Relevant bibliographies by topics / Urea in soils

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  2. Dissertations / Theses
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Academic literature on the topic 'Urea in soils'

Author: Grafiati
Published: 4 June 2021
Last updated: 12 February 2022

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Journal articles on the topic "Urea in soils"

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.
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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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Dissertations / Theses on the topic "Urea in soils"

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Ali, Abdul-Mehdi Saleh. "Reactions of urea phosphate in calcareous and alkaline soils: Ammonia volatilization and effects on soil sodium and salinity." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184694.

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Nitrogen (N) loss in the form of volatilized ammonia (NH₃) is a considerable problem when ammonium (NH₄⁺) forming fertilizers are applied to calcareous or alkaline soils. Large areas of agricultural land, contain alkalinity and salinity problems, are potentially suitable for crop production with little alteration. This study was conducted to determine and compare the effectiveness of urea phosphate (UP) in reducing soil alkalinity and NH₃ loss. The volatilization of NH₃ from UP and urea (U) was studied on 3 selected soils (Hayhook SL, Laveen L and Latene L) using an aeration system. Urea phosphate and U were each applied at rates of 0, 50, 100 and 200 ppm-N either to the surface dry or in solution or mixed with the soil. The volatilized NH₃ was trapped in sulfuric acid, sampled periodically and analyzed for N using the semi microkjeldahl distillation apparatus. The effect of UP, Sulfur-Foam (SF), Phosphuric Solution (PHP) and a mixture of SF and UP (Mix) on leaching soil sodium (Na) and salinity was also studies on two soils (Pima L and Crot CL) in columns. Each of these amendments was applied at a rate of one and two equivalent amounts of the exchangeable Naₑₓ. The highest N loss in the form of NH₃ occurred when U was applied to Hayhook soil. However, UP applied to Hayhook soil (neutral to acidic, coarse textured and low CaCO₃ content) resulted in the lowest NH₃-N loss. Less NH₃-N loss was found from U application to Laveen and Latene soils (fine textured with higher CaCO₃ content) than with Hayhook soil. The general trend was higher N loss, in the form of volatilized NH₃, with surface application dry or in solution than when mixed with the soil. This trend showed an increase in the amount of volatilized NH₃ with increasing rate of N application. Urea phosphate was as effective as PHP or Mix (acid containing fertilizers) treatments in reducing soil salinity and alkalinity in Pima and Crot soils. No difference was found between rates of application (1 and 2 equivalent amount of Naₑₓ) except for soil pH. A similar trend in the decrease in soil salinity was found to that of the pH which was in the order PHP, UP, Mix, SF and control treatments. No significant difference was found between SF and control treatments in all parameters. No significant difference was found between treatments for exchangeable Ca. This was affected by the Ca compounds present in the soil. Generally, UP is a potential fertilizer for supplying N and phosphorus (P) as plant nutrients, reducing NH₃ volatilization, and can be used as a soil amendment to control soil salinity and alkalinity.
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Meier, Jackie N. "Effects of lignosulfonate in combination with urea on soil carbon and nitrogen dynamics." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56658.

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Lignosulfonate (LS), a by-product of the pulp and paper industry, may have the potential to increase fertilizer N availability by acting as a urease and nitrification inhibitor. Four consecutive laboratory studies were conducted to evaluate the behavior of LS in agricultural soils. The effects of various types and rates of LS on soil respiration and soil N dynamics were determined. Effects of LS in combination with fertilizers on microbial activity and N dynamics were measured. Due to the high water solubility of LS a leaching column study was conducted to determine the potential leaching of LS.
Higher rates (20% w/w) of LS initially inhibited microbial activity. Generally LS was relatively resistant to degradation by soil microorganisms and small proportions of added LS-C ($<$2.1%) were leached from the soil columns, but leaching was a function of soil and moisture regime. Recovery of added mineral LS-N from soil treated with LS was low ($<$41%). Mineral N recovered from LS plus fertilizer amended soil was higher than recovery from corresponding fertilizer treatments. Lignosulfonate reduced urea hydrolysis and the proportion of added N volatilized as NH$ sb3$-N from a LS plus urea treatment. The mineral N pool from LS plus fertilizer treated soils had significantly lower NO$ sb3$-N concentrations than corresponding fertilizer treatments. Nitrification inhibition was believed to have been due to high fertilizer concentrations. At reduced urea and LS concentrations, LS decreased NO$ sb3$-N recovery in one of four soil types. However, reduced recovery may not have been from nitrification inhibition but possibly from denitrification or chemical reactions between N and phenolics from LS.
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Huang, Yuh-Ming. "The effects of precipitation of calcium carbonate on soil pH following urea application." Thesis, University of Oxford, 1990. https://ora.ox.ac.uk/objects/uuid:a81844cb-c0c1-4dd3-a3c5-fc7a1b716021.

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This thesis describes a series of experiments both in solution systems and soil systems to study the precipitation of calcium carbonate in soils and the effects of the precipitation on soil pH after urea had been applied. (1) A gas bubbling system has been established which introduces ammonia at a steady rate to the reaction solution and keeps it equilibrated at 0.00484 atm partial pressure of carbon dioxide. (2) In a non-seeded system, the effects of calcium, urea, Mg (magnesium), P (phosphate), and DOC (water-dissolved organic matter) on the precipitation were examined individually and in various combinations. Calcite and vaterite were found in the 10 mM CaC12 solutions with and without the addition of urea. When the solutions contained Mg, P, and DOC, vaterite was not found. Aragonite was found in the reaction solution containing 5 mM Mg. In high initial concentration of P (5x10-4 M) , the formation of calcium phosphate (amorphous by X-ray analysis) catalysed the formation of calcite. The effects of urea and Mg on the precipitation are negligible compared with the effects of P and DOC. (3) In a seeded system, 16 sets of experiments with four sizes of calcite-seeds were carried out to study the precipitation rate of calcium carbonate. This was described by the equation LR=-4.113±0.132 + 0.379±0.029 LWA + LSI where LR=log (precipitation rate, PR, in mole litre-1 min-1), LWA= log (newly formed calcium carbonate, g ml-1), and LSI=log (degree of supersaturation of calcium carbonate, SI). (4) A wide range of concentrations of urea (0.05, 0.1, 0.3, 0.5, 0.7, and 1 M) were added to three soils (Beg., Uni., and VWH) with or without the addition of 5 per cent of calcite (10-15 μm) to establish a rate model for the precipitation of calcium carbonate in soils. The precipitation model (in logarithmic form) in soils is lnPR=-9.47±0.30 + lnKSOIL + 0.379±0.029 InWA + InSI - 1686±703 P - 6.13±3.02 DOC + 3854±1775 (P DOC) where P and DOC are the concentrations in soil solutions, and lnKSOIL is the effect of soils on the precipitation, which is - 1.98, 0.43, and -0.10 for Beg., Uni., and VWH soils respectively. The amount of newly formed calcium carbonate is about a third to a half of the amount of ammoniacal-N released by urea hydrolysis. It was able to reduce the increase of soil pH by more than 0.6 pH units in some circumstances.
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Schindler, Frank Vincent. "Redistribution and fate of applied ??N-enriched urea under irrigated continuous corn production." Thesis, North Dakota State University, 1996. https://hdl.handle.net/10365/28973.

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Understanding the redistribution and fate of N is essential for justification of Best Management Practices (BMP). This project was conducted on a Hecla fine sandy loam (sandy, mixed, Aquic Haploboroll) soil at the BMP field site near Oakes, North Dakota. One objective of this investigation was to evaluate the residence times of N03- -N in 20 undisturbed lysimeters and its infiltration time through the soil profile to tile drains. Corn (Zea mays L.) was fertilized with 135 kg N ha -1 as ??N-enriched urea plus 13.5 and 48.1 kg N ha -1 preplant for 1993 and 1994, respectively. Urea-N was band applied to 20 and 10 undisturbed lysimeters at 2.0 and 5.93 atom percent (at %) ??N in 1993 and 1994, respectively. Average resident times of N03- -N in the lysimeters was 11.7 months. Lysimeter and tile drainage indicate the presence of preferential pathways. Residence times of N03- -N depend on frequency and intensity of precipitation events. Another objective was to determine what portion of the total N in the crop was from applied urea-N and what portion was from the native soil-N. Nitrogen plots received ??N enrichments of 4.25 and 5.93 at % ??N in 1993 and 1994, respectively. At the end of the 1993 and 1994 growing season, 41.5% and 35.7% of the labeled fertilizer N remained in the soil profile, while the total recovery of applied ??N in the soil-plant system was 86.2% and 75.4%, respectively. Low recoveries of applied N may have been the result of soil or aboveground plant biomass volatilization, or denitrification or preferential flow processes. Further research needs to be conducted with strict accountability of gaseous loss and the mechanism(s) responsible.
U.S. Bureau of Reclamation
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Yusran, Fadly Hairannoor. "Triple superphosphate and urea effects on availability of nutrients in the fertilizer band for soybean (Glycine max L.) growth with emphasis on molybdenum." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=69710.

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Fertilizer applications of urea and triple superphosphate (TSP) may affect availability of plant nutrients in the soil through alteration of soil pH and sorption-displacement effects. The objectives of this experiment were to evaluate urea and TSP effects on nutrient availability to soybean (Glycine max L.). Field experiments were carried out on three Quebec soils; a Chicot sandy clay loam (Gleyed Melanic Brunisol), an Ormstown silty clay loam (Luvic Gleysol) and a Ste. Rosalie clay (Humic Gleysol). Three levels of TSP (0, 40, 80 kg $ rm P sb2O sb5 ha sp{-1}),$ and three levels of urea (0, 25, 50 kg N ha$ sp{-1})$ were incubated in the field and sampled at 4, 8, 12, and 16 weeks. Added TSP increased extractable P and decreased NO$ sb3$-N. Overall, alterations in nutrients other than N and P with added TSP or urea were not agronomically significant. There was increased concentration of N, P and Mo in soybean in some soils due to TSP application. Added urea increased Mg concentration in soybean. The concentration and uptake of Mo was positively correlated with soil extractable P and Mg. Consequently, application of TSP and urea together improved Mo uptake in the Chicot soil, while in slightly acid soils, Ormstown and Ste. Rosalie, TSP alone increased Mo uptake.
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Noellsch, Adam J. "Optimizing crop N use efficiency using polymer-coated urea and other N fertilizer sources across landscapes with claypan soils." Diss., Columbia, Mo. : University of Missouri-Columbia, 2008. http://hdl.handle.net/10355/5643.

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Thesis (M.S.)--University of Missouri-Columbia, 2008.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 12, 2008) Includes bibliographical references.
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Ouyang, Duosheng. "New fertilizer combinations for improved nitrogen and phosphorus use efficiency and reduced environmental damage in corn production." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0004/NQ30353.pdf.

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Stark, Christine. "Effects of long- and short-term crop management on soil biological properties and nitrogen dynamics." Phd thesis, Lincoln University. Agriculture and Life Sciences Division, 2005. http://theses.lincoln.ac.nz/public/adt-NZLIU20070220.010748/.

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To date, there has been little research into the role of microbial community structure in the functioning of the soil ecosystem and on the links between microbial biomass size, microbial activity and key soil processes that drive nutrient availability. The maintenance of structural and functional diversity of the soil microbial community is essential to ensure the sustainability of agricultural production systems. Soils of the same type with similar fertility that had been under long-term organic and conventional crop management in Canterbury, New Zealand, were selected to investigate relationships between microbial community composition, function and potential environmental impacts. The effects of different fertilisation strategies on soil biology and nitrogen (N) dynamics were investigated under field (farm site comparison), semi-controlled (lysimeter study) and controlled (incubation experiments) conditions by determining soil microbial biomass carbon (C) and N, enzyme activities (dehydrogenase, arginine deaminase, fluorescein diacetate hydrolysis), microbial community structure (denaturing gradient gel electrophoresis following PCR amplification of 16S and 18S rDNA fragments using selected primer sets) and N dynamics (mineralisation and leaching). The farm site comparison revealed distinct differences between the soils in microbial community structure, microbial biomass C (conventional > organic) and arginine deaminase activity (organic > conventional). In the lysimeter study, the soils were subjected to the same crop rotation (barley (Hordeum vulgare L.), maize (Zea mays L.), rape (Brassica napus L. ssp. oleifera (Moench)) plus a lupin green manure (Lupinus angustifolius L.) and two fertiliser regimes (following common organic and conventional practice). Soil biological properties, microbial community structure and mineral N leaching losses were determined over 2½ years. Differences in mineral leaching losses were not significant between treatments (total organic management: 24.2 kg N per ha; conventional management: 28.6 kg N per ha). Crop rotation and plant type had a larger influence on the microbial biomass, activity and community structure than fertilisation. Initial differences between soils decreased over time for most biological soil properties, while they persisted for the enzyme activities (e.g. dehydrogenase activity: 4.0 and 2.9 µg per g and h for organic and conventional management history, respectively). A lack of consistent positive links between enzyme activities and microbial biomass size indicated that similarly sized and structured microbial communities can express varying rates of activity. In two successive incubation experiments, the soils were amended with different rates of a lupin green manure (4 or 8t dry matter per ha), and different forms of N at 100 kg per ha (urea and lupin) and incubated for 3 months. Samples were taken periodically, and in addition to soil biological properties and community structure, gross N mineralisation was determined. The form of N had a strong effect on microbial soil properties. Organic amendment resulted in a 2 to 5-fold increase in microbial biomass and enzyme activities, while microbial community structure was influenced by the addition or lack of C or N substrate. Correlation analyses suggested treatment-related differences in nutrient availability, microbial structural diversity (species richness or evenness) and physiological properties of the microbial community. The findings of this thesis showed that using green manures and crop rotations improved soil biology in both production systems, that no relationships existed between microbial structure, enzyme activities and N mineralisation, and that enzyme activities and microbial community structure are more closely associated with inherent soil and environmental factors, which makes them less useful as early indicators of changes in soil quality.
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Condron, Leo M. "Chemical nature and plant availability of phosphorus present in soils under long-term fertilised irrigated pastures in Canterbury, New Zealand." Lincoln College, University of Canterbury, 1986. http://hdl.handle.net/10182/1875.

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Soil P fractionation was used to examine changes in soil inorganic and organic P under grazed irrigated pasture in a long-term field trial at Winchmore in Mid-Canterbury. The soil P fractionation scheme used involved sequential extractions of soil with O.5M NaHCO₃ @ pH 8.5 (NaHCO₃ P), 0.1M NaOH (NaOH I P), 1M HCl (HCl P) and 0.1M NaOH (NaOH II P). The Winchmore trial comprised 5 treatments: control (no P since 1952), 376R (376 kg superphosphate ha⁻¹ yr⁻¹ 1952-1957, none since), 564R (564 kg superphosphate ha⁻¹ yr⁻¹ 1952-1957, none since) 188PA (188 kg superphosphate ha⁻¹ yr⁻¹ since 1952) and 376PA (376 kg superphosphate ha⁻¹ yr⁻¹ since 1952: Topsoil (0-7.5cm) samples taken from the different treatments in 1958, 1961, 1965, 1968, 1971, 1974 and 1977 were used in this study. Changes in soil P with time showed that significant increases in soil inorganic P occurred in the annually fertilised treatments (l88PA, 376PA). As expected, the overall increase in total soil inorganic P between 1958 and 1977 was greater in the 376PA treatment (159 µg P g⁻¹) than that in the 188PA treatment (37 µg P g⁻¹). However, the chemical forms of inorganic P which accumulated in the annually fertilised treatments changed with time. Between 1958 and 1971 most of the increases in soil inorganic P in these treatments occurred in the NaHCO₃ and NaOH I P fractions. On the other hand, increases in soil inorganic P in the annually fertilised treatments between 1971 and 1977 were found mainly in the HCl and NaOH II P fractions. These changes in soil P forms were attributed to the combined effects of lime addition in 1972 and increased amounts of sparingly soluble apatite P and iron-aluminium P in the single superphosphate applied during the 1970's. In the residual fertiliser treatments (376R, 564R) significant decreases in all of the soil inorganic P fractions (i.e. NaHCO₃ P, NaOH I P, HCl P, NaOH II p) occurred between 1958 and 1977 following the cessation of P fertiliser inputs in 1957. This was attributed to continued plant uptake of P accumulated in the soil from earlier P fertiliser additions. However, levels of inorganic P in the different soil P fractions in the residual fertiliser treatments did not decline to those in the control which indicated that some of the inorganic P accumulated in the soil from P fertiliser applied between 1952 and 1957 was present in very stable forms. In all treatments, significant increases in soil organic P occurred between 1958 and 1971. The overall increases in total soil organic P were greater in the annually fertilised treatments (70-86 µg P g⁻¹) than those in the residual fertiliser (55-64 µg P g⁻¹) and control (34 µg P g⁻¹) treatments which reflected the respective levels of pasture production in the different treatments. These increases in soil organic P were attributed to the biological conversion of native and fertiliser inorganic P to organic P in the soil via plant, animal and microbial residues. The results also showed that annual rates of soil organic P accumulation between 1958 and 1971 decreased with time which indicated that steady-state conditions with regard to net 'organic P accumulation were being reached. In the residual fertiliser treatments, soil organic P continued to increase between 1958 and 1971 while levels of soil inorganic P and pasture production declined. This indicated that organic P which accumulated in soil from P fertiliser additions was more stable and less available to plants than inorganic forms of soil P. Between 1971 and 1974 small (10-38 µg P g⁻¹) but significant decreases in total soil organic P occurred in all treatments. This was attributed to increased mineralisation of soil organic P as a result of lime (4 t ha⁻¹) applied to the trial in 1972 and also to the observed cessation of further net soil organic P accumulation after 1971. Liming also appeared to affect the chemical nature of soil organic P as shown by the large decreases in NaOH I organic P(78-88 µg P g⁻¹) and concomitant smaller increases in NaOH II organic P (53-65 µg P g⁻¹) which occurred in all treatments between 1971 and 1974. The chemical nature of soil organic P in the Winchmore long-term trial was also investigated using 31p nuclear magnetic resonance (NMR) spectroscopy and gel filtration chromatography. This involved quantitative extraction of organic P from the soil by sequential extraction with 0.1M NaOH, 0.2M aqueous acetylacetone (pH 8.3) and 0.5M NaOH following which the extracts were concentrated by ultrafiltration. Soils (0-7.5cm) taken from the control and 376PA annually fertilised treatments in 1958, 1971 and 1983 were used in this study. 31p NMR analysis showed that most (88-94%) of the organic P in the Winchmore soils was present as orthophosphate monoester P while the remainder was found as orthophosphate diester and pyrophosphate P. Orthophosphate monoester P also made up almost all of the soil organic P which accumulated in the 376PA treatment between 1958 and 1971. This indicated that soil organic P in the 376PA and control treatments was very stable. The gel filtration studies using Sephadex G-100 showed that most (61-83%) of the soil organic P in the control and 376PA treatments was present in the low molecular weight forms (<100,000 MW), although the proportion of soil organic P in high molecular weight forms (>100,000 MW) increased from 17-19% in 1958 to 38-39% in 1983. The latter was attributed to the microbial humification of organic P and indicated a shift toward more complex and possibly more stable forms of organic P in the soil with time. Assuming that the difference in soil organic P between the control and 376PA soils sampled in 1971 and 1983 represented the organic P derived from P fertiliser additions, results showed that this soil organic P was evenly distributed between the high and low molecular weight fractions. An exhaustive pot trial was used to examine the relative availability to plants of different forms of soil inorganic and organic P in long-term fertilised pasture soils. This involved growing 3 successive crops of perennial ryegrass (Lolium perenne) in 3 Lismore silt loam (Udic Ustochrept) soils which had received different amounts of P fertiliser for many years. Two of the soils were taken from the annually fertilised treatments in the Winchmore long term trial (188PA, 376PA) and the third (Fairton) was taken from a pasture which had been irrigated with meatworks effluent for over 80 years (65 kg P ha⁻¹ yr⁻¹). Each soil was subjected to 3 treatments, namely control (no nutrients added), N100 and N200. The latter treatments involved adding complete nutrient solutions with different quantities of N at rates of 100kg N ha⁻¹ (N100) and 200kg N ha⁻¹ (N200) on an area basis. The soil P fractionation scheme used was the same as that used in the Winchmore long-term trial study (i.e. NaHCO₃ P, NaOH I P, HCl P, NaOH II p). Results obtained showed that the availability to plants of different extracted inorganic P fractions, as measured by decreases in P fractions before and after 3 successive crops, followed the order: NaHCO₃ P > NaOH I P > HCl P = NaOH II P. Overall decreases in the NaHCO₃ and NaOH I inorganic P fractions were 34% and 16% respectively, while corresponding decreases in the HCl and NaOH II inorganic P fractions were small «10%) and not significant. However, a significant decrease in HCl P (16%) was observed in one soil (Fairton-N200 treatment) which was attributed to the significant decrease in soil pH (from 6.2 to 5.1) which occurred after successive cropping. Successive cropping had little or no effect on the levels of P in the different soil organic P fractions. This indicated that net soil organic P mineralisation did not contribute significantly to plant P uptake over the short-term. A short-term field experiment was also conducted to examine the effects of different soil management practices on the availability of different forms of P to plants in the long-term fertilised pasture soils. The trial was sited on selected plots of the existing annually fertilised treatments in the Winchmore long-term trial (188PA, 376PA) and comprised 5 treatments: control, 2 rates of lime (2 and 4 t ha⁻¹ ) , urea fertiliser (400kg N ha⁻¹ ) and mechanical cultivation. The above ground herbage in the uncultivated treatments was harvested on 11 occasions over a 2 year period and at each harvest topsoil (0-7.5 cm) samples were taken from all of the treatments for P analysis. The soil P fractionation scheme used in this particular trial involved sequential extractions with 0.5M NaHCO₃ @ pH 8.5 (NaHCO₃ P), 0.1M NaOH (NaOH P), ultrasonification with 0.1M NaOH (sonicate-NaOH p) and 1M HCl (HCl P). In addition, amounts of microbial P in the soils were determined. The results showed that liming resulted in small (10-21 µg P g⁻¹) though significant decreases in the NaOH soil organic P fraction in the 188PA and 376PA plots. Levels of soil microbial P were also found to be greater in the limed treatments compared with those in the controls. These results indicated that liming increased the microbial mineralisation of soil organic P in the Winchmore soils. However, pasture dry matter yields and P uptake were not significantly affected. Although urea significantly increased dry matter yields and P uptake, it did not appear to significantly affect amounts of P in the different soil P fractions. Mechanical cultivation and the subsequent fallow period (18 months) resulted in significant increases in amounts of P in the NaHCO₃ and NaOH inorganic P fractions. This was attributed to P released from the microbial decomposition of plant residues, although the absence of plants significantly reduced levels of microbial P in the cultivated soils. Practical implications of the results obtained in the present study were presented and discussed.
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10

Hulm, Sharon C. "Fertilizer nitrogen transformations following urea application to an afforested ecosystem." Thesis, University of Aberdeen, 1987. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU010535.

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Fertilizer nitrogen transformations in two Sitka spruce stands in northeast Scotland were studied using 15N-labelled (2.5 atom % 15N) urea at a rate equivalent to 160 kg N ha-1. The use of urea fertilizer resulted in accelerated growth of the tree crowns, and higher concentrations of total N in foliage, twigs and new wood. There was no fertilizer effect observed for bark. Despite a positive growth response by the trees to fertilizer N, only an estimated 17% of applied-N was utilized by the tree biomass. Application of urea-N resulted in a reduction in the leaching of inorganic N and certain cations (particularly Ca 2+). Gaseous losses of N were elevated following urea application, but estimated losses of fertilizer N via NH3 volatilization and denitrification were negligible. Data from both sites indicated a retention of volatilized NH3 in the tree canopy which was returned to the soil in throughfall. Urea application to the forest floor resulted in elevated pH of the LFH for a period of about 100 days. Urea application also led to a flush of acetic acid extractable PO4-P in the LFH. The addition of urea also resulted in increased counts of bacteria in the LFH. Data indicacted that elevated NO3- concentrations in the LFH may have been due to bacterial nitrification. Little effect of fertilizer N was observed for mineral soil, with a retention of the bulk of fertilizer N in the LFH.
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Books on the topic "Urea in soils"

1

Harsh, James Birney. Supercritical fluid extraction of 2,4-D, metribuzin, and urea herbicides from selected Washington soils: Final report. [Pullman, Wash: State of Washington Water Research Center, 1993.

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M, Simihǎian, ed. Improving efficiency of urea fertilizers by inhibition of soil urease activity. Dordrecht: Kluwer Academic Publishers, 2002.

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Kiss, S., and M. Simihăian. Improving Efficiency of Urea Fertilizers by Inhibition of Soil Urease Activity. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-017-1843-1.

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Rekhi, R. S. Fate and efficiency of urea fertilizers in India: Fate and efficiency of nitrogen fertilizers using ℗£??ǽN as testing material. Ludhiana: Dept. of Soils, Punjab Agricultural University, 1986.

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Workshop on Urea Deep-Placement Technology (1984 Bogor, Indonesia). Proceedings of the Workshop on Urea Deep-Placement Technology, Bogor, Indonesia, September 1984. Muscle Shoals, AL: IFDC, 1985.

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J, Radel R., ed. Degradation of urease inhibitors in soils. [Muscle Shoals, Ala: Tennessee Valley Authority National Fertilizer Development Center, 1988.

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L, Obermeyer Edmund, Anderson Harry William, and Pacific Northwest Research Station (Portland, Or.), eds. Comparative effects of precommercial thinning, urea fertilizer, and red alder in a site II, coast Douglas-fir plantation. Portland, OR: U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station, 1999.

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Marion, Carol I. Effects of nitrogen source, rate and a nitrification inhibitor on soil nitrogen status and mineral composition of strawberry. 1992.

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Kiss, S., and M. Simihaian. Improving Efficiency of Urea Fertilizers by Inhibition of Soil Urease Activity. Springer, 2002.

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Kiss, S., and M. Simihaian. Improving Efficiency of Urea Fertilizers by Inhibition of Soil Urease Activity. Springer, 2013.

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Book chapters on the topic "Urea in soils"

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Samater, A. H., and O. Van Cleemput. "Nitrite Accumulation in Soils upon Urea Application." In Progress in Nitrogen Cycling Studies, 621–26. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-011-5450-5_101.

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Kissel, D. E., M. L. Cabrera, and S. Paramasivam. "Ammonium, Ammonia, and Urea Reactions in Soils." In Nitrogen in Agricultural Systems, 101–55. Madison, WI, USA: American Society of Agronomy, Crop Science Society of America, Soil Science Society of America, 2015. http://dx.doi.org/10.2134/agronmonogr49.c4.

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Bremner, J. M. "Recent research on problems in the use of urea as a nitrogen fertilizer." In Nitrogen Economy in Tropical Soils, 321–29. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-009-1706-4_30.

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Kiss, S., and M. Simihăian. "Use of Urease Inhibitors in the Analysis of Urea and/or Ammonium from Urea-treated Soils." In Improving Efficiency of Urea Fertilizers by Inhibition of Soil Urease Activity, 343–45. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-017-1843-1_10.

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Cajuste, L. J., E. Sánchez-A, and R. J. Laird. "Behaviour of urea and ammonium sulfate fertilizers and their N uptake relationships in calcareous soils." In Nitrogen Economy in Tropical Soils, 347–53. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-1706-4_33.

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Gouveia, Gregory A., Nazeer Ahmad, and Selwyn M. Griffith. "Urea-N uptake by dasheen (Colocasia esculenta L. Schott) in relation to the fertilizer placement method." In Nitrogen Economy in Tropical Soils, 205–14. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-009-1706-4_21.

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Kiss, S., and M. Simihăian. "Effect of Urease Inhibitors on Other Enzyme Activities, Microbial Counts and Biomass as well as on Respiration and Other Microbial Processes in Soils." In Improving Efficiency of Urea Fertilizers by Inhibition of Soil Urease Activity, 321–42. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-017-1843-1_9.

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Roelcke, M., Y. Han, S. X. Li, and J. Richter. "Laboratory measurements and simulations of ammonia volatilization from urea applied to calcareous Chinese loess soils." In Progress in Nitrogen Cycling Studies, 491–97. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-011-5450-5_80.

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Jianga, Zhaohui, Qingru Zeng, Hejie Pi, Bohan Liao, Xiaoyou Feng, and Yulin Sun. "Transformation of Nitrogen and Its Effects on Metal Elements by Coated Urea Application in Soils from South China." In Molecular Environmental Soil Science at the Interfaces in the Earth’s Critical Zone, 137–40. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-05297-2_42.

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Csitári, Gábor, Katalin Debreczeni, and István Sisák. "Effect of herbicides on the urea transformation in soil." In Progress in Nitrogen Cycling Studies, 191–94. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-011-5450-5_30.

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Conference papers on the topic "Urea in soils"

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Mackevičius, Rimantas, Danutė Sližytė, Tatyana Zhilkina, and Vadim Turchin. "Investigation of influence of additives on properties of multi-molecular organic solutions used for permeation grouting." In The 13th international scientific conference “Modern Building Materials, Structures and Techniques”. Vilnius Gediminas Technical University, 2019. http://dx.doi.org/10.3846/mbmst.2019.112.

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Permeation grouting for stabilization of dispersive sandy and gravely soils is in use from beginning of 19th century and has high importance for various underpinning, tunneling, and structural strengthening works. As materials for permeation grouting are applied not only cement mortar or silica gel in many compositions but multi-molecular organic solutions too. From multi-molecular organic solutions for permeation grouting are in use various synthetic resins such as acrylic, urea-formaldehyde, or other polymer resins. Urea-formaldehyde resin has right physical and mechanical properties for applying in soil stabilization but additives can change these properties. For example, additives can increase density, pH-rate, and gel-formation time of urea-formaldehyde resin. Additives can decrease viscosity of solutions based on urea-formaldehyde resin. Additives can improve environmental aspects of use of multi-molecular organic solutions for grouting of sandy soils. Long-time investigations of influence of additives on properties of multi-molecular organic solutions used for soil stabilization give good results for optimization of composition of materials for grouting.
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Chang-Ai, Zhang, Xin Shurong, and Li Yan. "Nitrogen Release of Controlled Release Coated Urea in Soil." In 2016 International Conference on Smart City and Systems Engineering (ICSCSE). IEEE, 2016. http://dx.doi.org/10.1109/icscse.2016.0043.

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Arab, Mohamed G. "Soil Stabilization using Calcium Carbonate Precipitation via Urea Hydrolysis." In The 4th World Congress on Civil, Structural, and Environmental Engineering. Avestia Publishing, 2019. http://dx.doi.org/10.11159/icgre19.149.

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Vernekar, Sulaxana R., Ingrid Anne P. Nazareth, Jivan S. Parab, and Gourish M. Naik. "Error analysis in soil urea prediction based on RF spectroscopy." In 2016 IEEE International Conference on Advances in Electronics, Communication and Computer Technology (ICAECCT). IEEE, 2016. http://dx.doi.org/10.1109/icaecct.2016.7942591.

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Ajdary, Khalil, and Hamid Zare Abianeh. "Modeling of nitrogen leaching by using urea fertilizer in sandy loam soil." In Proceedings of the III International Conference on Environmental, Industrial and Applied Microbiology (BioMicroWorld2009). WORLD SCIENTIFIC, 2010. http://dx.doi.org/10.1142/9789814322119_0017.

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Zhou, Xuan, Liang-Huan Wu, Ruo-Hui Lu, and Feng Dai. "Effects of Biochemical Inhibitors on Transformation of Urea Nitrogen in Yellow Clayey Soil." In 2015 International Conference on Energy, Environmental & Sustainable Ecosystem Development (EESED 2015). WORLD SCIENTIFIC, 2015. http://dx.doi.org/10.1142/9789814723008_0121.

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VAGUSEVIČIENĖ, Ilona, and Aistė JUCHNEVIČIENĖ. "THE EFFECT OF NITROGEN FERTILISERS ON THE GRAIN YIELD OF DIFFERENT CULTIVARS OF WINTER WHEAT." In Rural Development 2015. Aleksandras Stulginskis University, 2015. http://dx.doi.org/10.15544/rd.2015.032.

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The article deals with the effect of nitrogen fertilizer on the yield of different cultivars of winter wheat. Field experiments were conducted in 2011–2013 at the Experimental Station of Aleksandras Stulginskis University in carbonate shallow gleyic leached soil, (Calc(ar)i-Epihypogleyic Luvisol). The object of the investigation was winter wheat cultivars ‘Zentos’ and ‘Ada’. In sowing time the wheat was treated with granular superphosphate (P60) and potassium chloride (K60), and in spring, after the vegetative growth had resumed, in tillering time (BBCH 23–15) with ammonium nitrate (N60). Additionally, foliar fertilizer urea solution was used: N30, N40 at booting stage (BBCH 34–36) and N15, N30 at milk ripening stage (BBCH 71–74). It has been established that application of nitrogen fertilizer at booting and milk ripening stages increased the yield of wheat cultivars ‘Zentos’ and ‘Ada’ (0.06–1.74 and 0.41–1.74 t ha–1). The correlation and regression analysis confirmed that wheat grain yield statistically significantly correlated with nitrogen fertilizer application rates. The correlative relationships were very strong (r = 0.983 and r = 0.987). Irrespective of additional fertilization, genetic properties of the cultivars also had influence on the yield.
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JUCHNEVIČIENĖ, Aistė, and Ilona VAGUSEVIČIENĖ. "THE DYNAMICS OF PHOTOSYNTHETIC PIGMENTS IN WINTER WHEAT LEAVES WHEN USING NITROGEN FERTILISERS." In Rural Development 2015. Aleksandras Stulginskis University, 2015. http://dx.doi.org/10.15544/rd.2015.033.

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The paper investigates the effect of nitrogen fertilisers on the amount of photosynthetic pigments in winter wheat leaves. The research was carried out in the period between 2012 and 2013 at the Experimental Station of Aleksandras Stulginskis University in carbonate shallow gleyic leached soil, (Calc(ar)i-Epihypogleyic Luvisol). The object of investigation: winter wheat cultivars ‘Zentos’ and ‘Ada’. Granular superphosphate (P60) and potassium chloride (K60) fertilisers were spread during sowing, while amonium nitrate (N60) was used in tillering time (BBCH 23–25), after the vegetative growth had resumed. Additionally, the plants were treated with foliar fertiliser urea solution: N30, N40 at booting stage (BBCH 34–36) and N15, N30 at milk ripening stage (BBCH 71–74). After the analysis of the data, it was established that additional fertilization with N30 and N40 fertiliser application rates at later stages of plant development stimulated the accumulation of photosynthetic pigments and prolonged the period of active photosynthesis. Irrespective of treatment with nitrogen fertilisers, genetic properties of the cultivar also had influence on the accumulation of the pigments. Wheat cultivar ‘Zentos’ tended to accumulate larger amounts of pigments. The highest amounts of pigments were found at the beginning of milk ripening stage before additional treatment with N15, N30 fertiliser application rates.
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