Conventional Urea Application Research Articles

Effect of Nano Urea on Growth, Yield and Nutrient uptake of Finger Millet (Eleusine coracana L.)

Aim: The foliar application of nano urea is aimed at reducing the soil application of conventional urea. Nano fertilizers enhance crop growth and yield while enhancing nutrient uptake and reducing costs. They provide precise nutrient management, match crop growth stages, and offer an increased surface area for metabolic reactions. This boosts photosynthesis, leading to higher dry matter production and crop yield. Foliar application of nano urea (liquid) at tillering and booting stages in finger millet fulfills the nitrogen requirement and reflects higher crop productivity. Higher productivity of crops in a sustainable manner could be achieved by applying an appropriate combination of conventional fertilizers and nano fertilizers. Study Design: The experiment was laid out in split design with three replications. Place and Duration of Study: A field experiment was conducted in deep black soils at Agricultural Research Station, Siruguppa, during kharif 2022. Methodology: There were sixteen treatment combinations, consisting of different doses of nitrogen (no nitrogen, 50% RDN, 75% RDN and 100% RDN) with different concentrations of nano urea and conventional urea sprayed at tillering and booting stages for HR-13 variety of finger millet. Results: Application of 100% RDN has recorded significantly higher plant height, tillers plant-1, total dry matter accumulation, grain yield and straw yield (129.82 cm, 10.10, 36.17 g plant-1, 36.87 q ha-1 and 71.72 q ha-1, respectively) in comparison to no nitrogen and 50% RDN. However, 75% RDN (123.04 cm, 9.61, 34.02 g plant-1, 34.84 q ha-1 and 68.01 q ha-1, respectively) found on par with 100% RDN. Among foliar nitrogen, spray of nano urea @ 4 ml L-1 recorded significantly higher plant height (121.59 cm), tillers plant-1 (9.37), total dry matter accumulation (33.16 g plant-1), grain yield (31.97 q ha-1) and straw yield (65.52 q ha-1) compared to 0.5% and 1% conventional urea. However, nano urea @ 2 ml L-1 was on par with 4 ml L-1 nano urea and 1% conventional urea. Similar trend was recorded with regard to nutrient uptake by finger millet. Conclusion: Foliar application of nano urea reduced the dosage of conventional urea by 25 per cent.

Field Evaluation of Urea Fertilizers Enhanced by Biological Inhibitors or Dual Coating

Relative to soluble N sources, enhanced-efficiency fertilizers (EEFs) support steady turfgrass growth and dense canopy quality while abating N loss as nitrate, ammonia, and/or N2O from turfgrass systems. Modern EEFs provide turfgrass managers greater operational effect and versatility in their nutrient management efforts and compel field characterization of their temporal response. Likewise, field confirmation of commercial EEF nutrient recovery helps stakeholders select the appropriate EEF for their specific application. Our research objective was to quantify the temporal response of Kentucky bluegrass growth/yield, canopy density and color, and fertilizer N recovery to a practical application of conventional urea or an enhanced-efficiency granular fertilizer. In May 2014 and June 2018, Kentucky bluegrass plots were fertilized by granules of conventional urea, N-(n-butyl) thiophosphoric triamide (NBPT)-, and dicyandiamide (DCD)-stabilized urea, or polymer-/sulfur-coated urea (PSCU) at a N rate of 43.9 kg ha−1 (0.9 lbs/1000 sq. ft.). The dependent variable response over the two growing seasons was highly affected by efficiency enhancement. Following the repeated 16.5-week evaluations, the mean percent of fertilizer N recovered from conventional urea, stabilized urea, and PSCU totaled 57.5, 68.4, and 89.1%, respectively. In the 23 to 51 days from treatment (DFT), recovery of PSCU-N significantly exceeded that from conventional or stabilized urea.

A comparative assessment of polymer-coated and non-coated urea in direct-seeded rice: agronomic, economic, and environmental performance and sensitivity analysis

The application of polymer-coated urea (PCU) to crops is likely restricted because the product’s capsules cause plastic pollution. Although conventional fertilizer use reduces plastic pollution, it may increase nitrogen (N) pollution owing to its lower N recovery than that of PCU. Therefore, we need to develop optimal N application methods to reduce both plastic and N pollution. Here, we aimed to (1) compare the agronomic, economic, and environmental outcomes of PCU application with those of conventional urea application and (2) provide quantitative targets for developing alternatives to PCU application in dry direct-seeded rice production. We developed a model incorporating yield, brown-rice protein content, farmer profit, and environmental damage cost due to N and polymer loss according to N fertilizer application. Data were collected from field experiments at a farm in Iwate, Japan, from 2020 to 2022. The average apparent N recovery was 0.43 for PCU and 0.37 for conventional urea. Despite the plastic damage cost, the estimated total environmental cost of PCU was lower than that of normal urea owing to the former’s higher N recovery. However, our ability to simulate plastic pollution is limited, as few of the environmental effects of microplastics are understood. If new N application methods with N recovery above 0.5 are developed, an N fertilization cost within $5 × 10–3 g N–1 can maintain the same benefit as that obtained here. This model can be used to evaluate the quantitative relationships among N recovery, benefits, and implementation costs of each candidate N application method.

Modelling future climate effects on N2O emission and soil carbon storage in maize fields under controlled-release urea and straw incorporation

Controlled-release urea application and straw incorporation have been conducted in recent years as environmental-friendly and sustainable farming strategies, but the long-term effects of controlled-release urea application and combination with straw on the dryland maize yield, soil fertility and the environment under future climate scenarios remain unclear. Hence, based on a six-year field experiment, four treatments were used to calibrate and validate the DeNitrification-DeComposition (DNDC) model, including non-nitrogen (CK), split applications of conventional urea (UR), single basal application of conventional urea and controlled-release urea at a ratio of 2:1 (CU), and CU combined with straw (CUS). Subsequently, coupled the well-validated model with future climate to evaluate suitable agricultural production practices under two shared socioeconomic pathways (SSP)-SSP245 and SSP585. The validation results indicated a good fit between the simulated and observed data of greenhouse gas emissions, soil organic carbon (SOC) contents and maize yields. With the anticipation of warmer temperatures and increased precipitation in the future, the yields of UR, CU, and CUS treatment significantly rose. Under SSP585 scenario, the positive impacts of CU treatment on maize yields reduced after the 2050s, exhibiting an average decline of 12.03%. Compared with the UR treatment, the CU treatment markedly reduced cumulative N2O emissions, and both treatments maintained the original state of SOC storages in the 2030s, furthermore, the CUS treatment reduced N2O emissions by 47.10%, 35.07%, 23.80% and 10.04% in the 2030s, 2050s, 2070s and 2090s, respectively. SOC storages for the CUS treatment gradually increased with an average of 464.58, 350.22, 250.87 and 177.75 kg C ha−1 y−1 for two SSP scenarios in the 2030s, 2050s, 2070s and 2090s, which excellently offset the CO2 equivalent of emissions caused by N2O emissions. Therefore, in dryland maize production, combined controlled-release urea with straw incorporation could achieve the best comprehensive effect among increase of yield, improvement of SOC storages and alleviation of greenhouse gas emissions under future climate scenario.

Urease inhibitors technologies as strategy to mitigate agricultural ammonia emissions and enhance the use efficiency of urea-based fertilizers

Experiments were conducted to evaluate the stability and degradation of NBPT under storage conditions and to quantify urease activity, ammonia losses by volatilization, and agronomic efficiency of urea treated with different urease inhibitors, measured in the field. Experiments included urea treated with 530 mg NBPT kg−1 (UNBPT) in contact with six P-sources (monoammonium phosphate-MAP; single superphosphate; triple superphosphate; P-Agrocote; P-Phusion; P-Policote), with two P-concentrations (30; 70%); the monitoring four N-technologies (SoILC; Limus; Nitrain; Anvol); and the application of conventional urea (UGRAN) or urea treated with urease inhibitors as topdressing in three maize fields, at three N rates. It is concluded that: the mixture of UNBPT and P-fertilizers is incompatible. When MAP granules were coated to control P-release (P-Agrocote), the degradation of NBPT was moderate (approximately 400 mg kg−1 at the end of the storage test). SoILC and Limus solvent technologies extended the NBPT half-life by up to 3.7 and 4.7 months, respectively. Under field, each inhibition technology reduced urease activity, and lowered the intensity of ammonia emission compared to UGRAN by 50–62%. Our results show that the concentration of NBPT is reduced by up to 53.7% for mixing with phosphates. In addition, even with coatings, the storage of mixtures of urea with NBPT and phosphates should be for a time that does not reduce the efficiency of the inhibitor after application, and this time under laboratory conditions was 168 h. The reduction of NBPT concentration in urea is reduced even in isolated storage, our results showed that the half-life time is variable according to the formulation used, being 4.7, 3.7, 2.8 and 2.7 days for Limus, SoILC, Nitrain and Anvol, respectively. The results of these NBPT formulations in the field showed that the average losses by volatilization in the three areas were: 15%, 16%, 17%, 19% and 39% of the N applied, for SoILC, Anvol, Nitrain, Limus and urea, respectively. The rate of nitrogen application affected all agronomic variables, with varied effects in Ingaí. Even without N, yields were higher than 9200 kg ha−1 of grains. The increase in nitrogen rates resulted in linear increases in production and N removal in Luminárias and Ingaí, but in Lavras, production decreased above 95.6 kg ha−1 of N. The highest production in Lavras (13,772 kg ha−1 of grains) occurred with 100 kg ha−1 of N. The application of Anvol reduced the removal of N in Ingaí.

Influence of Super Nano Urea and Nano DAP on Growth Parameters of Rice Fallow Cotton under High Density Planting System

The experiment was carried out at wetlands farm, Tamil Nadu Agricultural University, Coimbatore, during summer, 2023 in a Randomized block design with ten treatments and replicated thrice. The main objective of this study is to find out the effect of varied dose of basal nitrogen & phosphorus and foliar application of conventional urea, super nano urea and nano DAP on rice fallow cotton under High Density Planting System (HDPS) on growth parameters. Cotton variety CO 17 was taken up for the study with RDF of 150:50:50 NPK Kg ha-1. The experimental details viz., T1- control (without N&P) K alone, T2- RDF (150:50:50 NPK Kg ha-1), T3- 50% RDN&P,100% K+ conventional urea @ 1% and nano DAP @ 0.5% at 25 DAS, T4- 50% RDN&P,100% K+ conventional urea @ 1% and nano DAP @ 0.5% at 25 DAS and 45 DAS, T5- 50% RDN&P,100% K+ SNU(Super Nano Urea) @ 0.25% and nano DAP @ 0.5% at 25 DAS (Days After Sowing) and 45 DAS, T6- 50% RDN&P,100% K+ SNU @ 0.25% and nano DAP @ 0.5% at 25 DAS, 45 DAS and 65 DAS, T7- 50% RDN&P,100% K+ SNU @ 0.5% and nano DAP @ 0.5% at 25 DAS and 45 DAS, T8- 25% RDN&P,100% K+ SNU @ 0.5% and nano DAP @ 0.5% at 25 DAS 45 DAS and 65 DAS, T9- 50% RDN&P,100% K+ SNU @ 1% and nano DAP @ 0.5% at 25 DAS, T10- 50% RDN&P,100% K+ SNU @ 1% and nano DAP @ 0.5% at 25 DAS and 45 DAS. The experimental results revealed that, among all the treatments, T10 significantly registered the increased plant height (112.33 cm) and highest leaf area index (4.11) and enhanced light interception (91%). Based on the experimental results, it is concluded T10 i.e., reduced application of basal nitrogen and phosphorus (50% RDN&P + 100% K) with super nano urea foliar spray @ 1% and nano DAP foliar spray @ 0.5% at 25 DAS and 45 DAS found to be the optimal dosage for increased growth parameters under high density planting system in rice fallow cotton.

Optimization of One-Time Fertilization Scheme Achieved the Balance of Yield, Quality and Economic Benefits of Direct-Seeded Rice.

There is limited information available to assess the impact of one-time fertilization on the yield, quality, and economic benefits of direct-seeded rice. This study reports the effects of three one-time fertilizer treatments (BBU1, BBU2, and BBU3) on the yield, quality, and economic benefits of direct-seeded rice, where controlled-release nitrogen (N) fertilizer (CRNF) provided 50%, 60%, and 70% of the total N (270 kg N ha-1), and the control treatment (CK) was a split application of conventional urea (CU). The results showed that the yield of direct-seeded rice decreased significantly (p < 0.05) with the increased application ratio of CRNF under one-time fertilization, which was mainly related to N accumulation between the heading time and maturity stages. Compared to CK, the one-time fertilization treatments (BBU1, BBU2, and BBU3) maintained high milling quality, with significantly reduced chalkiness (p < 0.05), which could be related to the slow rate of N release from the CRNF. In addition, the one-time fertilization treatments reduced the protein content and increased the amylose content of the milled rice, which significantly improved the eating quality (p < 0.05). Furthermore, there was no significant difference in yield and economic benefit between BBUI and CK (p > 0.05). Overall, CRNF replacing conventional urea with 50% total N could be helpful to reduce fertilization frequency, achieve high yield and high economic efficiency, and improve rice quality of direct-seeded rice under one-time fertilization.

Innovative nitrogen management strategy reduced N2O emission while maintaining high pepper yield in subtropical condition

High N fertilizer inputs in subtropical vegetable systems under the warm and humid climatic conditions increase the risk of nitrous oxide (N2O) emissions. However, there is limited information available on integrated N management strategies to reduce N2O emissions from intensive open-field vegetable systems in subtropical region. Two plot-based field experiments were conducted in subtropical southwest China to examine the effects of different N management strategies on N2O emissions from a typical open-field pepper (Capsicum annuum L.) production system. Experiment 1 included five N rates (0, 175, 250, 325, and 400 kg ha−1) with conventional urea. Experiment 2 included a 0 N control and four N sources (conventional urea, organic fertilizer, nitrification inhibitor-based enhanced efficiency fertilizer ENTEC26, and controlled release urea) applied under an optimized N rate (250 kg N ha−1). The results of Experiment 1 showed that cumulative N2O emission and emission factor were 4.05 kg N ha−1 season−1 and 0.96%, respectively, under the conventional management (N400). N2O emissions increased exponentially with increasing N rates. Compared to the N400 treatment, application of conventional urea at the optimal rate (250 kg N ha−1) significantly reduced cumulative N2O emissions by 54% while maintaining similar pepper yield. The results from Experiment 2 indicated that the use of enhanced efficiency fertilizers at the optimal rate further reduced N2O emission by 30%− 50% compared to conventional urea, while increasing pepper yield by 6.7%− 9.0%. This resulted in a 36%− 53% reduction of yield-scaled N2O emission intensity. In particular, the use of nitrification inhibitor was 28% more effective than controlled release urea for N2O mitigation. These results suggest that the application of enhanced efficiency fertilizers at an optimum N rate could produce more vegetables while reducing N2O emission, thereby promoting sustainable vegetable production in the subtropic regions.

Controlled-release urea application and optimized nitrogen applied strategy reduced nitrogen leaching and maintained grain yield of paddy fields in Northwest China.

Nitrogen loss from paddy fields contributes to most of the nitrogen pollution load in the Ningxia Yellow River irrigation area, threatening the water quality of the Yellow River. Consequently, optimizing the nitrogen management practices in this area is essential, which can maintain paddy grain productivity and reduce nitrogen loss simultaneously. Five treatments with different nitrogen application rates and nitrogen fertilizer types were set in this study, including conventional urea application with zero nitrogen application rate (CK, 0kg hm-2), nitrogen expert-based fertilization application strategy (NE, 210kg hm-2), optimized nitrogen fertilizer application strategy recommended by local government (OPT, 240kg hm-2), and farmer's experience-based nitrogen fertilizer application strategy (FP, 300kg hm-2), and controlled-release urea application (CRU, 180kg hm-2). The data from one growth season field experiment in 2021 revealed the dynamics of nitrogen concentration, paddy yield and its nitrogen uptake characteristic, and nitrogen balance in the paddy field under different nitrogen application practices. Most nitrogen leaching was observed during the seedling and tillering stages in the form of nitrate nitrogen (NO3 -N). Compared with the FP, the CRU and OPT significantly reduced the nitrogen concentrations of total nitrogen (TN), ammonium nitrogen (NH4 +-N), and NO3 -N in the surface and soil water and reduced the nitrogen leaching at 100cm soil depth. Meanwhile, the paddy grain yield in CRU (7737kg hm-2) and OPT (7379kg hm-2) was not significantly decreased compared with FP (7918kg hm-2), even though the nitrogen uptake by grain and straw was higher in FP (135kg hm-2) than in other treatments (52.10~126.40 kg hm-2). However, the grain yield in NE (6972kg hm-2) was decreased compared with the FP. The differences in grain yield among these treatments were mainly attributed to the ear number and grain number changes. Also, the highest nitrogen use efficiency (40.14%), apparent nitrogen efficiency (19.53kg kg-1), and nitrogen partial productivity (43.98kg kg-1) were identified in CRU than in other treatments. Considering increased grain yield and reducing nitrogen loss in the paddy field simultaneously, the treatments of CRU (i.e., 180kg hm-2 nitrogen application rate with controlled-release urea) and OPT (i.e., 240kg hm-2 nitrogen application rate with conventional urea) were recommended for nitrogen fertilizer application in the study area.

Polymer-coated urea application can increase both grain yield and nitrogen use efficiency injaponica-indicahybrid rice

AbstractWe investigated whether the one-time application of polymer-coated urea (PCU) before transplanting could simultaneously improve the grain yield and nitrogen use efficiency (NUE) ofjaponica-indicahybrid rice (JIHR) through a field experiment. The local high-yield JIHR cultivar Chunyou-927 was field grown during the rice-growing seasons in 2019 and 2020. The experiment consisted of three treatments: no nitrogen application (0N), application of conventional urea (CU), and the one-time application of PCU. Grain yield was 1.0–1.3 t/ha higher, and agronomic NUE (kg grain yield increase per kg N applied) was 5.2–5.9 kg/kg higher, respectively, under the PCU treatment compared with the CU treatment across the two study years. When compared with the CU treatment, the PCU treatment could (1) improve root morphological trait, (2) reduce redundant vegetative growth during the early growth period, (3) increase matter production during the mid and late growth period, and (4) increase plant activity during the grain-filling period. Overall, our findings indicate that one-time PCU application before transplanting of the JIHR cultivar holds great promise for increasing grain yield and NUE.

Deep Placement of Npk Briquette in Rice: Environment Friendly Technology for Sustainable Rice Production

Nine experiments were conducted at the Bangladesh Rice Research Institute (BRRI) farm, Gazipur, BRRI regional station, Sagardi, Barisal and farmers’ field of Barisal during Boro, T. Aus and T. Aman season, 2012 to evaluate the NPK briquette efficacy in rice production. Experimental results revealed that deep placement of NPK briquette (2 x 2.4 g) increased rice grain yield about 10 % and it saves 51, 9 and 20 kg NPK ha-1 than BRRI fertilizer recommended rate in Boro season. Similarly, NPK briquette (1 x 3.4 g) produced 28 and 18% more rice grain yield than BRRI fertilizer recommended rate with a savings of 29 kg N and 7 kg K ha-1 in T. Aus and T. Aman season, respectively. In general, deep placement method gave higher grain yield compared to conventional urea application. Undiscounted benefit cost ratio (BCR) was 1.44, 2.40 and 3.20 for Boro, T. Aus and T. Aman, respectively when comparing at the same rates of N application. Thus, use of NPK briquette over urea broadcast and incorporation was economically viable and efficient for rice cultivation. This method helps to reduce N loss through soil-water interface which plays a vital role in reducing environmental pollution.&#x0D; Bangladesh Agron. J. 2021, 24(2): 127-136

One‐time N fertilization reduces greenhouse emissions and N leaching while maintaining high yields in a rape–rice rotation system

AbstractIn China, the rice (Oryza sativa L.)–rapeseed (Brassica napus L.) rotation system is facing great challenges, including constantly growing demand, on‐going labor shortages, and increasing environmental burdens. Thus, producing more food and higher benefits while minimizing environmental costs is required for future development. A 2‐yr field experiment comparing three nitrogen (N) fertilization treatments (non‐N treatment as control [CK], conventional urea application [CU], one‐time application of controlled‐release urea [CRU]) was performed. Results showed that the rice season dominated annual CH4 emissions (&gt;95%) and on average contributed more than 50% of the annual N2O emissions. Additionally, the main forms of mineral N leaching were different for rape and rice. Nitrate (NO3–)–N was the major component of leaching in rape season, while for rice season NO3––N and NH4+–N were equal. Relative to CU, CRU significantly increased the rapeseed yield by 10.7∼13.9% and maintained the rice productivity, reduced mineral N leaching losses by 19.6∼20.8% for the rice season, and resulted in less total methane (CH4) and nitrous oxide (N2O) emissions (TGHGs) by 12.1% across the two rotations. Furthermore, a net economic benefit (NEB) considering yields, fertilizer input, labor, and other input costs indicated CRU increased the economic return by 58.3%. However, CRU did not improve partial factor productivity of nitrogen fertilizer (PFPN) and decreased the NEB by 3.1% without considering the labor cost. It indicated a one‐time application of the CRU for rice–rapeseed rotation system was an environmentally and economically profitable technology. This paper provided a promising solution for farmers to enhance rice–rapeseed productivity and increase income while minimizing the environmental footprint.

Effects of reducing and postponing controlled-release urea application on soil nitrogen regulation and maize grain yield

Controlled-release urea (CRU-N) fertilizer application is a solution to improve the utilization rate of nitrogen (N), reduce economic costs and improve crop yields. It is significant to study the effects of release CRU-N reduction and the combined application of conventional urea on soil N control and the large-scale maize planting system. In this study, the effects of controlled-release nitrogen fertilizer reduction and postponement on soil nitrogen components, enzyme activities, and yields were investigated. Seven treatments were set up in this study, including no N fertilizer (CK), 100% conventional urea (U), 100% controlled-release urea (S), 30% controlled-release urea (SU3/7), 50% controlled-release urea (SU5/5), 70% controlled-release urea (SU7/3) and Sodium Salt of Polyaspartic Acid (PASP)-N. The results showed that mixed CRU-N and urea increased yields and net benefits compared with conventional urea at the same application rate of N, and reduced N loss. The application of CRU-N at 70% for maize represented the best overall effects. Compared with U treatment, soil ammonium nitrogen (NH4-N), soil nitrate-nitrogen (NO3-N), and microbial biomass nitrogen (SMB-N) of CRU-N at 70% (SU7/3) increased by 35.00%, 15.53%, and 25.04%. However, soil nitrate reductase (S-NR) and urease (S-UA) were the best in SU5/5 and significantly higher than other treatments. The applications of CRU-N would effectively increase soil N; CRU-N in 50% proportion can promote the maize root growth and improve the efficient utilization of N by soil microorganisms. Like the yields (9186.61 kg/hm2), expertly in the proportion of 70% CRU-N (SU7/3) plays a vital role in a wheat-maize rotation system, which can potentially be used to improve the yields, nitrogen use efficiency, and net benefit with low N losses. In conclusion, using CRU-N fertilize effectively improves soil nitrogen, and various ratios of CRU-N can ensure the continuous release the nutrients during the growing period. And among the different proportions of CRU-N, it is optimal in SU7/3. Keywords: controlled-release urea, nitrogen regulation, maize grain yield, soil, reducing, postponing DOI: 10.25165/j.ijabe.20221501.6888 Citation: Ji P T, Peng Y J, Cui Y W, Li X L, Tao P J, Zhang Y C. Effects of reducing and postponing controlled-release urea application on soil nitrogen regulation and maize grain yield. Int J Agric & Biol Eng, 2022; 15(1): 116–123.

Nitrogen Fertilizers and Volatilization of Ammonia, Carbonic Gas Emissions and Urease Activity

ABSTRACT The large-scale use of fertilizers is an essential process for replacement fertilization, maintenance or correction of nutrient levels in tropical environments. Nitrogen stands out among the elements that plants need in greater quantity, and for this reason, nitrogen fertilizer is the most consumed, with an emphasis on urea. The urea [(NH2)2CO] can present high losses of ammonia (NH3), besides potentiating carbonic gas (CO2) emissions, especially in high temperatures. For this purpose, the objective of this work was to: (a) evaluate three temperature conditions (25, 35, 45°C) in N losses through NH3 volatilization, CO2 gas emissions, soil urease enzyme activity; (b) and evaluate the potential of N losses in conventional urea fertilizers and associated technology (urea with N-(n-butyl)thiophosphoric triamide (NBPT), polymer-sulfur coated urea). The application of conventional urea (CU) promoted volatilization losses of 30.19 mg dm−3, followed by urea with NBPT (UNBPT) (27.35 mg dm−3) and polymer-sulfur coated urea (UPS) (5.21 mg dm−3) from the application of 100 mg dm−3 in the soil. Fertilizers with associated technology were more efficient than CU, with emphasis on UPS. The highest values for NH3 volatilization were recorded at 45°C for CU (38.97 mg dm−3), followed by UNBPT (38.14 mg dm−3) and UPS (10.41 mg dm−3). It is concluded that, in general, volatilization losses of NH3 and gaseous emissions of CO2 followed the following order for the applied sources: UPS <CU and order: 25°C < 35°C < 45°C for the temperatures.

Nitrification inhibitor 3,4-Dimethylpyrazole phosphate improves nitrogen recovery and accumulation in cotton plants by reducing NO3− leaching under 15N-urea fertilization

PurposeThe use of nitrification inhibitors could be an interesting alternative when applied to enhance nitrogen (N) fertilizer use efficiency in annual crops such as cotton under tropical soil conditions. Thus, our aim was to evaluate the efficiency of the nitrification inhibitor 3,4-Dimethylpyrazole phosphate (DMPP) in a typical tropical soil by evaluating the fate of nitrogen (N-NO3−, N-NH4+ and total N in soil and leached water), N accumulation and N recovery by cotton plants and soil.MethodsLeaching columns with cotton plants were used to assess N-NO3− and N-NH4+ losses in drainage water. The treatments consisted of three N levels applied in side-dressing (corresponding to 50, 100 and 150 kg N ha−1) as 15N-urea with and without DMPP application. An additional treatment (absence of N application in side-dressing) was used as a control.Results3,4-Dimethylpyrazole phosphate efficiently improved N recovery after urea fertilizer was applied to plants and in the soil by reducing NO3− leaching, leading to enhanced N acquisition from fertilizer and soil and augmenting N accumulation in plants, mainly when high N levels above 100 kg N ha−1 were applied. We found that total N recovery increased 31% when 150 kg N ha−1 was applied as a urea + DMPP source compared to the application of conventional urea. In addition, DMPP application reduced NO3− leaching losses (by approximately 11 to 20%), although it had no significant effect on the shoot or root dry matter yields.ConclusionThe reduction in NO3− leaching losses obtained herein highlights the potential of DMPP to mitigate the impact of increased urea inputs on leaching losses, thereby improving N use efficiency and N uptake in cotton crops.

Foliar Application of Nitrogen Affects Metabolism and Productivity of Soybean

Soybean is one of the world&amp;rsquo;s most economically important crops and several factors can affect the productivity of this culture. Among these factors is the supply of needed nitrogen, especially in the reproductive stage, as it acts in photosynthetic activity and in grain filling. In view of this, the objective of our work was to evaluate the effect of foliar application of nitrogen in different reproductive stages in soybean culture. Two sources of nitrogen were used: conventional urea and urea-formaldehyde/triazone, both applied in reproductive stages R2, R3, R4, or R5, as well as a control treatment without foliar application of nitrogen. Plants submitted to foliar application of urea-formaldehyde/triazone showed an increase in nitrogen metabolism (percentage of nitrogen derived from the atmosphere [Ndfa] and nitrate reductase activity [NR]), an increase in peroxidase (POD), and the consequent reduction in hydrogen peroxide (H2O2) in all stages of application of this treatment. When urea-formaldehyde/triazone was applied in R4, it resulted in a 7% increase in yield. The application of conventional urea in reproductive stages R4 and R5 increased nitrogen metabolism and resulted in an increase in yield by 4%. However, conventional urea reduced yield when applied in stages R2 and R3. The use of low doses of foliar nitrogen in stages R4 and R5, increased nitrogen metabolism in soybean plants. The timing of the application has a direct impact on the results with the slow-release nitrogen (urea formaldehyde /triazone) showing better results when applied in stage R4 and better results for conventional urea in R5.

Effect of pyroligneous acid on soil urease, amidase, and nitrogen use efficiency by Chinese cabbage (Brassica campestris var. Pekinensis)

Urea is one of the most commonly used nitrogen fertilizers in agricultural soil and is easily decomposed by soil urease resulting in ammonium release. The produced ammonium can be volatilized or converted to nitrate, which is susceptible to leaching, leading to groundwater contamination unless used by plants. Hence, it is important to control the release of nitrogen from the urea. Pyroligneous acid inhibited the urease activity and decreased ammonium release up to 80% compared to the control. Amidase including asparaginase and glutaminase is an enzyme that catalyzes hydrolysis of amide group, similar to urease. Therefore, the effect of pyroligneous acid on the inhibition of soil amidase was also tested and the results showed that pyroligneous acid competitively inhibited asparaginase while glutaminase was not inhibited. However, inhibitory effect of pyroligneous acid on asparaginase was negligible compared to the urease. The application of pyroligneous acid with a smaller amount of urea for controlled nitrogen release during Chinese cabbage growth showed that dry biomass and nutrient contents of Chinese cabbage were similar to the case of the conventional urea application. The nitrogen utilization efficiency (NUE) was highest for 33% less amount of urea supply with pyroligneous acid (2.21) compared to conventional treatment (1.81). Consequently, the use of pyroligneous acid with urea enhances nitrogen use efficiency while also protecting environments from non-point source contamination.

Reduced application and different combined applications of loss-control urea on summer maize yield and fertilizer efficiency improvement

<p id="C3">Loss-control urea with nanometer mineral loss control agent added during production period could reduce the loss of nitrogen (N) through adsorption. Figuring out the application rate of loss-control urea and the appropriate rate with conventional urea could provide evidences for summer maize one-time fertilization, N fertilizer reduction, and use efficiency improvement. Under different yield level soil conditions, field experiment was arranged to investigate the effects of different N fertilizer managements on summer maize yield, aboveground biomass, nutrient accumulation, photosynthetic characteristic, and N utilization efficiency. Treatments of conventional urea (N at 210 kg hm^-2), loss-control urea (full dose with N at 210 kg hm^-2, 10% reduction with N at 189 kg hm^-2, and 20% reduction with N at 168 kg hm^-2), and different combined proportions of loss-control urea and conventional urea (at 7:3, 5:5, and 3:7) were carried out. The results revealed that N fertilizer application could significantly increase the yield of summer maize and the full-dose loss-control urea treatments increased the yield by 22.96%-27.55%, compared with that under conventional urea application at high- and middle-yield soil conditions. The application of loss-control urea at 10% and 20% reduction sustained the summer maize yield at high- and middle-yield soil condition with improved grains per ear, compared with full-dose loss-control urea application. The N fertilizer utilization efficiency under loss-control urea at 20% reduction treatment at high-yield soil condition reached 41.60%. N accumulation was comparable with full-dose loss-control urea application under proportions of loss-control urea and conventional urea at 7:3 application. Meanwhile, this treatment could sustain the yield and straw biomass at high- and middle-yield level soil and significantly increased the yield and straw biomass at low-yield field. In conclusion, one-time application of loss-control urea with N at 210 kg hm^-2 could significantly improve the yield of summer maize and N efficiency of the fertilizer utilization. The application of loss-control urea with 20% reduction could sustain the summer maize yield with significantly improved N utilization efficiency at high- and middle-yield soil conditions, which was the suitable N fertilizer application for high- and middle-yield field. Loss-control urea and conventional urea at 7:3 application was suitable for N fertilizer application for low-yield field.

Controlled-release N fertilizer to mitigate ammonia volatilization from double-cropping rice

Controlled-release nitrogen fertilizer (CRNF) can effectively enhance crop yields and raise the efficiency of nitrogen fertilizer in agroecosystems. In the present study, the volatilization of NH3 was determined by airflow enclosure chamber technique after the application of different CRNF rates in double-cropping rice fields in southern China for continuous 3 years. The early and late season rice (ESR and LSR) were cultivated each year. The results showed that the total NH3 volatilization losses ranged from 25 to 56 kg N ha−1 in ESR and from 32 to 61 kg N ha−1 in LSR. The loss of N to the total applied N ranged from 12 to 29% in ESR and from 12 to 27% in LSR. The application of CRNF significantly reduced the cumulative NH3 volatilization losses by 20–43% for ESR and by 20–32% for LSR compared with conventional urea application. CRNF in LSR was less effective to reduce NH3 volatilization than that in ESR. Furthermore, the application of 80% of N rate in the form of CRNF gave higher grain yield and apparent nitrogen recovery efficiency (ANRE) than that of application of 100% of N rate from conventional urea. CRNF can effectively reduce NH3 volatilization, and increase rice yield and ANRE. Considering higher price of CRNF, the application of CRNF at lower (20% applied N) rate than conventional urea in LSR may be a reasonable fertilization strategy for improving N use efficiency, environment effectiveness, and sustaining the development of rice production systems in double-cropping rice.

Coated controlled-release urea creates a win-win scenario for producing more staple grains and resolving N loss dilemma worldwide

Abstract Attaining greater crop productivity to feed the increasing population while minimizing the unwanted environmental consequences is challenging for nitrogen (N) management. Coated controlled-release urea (CRU) has been widely recommended in recent decades for improving crop productivity and reducing reactive N (Nr) losses. However, the overall effects of CRU application on crop productivity, soil N transformations and N losses to the environment remain unclear. It is also unclear whether the overall benefit of CRU, including reducing N’s environmental impact and increasing crop yield, could offset or even outweigh the application cost. Thus, we conducted a global meta-analysis using 85 publications across the world to assess the above issues. We found that on average, compared to conventional urea application, CRU application significantly increased crop yield and crop N uptake by 7.7% and 12.6%, respectively. Moreover, Nr losses in the form of ammonia (NH3) volatilization, nitrous oxide (N2O) emissions and N leaching were significantly reduced by 24.3–45.9%, mainly due to the relatively slow and continuous N substrate supply from the CRU application. The cost-benefit analysis indicated that the overall benefit outweighed the CRU application cost, producing a net monetary benefit of $117.0 ha-1 that was equivalent to an increase of 6.4% in revenue. Our results highlighted that the positive effect of CRU application on crop productivity and ecosystem services achieved a win-win scenario that, unlike the enhanced NH3 volatilization by nitrification inhibitors, resolved various N-loss dilemmas while increased the economic outcome.