新型尿素对冬小麦产量及氮素吸收利用的影响

为明确新型尿素在冬小麦的应用效果,采用田间试验,研究了普通尿素（Urea）、控失尿素（LC Urea）、海藻酸尿素（H Urea）、聚能网尿素（N Urea）、含锰尿素（Mn Urea）、控失尿素一次施肥（LC Urea 1）、普通尿素+等量锰（Urea+Mn）和不施肥（CK）对冬小麦产量、叶片SPAD、叶片光合生理特性和氮素吸收利用的影响。结果表明,LC Urea和H Urea处理较Urea处理的小麦拔节期叶片SPAD分别显著提高1500%和1300%,灌浆期净光合速率分别显著增加3304%和2076%,气孔导度分别显著提高2609%和2174%,氮素积累量分别显著增加1439%和1236%,氮肥利用率分别提高4575%和3902%。N Urea和Mn Urea处理与Urea处理的产量无显著差异,LC Urea和H Urea处理较Urea处理显著增产1449%和1333%。控失尿素和海藻酸尿素能够有效提高穗数,改善冬小麦光合生理特性,促进氮素吸收利用,提高冬小麦产量和氮肥利用率,可在豫北潮土区推广应用。     

不同氮源对铜绿微囊藻增殖的影响

在实验室条件下,利用单细胞藻一次性培养方法,研究了硝酸氮、铵氮和尿素对铜绿微囊藻（Microcystis aeruginosa）增殖的影响。结果表明：以硝酸氮作为氮源时,铜绿微囊藻增殖速率优于另外2种氮源条件下的,其最适增殖浓度为1.5～5.0mmol/L。低浓度铵氮（0.5mmol/L）即适宜铜绿微囊藻生长,而高浓度时会抑制铜绿微囊藻生长。尿素氮浓度0.5～1.5mmol/L时最利于铜绿微囊藻生长。试验结果提示在监测水体氮营养盐时应该包括多种无机氮和有机氮,只测总氮难于准确预测水华。     

Evaluating Sugarcane Diets for Dairy Cows Using a Digestion Model

To eliminate unnecessary feeding trials, a mechanistic model of sugarcane digestion was used in the search for suitable supplements to improve milk production. Milk production simulated by the model was compared with data observed in four feeding trials published in the tropical literature where crossbred dairy cows were fed sugarcane/urea diets with different types of supplements. The predicted effects of the supplements on the ruminal microbial population, concentrations of ammonia and volatile fatty acids were also compared with the published results in one experiment. The model indicated the nutrient most limiting milk production for the different feeding situations. The addtion of Leucaena to the basal sugarcane/urea improved the availability of amino acids and long-chain fatty acids, with energy becoming the limiting factor. Supplementation with rice bran increased the availability of energy and long-chain fatty acids, but amino acids then became the limiting factor. Supplementation with both Leucaena and rice bran further improved the milk yield, but availability of energy now limited milk production. Supplementation with Leucaena increased milk production more than supplementation with king grass. The main reason for this increase was increased amino acid absorption due to increased microbial outflow. In all feeding situations, the average difference between the predicted milk production and that observed experimentally was 0.57 kg/d (ranging from 0.08 to 1 kg/d).     

Tolerance to the Nephrotoxic Component of Narthecium ossifragum in Sheep: The Effects of Repeated Oral Doses of Plant Extracts

Young adult sheep were dosed with extracts of Narthecium ossifragum plants by the oral or parenteral routes and the resulting nephrotoxicity was assessed from the increases in the concentrations of creatinine and urea in the serum. Following single intraruminal or intraperitoneal doses of extracts derived from 30 g N. ossifragum (wet weight) per kg live weight (kg lw), serum creatinine concentrations increased from about 100 mol/L to between 260 and 510 mol/L. The serum urea concentrations increased from about 5–8 mmol/L to between 11 and 66 mmol/L in individual sheep. Daily intraruminal administration of 5–30 g/kg lw to three sheep over a 10- or 15-day period increased creatinine concentrations from 100 mol/L to 300–760 mol/L, and urea concentrations from 5–8 mmol/L to 35 mmol/L. A single intraperitoneal challenge dose of 30 g/kg lw, delivered 7 or 12 days after the final intraruminal dose, did not lead to increased serum creatinine or urea concentrations, indicating that oral treatment had apparently resulted in an increased tolerance to the nephrotoxic principle(s) in N. ossifragum.     

包膜控释尿素对大棚番茄的增产与品质提高效应

对施用包膜控释尿素和普通尿素的大棚番茄进行了田间生产条件下产量与品质对比分析试验。结果表明:与普通尿素相比施用控释尿素有显著的增产效果。D 60控释处理(控释期60 d)产量最高,为68.85 t/hm2,比对照增产19.39 t/hm2,增产率为39.2%;比尿素增产10.10 t/hm2,增产率为17.2%;D 90(控释期90 d)比对照增产15.37 t/hm2,增产率为31.0%;比尿素增产6.08 t/hm2。增产率为10.3%;D 90与D 60两种控释尿素之间产量差异不显著。控释尿素具有增加单株果数、单果重的效果。D 90与D 60氮素当季利用率比普通尿素分别高65.5%和108.8%。硝酸盐含量,以D 90为最低,仅比对照高4.4%,比普通尿素低56%;D 60比对照高15%,比尿素处理低51.6%;尿素处理比对照高137.3%。V c和氨基酸含量,D 90为最高,分别比对照高1.00倍和2.46倍;比普通尿素处理高22%和100%;D 60与尿素两处理V c含量差异不显著,但氨基酸总量前者却比后者高48%。可溶性糖含量以D 60较高,普通尿素为最低。综合品质指标为:D 90>D 60>U。说明控释尿素具有显著地增产效应和提高蔬菜品质的突出效应,特别在提高蔬菜的安全品质方面贡献最大。综合各项,在番茄生产中以选用控释期为60 d的包膜控释尿素为最好。     

Accumulation of Sapogenin Conjugates and Histological Changes in the Liver and Kidneys of Lambs Suffering from Alveld,a Hepatogenous Photosensitization Disease of Sheep Grazing Narthecium ossifragum

Sixteen lambs exhibiting hepatogenous photosensitization (alveld) after grazing pasture containing Narthecium ossifragum and seven nonphotosensitized lambs grazing the same pastures were studied. All the alveld-affected lambs revealed liver damage dominated by single cell necrosis, portal fibroplasia and bile duct proliferation. Crystalloid clefts were demonstrated in the bile ducts of two and in the hepatocytes and Kupffer cells of nine photosensitized lambs. Plasma bilirubin concentration was severely increased in ten of the cases of alveld whereas the activity of aspartate aminotransferase was moderately to severely increased in seven cases. The activity of glutamate dehydrogenase was moderately elevated in one of the photosensitized lambs. The main histopathological findings in the kidneys from the alveld-affected lambs were dilated tubules, often with eosinophilic material in the tubular lumina. Regenerative changes were seen in a large proportion of the renal sections. Elevated plasma concentrations of urea and creatinine, and the renal histopathological changes, suggested that the photosensitized lambs had been through a phase of renal injury. Analysis of the free and conjugated sapogenin content in liver tissue and bile was performed by gas chromatography–mass spectrometry. There were significantly higher concentrations of conjugated episapogenins in both the liver and bile in the alveld-affected lambs than in the nonphotosensitized lambs.     

不同添加剂处理对小麦秸黄贮饲料发酵品质的影响

为研究纤维素酶和乳酸菌制剂以及尿素对小麦秸黄贮饲料品质的影响,分别设不同的处理组及对照进行小麦秸黄贮饲料的发酵试验。实验Ⅰ结果表明:尿素单独添加、尿素和纤维素酶混合添加显著提高粗蛋白的含量,尿素和乳酸菌制剂、以及尿素与乳酸菌制剂和纤维素酶混合添加都不能得到品质较好的小麦秸黄贮饲料。实验Ⅱ结果表明:各添加剂处理均显著降低黄贮饲料的pH值和中性洗涤纤维含量(P<0.05),显著提高乳酸、总酸和粗蛋白含量(P<0.05);添加剂处理能够明显改善小麦秸黄贮饲料的发酵品质,提高小麦秸的饲用价值。纤维素酶和乳酸菌制剂同时添加时,小麦秸黄贮饲料品质最好。     

EFFECT OF WATER MANAGEMENT AND POLYOLEFIN-COATED UREA ON GROWTH AND NITROGEN UPTAKE OF INDICA RICE

ABSTRACT

Poor water management and high nitrogen (N) losses are the key problems faced by rice farmers under rainfed inland valley systems. There is a need to evaluate different N fertilizers so as to identify one that could withstand these problems. The performance of polyolefin-coated urea (POCU) was therefore compared with conventional urea in a pot experiment with indica rice (Oryza sativa L. cv. IR36), using two water management systems: 1) Submerged condition referred to as good water management (GWM), and 2) excessive irrigation (over 4000 mm in 120 days) referred to as poor water management (PWM). The study was carried out during 1997 and 1998 cropping seasons under glasshouse conditions. For PWM in 1997, the pots were subjected to leaching only whereas in 1998, they were subjected to both surface runoff and leaching. For both cropping seasons, POCU-treated plants under PWM had a significantly higher grain yield (377.5 and 343.0 g m^?2) than urea-treated plants (316.5 and 260.5 g m^?2). In addition, POCU-treated plants had a significantly higher number of grains per panicle than urea-treated plants. In 1998, both the partial factor productivity of applied N and the agronomic nitrogen-use efficiency of POCU-treated plants under GWM and PWM were significantly higher than those of urea-treated plants. It can be inferred that (using sandy soils and under PWM), POCU could perform significantly better than conventional urea. This finding is important, considering the usually high nitrogen losses in rice-growing inland valley swamps.     

粒状生物质炭基尿素肥料制备及其性能研究

利用沙柱间歇淋溶试验研究评价粒径、尿素和生物质炭质量比、高岭土添加量对肥料缓释性能及颗粒,承受最大破坏力影响规律。当高岭土添加量为10%,在尿素与炭比为1??1~1??5时,可获得80%以上的最大成型率,颗粒的最大破碎压缩力可达10 N以上。随着生物质炭含量增加和肥料颗粒粒径增大,颗粒缓释肥缓释性能提高,当颗粒粒径为5~6 mm,尿素与生物质炭质量比由1??1变化至1??5时,第1次淋溶其累积释放率由43.35%下降至15.64%,比纯尿素颗粒肥下降33%~60%,纯尿素颗粒肥养分到第2次淋溶已完全释放,而缓释肥的尿素的累积释放到第5次淋溶才基本完成。可见缓释肥的缓释性能可通过改变炭粉添加量调节以满足不同作物生长需求。通过对生物质炭基尿素肥料生产流程和经济性分析,说明生物质炭基尿素肥料生产工艺简单、运输方便、价格合理。     

周期性变动饲粮蛋白质水平对内蒙古白绒山羊内源尿素氮循环和微生物蛋白质合成的影响

本试验旨在探讨周期性变动饲粮蛋白质水平对内蒙古白绒山羊内源尿素氮循环和微生物蛋白质合成的影响。饲粮分为低(7.5%)、中(10.5%)和高(13.5%)3个蛋白质水平。选用9只体况良好,体重为(45.63±3.15)kg,装有瘤胃瘘管的内蒙古白绒山羊,采用单因子随机区组试验设计分为3组,即中蛋白质饲粮组(对照组)、变动低蛋白质饲粮组(2 d低蛋白质饲粮—2 d高蛋白质饲粮,循环饲喂)、变动高蛋白质饲粮组(2 d高蛋白质饲粮—2 d低蛋白质饲粮,循环饲喂)。预试期16 d,正试期12 d。通过全收粪尿法、嘌呤衍生物法和同位素灌注法测定山羊氮代谢、内源尿素氮循环以及微生物蛋白质合成的变化。结果表明:1)中蛋白质饲粮组与变动蛋白质饲粮组比较,瘤胃液氨氮(NH3-N)浓度显著增加(P<0.05),粪氮、尿氮排出量显著增加(P<0.05),沉积氮/摄入氮显著降低(P<0.05),尿中嘌呤衍生物排出量和微生物蛋白质合成的量显著降低(P<0.05);2)变动低蛋白质饲粮组与变动高蛋白质饲粮组比较,瘤胃液NH3-N浓度显著降低(P<0.05);3)周期性变动饲粮蛋白质水平后,进入胃肠道的尿素氮/肝脏合成的内源尿素氮显著增加(P<0.05),进入尿中的尿素氮/肝脏合成的内源尿素氮显著减少(P<0.05),返回鸟氨酸循环的尿素氮/进入胃肠道的尿素氮显著减少(P<0.05),用于再合成的尿素氮/进入胃肠道的尿素氮显著增加(P<0.05)。综上所述,周期性变动饲粮蛋白质水平有利于提高内蒙古白绒山羊氮利用率和微生物蛋白质合成量。