• Asian-Australasian Journal of Animal Sciences
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• v.13 no.12
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• pp.1674-1680
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• 2000

A study was conducted to compare the feeding value of urea treated and untreated mustard straw (MS) for sheep. Treated MS was prepared by adding urea-N at 1.84% and followed by packing in a pit silo for 21 days. Two groups of six empty Avikaline ewes were fed untreated (UTMS) and treated (TMS) mustard straw along with 200 g concentrate per head daily for 90 days. Untreated MS had 0.41% N and the urea treatment increased its N value to 1.58 %. The cell wall constituents were decreased in the TMS except for cellulose which remained unaffected. Dry matter intake of TMS was consistently higher than that of UTMS. Digestibility of DM, OM and fibre fractions of MS improved by the urea treatment. Ewes in both groups were in positive N balance while % N retention was lower in UTMS (26.30%) than in TMS (52.14%). The TMS fed group on average consumed 30.2 g DM, 2.9 g digestible crude protein and $0.2MJ\;DE\;per\;kg\;BW\;day^{-1}$ and maintained their weight whereas, the UTMS fed ewes lost weight. The VFA concentration in rumen liquor was higher in TMS than in UTMS. Total-N, ammonia-N and TCA-precipitable-N were also higher in TMS fed ewes. Blood glucose concentrations in the two groups were similar at initiation of the study. However the glucose concentration of UTMS fed group was significantly (p<0.01) lower than those fed UTMS at the termination of the study. Urea-N concentration was also higher in TMS fed group after 90 days of feeding period. It is concluded that urea treatment of MS improved N value of MS from 0.41% to 1.58% along with sizable improvement in nutritive value and in conjunction with 200 g concentrate, TMS can serve as maintenance ration for sheep. ($ME_{lakt}/ME_{m}=1.46$).

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.114-121
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• 1997

Latex Coated Urea(LCU) was compared with ordinary urea under different methods of application in terms of N use efficiency and yield of rice, 1995 and 1996. The study was carried out on Jeonbug silty clay loam, in Honam Agricultural Experiment Station. The fertilizer treatments involved (1) conventional application of urea (44kg N/ha at transplanting, 33kg N/ha at five leaves stage, 33kg N/ha. (4) 55kg N/ha at transplanting and 33kg N/ha as urea at panicle initiation stage, and (5) without N. It was found that by combining LCU(as basal application) and urea(as topdressing at panicle initiation stage), at the rate of 80% of conventional rate with ordinary urea is most effective for the saving of N and increasing the use efficiency of N by rice. It was, however, observed that the efficacy of LCU was affected by the temperature during the growth of rice.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.6
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• pp.321-327
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• 2005

Ammonia ($NH_3$) volatilization was measured from latex coated urea (LCU) and normal urea treated rice paddy under transplanting rice culture in Milyang in 2002 and 2003. The $NH_3$ volatilization from incubation experiment was significantly related with ammonium-N ($NH_4-N$) concentration and pH in the surface water. The correlation coefficients of $NH_3$ volatilization compared to the $NH_4-N$ and pH in surface water were significantly higher in urea than LCU. The $NH_3$ volatilization from both urea and LCU treatments was not increased in surface water of pH less than 8.0, while $NH_3$ volatilization increased significantly in the surface water of pH over 8.0. The results in the field experiment indicated that $NH_3$ volatilization after top-dressing of urea increased rapidly with increasing $NH_4-N$ concentration in soil and floodwater, and highest from 7 to 10 days after top-dressing. The amount of $NH_3$ volatilized from urea treatment was in the range of $4.9-8.4kg\;N\;ha^{-1}$. The variations of $NH_3$ volatilization in 2002 and 2003 were caused by changed N dynamics due to the different weather conditions such as rainfall and temperature. The amount of $NH_3$ volatilized from LCU treatment was significantly reduced compared to that of urea. The reason for the reduced $NH_3$ volatilization in LCU treatment would be due to the lower concentration of $NH_4-N$ in floodwater. The amount of $NH_3$ volatilized from LCU treated rice paddy was in the range of $1.2-1.8kg\;N\;ha^{-1}$, and the loss of N by ammonia volatilization was 2.0-2.3%. Loss of N by $NH_3$ volatilization with LCU treatment was reduced by 75-79% comparing to urea treatment.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.4
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• pp.583-590
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• 1989

Increasing levels of ammonia-N in the rumen fluid used for in vitro incubation were achieved by supplementation of the ration of the donor cows with urea and by addition of urea either with or without glucose to the rumen fluid after collection. The ration of the donor animals consisted of wheat straw (80%) and maize silage (20%). During the second half of the experiment the basal ration was supplemented with a mineral mixture. Wheat straw, Guinea grass and two rice straw varieties were incubated with the various kinds of rumen fluid. Parameters studied were: solubility, apparent organic matter disappearance after 48 hours of incubation ($OMD_{48}$), rate of organic matter degradation from 0 to 24 hours of incubation ($k_1$) and from 24 to 95 hours ($k_2$). The concentration of ammonia-N in the rumen fluid at which 95% of the maximal $OMD_{48}$ and k1 were reached (88.2 and 100.0 mg/l) were independent of the feed. With regard to the $k_2$ the required ammonia-N concentration to reach 95% of the maximal $k_2$ differed per feed. Mineral supplementation increased the OMD48 and $k_1$, but not the solubility and $k_2$. Glucose addition in combination with urea had no beneficial effect compared to urea supplementation alone.

• Textile Coloration and Finishing
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• v.2 no.3
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• pp.36-42
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• 1990

The effect of urea and its derivatives, which are known as structure breakers of water, in the dyeing of silk with acid dyes was investigated. Without ureas the maximum dye uptake was observed at $60^{\circ}C$ when dyed with Milling Cyanine 5R, but in the presence of ureas the maximum dye uptake was decreased and its temperature also shifted to lower regin in the order of urea >N-methyl urea > N,N-dimethyl urea>tetramethyl urea. These tendencies were more marked in the dyeing of silk fiber with Orange II, a typical levelling type acid dye. These can be interpreted as the decrease in the hydropholic interaction between fiber molecules which results in the broadening of the inter micelie spacing. The increased partition coefficient of dye molecules in the bath by the action of ureas also contributes to dyeing results, and it can be seen from the spectral characteristics of dyes in aqueous urea solution.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.7
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• pp.992-997
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• 2002

Two in vivo experiments were conducted to evaluate the effect of novel urease inhibitor hydroquinone (HQ) on ammonia release rate from urea hydrolysis, nitrogen balance, nutrient digestibility and efficiency of microbial protein synthesis. In Exp. 1, twelve crossbred cannulated lambs were randomly assigned within initial body weight block to one of four HQ treatments, which included 0 (control), 30, 60 or 80 mg HQ/kg DM intake. Ammonia concentration and pH of ruminal fluid were immediately measured at 0, 2, 4, 6 and 8 h after feeding. Increasing the dose of HQ tended (p<0.15) to linearly decrease NH3 formation. The ammonia peak concentration (2 h post-feeding) in animals receiving HQ was approximately one-half of that in animals not receiving HQ (p<0.01), and a relatively sustained ammonia release could be obtained at the dose of 30 or 60 mg HQ/kg DM. In Exp. 2, sixteen intact crossbred lambs (weight $40{\pm}0.8kg$) were used in a $2{\times}2$ factorial design experiment. The four rations consisting of soybean meal-based (SBM) or urea-based (Urea) nitrogen source with or without HQ (S1, S0, U1 and U0) were fed in digestion and N balance trials. Apparent digestibility of major nutrients except that of ADF was not affected by either nitrogen source or addition of HQ. Regardless of nitrogen source, supplementation of HQ significantly improved ADF digestibility (p<0.05). The various ration had no effects on N metabolism in the presence of HQ. There was significant difference between total purine derivatives (PD), estimated efficiency of microbial N synthesis (p<0.05) and urea-N excretion (p<0.01) in the urine for the SBM ration and for the Urea ration. However, HQ had little influence on efficiency of microbial N synthesis as proportion of daily intake of total tract digestible OM (p>0.05). No interactions between main nitrogen source and HQ were measured throughout the trial. Results of this study suggest that addition of HQ to ration may improve ADF digestion with having no negative effect on N metabolism and microbial protein production.

• Journal of Environmental Science International
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• v.32 no.11
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• pp.777-788
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• 2023

Potato common scab disease is caused by pathogens belonging to Streptomyces spp. and results in a serious yield loss worldwide. Despite decades of research aimed at disease management, a definitive control method remains undiscovered. This study aims to explore the correlation between the C/N ratio and urea application with potato common scab pathogen dynamics and disease severity. We applied sawdust with a high C/N ratio and urea into the soil prior to potato cropping, both in pot and field experiments. Disease severity assessments and quantification of the TxtB gene were conducted at the harvest stage. Furthermore, culture experiments were performed to assess the direct impact of urea on the pathogen. Our findings revealed that higher disease severity was correlated with a high C/N ratio application and pathogenic gene quantity. Urea exhibited a direct influence on S. scabiei activity, reducing the disease severity in pot experiments. However, the effects of urea application on disease suppression in the conductive field were inconclusive. Although the results of urea application experiments displayed inconsistencies between pot and field trials, urea worked as the control to suppress S. scabiei activity. Further investigations are needed under various field conditions to confirm these findings.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.4
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• pp.653-658
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• 1992

Crossbred dairy does were fed a roughage diet (IVOMD 56%, N 2.27%) ad libitum, and supplemented with urea-molasses (3% W : W) (UM) at levels on an air dry basis of 1.5% or 3% of liveweight or an iso-energetic, iso-nitrogenous mixture of cottonseed meal and molasses (25 : 75 w : w) (CM). Eight does, four lower-producers and four higher-producers (1.9 and 2.5 kg/day respectively in week 7 of lactation) arranged in two Latin Squares, received each of the four diets for three weeks. Dry matter, digestible organic matter and N intakes were higher for high-producers and high levels of supplement but did not differ between nitrogen sources. Milk production was higher by high-producers; interactions were significant between level of supplement and production group and between level of supplement and N-source, with maximum production by high producers on high levels of CM. The main effects of level of supplement were only significant for production or composition. and total solids; N-source did not have significant effects on liveweight, milk production or composition. We conclude that does of moderate capacity for milk production, receiving a diet of two-thirds moderate quality roughage, one third urea-molasses, will not respond to increased level of supplementation or to replacement of urea with cottonseed meal.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.533-534
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• 1989

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.6
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• pp.376-383
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• 2003

To utilize composts more efficiently, combining composts with fertilizer to meet crop requirements is an appealing alternative. A pot experiment was conducted to study the effect of application rate of composted pig manure blended with fertilizer on the availability and loss of fertilizer-N. Chinese cabbage (Brassica campestris L. cv. Samjin) plants were cultivated for 30 and 60 days. 15N-Labeled urea ($5.24\;^{15}N\;atom\;%$) was added to soil at $450mg\;N\;kg^{-1}$, and unlabeled compost ($0.37\;^{15}N\;atom\;%$) was added at 0, 200, 400, and $600mg\;N\;kg^{-1}$. The amount of plant-N derived from urea was not affected by compost application at rate of $200mg\;N\;kg^{-1}$. However, compost application at 400 and $600mg\;N\;kg^{-1}$ significantly (P<0.05) increased plant assimilation of N from urea irrespective of sampling time, probably because of physicochemical changes in the soil properties allowing urea-N to be assimilated more efficiently. The amount of immobilized urea-N increased with increasing rate of compost application at both growth periods, as the results of increased microbial activities using organic C in the compost. Total recovery of urea-N (as percentage of added N) by Chinese cabbage and soil also increased with increasing rate of compost from 71.5 to 95.6% and from 67.0 to 88.2% at the 30- and 60-days of growth, respectively. These results suggest that increasing rate of compost blending increases plant uptake of fertilizer-N and enhances immobilization of fertilizer-N, which leads to decrease in loss of fertilizer-N. However, information about the fate of immobilized N during future crop cultivation is necessary to verify long-term effect of compost blending.