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Journal articles on the topic 'Urea in soils'
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1
Suter, H. C., P. Pengthamkeerati, C. Walker, and D. Chen. "Influence of temperature and soil type on inhibition of urea hydrolysis by N-(n-butyl) thiophosphoric triamide in wheat and pasture soils in south-eastern Australia." Soil Research 49, no. 4 (2011): 315. http://dx.doi.org/10.1071/sr10243.
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Incubation experiments were conducted to assess the effectiveness of N-(n-butyl) thiophosphoric triamide (NBPT) for inhibiting hydrolysis of urea in three wheat-growing soils and one pasture soil in south-eastern Australia, under a range of temperatures (5, 15, 25°C). The effectiveness of NBPT decreased with increasing temperature and with increasing urease activity. In the acidic pasture soil with high urease activity (186 μg N/g soil.h) and high organic carbon content (11%), NBPT (0.1% w/w urea) had little impact on urea hydrolysis rates over all temperatures, with <1% urea remaining at Day 14. In the alkaline, wheat-cropping soils with lower urease activity (54–90 μg N/g soil.h) and lower organic carbon content (<1.5%), NBPT was able to effectively reduce urea hydrolysis over 14–15 days at 5°C and 15°C (>55% urea remaining). At 25°C in the wheat soils, NBPT slowed the rate of urea hydrolysis, but by Days 14 and 15, <2% of the urea remained. NBPT applied at a rate of 0.1% urea would be an effective tool for slowing urea hydrolysis in the wheat-cropping soils under cool-climate conditions. The delay in urea hydrolysis in the pasture soil still provides the opportunity for increased flexibility in farm management, such as irrigation scheduling.
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Ali, Maru, Ahmed Osumanu Haruna, Nik Muhamad Abd Majid, Walter Charles Primus, Nathaniel Maikol, Audrey Asap, Aini Nadzirah Naharuddin, and Alicia Vanessa Jeffary. "Using Soil Water to Control Ammonia Emission from Acid Soils with and Without Chicken Litter Biochar." Sustainable Agriculture Research 8, no. 3 (May 14, 2019): 23. http://dx.doi.org/10.5539/sar.v8n3p23.
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Although urea use in agriculture is on the increase, increase in pH at soil microsite due to urea hydrolysis which causes ammonia emission can reduce N use efficiency. Among the interventions used to mitigate ammonia loss include urease inhibitors, clinoptilolite zeolite, coated urea, and biochar but with little attention to the use of soil water levels to control ammonia volatilization. The objective of this study was to determine the effects of soil water levels on ammonia volatilization from soils with and without chicken litter biochar. Dry soils with and without chicken litter biochar were subjected to 0%, 25% 50%, 75%, 100%, and 125% soil water. There was no urea hydrolysis in the soil without water. Chicken litter biochar as soil amendment effectively mitigated ammonia loss at 1% to 32% and 80% to 115% field capacity. However, urea used on soil only showed lower ammonia loss at 33% to 79% and 116% to 125% field capacity compared with the soils with chicken litter biochar. At 50% field capacity ammonia loss was high in soils with and without chicken litter biochar. Although chicken litter biochar is reputed for improving soil chemical properties, water levels in this present study affected soil chemical properties differently. Fifty percent field capacity, significantly reduced soil chemical properties. These findings suggest that timely application of urea at the right field capacity can mitigate ammonia emission. Therefore, whether soils are amended with or without chicken litter biochar, urea application should be avoided at 50% field capacity especially in irrigated crops.
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Motasim, Ahmmed Md, Abd Wahid Samsuri, Arina Shairah Abdul Sukor, and Amin Mohd Adibah. "Nitrogen Dynamics in Tropical Soils Treated with Liquid and Granular Urea Fertilizers." Agriculture 11, no. 6 (June 14, 2021): 546. http://dx.doi.org/10.3390/agriculture11060546.
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The mineralization of urea fertilizer mostly regulates the nitrogen dynamics in the soil. A laboratory-scale study was conducted to compare the nitrogen dynamics in two tropical soil series incubated with either liquid urea (LU) or granular urea (GU) at 0, 300, 400 or 500 mg/kg of soil. The soils samples used in the experiment were the Bungor and Selangor soil series which have a sandy clay loam and clay texture, respectively. The NH4+-N, NO3−-N concentration in the soils were measured for four weeks to determine the urea-N mineralization while ten pore volumes of water were used for the NH4+-N and NO3−-N leaching loss. At the same application rate, higher NH4+-N and NO3−-N concentrations were recorded in the LU applied soils throughout the incubation period in case of N mineralization. Urea-N recovery was higher in GU than LU treated soils in the first two weeks while no urea-N was present in both GU and LU treated soils after the third week of incubation. The leaching of N (NH4+-N and NO3−-N) was higher in GU treated soils than that of LU and leaching was increased with increased application rate in both LU and GU in both soils. The NH4+-N and NO3−-N concentrations were higher in the Selangor soil whereas the total N leaching loss was higher in Bungor soil. The results suggest that the LU was a better N fertilizer source than GU for rapid mineralization, quicker N availability and lower N leaching loss.
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Singh, Balwinder, and M. S. Bajwa. "Studies on the leaching of urea in sodic soils." Journal of Agricultural Science 106, no. 2 (April 1986): 323–30. http://dx.doi.org/10.1017/s0021859600063917.
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SUMMARYLaboratory experiments were conducted in PVC columns to study the leaching and transformation of applied urea in sodic soils (Gharachon loam-Aquic Natrustalf and Domeli silty clay loam-Aquic Camborthid) reclaimed by gypsum application and kept submerged for 7 or 14 days after fertilizer application. The effect of different depths of irrigation water (5, 7·5, 10, 20 and 30 cm) on urea leaching was studied in a sandy loam sodic soil. In another experiment, the effect of time interval (0 or 4 days) between urea application and initiation of submergence with distilled water (for 7 or 14 days) was investigated involving two recently reclaimed sodic soils (Gharachon loam and Domeli silty clay loam). The results showed that the extent of urea leaching mainly depended upon soil texture. In Domeli silty clay loam, urea penetrated to 20 cm depth with peaks in concentration at 12·5 cm at both 7 and 14 days of submergence. In Gharachon loam urea-N moved to 25 cm depth after 7 days and to 35 cm after 14 days. In the sandy loam sodic soil peaks of urea-N concentration were observed at 12·5, 22·5 and 27·5 cm depths after infiltration of 5, 7·5 and 10 cm depth of water, respectively. Leaching with 20 and 30 cm depths of water moved urea deeper (below 50 and 70 cm, respectively). In recently reclaimed soils, leaching initiated immediately after fertilizer application displaced urea to slightly deeper layers compared with leaching initiated 4 days after urea application. Leaching may not be an important loss mechanism of urea-N in loam or silty clay loam sodic soils. However, in light-textured sandy loam sodic soils leaching beyond the root zone can be expected to create fertilizer management problems.
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Olaleye, Abimfoluwa, Derek Peak, Akeem Shorunke, Gurbir Dhillon, Durodoluwa Oyedele, Odunayo Adebooye, and P. B. Irenikatche Akponikpe. "Effect of Manure and Urea Fertilization on Yield, Carbon Speciation and Greenhouse Gas Emissions from Vegetable Production Systems of Nigeria and Republic of Benin: A Phytotron Study." Agronomy 10, no. 3 (March 14, 2020): 400. http://dx.doi.org/10.3390/agronomy10030400.
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Fertility management techniques being promoted in sub-Saharan Africa (SSA) seek to grow indigenous vegetables economically and sustainably. This study was conducted in a phytotron chamber and compared yield, soil carbon (C) speciation and greenhouse gas (nitrous oxide (N2O) and carbon dioxide (CO2)) emissions from SSA soils of two ecoregions; the dry savanna (lna, Republic of Benin) and rainforest (Ife, Nigeria) cultivated with local amaranth (Amaranthus cruentus) under manure (5 t/ha) and/or urea (80 kg N/ha) fertilization. Vegetable yield ranged from 4331 kg/ha to 7900 kg/ha in the rainforest, RF, soils and 3165 kg/ha to 4821 kg/ha in the dry savanna, DS, soils. Yield in the urea treatment was slightly higher compared to the manure, and manure+urea treatment, but the difference was not statistically significant. Cumulative CO2 emissions over 21 days ranged from 497.06 to 579.47 g CO2-C/kg soil/day in the RF, and 322.96 to 624.97 g CO2-C/kg soil/day in the DS, while cumulative N2O emissions ranged from 60.53 to 220.86 mg N2O-N/kg soil/day in the RF, and 24.78 to 99.08 mg N2O-N/kg soil/day in the DS. In the RF samples, when compared to the use of urea alone, the combined use of manure and urea reduced N2O emissions but led to an increase in the DS samples. ATR-FTIR analysis showed that the combined use of manure and manure+urea increased the rate of microbial decomposition in the soils of the DS, but no such effect was observed in soils of the RF. We conclude that combining manure and urea fertilization has different effects on soils of the two ecoregions, and that RF farmers can reduce agricultural N2O emissions without compromising soil productivity and yield potential.
6
Wali, Pardeep, Vinod Kumar, and J. P. Singh. "Effect of soil type, exchangeable sodium percentage, water content, and organic amendments on urea hydrolysis in some tropical Indian soils." Soil Research 41, no. 6 (2003): 1171. http://dx.doi.org/10.1071/sr01090.
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Urea has emerged as one of the most extensively used sources of nitrogen fertiliser in recent years because of its low cost per unit nitrogen. Urea hydrolysis in soils is an enzymatic decomposition process by the enzyme urease. The effects of soil type, exchangeable sodium percentage, moisture regime, and organic manures and their levels on the kinetics of urea hydrolysis were studied in a series of laboratory incubation experiments at 25 ± 1�C. Urea transformation followed first-order kinetics, and the first-order rate constants for soils varied from 0.0321 to 0.1182/h. The rate of urea hydrolysis in the different soils increased with greater clay content and followed the order: Gulkani clay loam > Dadupur loam > Hisar sandy loam > Jakhol silty clay loam > Bawal loamy sand > Balsamand sand. Increasing the exchangeable sodium percentage in soils decreased the rate of urea hydrolysis both at field capacity and flooded conditions (2 cm standing water). Application of vermicompost, sheep manure, poultry manure, pig manure, and urban waste to soil at the 1% level increased the rate of hydrolysis over the untreated soil.
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Shetty, Premalatha, Chaithra Acharya, and Nalavi Veeresh. "Effect of Urea Fertilizer on the Biochemical Characteristics of Soil." International Journal of Applied Sciences and Biotechnology 7, no. 4 (December 28, 2019): 414–20. http://dx.doi.org/10.3126/ijasbt.v7i4.26778.
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Urea-potash mixture was added to the manured soil at three different concentrations equivalent to 0.8, 1.6 and 2.4g f urea per 10Kg of soil. Nitrate and nitrite N concentration in the soil increased within 24h after addition of urea. The nitrate N content in soil without urea was 17 µg and in urea fertilized soils, it ranged from 39.9-47 µg/g of soil after 19h. . Increase in total mineralizable N was around 67- 160% in urea fertilized soils in comparison to the control. Percent conversion of urea to nitrate and nitrite N decreased at higher concentrations of the fertilizer. Addition of biochar to urea amended soil did not bring about significant change in the available N content. Decrease in total mineralizable N and accumalation of available P was observed over the period of 15 days. Addition of urea resulted in acidification of the soil. Acidification of the soil could be correlated with increase in acid phosphatase concentration. The soil amended with biochar exhibited significant buffering capacity in the region of pH 7.4-9.
Int. J. Appl. Sci. Biotechnol. Vol 7(4): 414-420
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Motasim, Ahmmed Md, Abd Wahid Samsuri, Arina Shairah Abdul Sukor, and Amin Mohd Adibah. "Gaseous Nitrogen Losses from Tropical Soils with Liquid or Granular Urea Fertilizer Application." Sustainability 13, no. 6 (March 12, 2021): 3128. http://dx.doi.org/10.3390/su13063128.
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Gaseous loss of N leads to lower nitrogen use efficiency (NUE) of applied urea and N content of the soil. This laboratory study was conducted to compare the nitrogen losses from two tropical soil series (Bungor sandy clay loam and Selangor clay) incubated with either liquid urea (LU) or granular urea (GU) at 0, 300, 400, or 500 mg/kg of soil for thirty days. The NH3 volatilization, N2O emission, and N content in the soils were measured throughout the incubation period. For the same application rate, the total NH3 volatilization loss was higher in GU-treated soils than the LU-treated soils. NH3 volatilization loss continued up to the 15th day in the Selangor soil, while in the Bungor soil series it continued up to the 26th day. Higher amounts of N2O emissions were recorded in GU-treated soils than the LU-treated soils, and N2O emission increased with increasing rate of GU and LU applications in both soils. The N2O emission was higher only in the first few days and then tapered off at the seventh and eighth day in Bungor and Selangor soil series, respectively. The total N2O emission was higher in the Selangor soil series than that of Bungor soil series. The total N content that remained in the LU-treated soils after 30 days of incubation was higher than the GU-treated soils. The total N loss from applied urea was higher in the sandy clay loam Bungor soils than that of clayey Selangor soil series. The results suggest that the LU may be a better N fertilizer source than GU due to lower N loss from NH3 volatilization and N2O emission.
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OBI, A. OLU, R. A. HEDLIN, and C. M. CHO. "CROP UTILIZATION AND SOIL RETENTION OF NITROGEN FROM 15N-LABELLED UREA, CALCIUM NITRATE, and AMMONIUM SULPHATE IN SEVERAL MANITOBA SOILS." Canadian Journal of Soil Science 66, no. 4 (November 1, 1986): 661–71. http://dx.doi.org/10.4141/cjss86-066.
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A growth chamber study was carried out to determine crop utilization of nitrogen added as 15N-labelled calcium nitrate or urea to eight Manitoba soils of diverse characteristics. Dry matter yield of wheat was significantly greater where calcium nitrate was used as a nitrogen source than when urea was the nitrogen source in Pine Ridge, Wellwood, and Granville soils. Residual nitrogen in the soil at the end of the experiment was greater where urea was used than where calcium nitrate was used. Total recovery of urea nitrogen generally exceeded recovery of nitrogen from calcium nitrate. In a laboratory study it was found that more of the nitrogen added as urea or ammonium sulphate was retained than when nitrogen added was as calcium nitrate. Rapid ammonium fixation from ammonium-yielding carriers occurred, especially in the Granville and Waitville soils. Ammonium fixation could be one reason for the higher utilization of nitrogen from nitrate than from ammonium sources. Key words: Nitrogen availability, ammonia-soil interaction
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Mavi, M., B. Singh, and R. Setia. "Effect of organics on nitrogen transformations in soil under different moisture regimes." Acta Agronomica Hungarica 56, no. 3 (September 1, 2008): 285–93. http://dx.doi.org/10.1556/aagr.56.2008.3.4.
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Awareness of the environmental aspects of the quality of crop production has increased in recent decades, leading to renewed interest in organics such as crop residues, green manures and organic manures. The effect of organics on urea transformation was investigated by conducting a laboratory incubation experiment in alluvial clay loam soil (Typic Ustifluvents) at 33±1°C with two moisture levels (1:1 soil:water ratio and field capacity). The rate of urea hydrolysis decreased as the time of incubation increased and the disappearance of urea N was associated with a corresponding increase in the (NH 4+ + NO 3− )-N content in soils treated with crop residues (rice straw and wheat straw), organic manures (poultry manure and farmyard manure) and green manures (cowpea and sesbania). In untreated soil, the time taken for the complete hydrolysis of the applied urea (200 μg urea N g −1 soil) was more than 96 h at both the moisture levels, whereas in amended soils it was completed in 48 h. The rate of urea hydrolysis was more rapid at field capacity than at the 1:1 soil:water ratio. Urea hydrolysis was higher in sesbaniatreated soils, followed by cowpea, poultry manure, farmyard manure, rice straw and wheat straw at both the moisture levels. At field capacity, 85.5% urea was hydrolysed in sesbania-treated soil as compared to 32% in untreated soil after 24 hours of incubation, while at the 1:1 soil:water ratio the corresponding values were 81.5 and 27.5%. Urea hydrolysis followed first order reaction kinetics at both the moisture levels.
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Ahmad, Ayaz, Shahzada Sohail Ijaz, and Zhenli He. "Effects of Zeolitic Urea on Nitrogen Leaching (NH4-N and NO3-N) and Volatilization (NH3) in Spodosols and Alfisols." Water 13, no. 14 (July 12, 2021): 1921. http://dx.doi.org/10.3390/w13141921.
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Global use of urea nitrogen (N) fertilizer is increasing, but N losses are still very high (40–70%). Zeolites have the capability of holding NH4+, thus reducing N losses when applied as a soil amendment. However, application of a large quantity of zeolite is costly and inconvenient. In this study, zeolitic fertilizers were evaluated to select the best formulation with reduced leaching of NH4-N and NO3-N and NH3 volatilization in agricultural soils (Alfisol and Spodosol). The treatments included the following: T0 = control, T1 = urea fertilizer, T2 = zeo-urea (1:1), T3 = zeo-urea (2:1), T4 = zeo-urea (3:1), T5 = zeo-urea (1:2), and T6 = zeo-urea (1:3). Leaching was performed at 4, 8, 12, 19, 25, 32, 39 and 45 days after the soils were treated with the designated fertilizers, including control, and packed into columns. Leachate samples were collected after each leaching event and analyzed for the concentrations of NH4-N and NO3-N and the quantity of leachate. Ammonia volatilization was recorded at days 1, 5, 9, 13 and 20 of soil treatments. Results indicate that zeolitic fertilizer formulations effectively reduced N losses. NH4-N loss was reduced by 13% and 28% by zeo-urea (1:1) in Alfisol and Spodosol soils, respectively, whereas zeo-urea (2:1) and zeo-urea (3:1) effectively decreased NO3-N leaching in Alfisol. Volatilization loss of NH3 was reduced by 47% in Spodosol and 32% in Alfisol soil with zeo-urea (1:1) as compared with that of urea fertilizer. The results suggest that zeo-urea (1:1) is an effective fertilizer formulation for reducing N losses, especially in Alfisol, as compared with conventional urea fertilizer.
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Ning, Jianfeng, Yuji Arai, Jian Shen, Ronghui Wang, and Shaoying Ai. "Effects of Phosphorus on Nitrification Process in a Fertile Soil Amended with Urea." Agriculture 11, no. 6 (June 4, 2021): 523. http://dx.doi.org/10.3390/agriculture11060523.
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While the effects of carbon on soil nitrogen (N) cycle have been extensively studied, it is not clearly understood how co-existing macronutrients, such as phosphorus (P), affect the N cycle in agroecosystems. In this study, P amendment effects on nitrification in a fertile agricultural soil were investigated under a typical N-P amendment rate. In a laboratory incubation study, soils were amended with urea, monopotassium phosphate and a mixture of urea and monopotassium phosphate at the same rate. In soils that received no amendments (control), P only, urea only, and urea plus P amendment, nitrification occurred within the first five days, with an average net nitrification rate of 5.30, 5.77, 16.66 and 9.00 mg N kg−1d−1, respectively. Interestingly, nitrification in urea-treated soils was retarded by P addition where a N:P ratio seemed to be a key factor impeding nitrification. This was also supported by the response of ammonia-oxidizing bacteria (AOB), which was more sensitive to P addition than ammonia-oxidizing archaea (AOA). The outcome of this study showed that application of P fertilizer suppressed the nitrification process in urea amended soil, suggesting that a synergistic aspect of N and P nutrient management should be further explored to retard N losses from agricultural systems.
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Chen, J. S., and A. F. MacKenzie. "Effects of rates and placement methods of urea and potassium chloride on soil nitrogen and potassium and corn dry matter yield." Canadian Journal of Soil Science 73, no. 2 (May 1, 1993): 147–55. http://dx.doi.org/10.4141/cjss93-017.
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Placement and interaction of urea and KCl fertilizers for corn production needs to be evaluated to develop rational fertilizer management programs. A field study, involving three rates of urea and KCl with band and broadcast placements, was conducted with corn on two Quebec soils in 1988 and 1989 to determine nutrient interactions on corn (Zea mays L.) dry matter yields, N and P uptake and on soil N and K. In two sites (Chicot 1988 and Ormstown 1989) with dry surface soils, no rainfall for 5 d and significant rainfall after 5 d, broadcast urea resulted in higher dry matter yields and uptake of N than banded urea. In the Chicot 1989 site where urea application was on moist soil and followed by rainfall insufficient to move broadcast urea into the soil, banded urea was more effective than broadcast urea. Banded urea generally resulted in increased inorganic N and fixed [Formula: see text] in soil sampled from within fertilizer bands but lower levels in soil between bands in comparison with broadcast urea. Banding KCl resulted in increased exchangeable K+ in the band. Compared with exchangeable K+, fixed K+ was less affected by placement methods and rates of added N and K. Interactions between rates and placement methods of N and K on dry matter yield, N and K uptake and soil N and K were few and relatively small. Key words: Fertilizer placement, urea, KCl, Zea mays, grain, corn
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Manikandan, Angamuthu, and Kizhaeral S. Subramanian. "Study on mitigation of ammonia volatilization loss in urea through adsorbents." Journal of Applied and Natural Science 9, no. 2 (June 1, 2017): 688–92. http://dx.doi.org/10.31018/jans.v9i2.1258.
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Volatilized ammonia loss (VAL) and toxicity are major disadvantages on urea amendment. In order to mitigate, slow (or) controlled release urea based fertilizers are prepared with low cost materials. Therefore, micro and nano-sized adsorbents such as zeolite, biochar were impregnated with urea @1:1 ratio for fertilizer formulations. The objective of the study was to evaluate the VAL rate. To study the effect of soil texture, incubation experiment on two different soils of Tamil Nadu (TypicHaplustalf and VerticUstropepts) with 4 physically mixed, 4 fabricated, conventional urea and control without urea determined. Fertilizer formulations were surface applied @ 250 kg N ha-1 and assessed the VAL rate for 16 days. The trapped ammonia was observed with colour change from pink to greenish and titrated with diluted sulfuric acid. Initial 3 days VAL rate was high on urea, physically mixed adsorbent fertilizers than urea impregnated fertilizers and colour change was observed on every 4-6 h of both soils. In contrast, the urea impregnated fertilizers had colour change after 9-10 h regardless of adsorbent and soils. The fabricated fertilizer observed VAL rate on gradual with low quantity on T5- Zeourea (13.5 days, 15.1 days) T6- Nano-zeourea (15.5 days, 16 days), T9- Biourea (7.5 days, 7.1 days) and T10- Nano-biourea (9 days, 9.7 days) than T2- Urea (5.5 days, 4.6 days) of Alfisols and Inceptisols respectively. Cumulative VAL rate percentage was low on T5- Zeourea (30 %, 34 %), T6- Nano-zeourea (28 %, 29.3 %) T9- Biourea (39 %, 41.5 %) and T10- Nano-biourea (36 %, 37.5 %) of Alfisols and Inceptisols, respectively on comparison with other fertilizer type.It is concluded that the surface amendment of physically mixed fertilizers not influenced any change on both soils. Urea impregnation influenced on days and cumulative VAL percentage. Our study elucidates that micro and nano porous adsorbents are potential substrate to reduce VAL rate of urea in both soils.
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Adhikari, Kamal P., Surinder Saggar, James A. Hanly, Danilo F. Guinto, and Matthew D. Taylor. "Why copper and zinc are ineffective in reducing soil urease activity in New Zealand dairy-grazed pasture soils." Soil Research 56, no. 5 (2018): 491. http://dx.doi.org/10.1071/sr17278.
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Micronutrients copper (Cu) and zinc (Zn) have the potential to inhibit soil urease activity (UA) and reduce ammonia (NH3) emissions over long duration (8–12 weeks) but have not been tested for reducing NH3 losses from cattle urine deposited in dairy-grazed pasture soils. The objective of this study was to assess the effectiveness and longevity of Cu and Zn in reducing soil UA, for the use of these metals to reduce NH3 emissions from deposited urine by grazing cattle. A series of experiments were conducted to (i) assess the relationship between inherent Cu and Zn status and soil UA of New Zealand dairy-grazed pasture soils, (ii) determine the impact of Cu and Zn addition to pasture soils on soil UA and (iii) investigate how soil organic carbon (C) and other C-related textural and mineralogical properties such as clay content and cation exchange capacity influence the effectiveness of added Cu and Zn in reducing urea hydrolysis. The results showed significant positive correlations of soil total C and total nitrogen (N) with soil UA. However, there were no significant negative correlations of soil UA with inherent Cu and Zn levels. Similarly, addition of Cu and Zn to soil did not significantly reduce soil UA. However, when Cu was added to two different soil supernatants there was a significant reduction in hydrolysis of urea applied at 120 and 600 mg urea-N kg–1 soil. Additions of Zn achieved negligible or small reductions in urea hydrolysis after 120 and 600 mg urea-N kg–1 soil applications to soil supernatants. This result suggests that Cu can inhibit soil UA and urea hydrolysis in soil supernatants with potentially low C, clay and cation exchangeable base contents. However, the interaction of bioavailable Cu with labile soil organic C and clay particles leads to its inactivation, resulting in ineffectiveness in organic C-rich pasture soils. Although most of the added Zn did not complex and remained bioavailable, the observed levels of bioavailable Zn had limited effect on soil UA.
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Raveh-Amit, Hadas, and Michael Tsesarsky. "Biostimulation in Desert Soils for Microbial-Induced Calcite Precipitation." Applied Sciences 10, no. 8 (April 23, 2020): 2905. http://dx.doi.org/10.3390/app10082905.
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Microbial-induced calcite precipitation (MICP) is a soil amelioration technique aiming to mitigate different environmental and engineering concerns, including desertification, soil erosion, and soil liquefaction, among others. The hydrolysis of urea, catalyzed by the microbial enzyme urease, is considered the most efficient microbial pathway for MICP. Biostimulated MICP relies on the enhancement of indigenous urea-hydrolyzing bacteria by providing an appropriate enrichment and precipitation medium, as opposed to bioaugmentation, which requires introducing large volumes of exogenous bacterial cultures into the treated soil along with a growth and precipitation medium. Biostimulated MICP in desert soils is challenging as the total carbon content and the bacterial abundance are considerably low. In this study, we examined the biostimulation potential in soils from the Negev Desert, Israel, for the purpose of mitigation of topsoil erosion in arid environments. Incubating soil samples in urea and enrichment media demonstrated effective urea hydrolysis leading to pH increase, which is necessary for calcite precipitation. Biostimulation rates were found to increase with concentrations of energy (carbon) source in the stimulation media, reaching its maximal levels within 3 to 6 days. Following stimulation, calcium carbonate precipitation was induced by spiking stimulated bacteria in precipitation (CaCl2 enriched) media. The results of our research demonstrate that biostimulated MICP is feasible in the low-carbon, mineral soils of the northern Negev Desert in Israel.
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de Freitas, J. R., J. J. Schoenau, S. M. Boyetchko, and S. A. Cyrenne. "Soil microbial populations, community composition, and activity as affected by repeated applications of hog and cattle manure in eastern Saskatchewan." Canadian Journal of Microbiology 49, no. 9 (September 1, 2003): 538–48. http://dx.doi.org/10.1139/w03-069.
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A field site near Humboldt, Saskatchewan, was annually treated with hog or cattle manure and cropped to canola, spring wheat, barley, and canola from 1997 to 2000. During each growing season, soil was analyzed for microbial populations in terms of activity and community structure, and crops were assessed for root rot and foliar diseases. Microbial activity in soils treated with cattle manure was higher than in soils treated with hog manure or urea. Similarly, nitrous oxide emissions from soil increased with increasing rates of hog and cattle manure. Potential human pathogens, including Rahnella, Serratia, Proteus, Leclercia, and Salmonella species, were identified in soils that received cattle manure, whereas pseudomonads were the dominant species in the hog-manure-treated soil. Fecal coliforms were confirmed in soils that received hog or cattle manure. However, Enterobacteriaceae populations were 10-fold higher in soils receiving cattle manure than in soils receiving the other treatments. Increasing cattle manure rates increased fecal coliform population, but there was no indication that increased hog manure rates increased fecal coliform populations. Addition of urea, hog manure, or cattle manure to the soil did not increase foliar disease in wheat, barley, and canola and had variable effects on root rot incidence in cereals.Key words: soil microbial activity, soil microbial populations, microbial community, plant disease, hog manure, cattle manure, urea.
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Duncan, Elliott G., Cathryn A. O'Sullivan, Anna K. Simonsen, Margaret M. Roper, Mark B. Peoples, Karen Treble, and Kelley Whisson. "The nitrification inhibitor 3,4,-dimethylpyrazole phosphate strongly inhibits nitrification in coarse-grained soils containing a low abundance of nitrifying microbiota." Soil Research 55, no. 1 (2017): 28. http://dx.doi.org/10.1071/sr15359.
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The effectiveness of the nitrification inhibitor 3,4,-dimethylpyrazole phosphate (DMPP) on sandy soils containing low nitrifying microbial abundance has not been established. Two coarse-grained soils, representative of Western Australia’s agricultural zones, were incubated with 100mgNkg–1 soil, added as either urea, urea+DMPP or urea+nitrapyrin as an alternative nitrification inhibitor for comparative purposes. Ammonium (NH4+) and nitrate (NO3–) concentrations, potential nitrification rates (PNR) and the abundance of ammonia-oxidising bacteria (AOB) and archaea (AOA) were measured over time. Interactions between soil type and inhibitor type altered the extent of nitrification observed in these soils. When N was supplied as urea alone, NH4+-N concentrations decreased from 100mgNkg–1 soil to approximately 20mgNkg–1 soil in the high nutrient soil (Williams) and approximately 60mgNkg–1 soil in the low nutrient soil (Vasse). These differences were reflected in AOB abundance, which was higher (~105genecopiesg–1 soil) in Williams soil than in Vasse soil (<104genecopiesg–1 soil). This difference could have been attributable to differences in soil pH between Williams and Vasse (5.4 vs 4.0 respectively) and/or copper (Cu) availability (~1.5 vs ~0.5mgCukg–1 soil respectively), both of which have been demonstrated to reduce AOB abundance or limit nitrification. On the Williams soil, DMPP limited nitrification, resulting in approximately 80mgNkg–1 soil being retained as NH4+-N. Nitrapyrin was similarly effective for the first 56 days of incubation, but declined considerably in effectiveness between Days 56 and 100. Changes in soil nitrification rates were accompanied by changes in AOB abundance, which was below 103genecopiesg–1 soil when nitrification was impaired. Both DMPP and nitrapyrin inhibit nitrification via chelating Cu and, because these soils contained low Cu concentrations, it may be possible that interactions between DMPP, naturally low abundance of AOB and low Cu availability facilitated the long-term inhibition of nitrification in these soils.
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Niraula, Suresh, Shafiqur Rahman, and Amitava Chatterjee. "Release of Ammonia and Greenhouse Gases along Moisture Gradient from Manure and Urea Applied Fargo Silty Clay Soil." Applied Engineering in Agriculture 34, no. 6 (2018): 939–52. http://dx.doi.org/10.13031/aea.12985.
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Abstract. Greenhouse gas (GHG) [nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4)] emission and ammonia (NH3) volatilization from organic and commercial fertilizers are likely related to soil moisture levels. Effect of soil moisture [(30%, 60%, and 90% water-holding capacity (WHC)] on emissions from urea and manure treated (215 kg ha-1) Fargo-Ryan silty clay soil was studied under laboratory conditions. Soils (250 g) amended with solid beef manure (SM), straw-bedded solid beef manure (BM), urea (UR), and control (CT) were incubated for 28 days at 22±1°C, to determine GHGs (N2O, CO2, and CH4) emission and NH3 volatilization loss. The cumulative emission of N2O-N, CO2-C, and CH4-C ranged from 27 to 4402 µg N2O-N kg-1, 272 to 2030 mg CO2-C kg-1, and 10.1 to 1389 µg CH4-C kg-1 soil, respectively. The daily fluxes and cumulative emissions of N2O and CO2 generally followed the decreasing order of 30% < 90% < 60% of WHC. At 60% WHC, 1.01% of the total applied N was lost as N2O from urea treated soil. Carbon dioxide emission from manure treated soil (SM and BM) was up to two times the emission from UR treated soils. The Fargo clay soils showed higher CH4 emission at 90% WHC level. The cumulative NH3 volatilization loss from soil ranged from 29.4 to 1250.5 µg NH3-N kg-1, with the highest loss from UR amended soils at 30% WHC. These results suggest that gaseous emissions from manure and urea application under laboratory study are influenced by moisture levels of Fargo-Ryan silty clay soil. Keywords: Beef manure, Greenhouse gas, Soil water, Urea, Water holding capacity.
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Regina, K., H. Nykänen, M. Maljanen, J. Silvola, and P. J. Martikainen. "Emissions of N2O and NO and net nitrogen mineralization in a boreal forested peatland treated with different nitrogen compounds." Canadian Journal of Forest Research 28, no. 1 (January 1, 1998): 132–40. http://dx.doi.org/10.1139/x97-198.
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Fluxes of nitrous oxide (N2O) and nitric oxide (NO) were measured on a drained and forested peatland in 1992-1995. Net mineralization and nitrification were studied in situ in 1993-1994. Nitrogen additions in 1992 as KNO3, NH4Cl, or urea (100 kg N ·ha-1) were used to study the fate and transformations of N in peat. The mean N2O emissions during the growth season in 1993 were 1.9, 2.6, 3.3, and 3.5 mg N ·m-2·day-1in the control soil, KNO3, NH4Cl, and urea-treated soils, respectively. Mean NO fluxes during the growth season in 1993 averaged 0.3, 0.4, 0.7, and 0.6 mg N ·m-2·day-1in the control soil, KNO3, NH4Cl, and urea treatment, respectively. Annual net N mineralization was 87 kg N ·ha-1in the control soil and 107, 129, and 91 kg ·ha-1in the KNO3, NH4Cl, and urea-treated soils, respectively. Added N increased the fluxes of N oxides at least for a year after the treatments. The study showed that forests on drained N-rich peat soils may be significant sources of N2O and NO and that their production of nitrogenous trace gases is enhanced by additional N.
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Koivunen, Marja E., Christophe Morisseau, William R. Horwath, and Bruce D. Hammock. "Isolation of a strain of Agrobacterium tumefaciens (Rhizobium radiobacter) utilizing methylene urea (ureaformaldehyde) as nitrogen source." Canadian Journal of Microbiology 50, no. 3 (March 1, 2004): 167–74. http://dx.doi.org/10.1139/w04-001.
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Methylene ureas (MU) are slow-release nitrogen fertilizers degraded in soil by microbial enzymatic activity. Improved utilization of MU in agricultural production requires more knowledge about the organisms and enzymes responsible for its degradation. A Gram-negative, MU-degrading organism was isolated from a soil in Sacramento Valley, California. The bacterium was identified as Agrobacterium tumefaciens (recently also known as Rhizobium radiobacter) using both genotypic and phenotypic characterization. The pathogenic nature of the organism was confirmed by a bioassay on carrot disks. The MU-hydrolyzing enzyme (MUase) was intracellular and was induced by using MU as a sole source of nitrogen. The bacterial growth was optimized in NH4Cl, urea, or peptone, whereas the production and specific activity of MUase were maximized with either NH4Cl or urea as a nitrogen source. The result has a practical significance, demonstrating a potential to select for this plant pathogen in soils fertilized with MU.Key words: methylene urea, ureaformaldehyde, slow-release fertilizer, soil, nitrogen, isolation, Agrobacterium tumefaciens, Rhizobium radiobacter.
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Janke, Chelsea K., Ryosuke Fujinuma, Phil Moody, and Michael J. Bell. "Biochemical effects of banding limit the benefits of nitrification inhibition and controlled-release technology in the fertosphere of high N-input systems." Soil Research 57, no. 1 (2019): 28. http://dx.doi.org/10.1071/sr18211.
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Enhanced efficiency fertilisers (EEFs) may have an important role in improving nitrogen (N) use efficiency in agricultural systems. The performance of EEFs when applied by broadcasting and incorporation is well documented; however, little information is available for sub-surface banded N-fertiliser. This study aimed to determine the effectiveness of EEFs within the fertosphere in several soils. This was determined by: (i) establishing the key chemical effects and N-transformation activity within a urea band, and (ii) contrasting these findings with nitrification inhibitor (NI)-coated urea and a controlled-release polymer-coated urea (PCU). A 112-day incubation experiment was conducted with the EEFs band-applied in three contrasting soils with a history of sugarcane production. In standard urea and NI-urea treated soils, the pH within the fertosphere significantly increased to a maximum of ~pH 9.2–9.3. Alkaline conditions and high ammonium concentrations promoted elevated aqueous ammonia concentrations, resulting in complete nitrification inhibition. The PCU granules released ~40% of total urea content within 14 days, followed by subsequent release at significantly lower rates. The initial rapid urea release was attributed to damaged polymer coats, while close proximity of neighbouring granules within the band may have contributed to the subsequent slower release phase through reduced concentration gradients and restricted diffusion from granules. Variation between soils suggests that soil properties such as clay content and pH buffer capacity may influence urea hydrolysis, but not nitrification. These results suggest that both NI and controlled-release technology may not have the expected impacts on N transformations and availability when applied in a concentrated band.
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Hoa, Nguyen My, Trinh Thi Thu Trang, and Tran Kim Tinh. "Net N mineralisation in acid sulfate soils amended with different sources of organic matter, lime, and urea." Soil Research 42, no. 6 (2004): 685. http://dx.doi.org/10.1071/sr03081.
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Acid sulfate soils in the Mekong Delta, Vietnam, are often high in organic matter content, but net N mineralisation is low. This may be due to low soil pH or low easily decomposable organic matter content. This study aimed at investigating net N mineralisation in acid sulfate rice soil (anaerobic incubation) and acid sulfate upland soil (aerobic incubation) amended with 1% biogas sludge, 1% straw, 1% starch, 2.5‰ CaCO3 (about 10 t CaCO3/ha for acid sulfate soils), and 0.22‰ urea. Non-acid alluvial soils were used for comparison. Results showed that addition of straw and starch to acid sulfate rice soil decreased net N mineralisation, but addition of biogas sludge increased cumulative N-NH4 due to both the increase in soil pH after submergence and the supply of low C/N organic matter. Addition of biogas sludge can therefore increase N-supplying capacity in acid sulfate rice soil. During aerobic incubation of acid sulfate upland soil with biogas sludge, cumulative N (NH4 + NO3) was also increased compared with the control, although pH was not increased. It is concluded, therefore, that in acid sulfate soils in the Mekong Delta, the supply of easily decomposable organic matter with low C/N ratio can increase activity of microorganisms and hence increase net N mineralised compared with soils not supplied with biogas sludge. Liming can increase net N mineralisation in acid sulfate rice soil during anaerobic incubation, but not in acid sulfate upland soil during aerobic incubation. Addition of rice straw and starch to soil amended with urea increased N immobilisation; therefore, urea can be temporally immobilised in soils and hence may reduce loss of N in field conditions.
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Watson, Catherine J. "Factors affecting the efficiency of urea for pot-grown ryegrass." Journal of Agricultural Science 109, no. 3 (December 1987): 611–14. http://dx.doi.org/10.1017/s0021859600081879.
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Urea can be an inefficient nitrogen source, compared with ammonium nitrate, on calcareous soils (Ernst & Massey, 1960) and under dry conditions (Murphy, 1978) as a result of ammonia volatilization. However, the interaction between factors which can affect the performance of urea is not clearly understood. The risk of ammonia volatilization would appear to be higher on light soils with a low cation exchange capacity than on heavier soils (Fenn & Hossner, 1985). Field trials in the Netherlands indicated that a minimum of 5 mm of rain must fall within 2 days of application to give good dry-matter yields with urea (Van Burg, Dilz & Prins, 1982). In addition ammonia volatilization has been affected by initial soil moisture content in some studies (Fenn & Escarzaga, 1977) but not in others (Gasser, 1964).
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BOLE, J. B., and W. D. GOULD. "OVERWINTER LOSSES OF NITROGEN-15 LABELLED UREA FERTILIZER." Canadian Journal of Soil Science 66, no. 3 (August 1, 1986): 513–20. http://dx.doi.org/10.4141/cjss86-051.
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Field studies using 15N microplots were conducted to quantify the uptake and disappearance of fall- and spring-applied urea N on low organic matter, irrigated soils. Urea was mixed with the surface soil to maximize the potential for overwinter nitrification and subsequent losses of the fertilizer N. In three irrigated soils, losses of fall-applied urea averaged 24–31% compared with 11–21% of that applied at seeding. Barley took up 33–42% of spring-applied urea N but only 16–36% of fall-applied urea N. The lower uptake of fall-applied N apparently resulted from higher N losses rather than from the immobilization of fall-applied urea. Fall application resulted in lower soil reserves of residual fertilizer N after the growing season, as compared to spring application, in two of the three studies. Sixty percent of the fertilizer N recovered from the soil remained in the surface 15 cm. The application of 50 mm of water in the fall or 100 mm in the early spring, to intensify any effects of moisture, had a minimal effect on N losses or the distribution of N in the soil. This suggests that an individual rainfall event would not greatly affect the uptake or losses of fall-applied fertilizer on well-drained soil. The observed fertilizer losses, however, support practices such as concentrating fall-applied fertilizers in bands or the use of nitrification inhibitors. Key words: Denitrification, nitrogen, fertilizer, N balance, N losses, urea
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Cabral, Carlos E. A., Carla H. A. Cabral, Alyce R. M. Santos, Kassio S. Carvalho, Edna M. Bonfim-Silva, Jenifer S. Mattos, Letícia B. Alves, and Ana P. Bays. "Ammonium sulfate enhances the effectiveness of reactive natural phosphate for fertilizing tropical grasses." Tropical Grasslands-Forrajes Tropicales 8, no. 2 (May 30, 2020): 86–92. http://dx.doi.org/10.17138/tgft(8)86-92.
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Reactive natural phosphate is a slow and gradual solubilizing fertilizer, which makes it difficult to use in neutral to alkaline soils. Nitrogen fertilizers which acidify the soil may increase the possibility of using this phosphate fertilizer commercially. Two greenhouse experiments were conducted to compare responses of Xaraés palisadegrass (Urochloa brizantha syn. Brachiaria brizantha cv. Xaraés) and Mombasa guineagrass (Megathyrsus maximus syn. Panicum maximum cv. Mombasa), when different combinations of P and N fertilizers were applied during the establishment phase in non-acidic soils or with corrected acidity. The experiments were carried out in a completely randomized design with 3 fertilizer combinations (simple superphosphate plus urea, SSU; natural reactive phosphate plus urea, RPU; and natural reactive phosphate plus ammonium sulfate, RPAS). There was no difference in tiller density, leaf numbers, forage mass, leaf mass and stem mass for either forage on SSU and RPAS treatments but they exceeded those on RPU. Soil pH was lower in soil fertilized with ammonium sulfate than in soil fertilized with urea. Applying natural reactive phosphate plus ammonium sulfate seems as effective as simple superphosphate plus urea in promoting increased growth in tropical grasses on low-P soils. Longer-term and more extensive field studies are needed to determine if these results can be reproduced in the long term, and the level of soil acidification over time.
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Panwar, N. R., A. Saxena, D. V. Singh, and P. Kumar. "Yield sustainability of pearl millet and soil biological health with organic and inorganic fertilizer in arid environment." Journal of Environmental Biology 41, no. 6 (November 15, 2020): 1724–34. http://dx.doi.org/10.22438/jeb/41/6/si-262.
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Aim: To assess sustainable yield levels and manure and/or urea needed to sustain in arid zone. Methodology: A field experiment was conducted over a period of 25 years in arid soils of Jodhpur with three levels of manure (0, 2.5 and 5.0 t ha-1 yr-1), urea (0, 20 and 40 kg N ha-1 yr-1) and their combinations to assess the rate of change in yield of pearl millet cultivated with manure and/or urea; minimum quantity of manure and/or urea to be applied for achieving yield stability and minimum quantity of manure and/or urea to be applied for improved soil biological health vis-a-vis yield sustainability.? Results: Application of fertilizers over the years showed significant impact on the status of soil organic carbon (SOC) and soil fertility, which in turn influenced sustainability. The results showed that SOC had significant effect on sustainable yield index (SYI). However, available soil N status did not much influence the SYI. Application of urea-N alone or even that of 2.5 ton manure alone is not adequate to achieve agronomic sustainability of yield. Interpretation: Integration of FYM @ 2.5 t ha-1 yr-1 with 20kg N ha-1 sustained higher productivity to self-effacing economic status for farmers in a fragile ecosystem with the available minimum resources for livelihood and also sustain soil biological health of arid soils.
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el Fantroussi, Saïd, Laurent Verschuere, Willy Verstraete, and Eva M. Top. "Effect of Phenylurea Herbicides on Soil Microbial Communities Estimated by Analysis of 16S rRNA Gene Fingerprints and Community-Level Physiological Profiles." Applied and Environmental Microbiology 65, no. 3 (March 1, 1999): 982–88. http://dx.doi.org/10.1128/aem.65.3.982-988.1999.
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ABSTRACT The effect of three phenyl urea herbicides (diuron, linuron, and chlorotoluron) on soil microbial communities was studied by using soil samples with a 10-year history of treatment. Denaturing gradient gel electrophoresis (DGGE) was used for the analysis of 16S rRNA genes (16S rDNA). The degree of similarity between the 16S rDNA profiles of the communities was quantified by numerically analysing the DGGE band patterns. Similarity dendrograms showed that the microbial community structures of the herbicide-treated and nontreated soils were significantly different. Moreover, the bacterial diversity seemed to decrease in soils treated with urea herbicides, and sequence determination of several DGGE fragments showed that the most affected species in the soils treated with diuron and linuron belonged to an uncultivated bacterial group. As well as the 16S rDNA fingerprints, the substrate utilization patterns of the microbial communities were compared. Principal-component analysis performed on BIOLOG data showed that the functional abilities of the soil microbial communities were altered by the application of the herbicides. In addition, enrichment cultures of the different soils in medium with the urea herbicides as the sole carbon and nitrogen source showed that there was no difference between treated and nontreated soil in the rate of transformation of diuron and chlorotoluron but that there was a strong difference in the case of linuron. In the enrichment cultures with linuron-treated soil, linuron disappeared completely after 1 week whereas no significant transformation was observed in cultures inoculated with nontreated soil even after 4 weeks. In conclusion, this study showed that both the structure and metabolic potential of soil microbial communities were clearly affected by a long-term application of urea herbicides.
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Zaman, M., M. L. Nguyen, F. Matheson, J. D. Blennerhassett, and B. F. Quin. "Can soil amendments (zeolite or lime) shift the balance between nitrous oxide and dinitrogen emissions from pasture and wetland soils receiving urine or urea-N?" Soil Research 45, no. 7 (2007): 543. http://dx.doi.org/10.1071/sr07034.
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To determine the effects of soil amendments (lime or ammonium-sorbed zeolite) on emissions of nitrous oxide (N2O) and dinitrogen (N2) gases from pasture and wetland soils, a 90-day incubation experiment was conducted under controlled moisture and temperature conditions. Soil samples (0–0.10 m soil depth) collected from pasture and adjacent wetland sites were treated with 2 nitrogen (N) sources (cow urine or urea) at 200 kg N/ha with and without added soil amendments using 10-L plastic containers and then incubated at 25°C. Subsoil samples were taken out at different intervals to measure gaseous emissions of N2O and N2 using the acetylene (C2H2) inhibition method, ammonium (NH4+), nitrate (NO3–), soluble organic C, and pH. The anaerobic conditions (81% water-filled pore space) in wetland soils precluded nitrification, and therefore no increase in NO3–, N2O, or N2 was observed during the 90-day incubation period. In the pasture soil, the application of urine, urea, and soil amendments significantly affected daily and total N2O and N2 emissions and their ratios over a 90-day incubation period. Total N2O emission from urea-treated soil (48 kg N2O-N/ha) was significantly higher than from urine-treated soil (39 kg N2O-N/ha) and the control soil (4.5 kg N2O-N/ha). The application of zeolite significantly reduced N2O emissions from urea and urine-treated soils by 45% and 33%, respectively, due to the sorption of NH4+ by zeolite. Liming had minor effect on N2O emission. However, when lime was applied with zeolite, a significant reduction in N2O emission was observed. Lime application alone was found to increase N2 emissions in urine and urea treated soils by 46% and 35%, respectively, and thereby lower N2O : N2 ratios. The results indicate that zeolite reduced N2O emission while lime increased N2 emissions and lowered N2O : N2 ratios, and warranting further attention for mitigation of N2O.
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Ochmian, Ireneusz, Karolina Kozos, Anna Jaroszewska, and Ryszard Malinowski. "Chemical and Enzymatic Changes of Different Soils during Their Acidification to Adapt Them to the Cultivation of Highbush Blueberry." Agronomy 11, no. 1 (December 28, 2020): 44. http://dx.doi.org/10.3390/agronomy11010044.
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Although there has been an increase in the cultivation of highbush blueberry (Vaccinium corymbosum L.) worldwide for several years now, the availability of suitable soils for this species remains a problem. Highbush blueberry is a plant that requires acidic soils (pH 3.8–5.5), which are well aerated and have a stable level of groundwater and high humus content. In the present study, substances such as urea phosphate fertilizer, sulfur, sulfuric acid, and phosphogypsum were used to acidify three soils: peat, loamy sand, and loamy silt. The study aimed to lower the pH of the tested soils and optimize this parameter to cultivate highbush blueberry. The resulting changes in pH, content of macro- and micro-elements, and enzymatic activity were evaluated. Acidifying substances mitigated peat and loamy sand’s reaction to highbush blueberry requirements, while the reaction of loamy silt was changed only slightly, which made this soil unsuitable for plant cultivation. Sulfur dust acidified the examined soils rapidly and to the highest degree, followed by urea phosphate and phosphogypsum, while the weakest acidification was achieved with sulfuric acid solutions. The salt concentration of the soil was increased the most by the highest dose of phosphogypsum, which indicated that it could not be used to acidify soil for the cultivation of highbush blueberry. Among the acidifying substances, only urea phosphate showed a stimulating effect on the soils’ enzymatic activity, whereas others did not significantly affect or decrease this parameter.
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Husnain, Ibrahim Adamy Sipahutar, Joko Purnomo, Hery Widyanto, and Nurhayati. "CO2 Emissions from Tropical Peat Soil Affected by Fertilization." Journal of Tropical Soils 22, no. 1 (January 2, 2017): 1–9. http://dx.doi.org/10.5400/jts.2017.v22i1.1-9.
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The conversion of peat soils to agricultural uses has been thought to increase CO2 emission due to several factors, including fertilization. However, evidence on the effect of fertilization on CO2emissionsfrompeat soils is rareand often inconsistence. We measured the effects of different types of fertilizer, including N, P and K sources, and clay as an ameliorant on CO2 emission from a bare peat soil in Lubuk Ogong, Riau Province. Nutrients were added in the following combinations: 0 (unfertilized plot), N source (urea), slow-release N (slow release urea), N and Psource (Urea+SP-36), N, P and K sources (urea+SP-36+KCl) and combined NPK-Clay. Fertilization resulted in a decreasein CO2 emissions compared to that prior to fertilization except when slow-release urea was applied. Decreasing of CO2 emissions was probably due to pH-related effects because the pH in the N treatment was lower than in both the control and the unfertilized plot. A decreasein the level of CO2 emissions among the treatments followed the order NPK-Clay>NP>NPK>urea>slow-release urea. Covariance analyses showed that the difference in CO2 emissions prior to treatment was not significant. The application of individual and combined treatments of N, P, K and NPK mixed with 5 Mg ha-1 clay led to significantly reduced CO2 emissions from bare peat soil in Lubuk Ogong, Riau Province. In addition to fertilization, the water table depth was the only parameter that significantly affected the CO2 emissions (P<0.05). We conclude that the application of nutrient combinations, including N, P, K and clay, could reduce CO2 emissions because these treatments maintain a balanced nutritional condition in the soil with respect to the microbial activity.Keywords: Amelioration, CO2 emission, fertilization, tropical peat soils
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Kiran, Usha. "Influence of Farm Yard Manure, Farm Yard Manure + Urea, and Urea on Crop Yield in Prishnaparni (Uraria picta Desv. ex DC.)." Journal of Drug Research in Ayurvedic Sciences 2, no. 1 (March 2017): 30–33. http://dx.doi.org/10.5005/jp-journals-10059-0005.
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ABSTRACT To evaluate the effect of farm yard manure (FYM) alone, FYM + urea, and urea alone on the growth and yield of Uraria picta Desv. ex DC. with two physicochemically different soils of Bundelkhand region, pot experiment was conducted during 2010 to 2011 and 2014 to 2015. FYM + urea applied in 50:50 ratio of nitrogen (N) gave best results as compared with the other treatments for crop yield in both the types of soils. Highest dry matter yield of 18.62 gm/pot was obtained during the year 2010 to 2011 and 24.33 gm/pot was obtained during the year 2014 to 2015 when FYM + urea was treated in black soil. The FYM alone and urea alone yielded dry matter of 16.03 gm/pot and 15.55 gm/pot respectively, during the year 2010 to 2011. Trends for the increase in dry matter yield were similar during both the years of study. In red soil also, dry matter yield was highest (10.23 gm/pot) during the year 2010 to 2011 and (14.33 gm/pot) 2014 to 2015 when FYM + urea was applied. The FYM + urea in 50:50 ratio is the best for the growth of Uraria picta. Desv. ex DC. How to cite this article Kiran U. Influence of Farm Yard Manure, Farm Yard Manure + Urea, and Urea on Crop Yield in Prishnaparni (Uraria picta Desv. ex DC.). J Drug Res Ayurvedic Sci 2017;2(1):30-33.
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Reynolds, C. M., D. C. Wolf, and J. A. Armbruster. "Factors Related to Urea Hydrolysis in Soils." Soil Science Society of America Journal 49, no. 1 (January 1985): 104–8. http://dx.doi.org/10.2136/sssaj1985.03615995004900010021x.
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Bleskina, N. A. "Experience with Urea-Resin Stabilization of Soils." Soil Mechanics and Foundation Engineering 42, no. 4 (July 2005): 139–41. http://dx.doi.org/10.1007/s11204-005-0039-2.
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Zaman, MM, MAH Chowdhury, and Tanzin Chowdhury. "Response of stevia to foliar application of prilled urea." Journal of the Bangladesh Agricultural University 13, no. 1 (July 14, 2016): 39–46. http://dx.doi.org/10.3329/jbau.v13i1.28710.
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Urea can be supplied to plants through the foliage, facilitating optimal N management, which minimizes N losses to the environment. The efficiency of N assimilation through foliage depends upon several factors including N levels and varieties or genotypes. No information is available on the effect of the foliar application of urea on stevia (Stevia rebaudiana, Bertoni). The objective of the study was to evaluate the effect of foliar application of prilled urea applied in different concentrations on the growth, yield components, leaf biomass yield, N content and its uptake by stevia. Seven levels of urea viz. 0.0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3g 2L-1 were sprayed 10 days after planting (DAP) in acid and non-calcareous soils at an interval of one week up to 60 DAP. Foliar urea application significantly increased plant height, branch and leaf number, leaf area, fresh and dry leaf weight, leaf N content and uptake by stevia. Most of the parameters were increased with the advancement of growth period from 30 to 60 DAP. The foliar spray of 2.0g urea solution was found to be most effective for enhancing the growth, leaf yield and yield attributes of stevia. The yield increase was 478% in acid soil and 485% in non-calcareous soil over control. Further increase in the concentrations of urea spray (2.5 and 3.0g) was not found to be useful as it declined the leaf yield by 135% in acid and 175% in non-calcareous soil probably due to its toxicity. N content in stevia leaves was significantly increased with the increased levels of urea up to 3.0g in both soils. Conversely, the trend of N uptake did not follow the trend of N contents of stevia leaves. N uptake as expected increased as foliar application of urea increased up to 2.0g and then decreased with further addition. The results suggest that farmers can be advised to apply prilled urea as foliar spray @ 1g L-1 for higher leaf biomass yield and N uptake by stevia either in acid or non-calcareous soils under the agro-climatic conditions of Bangladesh Agricultural University, Mymensingh.J. Bangladesh Agril. Univ. 13(1): 39-46, June 2015
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Alkanani, Thamir, and Angus F. MacKenzie. "Banding urea and lignosulfonate in corn (Zea mays L.) production and 15N recovery." Canadian Journal of Soil Science 76, no. 3 (August 1, 1996): 365–71. http://dx.doi.org/10.4141/cjss96-044.
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The use of urea in corn (Zea mays L.) production is common. Under current N fertilizer recommendations for corn, urea may have adverse effects on corn growth when applied in a band. The effects of ammonium lignosulfonate (LS) on corn growth and on N uptake from the banded application of urea and diammonium phosphate (DAP) mixtures were investigated on two soils from eastern Quebec. Field experiments were initiated in the first week of May 1991 on an Ormstown silty clay and a Ste. Rosalie clay soils (fine, mixed, nonacid, mesic Typic Humaquepts). Treatments were two rates of urea (30 and 90 kg urea-N ha−1) in combination with DAP (14 kg N ha−1), with or without banded fertilizer solutions of LS (8 kg N ha−1) applied at planting 5 cm to the side and 3 cm below the seed. A no treatment control was included. The low rate of urea and DAP (no LS added) resulted in a 19 and 24% increase in grain yield at the Ste. Rosalie and Ormstown, respectively, when compared with the unfertilized plots. When compared with the unfertilized treatment, the high rate of urea and DAP (no LS added) caused 10% increase in grain yield. However, addition of LS to the high rate of urea and DAP increase grain yield by band 20%. In general, LS significantly increased corn N uptake from urea on both soils. Separate 15N field experiments were initiated in June 1991. Mean recovery of 15N in total dry matter (grain and stover) was 51.9% in Ormstown and 47.9% in Ste. Rosalie soil. Denitrification estimates, calculated as 15N not accounted for, were not affected by LS and the rate of banded urea-N. Immobilization of 15N ranged from 17.8% to 30.9% of the applied labelled urea. The rate of urea-N banded had no significant effect on immobilization, but LS resulted in significantly less 15N immobilized. These observations suggest that LS can reduce the biological immobilization of urea-N and increase the efficiency of urea fertilizer by reducing the negative effects of banding high levels of urea, while attaining benefits of band placement. Key words: Lignosulfonate, corn, urea, 15N
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Martens, D. A., and J. M. Bremner. "Soil properties affecting volatilization of ammonia from soils treated with urea." Communications in Soil Science and Plant Analysis 20, no. 15-16 (September 1989): 1645–57. http://dx.doi.org/10.1080/00103628909368173.
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Mohd Zuki, Muhammad Muhaymin, Noraini Md. Jaafar, Siti Zaharah Sakimin, and Mohd Khanif Yusop. "N-(n-Butyl) Thiophosphoric Triamide (NBPT)-Coated Urea (NCU) Improved Maize Growth and Nitrogen Use Efficiency (NUE) in Highly Weathered Tropical Soil." Sustainability 12, no. 21 (October 22, 2020): 8780. http://dx.doi.org/10.3390/su12218780.
Full textAbstract:
Nitrogen (N) fertilizer is commonly used to supply sufficient N for plant uptake, for which urea is one of the highly preferred synthetic N fertilizers due to its high N content. Unfortunately, N provided by urea is rapidly lost upon urea application to soils through ammonia volatilization, leaching, and denitrification. Thus, treatment of urea with urease inhibitor (N-(n-Butyl) Thiophosphoric Triamide (NBPT)) is among the solutions to slow down urea hydrolysis, therefore reducing loss of NH3 and saving N available for plant uptake and growth. A field study was carried out to evaluate the effects of NBPT-coated urea (NCU) at varying rates on growth, yield, and nitrogen use efficiency (NUE) of maize in tropical soil. The experiment was conducted at Field 15, Universiti Putra Malaysia, Serdang, Selangor, Malaysia, and maize (Zea mays var. Thai Super Sweet) was used as the test crop. The results showed that all maize grown in soils applied with urea coated with NBPT (NCU) (T2, T3, T4, and T5) had significantly (P ≤ 0.05) higher chlorophyll content compared to the control (T0 and T1). The surface leaf area of maize grown in NCU-treated soils at 120 kg N h−1 (T3) was recorded as the highest. NCU at and 96 kg N ha−1 (T3 and T4) were relatively effective in increasing maize plant dry weight, yield, and N uptake. Improvement of NUE by 45% over urea was recorded in the treatment of NCU at 96 kg N ha−1. NBPT-coated urea (NCU) at 96 kg N ha−1 had potential to increase the growth, yield, nitrogen uptake, and NUE of maize by increasing the availability of N for plant growth and development.
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Schwenke, Graeme D., William Manning, and Bruce M. Haigh. "Ammonia volatilisation from nitrogen fertilisers surface-applied to bare fallows, wheat crops and perennial-grass-based pastures on Vertosols." Soil Research 52, no. 8 (2014): 805. http://dx.doi.org/10.1071/sr14107.
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Farmers on Vertosols in the northern grains region of Australia are increasingly using pre-crop broadcasting and in-crop topdressing of nitrogen (N) fertilisers. Surface application risks gaseous loss via ammonia volatilisation, but the magnitude of N loss is unknown. Because both soil properties and environmental conditions influence ammonia volatilisation, measurements need to be field-based and non-intrusive, e.g. micrometeorological. We used an integrated horizontal flux technique to measure ammonia volatilised from neutral to alkaline Vertosols for a month after the application of several fertiliser products in 10 bare-fallow paddocks, seven mid-tillering wheat crops, and two perennial-grass-based pastures. Ammonia loss from urea averaged 11% (5.4–19%) when applied to fallow paddocks, 4.8% (3.1–7.6%) when applied to wheat, and 27% when applied to pasture. Volatilisation from urea applied to pastures was high, because there was little rain after spreading. Losses from ammonium sulfate applied to pastures were >60% less than from urea. Nitrogen losses from ammonium sulfate were high (18.6–33.8%) from soils with >10 g 100 g–1 of calcium carbonate (CaCO3), but were 52% less than from urea at five of eight fallow paddocks on non-calcareous soils, and 76% less than from urea at the two pasture paddocks. Coating urea with N-(n-butyl)thiophosphoric triamide reduced ammonia loss at just two of eight fallow paddocks and one of three in-crop paddocks. Ammonia volatilisation from aqueous solutions of urea, urea ammonium nitrate, and ammonium nitrate were either less than or no different from losses from granulated urea, but not consistent. With the exception of ammonium sulfate applied to soils with >10 g 100 g–1 of CaCO3, surface application of N fertiliser during autumn–winter on cropped Vertosols in the Australian northern grains region does not lead to major N loss via ammonia volatilisation.
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Qian, P., and J. J. Schoenau. "Use of ion exchange membrane to assess soil N supply to canola as affected by addition of liquid swine manure and urea." Canadian Journal of Soil Science 80, no. 1 (February 1, 2000): 213–18. http://dx.doi.org/10.4141/s99-049.
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A growth chamber study was conducted using two Saskatchewan soils to evaluate how addition of urea and swine manure affects the supply of plant-available nitrogen (ammonium and nitrate) and its relationship with plant N uptake. Treatments consisted of two different N rates applied as urea and manure (100 and 800 mg N kg−1) and a control. Ion exchange membrane probes were used to measure plant-available N supply rate. Canola was grown under the same environmental conditions to determine plant N uptake. Additions of fertilizer and manure significantly increased the supply of plant-available N measured in the soil. Over an 84-d period the available N supply in the manured soil was about 40% lower than in the urea-fertilized soil at equivalent rates of total N addition due to incomplete mineralization of organic N in the manure. However, plant N uptake was similar between manure and urea-treated soils, which was attributed to other nutrients present in the manure that may have enhanced root growth and plant N uptake. High proportions of ammonium N were measured initially, especially at the high rates of urea and manure. However, inorganic N in the form of ammonium rapidly decreased with time and nitrate N became the main inorganic N form supplied. Overall, there was good correlation (r value 0.79 to 0.96) between plant N uptake and available N supply rate in the soil as measured by ion exchange membrane. Key words: Ion exchange membrane, available N supply rate, urea, swine manure, canola, plant N uptake
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MARSHALL, V. G., S. REYNOLDS, and J. A. DANGERFIELD. "PREDICTING UREA HYDROLYSIS AT LOW TEMPERATURES IN BRITISH COLUMBIA FOREST SOILS." Canadian Journal of Soil Science 70, no. 3 (August 1, 1990): 519–23. http://dx.doi.org/10.4141/cjss90-053.
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Urease activity in 14 sites, representing a wide range of forest and soil types, was determined by a non-buffer method. Urease activity in L-H horizons ranged from 23–203 μg N hydrolyzed (g soil)−1 h−1 at 40 °C. In all soils, urease activity decreased dramatically with depth. At 0 °C, hydrolysis was estimated at 26.8 and 1.9 μg N g−1 h−1 for L-H and Bf horizons, respectively, for one site. Theoretical estimation of hydrolysis at 0 °C for the site with the lowest activity suggested that an operational application of urea (200 kg N ha−1) applied to snow could be hydrolyzed within 6 days in the rooting zone of all the soils studied. Key words: Urease activity, energy of activation, forest fertilization, Brunisols, Luvisols, Podzols
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de Carvalho Arjona, Jessica, Maria das Graças Silva-Valenzuela, Shu-Hui Wang, and Francisco Rolando Valenzuela-Diaz. "Biodegradable Nanocomposite Microcapsules for Controlled Release of Urea." Polymers 13, no. 5 (February 26, 2021): 722. http://dx.doi.org/10.3390/polym13050722.
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Urea is the most used fertilizer around the world as the main source of nitrogen to soil and plants. However, the administration of nitrogen dosage is critical, as its excess can be harmful to the environment. Therefore, the encapsulation of urea to achieve control on its release rates has been considered in several areas. In this work, encapsulation of urea by biodegradable polymer poly(3-hydroxybutyrate) (PHB) and its nanocomposites, namely PHB/MMT and PHB/OMMT, producing microcapsules by emulsion method is carried out. MMT and OMMT refer to Brazilian clays in a natural state and organophilized, respectively. In addition, the microcapsules are thus prepared to have their physicochemical characteristics investigated, then tested for biodegradation. Increment of microcapsules’ crystallinity due to the increased amount of poly(vinylacetate) (PVA), as emulsifier agent in the continuous phase, was confirmed by X-ray diffractometry (XRD) and atomic force microscopy (AFM). The presence of urea within microcapsules was verified by XRD, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The soil biodegradation assessments showed that PHB/OMMT microcapsules present higher degradation rates in sandy soils. The overall results suggest that the composites performed better than neat PHB and are very promising; moreover, PHB/OMMT microcapsules proved to be the best candidate for the controlled-release of urea in soils.
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Babar, Saima Kalsum, Naheed Akhtar Talpur, and Aijaz Ali Khooharo. "Effects of Cu and Zn Coated Urea on Eh, pH and Solubility of Cu and Zn in Rice Soils." October 2018 37, no. 4 (October 1, 2018): 625–32. http://dx.doi.org/10.22581/muet1982.1804.14.
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The concentration of Cu (Copper) and Zn (Zinc) decreases upon flooded conditions of rice soil. To assess the effects of flooding and application of Cu and Zn coated urea on changes in Eh, pH and solubility of Cu and Zn, a glasshouse experiment was conducted at Universiti Putra Malaysia. Rice plants (30 days old seedlings of type MR-219) on two soils (riverine and alluvium and marine alluvium) were transplanted. Nine treatments with variable rates and combinations of Cu and Zn coated urea were applied. The sources of fertilizers were copper sulfate and zinc sulfate. Eh values decreased with flooding time in both soils. The changes of Eh values were more negative in control treatments and stabilized after 3 weeks of submergence. The Eh variation was not observed affectively in the treated soils however, soil pH increased with flooding time. During the 3rd week of submergence, pH was neutral (pH 7.0). In both soils, Cu and Zn treated soil showed lower Eh and higher pH values as compared to untreated soil. Concentration of Cu and Zn in soil solution decreased with flooding. The higher Cu and Zn contents in soil were recorded in treated soils. Reduced solubility of Cu and Zn in control soils was related to larger changes in Eh and pH values. Mean comparison with Tukey’s HSD (Honest Significant Difference) test showed that Cu and Zn solubility decreased with decreased Eh and increased pH in the soil solution (p < 0.05%).
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Hamidi, Nur Hidayah, Osumanu Haruna Ahmed, Latifah Omar, and Huck Ywih Ch'ng. "Combined Use of Charcoal, Sago Bark Ash, and Urea Mitigate Soil Acidity and Aluminium Toxicity." Agronomy 11, no. 9 (September 8, 2021): 1799. http://dx.doi.org/10.3390/agronomy11091799.
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Highly weathered tropical acidic soils are characterized by low pH, low organic matter, and aluminium and iron toxicity. These factors pose a challenge to achieving sustainable agriculture. The continued increase in the human population with the accompanied increasing food demand have negatively impacted the global N cycle partly because of excessive use N fertilizers particularly urea which is commonly used in agriculture. Ammonia volatilization from urea as an example, negatives the environmental quality. This study focuses on soil-N availability, pH, exchangeable acidity, Al3+, and H+ of a highly weathered acid soils (Bekenu series) through the combined use of charcoal, sago bark ash, and urea. To this end, an incubation study was conducted for 90 days through the combined use of charcoal, sago bark ash, and urea to determine if this approach could improve soil N availability and pH at the same time reducing exchangeable acidity, and Al3+, and H+ toxicity. The amount of urea used was fixed at 100% as the recommended rate. Charcoal and sago bark ash were varied by 25%, 50%, 75%, and 100%, respectively of the recommended rate. Selected soil physico-chemical properties were determined using standard procedures. This study revealed that combined use of charcoal, sago bark ash, and urea increased soil pH and base cations simultaneously the approach also reduced exchangeable acidity, exchangeable Al3+, and exchangeable H+. There were no significant differences in soil total N, exchangeable NH4+, and available NO3− for the combined use of charcoal, sago bark ash, and urea and urea alone because of the acid neutralizing effect of the amendments. Apart from the sago bark ash’s liming effect, the high affinity of the functional groups of the charcoal for Al3+ might have impeded Al3+ from undergoing hydrolysis to produce more H+ because a complete one mole of Al3+ hydrolysis produces three moles of H+. Thus, the combined use of charcoal and sago bark ash can mitigate soil acidity and aluminium toxicity, although this approach has minimal effect on-N.
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Martikainen, Pertti J., and Eeva-Liisa Nurmiaho-Lassila. "Nitrosospira, an important ammonium-oxidizing bacterium in fertilized coniferous forest soil." Canadian Journal of Microbiology 31, no. 3 (March 1, 1985): 190–97. http://dx.doi.org/10.1139/m85-037.
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Among ammonium-oxidizing autotrophic nitrifiers only Nitrosospira was found in two pine forest soils fertilized with urea or wood ash in southern Finland. A strain isolated from an ash-treated soil was partially characterized. The cells were spirals, mostly of one to three turns; they were either flagellated or not and pili were found. The strain grew best at 20–27 °C at Po2 of 0.21 (shortest doubling time, 29 h). Km(O2) at 27 °C was 0.20 mg/L. Activity per cell during exponential growth ranged from 0.0060 to 0.0085 pmol [Formula: see text] and growth yield from 2.53 × 106 to 3.60 × 106 cells/μmol [Formula: see text]. Pure cultures could not be isolated from urea-fertilized soils. Hyphomicrobium- and seliberia-like bacteria were frequent contaminants of enrichment cultures in these soils. Reasons for the persistence of Nitrosospira in forest soil were discussed.
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Rawluk, C. D. L., C. A. Grant, and G. J. Racz. "Ammonia volatilization from soils fertilized with urea and varying rates of urease inhibitor NBPT." Canadian Journal of Soil Science 81, no. 2 (May 1, 2001): 239–46. http://dx.doi.org/10.4141/s00-052.
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Loss of N as ammonia (NH3) from surface-applied urea fertilizer may be high if hydrolysis takes place at the soil surface. The urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) may reduce NH3 loss from urea by delaying hydrolysis. Field studies using surface chambers were conducted in 1996 and 1997 to compare the amount of NH3 volatilized from surface applications of granular urea (100 kg N ha–1) treated with varying concentrations of NBPT (0, 0.05, 0.10 and 0.15% NBPT wt/wt). The studies were conducted on two Orthic Black Chernozemic soils, a Stockton fine sandy loam and a Newdale clay loam, in May and again in July to determine the relative influence of soil texture and temperature on NBPT performance at the varying rates. Ammonia losses were measured at various times to 12 d after fertilization (DAF) in 1996 and to 21 DAF in 1997. Total NH3 losses decreased in the order of 0% > 0.05% > 0.15% > 0.10% where use of NBPT reduced total NH3 loss by 28-88% over the entire study duration, and by 82 to 96% during periods of peak loss from unamended urea. Ammonia volatilization losses from NBPT-amended urea treatments were lower in May than in July. The total loss measured at all rates of NBPT was higher for the fine sandy loam soil except in May 1997 where cool conditions resulted in slightly lower loss than for the clay loam soil. Amending urea with NBPT at a rate as low as 0.05% wt/wt can reduce NH3 loss from surface-placed urea fertilizer, so that a greater proportion of fertilizer N is retained in the soil for plant use. The inhibitor helps reduce the amount of NH3 derived from urea entering the atmosphere to react or to be deposited elsewhere, and may lessen the need to overfertilize to compensate for potential NH3 losses. Key words: N-(n-butyl) thiophosphoric triamide, urease inhibitor, surface applications
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Amanullah, Hidayat Ullah, Mohamed Soliman Elshikh, Mona S. Alwahibi, Jawaher Alkahtani, Asim Muhammad, Shah Khalid, and Imran. "Nitrogen Contents in Soil, Grains, and Straw of Hybrid Rice Differ When Applied with Different Organic Nitrogen Sources." Agriculture 10, no. 9 (September 2, 2020): 386. http://dx.doi.org/10.3390/agriculture10090386.
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In the rice–wheat (R–W) system, inorganic nitrogen (N) fertilizer (urea, etc.) is the largest component of the N cycle, because the supply of N from organic fertilizers is insufficient. But the 4% Initiative aims to improve organic matter and stimulate carbon sequestration in soils using best agronomic practices (sustainable management practices) which are economically, environmentally, and socially friendly. This research project was, therefore, designed to assess the impact of various organic sources (OS, animal manure versus plant residues), inorganic N (urea), and their different combinations on the N concentrations in soils and plants (i.e., grains and straw) of hybrid rice plants. The experiments were conducted on farmers’ fields in Batkhela (Malakand), northwestern Pakistan, over 2 years (2011–2012 (Y1) and 2012–2013 (Y2)). The results revealed that N concentrations in soil as well as in rice plants ranked first when applied with urea-N, followed by the application of N in mixture (urea + OS), while the control plots (no N applied) ranked at the bottom. Among the six OS (three animal manures: poultry, sheep, and cattle; and three crop residues: onion, berseem, and wheat), application of N in the form of poultry manure was superior in terms of higher N concentrations in both soil and plants. Applying the required total N (120 kg N ha−1) in the form of 75% N from urea +25% N from OS resulted in higher N concentrations in soil and plants in Y1. The required total N (120 kg N ha−1) application in the form of 50% N from urea +50% N from OS produced higher N concentrations in soil and plants in Y2. It was concluded from the results, that combined application of N sources in the form of urea + OS can produce good performances in terms of higher N concentrations in soil as well as in rice plants under the R–W system. Integrated use of urea (N-fertilizer) with organic carbon sources (animal manures and crop residue) could sustain rice-based (exhaustive) cropping system.
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Burrows, Rhoda L., and Frank J. Peryea. "Soil Acidification Potential of Four Commercial Nitrogen Solutions Used for Fertigation." HortScience 30, no. 4 (July 1995): 879D—879. http://dx.doi.org/10.21273/hortsci.30.4.879d.
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Nitrification-induced subsoil acidification is a major problem encountered with the use of ammonium- or urea-containing fertilizer solutions for drip fertigation of tree fruit crops. We conducted a laboratory experiment to evaluate the soil acidification potential of the four fertilizer N solutions most frequently used for fertigation within the Washington tree fruit industry. Treatments were five orchard soils x four commercial N solutions (calcium nitrate, calcium-ammonium nitrate, ammonium nitrate, urea-ammoniun nitrate) x four N rates (0, 100, 200, 500 mg N/kg). Air-dry subsamples of each soil were inoculated with fresh soil known to exhibit nitrifying behavior amended with treatment solutions. Subsamples were maintained at simulated field capacity of –15 kPa. Soil pH was measured after 5 weeks incubation. The treatment solutions were reapplied and pH measured after another 5 weeks. The soil were then leached with distilled water and further incubated to determine if pH would increase as has been observed in the field. The fertilizer solutions acidified the soils in direct relation to their ammonium plus urea content. The calcium nitrate solution was acidifying because it contains ammonium nitrate as an impurity. We will present the pH “rebound” data.
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Li, Jie, Shuai Wang, Jiafa Luo, Stuart Lindsey, Lingli Wang, Lei Zhang, and Yuanliang Shi. "Potential of Chamomile recutita Plant Material to Inhibit Urease Activity and Reduce NH3 Volatilization in Two Agricultural Soils." Atmosphere 12, no. 9 (September 18, 2021): 1223. http://dx.doi.org/10.3390/atmos12091223.
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The large amount of ammonia released during agricultural application of urea fertilizer can result in a partial loss of applied nitrogen, having a detrimental effect on air quality. Although Chamomile recutita has nitrogen transformation inhibitory properties, providing potential agricultural and environmental benefits, the full extent of the effects of the major constituents of this plant on urease activity and NH3 volatilization in soils is currently unknown. Soil incubation experiments were established using 2-Cyclopenten-1-one and Eugenol, two major constituents of C. recutita, to evaluate their effects on inorganic soil nitrogen pools, urease activity, and NH3 volatilization in grey desert soil and red soil. An application rate of 0.25 g N kg−1 soil fertilizer was applied as urea with and without additives. An unfertilized treatment was also included as a control. In order to compare results, N(butyl) thiophosphoric triamide (NBPT), a common synthetic urease inhibitor, was also used. NBPT, 2-Cyclopenten-1-one and Eugenol were applied at a rate of 0.00125 g kg−1 soil (equivalent to 0.5% N). The results indicated that the rate of urea hydrolysis was higher in grey desert soil compared to red soil. Soil in the urea-only treatments recorded urea hydrolysis to be almost complete within seven days of application. The rate of hydrolysis was inhibited by the two natural compounds, and higher concentrations of urea were maintained for more than two weeks. Soil amended with the two materials exhibited strong soil urease inhibition in both soil treatments (75.1% in the alkaline grey desert soil and 72.8% in the acidic red soil). The strongest inhibitory effect occurred one to three days after incubation in the Eugenol treatment. Moreover, the inhibitory effects of Cyclopenten-1-one and Eugenol were superior to that of NBPT in the two soils. Cyclopenten-1-one and Eugenol also significantly reduced soil NH3 emissions by 14.2 to 45.3%, especially in the acidic red soil. Molecular docking studies confirmed inhibition mechanisms, highlighting that natural compounds interacted with the amino acid residues of the urease active center. This action resulted in the urease active pocket being blocked, thereby inhibiting enzyme activity. Overall, our findings suggest that 2-Cyclopenten-1-one and Eugenol are both capable of hindering urease activity and reducing the risk of N loss in the two tested soils. Results highlight their applicability as urease inhibitors and their effect in delaying the release of ammonia nitrogen, thereby increasing fertilizer N use efficiency. However, in order to fully assess N use efficiency and the N balance due to the presence of Chamomile extract in soil-crop systems, further field scale investigations are required.
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SINGH, YADVINDER, and E. G. BEAUCHAMP. "NITROGEN TRANSFORMATIONS NEAR UREA IN SOIL WITH DIFFERENT WATER POTENTIALS." Canadian Journal of Soil Science 68, no. 3 (August 1, 1988): 569–76. http://dx.doi.org/10.4141/cjss88-055.
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Two laboratory incubation experiments were conducted to determine the effect of initial soil water potential on the transformation of urea in large granules to nitrite and nitrate. In the first experiment two soils varying in initial soil water potentials (− 70 and − 140 kPa) were incubated with 2 g urea granules with and without a nitrification inhibitor (dicyandiamide) at 15 °C for 35 d. Only a trace of [Formula: see text] accumulated in a Brookston clay (pH 6.0) during the transformation of urea in 2 g granules. Accumulation of [Formula: see text] was also small (4–6 μg N g−1) in Conestogo silt loam (pH 7.6). Incorporation of dicyandiamide (DCD) into the urea granule at 50 g kg−1 urea significantly reduced the accumulation of [Formula: see text] in this soil. The relative rate of nitrification in the absence of DCD at −140 kPa water potential was 63.5% of that at −70 kPa (average of two soils). DCD reduced the nitrification of urea in 2 g granules by 85% during the 35-d period. In the second experiment a uniform layer of 2 g urea was placed in the center of 20-cm-long cores of Conestogo silt loam with three initial water potentials (−35, −60 and −120 kPa) and the soil was incubated at 15 °C for 45 d. The rate of urea hydrolysis was lowest at −120 kPa and greatest at −35 kPa. Soil pH in the vicinity of the urea layer increased from 7.6 to 9.1 and [Formula: see text] concentration was greater than 3000 μg g−1 soil. There were no significant differences in pH or [Formula: see text] concentration with the three soil water potential treatments at the 10th day of the incubation period. But, in the latter part of the incubation period, pH and [Formula: see text] concentration decreased with increasing soil water potential due to a higher rate of nitrification. Diffusion of various N species including [Formula: see text] was probably greater with the highest water potential treatment. Only small quantities of [Formula: see text] accumulated during nitrification of urea – N. Nitrification of urea increased with increasing water potential. After 35 d of incubation, 19.3, 15.4 and 8.9% of the applied urea had apparently nitrified at −35, −60 and −120 kPa, respectively. Nitrifier activity was completely inhibited in the 0- to 2-cm zone near the urea layer for 35 days. Nitrifier activity increased from an initial level of 8.5 to 73 μg [Formula: see text] in the 3- to 7-cm zone over the 35-d period. Nitrifier activity also increased with increasing soil water potential. Key words: Urea transformation, nitrification, water potential, large granules, nitrifier activity, [Formula: see text] production