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191.
Sulian Junkes Dal Molin Paulo Roberto Ernani Pâmella Soldatelli Paulo Cezar Cassol 《Communications in Soil Science and Plant Analysis》2018,49(9):1099-1106
Following soil fertilization, nitrogen (N) is partially lost. The objective of this study was to evaluate leaching and recovery of N after addition of fertilizers to the soil. Two experiments were conducted in leaching columns submitted to frequent water percolations. In the leaching experiment, urea, ammonium nitrate, and six coated N fertilizers were utilized; in the N recovery experiment, treatments consisted of urea, potassium nitrate, ammonium sulfate, and ammonium nitrate, combined or not with percolation. Percolations were performed weekly with quantification of ammonium and nitrate in the percolated. The recovered N was obtained by summing total N percolated with N in the soil. Nitrate leaching was highest from amide-N fertilizers, with no differences between them showing that coating urea was not efficient to decrease N leaching. Nitric fertilizers had the lowest recovery of N, probably due to the occurrence of denitrification caused by the frequent water percolation. 相似文献
192.
Distributions of imidacloprid,imidacloprid‐olefin and imidacloprid‐urea in green plant tissues and roots of rapeseed (Brassica napus) from artificially contaminated potting soil
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Marcela Seifrtova Tatana Halesova Klara Sulcova Katerina Riddellova Tomas Erban 《Pest management science》2017,73(5):1010-1016
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194.
通过田间试验研究了不同氮肥及其施用方式对水稻养分吸收及产量形成的影响。结果表明,一次性施用普通尿素、稳定尿素及缓释尿素的处理之间田面水中铵态氮浓度差别不大,施肥结束后田面水中铵态氮浓度均呈现出不断降低的趋势;分次施肥处理田面水中铵态氮浓度随追肥次数呈现出周期性的升高降低过程;一次性施用缓释尿素可以提高土壤中碱解氮及植株氮的含量,对光合速率、蒸腾速率、胞间二氧化碳浓度也均有提升作用,对水稻具有稳产作用。一次性施用缓释尿素可以促进整个生育期内水稻对养分的需求,可以促进灌浆期碳水化合物的累积,因此能达到与分次施肥相同的稳产效果。 相似文献
195.
Dietary rice improves growth performance,mucosal enzyme activities and plasma urea nitrogen in weaning piglets
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In this study, we evaluated the nutritional functions of rice for weaning piglets. Sixteen weaning piglets with an average initial weight of 7.2 kg were divided into two groups. One group was fed a corn‐soybean meal based diet, and the other was fed a rice‐soybean meal based diet, containing 50% corn and rice, respectively. A 2 weeks growth trial was conducted and growth performance, intestinal mucosal enzyme activities and plasma urea nitrogen were measured. The average daily gain in rice‐fed piglets was significantly higher than that in corn‐fed piglets and the average daily feed intake tended to be higher in rice‐fed piglets than in corn‐fed piglets. Maltase and aminopeptidase activities (mol/g tissue) in the jejunum in rice‐fed piglets were significantly higher than those in corn‐fed piglets, although these enzyme activities were not different in the duodenum. Sucrase and dipeptidyl peptidase IV activities in the two groups were not different in either the duodenum or jejunum. Although the feed (nitrogen) intake was higher in rice‐fed piglets, the plasma urea nitrogen in rice‐fed piglets was significantly lower (P = 0.006) than that in corn‐fed piglets. These results indicate that rice is a good alternative feedstuff for the diet of weaning piglets. 相似文献
196.
Body condition and haematological indices provide powerful information when assessing wildlife health. Reference intervals for these indices can facilitate wildlife management, and would benefit initiatives to save the Critically Endangered geometric tortoise (Psammobates geometricus). We collected data from 126 geometric tortoises to establish baseline values reflecting variation over four seasons (spring 2000 to winter 2001) and among three groups (female, male and juvenile). We measured body condition index (BCI; mass to shell volume), blood urea nitrogen (BUN), plasma chloride, packed cell volume (PCV), haemoglobin concentration (Hb) and red blood cell count (RBC), and used PCV, Hb and RBC to calculate erythrocyte indices. BCI correlated poorly with haematological measures but had a strong inverse relationship with BUN. BCI did not vary among groups, but all groups had low condition indices in autumn, the end of the dry season. High BUN and chloride values in autumn indicate dehydration, particularly in males. Males had the highest PCV, Hb and RBC values, especially during summer and autumn when they moved long distances, likely pursuing mates. Female and juvenile indices were similar, except that female Hb was higher than juvenile Hb, possibly to meet female energy needs associated with their large size and reproductive metabolism. Low Hb levels in winter coincided with low temperatures and reduced movements. Our results illustrate how intrinsic and extrinsic factors influence the physiology of geometric tortoises and provide reference intervals to monitor their health. 相似文献
197.
种植密度和施肥水平对青海旱地覆膜种植甜高粱草产量及品质的影响 总被引:2,自引:0,他引:2
以甜高粱(Sorghum dochna)吉甜5号和九甜杂3号为材料,在海拔2 040m的青海旱地覆膜进行了不同种植密度(行株距分别为40cm×40cm、40cm×30cm、40cm×20cm)和追施不同尿素量(0、150和225kg·hm~(-2))对草产量及品质影响的研究。结果显示,吉甜5号和九甜杂3号两个品种在行距×株距为40cm×20cm(12.00万穴·hm~(-2))时的鲜草产量和干草产量最高,鲜草产量分别达99.75和108.17t·hm~(-2),干草产量分别达17.89和22.58t·hm~(-2);在生长中期追施150kg·hm~(-2)尿素时草产量较高,品质较好,两个品种的粗蛋白分别达5.47%和4.80%,粗脂肪分别达5.67和7.57g·kg~(-1),酸性洗涤纤维较低,综合表现良好。以上结果表明,青海旱地甜高粱种植密度为12.00万穴·hm~(-2),生长中期追施尿素150kg·hm~(-2)最为适宜。 相似文献
198.
腐植酸尿素对玉米生长及肥料氮利用的影响 总被引:13,自引:5,他引:8
199.
控释氮肥与尿素掺混比例对作物中后期土壤供氮能力和稻麦产量的影响 总被引:10,自引:2,他引:8
200.
普通、控释尿素配比对玉米物质积累及产量的影响 总被引:2,自引:1,他引:1
以普通尿素和包膜控释尿素为供试材料,设置5种普通尿素与控释尿素配比处理,分别为CRU0—100%普通尿素,CRU1—75%普通尿素+25%控释尿素,CRU2—50%普通尿素+50%控释尿素,CRU3—25%普通尿素+75%控释尿素和CRU4—100%控释尿素,以CK1—不施氮肥和CK2—常规施氮(普通尿素60%基施+40%大喇叭口期追施)为对照,研究控释尿素与普通尿素配施对玉米农艺性状、干物质积累分配及产量的影响。结果表明:(1)施氮显著提高了玉米株高、穗位高和叶面积,与常规施氮处理相比,普通、控释尿素配施可提高株高、穗位高、茎粗和叶面积,其中75%控释尿素处理提高显著。(2)与常规施氮处理相比,普通、控释尿素配施处理促进吐丝期干物质积累,最终增加成熟期总干物质量,其中以CRU2和CRU3处理最好。(3)与常规施氮处理相比,普通、控释尿素配施处理的干物质在叶片和茎秆中的分配比例均较低,而籽粒的分配比例较高,以CRU3处理比例最高。(4)随控释尿素比例增加,玉米产量、千粒重、穗粒数、穗长和穗粗均呈先升后降的趋势;25%,50%,75%,100%的控释尿素比例处理产量较常规施氮处理分别增产3.70%,8.83%,11.23%,5.43%。因此,普通尿素掺混75%比例的控释尿素进行一次底施,既能满足玉米植株生长需求,提高干物质积累,优化干物质分配,又可促进增产。 相似文献