation were 1.01 mmol L^(-1),0.992 and 7.7,respectively.The prediction effect and wavelength complexity were better than those of EC-PIS.Our results showed that NIR spectroscopy combined with the EC-PLS and WSP-PLS methods enabled the high-precision analysis ofSUN.WSP-PLS is a secondary optimization method that can further optimize any wavelength moc odel obtained through other continuous or discrete strategies to establish a simple and better model.

Effects of controlled-release urea application on the growth, yield and nitrogen recovery efficiency of cotton

Field experiments were conducted to study the effects of the controlled release urea (CRU) application on growth yield and nitrogen recovery efficiency of cotton in the main cotton zone of the Yangtze River basin in 2010. Different nitrogen levels were set in order to determine the suitable dosage of CRU on cotton. The special purpose was to provide evidence for the CRU application in cotton fields. The results show that the application of CRU promotes the growth of cotton significantly and enhances the nitrogen supply in the whole period. Compared to the treatment with total N as base fertilizer (UB), the bod, flower, little bolls and total bolls are increased significantly. There are no significant differences in the yield between the CRU treatment and the treatment of controlled release urea and urea combined application (60%CRU + 40%U), but an increase by 12.38%-22.67% compared to the UB treatment, and an increase by 4.49%-7.23% compared to the treatments of total N split application (UD). The nitrogen uptake of CRU treatment was significantly increased by 13.01%-48.32% and 30.27%-13.01% than UB treatment and UD treatment, respectively. The nutrient recovery efficiency of CRU treatment is increased by 16.42-20.59, 5.92-11.29 and 4.22-12.59 percentage points compared to the UB treatment, UD treatment and 60%CRU + 40%U treatment, respectively. In this study, there was a good linearity relationship between the cotton yield and amount of CRU in Wuxue site. The yield of cotton response to amount of CRU could be described by the model of linear plus plateau in Jingzhou site.

Urea hydrolysis and recovery of nitrogen and phosphorous as MAP from stale human urine

Laboratory-scale tests for magnesium ammonium phosphate（MAP）precipitation following urea hydrolysis of human urine were conducted using orthogonal experiment design.The effects of initial pH,temperature and the volumetric ratios of stale urine to fresh urine,on urea hydrolysis in urine were studied to determine the final hydrolysis time to recover most nitrogen from separated human urine by MAP.With a volumetric ratio of stale to fresh urine>10% and at temperature≥20℃,urea hydrolysis could be completed in two days.Alkaline pH inhibited urea hydrolysis progress.The final pH values were all around 9.0 following urine hydrolysis,while the suspension pH might act as an indicator to detect the start and extent of urea hydrolysis.Over 95% of ammonium nitrogen and over 85% of phosphorus from hydrolyzed urine as MAP precipitate were obtained using MgCl;·6H;O and Na;HPO;·12H;O as precipitation agents at pH 8.5,molar ratio of Mg;:NH;-N:PO;-P at（1.2-1.3）:1:1,mixing speed of 120 r/min,and precipitation time and reaction time of 3 h and 15 min,respectively.The precipitate has a structure resembling pure MAP crystal.

Nitrogen deposition and release pattern of slow release fertiliser made from urea-impregnated oil palm frond and rubberwood chips

The fertiliser industry faces a continuing challenge to improve the efficiency of their products,particularly of nitrogenous fertilisers,and to minimise adverse impacts.Therefore,a new slow release fertilizer,ureaimpregnated woodchips from tropical plant biomass(oil palm frond and rubberwood),was developed.The morphology of the impregnated woodchips was investigated by scanning electron microscopy and the success of impregnation of urea and nitrogen deposition into the woodchips was confirmed by energy dispersive X-ray spectrometry.When nitrogen release patterns from impregnated woodchips fertiliser were simulated using a soil solution and distilled water as leaching solutions in a static condition for 768 h,release was slow and steady,although the release rate was lower in distilled water than in the soil solution.

Kinetic of Adsorption of Urea Nitrogen onto Chitosan Coated Dialdehyde Cellulose under Catalysis of Immobilized Urease

The adsorption of urea nitrogen onto chitosan coated dialdehyde cellulose (CDAC) under catalysis of immobilized urease in gelatin membrane (IE) was studied in batch system. The pseudo first-order and second-order kinetic models were used to describe the kinetic data, and the rate constants were evaluated. The experimental data fitted well to the second-order kinetic model.