Liquid Urea Research Articles

Effects of liquid urea rates on nitrogen dynamics, growth, and yield of corn (Zea mays L.)

Arbitrary use of urea fertilizer reduces nitrogen use efficiency (NUE) and increases the risk of environmental pollution. An experiment was conducted at the Universiti Putra Malaysia from November 2019 to March 2020 to evaluate the application methods and rates of liquid urea (LU) on the yield performance of corn. The treatments were, U0 = control, GU100 = Granular urea (GU) 100%, LU100 = LU 100%, LU50 = LU 50% and LU33 = LU 33%, in two equal splits at 10th and 28th days after sowing (DAS) in randomized completely block design, replicates four. Results showed that plant height (206.99 cm, 216.92 cm, 214.61 cm), ear height (88.13 cm, 88.63 cm, 86.00 cm), days of maturity (88.75, 89.00, 86.75 days), number of grains per kernel row (32.25, 34.50, 33.75), fresh cob weight (10,886.60 kg ha−1, 10,946.60 kg ha−1, 10,927.93 kg ha−1) and 100-grain weight (20.51 g, 22.50 g, 21.39 g) of corn were not different significantly (p ≤ 0.05) in GU100, LU100 and LU50 treatments, respectively. The highest yield of corn was found with LU100 (6249.03 kg ha−1) treatment whereas the yield in LU50 (5666.50 kg ha−1) and GU100 (5746.64 kg ha−1) were not different significantly. Nitrogen (%) in plants was the highest in LU100 followed by LU50 treatment which was significantly higher than GU100 treatment. The total N content was also the highest in LU100 (102.83 kg ha−1) though the total N content was not different significantly in LU50 (77.62 kg ha−1) and GU100 (83.84 kg ha−1) treatments. The NUE was the highest in LU50 (66.92%) treatment followed by LU100 (51.47%) treatment. The results of the study suggested that LU was superior to GU and the LU100 was the best application rate while LU50 treatment was comparable to GU100 in corn cultivation.

Humic acid enriched with urea and NPK factory by-products promoted the growth and yield of Saccharum officinarum L.

Nutrient uptake efficiency in sugarcane (Saccharum officinarum L.) must be increased using organic matter to restore soil fertility, resulting in greater productivity. The humic substance is a complex organic material that is excellent for overcoming this challenge. This study aimed to determine the effect of the humic acid enriched by liquid urea by-product (PSUC) and liquid NPK by-product (PSNC) application on the growth and productivity of sugarcane. The experiment was conducted from October 2021 to September 2022 on PT RNI plantation land, Jatitujuh, Majalengka. The research was arranged in a completely randomized (CRD) using two different humic acid product prototypes (PSUC and PSNC) with two evaluation times, a screening and a semi-pilot scale. Solid humic at a dose of 15 Kg ha⁻¹ was applied by mixing it with inorganic fertilizers, while liquid humic at a total dose of 15 L ha⁻¹ was applied by foliar spray technique at 1, 2, and 3 months after planting (MAP). The results showed that applying humic acid PSUC and PSNC enhanced sugarcane shoot growth, segmented stem number, and diameter. In addition, it could consistently promote sugarcane yields on the semi-pilot scale up to 19.18% and 24.26% under humic acid PSUC and PSNC treatments, respectively. Therefore, both in the screening and semi-pilot evaluation, the solid and liquid humic acid PSUC and PSNC applied simultaneously are potential organic materials to enhance sugarcane growth and yield.

Nitrogen dynamics as a function of soil types, compaction, and moisture.

In this study, the complex interactions between soil types, compaction, and moisture on nitrogen (N) transformation processes such as ammonia (NH3) volatilization, ammonification, nitrification, and denitrification were examined over a 30-day period using a simulated column approach. Two soil types: loam, and sandy loam, were subjected to three compaction treatments-control, surface, and sub-surface compaction-and two moisture regimes, dry and wet. Liquid urea ammonium nitrate (32-0-0) was used as the N fertilizer source at a rate of 200 kg N ha-1. Key indicators of N transformations were measured, including residual concentrations of ammonium (NH4-N) and nitrate (NO3-N), NO3-N leaching, NH3 volatilization, and nitrous oxide (N2O) emissions. Findings revealed that compaction significantly increased residual NH4-N concentrations in deeper soil profiles, with the highest 190.80 mg kg-1 recorded in loam soil under sub-surface compaction and dry conditions. Nitrification rates decreased across both soil types due to compaction, evidenced by elevated residual NH4-N levels. Increased NO3-N leaching was observed in loam soil (178.06 mg L-1), greater than sandy loam (81.11 mg L-1), due to initial higher residual NO3- in loam soil. The interaction of compaction and moisture most affected N2O emissions, with the highest emissions in control treatments during dry weather at 2.88 kg ha -1. Additionally, higher NH3 volatilization was noted in moist sandy loam soil under control conditions at 19.64 kg ha -1. These results highlight the necessity of considering soil texture, moisture, and compaction in implementing sustainable N management strategies in agriculture and suggest recommendations such as avoiding broadcast application in moist sandy loam and loam soil to mitigate NH3 volatilization and enhance N use efficiency, as well as advocating for readjustment of fertilizer rate based on organic matter content to reduce potential NO3-N leaching and N2O emissions, particularly in loam soil.

Integrating plant morphological traits with remote-sensed multispectral imageries for accurate corn grain yield prediction.

Sustainable crop production requires adequate and efficient management practices to reduce the negative environmental impacts of excessive nitrogen (N) fertilization. Remote sensing has gained traction as a low-cost and time-efficient tool for monitoring and managing cropping systems. In this study, vegetation indices (VIs) obtained from an unmanned aerial vehicle (UAV) were used to detect corn (Zea mays L.) response to varying N rates (ranging from 0 to 208 kg N ha-1) and fertilizer application methods (liquid urea ammonium nitrate (UAN), urea side-dressing and slow-release fertilizer). Four VIs were evaluated at three different growth stages of corn (V6, R3, and physiological maturity) along with morphological traits including plant height and leaf chlorophyll content (SPAD) to determine their predictive capability for corn yield. Our results show no differences in grain yield (average 13.2 Mg ha-1) between furrow-applied slow-release fertilizer at ≥156 kg N ha-1 and 208 kg N ha-1 side-dressed urea. Early season remote-sensed VIs and morphological data collected at V6 were least effective for grain yield prediction. Moreover, multivariate grain yield prediction was more accurate than univariate. Late-season measurements at the R3 and mature growth stages using a combination of normalized difference vegetation index (NDVI) and green normalized difference vegetation index (GNDVI) in a multilinear regression model showed effective prediction for corn yield. Additionally, a combination of NDVI and normalized difference red edge index (NDRE) in a multi-exponential regression model also demonstrated good prediction capabilities.

Short‐term soil carbon mineralization on golf course sand‐based putting green and its effect on creeping bentgrass nitrogen uptake

AbstractA rapid soil test for accurately estimating nitrogen (N) supply from soil organic matter would help turfgrass managers develop N fertilization programs. In this study, we tested the feasibility of using a quick test, mineralizable carbon (min‐C), to predict turfgrass growth and N uptake from sand‐based putting green soils. A 2‐year field experiment was conducted in Verona, WI, on four sand‐based research golf greens planted with creeping bentgrass. Nitrogen fertilizer was applied at 0, 10, and 20 kg ha−1every 2 weeks as liquid urea during the growing seasons. Soil samples were collected at 0–5 cm and 5–10 cm and tested for min‐C by measuring the flush of CO2following the rewetting dried soil, where the soil was rewetted at 50% water‐filled pore space and incubated at 25°C for 24 h. Min‐C was greater at the shallower soil depth, and unaffected by N rates that were applied. On‐site air temperature, soil moisture content, and estimated soil temperature were negatively related with min‐C, wherer2 = 0.26–0.60 for air temperature,r2 = 0.32–0.71 for soil moisture content, andr2 = 0.16–0.53 for estimated soil temperature, indicating the test is quite sensitive to environmental conditions at the time of sampling. Furthermore, min‐C had weak positive to no relationship with creeping bentgrass growth rate (r2 = 0–0.17) and N uptake (r2 = 0–0.23) on sand‐based putting green, suggesting the test does not hold promise as a method for improving fertilizer decisions to these systems.

Design of Ingenious Electronic Actuated Tractor Operated Liquid Urea Applicator

Design of Ingenious Electronic Actuated Tractor Operated Liquid Urea Applicator

Growth and yield of shallot (<em>Allium ascalonicum</em> L.) as influenced by soil application of liquid urea and cow urine

This experiment was carried to evaluate the effect of liquid urea and cow urine with cow dung on the economic yield of shallot (Allium ascalonicum L.) in the Eastern Province of Sri Lanka. The experiment was arranged in a Completely Randomized Design (CRD) with eight replicates and six treatments namely, T1: 20 g cow dung, T2: 20 g cow dung + 3% urea, T3: 20 g cow dung + 3% cow urine, T4: 30 g cow dung, T5: 30 g cow dung + 3% urea, and T6: 30 g cow dung + 3% cow urine. The soil applications of liquid urea and cow urine were done as top dressing at two weeks interval from 3rd week after planting (WAP). Data were collected at 3rd, 5th, 7th, and 9th WAP and at harvesting stage. The results revealed that there were significant (P<0.001) variations in plant height, number of bulbs, bulb diameter, fresh weight of single bulb, number of roots, root length, dry weight of leaves, dry weight of bulbs per plant and bulb yield per unit land among the treatments. Relatively higher yield (37.5 t/ha) was obtained from the plants treated with 30 g cow dung and 3% urea (T5) than other treatments whereas 20 g cow dung alone (T1) produced the lowest yield (8.4 t/ha). T6 (30 g cow dung and 3% cow urine) gave 32.6 t/ha bulb yield. It was also noted that there was no remarkable (P>0.05) difference in the bulb yields between T2 and T3. However, significant variation was observed between T5 and T6. The combined effect of cow dung and liquid urea fertilizer increased the onion yield. From this study, it could be stated that 30 g cow dung with 3% urea or 3% cow urine could give high bulb yield in the shallot cultivation at rural areas in Sri Lanka where farmers could easily collect the locally available materials for crop production in ecofriendly manner.

Study of temperature changes in mineral fertiliser granules after contact with air in a granulation tower

The object of research is the process of granulation of nitrogen mineral fertilizers by the method of sprinkling. One of the most problematic areas is the lack of certainty regarding the dynamics of the temperature change of the granule when it is cooled by air in the granulation tower. The paper considers the process of urea granulation using a rotating vibrating granulator. The scheme of the rotating vibrating granulator as part of the experimental stand for granulating liquid urea is presented, the method of conducting experimental studies and the design parameters of the granulator are described. It is indicated that in the process of experimental research, the temperatures of the melt, granules and cooling air were recorded. It is emphasized that the contact of the cooling air with the flow of hot granules leads to a constant increase in air temperature due to the heat transferred from the granules, which makes it necessary to determine the final temperature of the air leaving the granulation tower. For this purpose, a mathematical model was developed and calculation equations were obtained to determine the temperature of the air in contact with the surface of the pellet and the temperature profile inside the pellet. Numerical calculations of the calculation equations made it possible to obtain temperature profiles of the granule along its radius. It is emphasized that the theoretically obtained temperature profile cannot be an accurate indicator of the real temperature of the pellet when it falls in the granulation tower. Analysis of the calculated results shows that the temperature of the granules in the lower part of the granulation tower is 60–62 °C. This temperature corresponds to the practically confirmed final temperature of the granule, which was measured on the experimental stand.

CFD Simulation of SCR Systems Using a Mass-Fraction-Based Impingement Model

Computational fluid dynamics (CFD) are an essential tool for the development of diesel engine aftertreatment systems using selective catalytic reduction (SCR) to reduce nitrous oxides (NOx). In urea-based SCR, liquid urea–water solution (UWS) is injected into the hot exhaust gas, where it transforms into gaseous ammonia. This ammonia serves as a reducing agent for NOx. CFD simulations are used to predict the ammonia distribution in the exhaust gas at the catalyst inlet. The goal is to achieve the highest possible uniformity to realize homogeneous NOx reduction across the catalyst cross section. The current work focuses on the interaction of UWS droplets with the hot walls of the exhaust system. This is a crucial part of the preparation of gaseous ammonia from the injected liquid UWS. Following experimental investigations, a new impingement model is described based on the superposition of four basic impingement behaviors, each featuring individual secondary droplet characteristics. The droplet–wall heat transfer, depending on surface temperature and impingement behavior, is also calculated using a newly parameterized model. Applying the presented approach, the cooling of a steel plate from intermittent spray impingement is simulated and compared to measurements. The second validation case is the distribution of ammonia at the catalyst inlet of an automotive SCR system. Both applications show good agreement and demonstrate the quality of the new model.

Performance evaluation of an electronically controlled tractor-operated applicator for liquid urea application

Currently, granular urea (most commonly used fertilizer) is applied through broadcasting by farmers in the field. Granular urea causes significant losses due to slower soil mineralization rates, as well as ammonia volatilization and immobilization. Hence, fertilizing crops is becoming an increasingly difficult task due to low use efficiency and in mulch field conditions, it becomes more severe. The research done on mechatronic systems of applying liquid fertilizer by spot injection in field is limited. In the present study, the performance of the developed tractor operated liquid urea applicator consisting of electronic metering mechanism was evaluated at the Research Farm of Punjab Agricultural University, Ludhiana, Punjab during 2020–22. Research was done at two different types of soil (S1: sandy loam, and S2: loam) for three different forward speeds (3.6, 2.7, 1.8 km/h). Results obtained from experiments indicated that both soil type and forward speed had a significant (P<0.05) effect on the application rate of liquid urea. The best results were obtained without affecting crop yield at a forward speed of the machine 2.7 km/h with the application rate of 1090.85 litre/ha and 1035.18 litre/ha, fuel consumption 4.13 litre/h and 4.02 litre/h and crop yield 39.50 q/ha and 39.63 q/ha, for soil type S1 and S2 respectively. The cost of operation of machine was found 1996.53 `/ha. Developed tractor operated liquid urea applicator would help in improving conventional practices which are not aligned with environmental protection (e.g. gaseous emissions and nutrient losses) and boost the adoption rate of mechanized fertigation in the crops.

Benefits of liquid urea and a microbial catalyst on biomass and the nutritional value of Mombasa grass

During 2019, an experiment was conducted at the Agricultural Experiment Station in Isabela (Puerto Rico) on an Oxisol with previously well-stablished stands of cv. Mombasa. This experiment assessed the effects of a microbial catalyst (MC) and liquid urea 22-0-0 (LU) at a rate of 168 kg ha-1 (in split applications), a mixture of LU+MC and a control on aboveground biomass, root biomass, nutritional value, nitrogen use efficiency and soil parameters on cv. Mombasa at 35-day (d) harvests during six harvests. The study was established in a completely randomized design with four replicates. The effects of LU and MC on belowground (root) biomass were determined by collecting samples in 1 m2 to determine the yield and chemical composition. Soil samples were collected at 15 cm depth using a soil corer at the first and 6th harvest from each plot to assess organic carbon (OC), total nitrogen (TN), pH, macronutrients, and cation exchange capacity (CEC). The results showed that aboveground biomass doubled using LU (2369 kg DM ha-1) compared to the control and MC (1100 kg DM ha-1). Crude protein (CP) was 10.1 % using LU. Neutral Detergent fiber was 70 % for the control, 74.2 % when LU was used, and around 40 % for acid detergent fiber (ADF) for any treatment. Overall, there were no significant effects of treatments on OC and organic matter percentages, P, N, Ca, Mg, and CEC. In conclusion, LU is an excellent source of N for Mombasa, but shorter harvest frequencies may be required to improve the fiber quality of Mombasa.

Split application of liquid urea as a tool to nitrogen loss minimization and NUE improvement of corn - A review

Split application of liquid urea as a tool to nitrogen loss minimization and NUE improvement of corn - A review

Effect of Liquid Urea on Growth and Yield of Grain Corn (Zea mays L.)

ABSTRACT Efficient nitrogen management is the key strategy for sustainable crop production. A two-season (south-west and north-east monsoon season) experiments were conducted in Ladang 15, Faculty of Agriculture, Universiti Putra Malaysia in 2020 to compare the effect of liquid (LU) and granular urea (GU) on growth and yield of grain corn. The treatments were T0 = No urea (Control), T1 = GU (100%) at 10 days after sowing (DAS) and 28 DAS, T2 = LU (100%) at 10 and 28 DAS, T3 = LU (100%) at 10, 40 and 65 DAS, T4 = LU (50%) at 10 and 28 DAS and T5 = LU (50%) at 10, 40 and 65 DAS. Plant height, stem diameter, ear height and dry grain weight were higher in season 1 (south-west monsoon), but other growth and yield parameters were similar to season 2 (north-east monsoon). The highest cob diameter (5.43 and 5.30 cm), kernel rows/cob (17.30 and 16.72), seeds/row (38.88 and 36.96) and fresh cob weight (325.45 g and 319.18 g) were recorded from T3 and T5 treatments but the highest 100-grain weight resulted in T3 (50.51 g) and T2 (49.02 g) treatments. The highest grain yield (11,019.23 kg/ha) was recorded in T3 treatment. The highest total N content was recorded in T3 (161.92 kg/ha) treatment followed by T2 (141.04 kg/ha). In addition, the highest NUE was recorded in T3 (77.42%) and T5 (75.42%) treatments. As a result, the three splits application of LU was the most efficient application method for maximizing the growth and yield of grain corn.

Effects of Liquid Urea Application Frequency on the Growth and Grain Yield of Corn (Zea mays L.)

ABSTRACT Efficient nitrogen (N) management is considered one of the most important strategies for increasing sustainable crop yield along with maximizing nitrogen use efficiency (NUE). The aim of the study was to evaluate the effects of liquid urea (LU) application frequency on the growth, yield, and NUE of grain corn (Zea mays L.). The application frequencies urea were two split (2S) applied equally at 10 and 28 days after sowing (DAS), three split (3S) applied equally at 10, 40, and 65 DAS, and four split (4S) applied equally at 10, 30, 50, and 70 DAS organized by following randomized completely block design with four replicates. Results showed that stem diameter, ear length, fresh and dry stover weight, fresh cob weight, husk weight, kernel row/cob, and grain yield were higher in the LU treatments than granular urea (GU). Among all the treatments, the grain corn receiving LU3S had the highest stem diameter (2.03 cm), cob weight (248.25 g), 100 grain weight (29.08 g), N uptake (133.96 kg/ha), and NUE (72.84%). The corn grain yield of LU3S was 6.77 t/ha compared to the GU2S, which was only 4.95 t/ha. The N uptake along with NUE was significantly higher in LU3S treatment than other treatments. The results of this study suggest that the yield and NUE of corn were significantly affected by the urea source and application frequency of LU while LU3S was the most efficient treatment for maximizing the growth and yield of grain corn grown in tropical soil.

Effects of Liquid Nano-Carbon Bio-Fertilizer on the Growth of Spinach

In order to compare the effects of liquid biological nano-carbon fertilizer, humic acid and urea on the growth of Spinach, a field plot experiment was conducted to study the effects of five different treatments on root length, yield and quality of annual Spinach. Fertilizer had a significant effect on root length of annual Spinach. The order of root length was T3 > T5 > T4 > T2 > T1. The growth rates of roots were 21.69%, 18.94%, 14.26%, 3.76% and 0.0%, respectively. Fertilizer significantly increased the yield of annual Spinach. The order of yield increase was T5 > T3 > T4 > T2 > T1. The yields were increased by 16.66%, 14.71%, 10.55%, 6.44% and 0.0%, respectively. Potato liquid nano-carbon bio-fertilizer has a significant effect on maintaining the growth and increasing yield of Spinach.

Potential of chemical stabilizers to prolong urease inhibition in the soil–plant system#

AbstractBackgroundUrea is the most common nitrogen fertilizer applied to agricultural lands, and it is often treated with urease inhibitors to prevent loss of ammonia during urea hydrolysis. However, urease inhibitors like N‐(n‐butyl) thiophosphoric triamide (NBPT) are susceptible to degradation in soil.AimsThis study tested dimethyl sulfoxide, ethylene glycol and glycerol as stabilizers that could extend the inhibition effect of NBPT in a soil–plant system that received liquid urea fertilizer.MethodsWe undertook a pot experiment in which two soil types (brown and black soils) were amended with liquid urea plus NBPT, with and without chemical stabilizers, then planted with bok choy. The urease activity, urea and mineral N concentration in soil and nitrogen uptake in bok choy were monitored for the next 30 days.ResultsFive days after adding fertilizer, urease activity was 27%–51% lower in brown soil amended with the urea‐NBPT solutions and 32%–75% less when black soil received urea‐NBPT solution than in the control soil that received urea solution. Nearly 100% of the urea was hydrolyzed in control soil receiving urea solution after 5 days, but only 21%–41% of urea was hydrolyzed in soil amended with urea‐NBPT solution after 5 days. Stabilizers did not improve the stability of NBPT, nor did they affect the nitrogen uptake by bok choy, which was similar in the urea‐amended control soil (124 mg N pot–1) and the urea‐NBPT‐treated soil (117 mg N pot–1) during the growth period.ConclusionsChemical stabilizers did not prolong the NBPT inhibition of urease activity, probably because the stabilizer compounds are vulnerable to degradation in well‐watered and planted soils.

Wetting and evaporation of pinned urea–water-droplets on substrates of different wettability

The formation of solid deposits in exhaust treatment systems operating based on selective catalytic reduction is a major reason for the decline in system efficiency and possible damage. To reduce the amount of deposits, precise information about influencing variables but also about necessary preliminary processes is required. One such process is the film formation of liquid urea water solution after the injection.The presented experiments aim to increase the understanding of film formation and evaporation preceding the deposit formation. In a controlled experimental setup, the wetting, spreading and evaporation behavior of single droplets depending on influencing parameters can be investigated. The focus here lies on the effect of hot wall surface finish as well as on the wall temperature.The experiments are conducted in an open test cell. A heated AlMg2 substrate acts as the hot wall on which single AdBlue® droplets are deposited via a needle. The following wetting and evaporation process is captured by a high-speed camera. The droplet geometry is then evaluated by an image processing script to determine sequences of geometry variables such as the contact angle and the contact radius.The results show a strong influence of both, the substrate temperature as well as the surface finishing on the initial wetting and spreading of the droplet. Especially on rough surfaces, the initial spreading decreases significantly for higher temperatures.Evaporation of the droplets is mainly observed in constant contact radius mode. Above the saturation point of water, the surface wettability strongly affects the boiling behavior of the droplets. Significant nucleate boiling is observed on rough surfaces while hydrophobic surfaces show bubbles merging within the droplet, not moving towards the liquid–gas interface. With rising urea concentration, the boiling subsides due to an increased saturation point. The remaining solution shows much stronger wetting of the rough and polished, heated surfaces compared to the initially applied AdBlue®.

Using Waste Sulfur from Biogas Production in Combination with Nitrogen Fertilization of Maize (Zea mays L.) by Foliar Application.

In Europe, mainly due to industrial desulfurization, the supply of soil sulfur (S), an essential nutrient for crops, has been declining. One of the currently promoted sources of renewable energy is biogas production, which produces S as a waste product. In order to confirm the effect of the foliar application of waste elemental S in combination with liquid urea ammonium nitrate (UAN) fertilizer, a vegetation experiment was conducted with maize as the main crop grown for biogas production. The following treatments were included in the experiment: 1. Control (no fertilization), 2. UAN, 3. UANS1 (N:S ratio, 2:1), 4. UANS2 (1:1), 5. UANS3 (1:2). The application of UAN increased the N content in the plant and significantly affected the chlorophyll content (N-tester value). Despite the lower increase in nitrogen (N) content and uptake by the plant due to the application of UANS, these combinations had a significant effect on the quantum yield of PSII. The application of UANS significantly increased the S content of the plant. The increase in the weight of plants found on the treatment fertilized with UANS can be explained by the synergistic relationship between N and S, which contributed to the increase in crop nitrogen use efficiency. This study suggests that the foliar application of waste elemental S in combination with UAN at a 1:1 ratio could be an effective way to optimize the nutritional status of maize while reducing mineral fertilizer consumption.

Nitrogen Dynamics in Tropical Soils Treated with Liquid and Granular Urea Fertilizers

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.

Laser-assisted preparation of C3N4/Fe2O3/Au nanocomposite: a magnetic reusable catalyst for pollutant degradation

Assorted common contaminants namely organic dyes and nitro compounds are generated by various industries and have caused alarming problems for the environment and humans. The development of effective and newer methods to eliminate these contaminants is imperative. One effective way to eliminate these pollutants is to deploy sustainable heterogeneous catalyst systems. Accordingly, a novel and efficient magnetic nanocomposite catalyst comprising graphitic carbon nitride (g-C3N4), gold (Au), and hematite (α-Fe2O3) nanoparticles (C3N4/Fe2O3/Au) is prepared through a cost-effective and green method. The individual components, g-C3N4 and Au nanoparticles (NPs), are prepared via thermal decomposition of urea and laser ablation in liquid, respectively. The behavior of C3N4/Fe2O3/Au nanocomposite as a catalyst for the borohydride reduction of methyl orange (MO) dye and 4-nitrophenol (4-NP) in aqueous solution, is illustrated.