Urea Ammonium Nitrate Research Articles

Water absorption from air and ammonia loss from urea fertilizers applied to grassland in southeastern United States

AbstractInformation on water absorption from the air by urea fertilizers and on NH3 loss when applied to grasslands is limited. Urea application to grassland is typically broadcast (Bcast), whereas urea‐ammonium nitrate (UAN) is applied either Bcast or in bands (dribble). This work was conducted to (1) evaluate water absorption from the air by Bcast granular urea, Bcast UAN, and dribble UAN under laboratory conditions, and (2) compare NH3 losses from Bcast urea, Bcast UAN, and dribble UAN when applied to a grassland. Six field studies were conducted from 2017 to 2019. In the laboratory, Bcast UAN exposed to 100% relative humidity absorbed water from air at a faster rate than dribble UAN and Bcast urea. In the field, all three fertilizers lost similar amounts of NH3 when applied to relatively wet soil (> −0.1 MPa). In contrast, when the fertilizers were applied to dry soil (≤ −1.2 MPa), Bcast UAN lost the most NH3 (17.3% and 19.8%) likely because of its capacity to absorb water from the air. Also, at −1.2 MPa, dribble UAN lost more NH3 than Bcast urea (15.3 vs. 10.7%, p < 0.05), probably because the low osmotic potential of UAN (−55 MPa) allowed it to absorb water from the soil at a faster rate than urea could absorb water from the air. In contrast, when the soil water potential was −5.7 MPa, dribble UAN lost less NH3 than Bcast urea (4.4 vs. 17.3%, p < 0.05), likely because the low soil water potential reduced its water absorption.

Evaluation of impacts of biosolids application and drainage water management on soil N2O and CH4 emissions using the flux gradient method

Existing studies have shown contradictory findings with respect to whether biosolids applications on agricultural lands lead to intensification of soil greenhouse gas (GHG) emissions. Here, we describe the results of deployment of the micrometeorological flux gradient method to quantify post-biosolid soil emissions of nitrous oxide (N2O) and methane (CH4) on a farm with drainage water management (DWM) on the Eastern Shore of Maryland. The fluxes following biosolid additions to cornfields in 2020 were compared with fluxes from the same farm in 2018, when no fertilizer was applied to soybeans, and in 2019, when urea ammonium nitrate (UAN) was applied to corn. Extractable soil nitrate was highest following biosolids application, contributing to the highest N2O emissions in the growing season of 2020 compared to 2018 (no fertilizer) and 2019 (UAN). Other contributing factors include the low C:N ratio of the biosolids and the above average precipitation in 2020. In contrast, different fertilization regimes did not generate distinct differences for CH4 fluxes, which were very low in all three years. No statistically significant treatment effect of DWM was found for either N2O or CH4 during the peak emission period after biosolids application, which aligns with the result of our earlier research. Annualized estimated N2O emission factors (EFs) for biosolids addition were 5–6 % in the DWM and 3–4 % in the non-DWM fields, although this includes uncertainties associated with gap filling. These biosolids EFs are 2–3 times the N2O EF for synthetic fertilizer application at this same farm in 2019 (1–2.5 %) and 2–4 times the IPCC Tier 1 EF (1.6 %) for synthetic fertilizer, demonstrating the intensification effect of biosolids addition on soil N2O emissions for the cropland studied here.

Electrical conductivity based algorithm for precise application of liquid nitrogenous fertilizers

Precise application of nitrogenous fertilizers mainly urea ammonium nitrate (UAN) and granular urea (both pure and neem-coated) in aqueous form, is critically important for basal and foliar applications. The physicochemical properties of aqueous solution of these nitrogenous fertilizers plays important role in design of any liquid fertilizer application system. The study was carried out during 2019–20 at ICAR-Indian Agricultural Research Institute, New Delhi with an aim to develop algorithms for use in sensors-based systems for real time monitoring of available N concentration in the fertilizer solution before its application. The physicochemical properties like pH, electrical conductivity (EC), specific gravity (SG), dynamic viscosity (DV), surface tension (ST) and percentage light absorbance (LA) of urea ammonium nitrate (UAN-28%), pure urea, and neem coated urea in diluted form (pre-selected N-concentrations i.e. 0.78, 0.9, 1.08, 1.33, 1.75, 2.54 and 4.67% corresponding to the dilution ratios of 1:35, 1:30, 1:25, 1:20, 1:15, 1:10 and 1:05) were measured and analyzed for their significance with N-concentration. Electrical conductivity (EC) alone showed a significant relationship with N-concentrations. Prediction models were developed for diluted UAN and granular urea fertilizers based on the EC and N-concentrations. The regression models in terms of EC to predict N-concentration had coefficients of determination (R2) of 0.998, 0.998, and 0.999 for diluted UAN, pure urea, and neem coated urea with water, respectively showed a great potential for their sensor based precise application. The controlled application of diluted liquid fertilizers with water can be achieved through sensing relevant physicochemical property.

Benefits of controlled-release fertilizers for potato sustainable nitrogen management

The evaluation of potato response to controlled-release fertilizers (CRFs), as a sole source of nitrogen (N) or as a blend with a soluble N source, is essential to 1) develop the best management recommendations for using CRFs in potato production and 2) provide guidelines to CRF manufacturers for developing an optimal product. This study aimed to evaluate the potato yield and quality responses to N CRFs (polymer-coated urea [PCU]) vs soluble N sources. The experiments were conducted in major potato-growing regions in the United States and China. The current industry-recommended practice of 112 kg N/ha pre-plant soil broadcast of urea plus five in-season fertigations of 224 kg N/ha as urea ammonium nitrate (UAN-32) was compared to a single pre-plant application of 224 kg N/ha as a CRF as the sole source of N or as multiple blends of CRFs and soluble N sources (i.e., urea) at various ratios. The results demonstrated that petiole nitrate_N (NO3_N) levels and tuber yield with single pre-plant broadcast applications of 224 kg N/ha as CRF/urea blends (ratio of 25/75 or 50/50) were similar to those obtained with industry-standard N management practice. N uptake and yield were significantly greater with 220 kg/ha N as the CRF than those with the same N rate as urea. Unlike the current potato industry N practice, using CRFs as either a sole source of N or blended with urea reduces the total N rate and application frequency.

Efficacy of fertilizer nitrogen source, stabilizer, and application timing for corn nitrogen nutrition

AbstractEnhancing fertilizer nitrogen use efficiency (NUE) in corn (Zea mays L.) production is critical for closing yield gaps, increasing producer profitability, and promoting environmental stewardship. In 2014 and 2015, a field experiment was conducted to determine the potential for fertilizer N stabilizer products to improve NUE of granular urea and urea ammonium nitrate (UAN) solution applied to strip‐till corn. A urease inhibitor (UI) or nitrification inhibitor (NI) or both were added at labeled rates to urea or UAN solution for a target rate of 180 kg N ha−1. At V3, a single application of broadcast granular urea and subsurface banded UAN solution with and without fertilizer N stabilizers was made. A split application (50% at V3; 50% at V6) of subsurface banded UAN solution served as a control representing a standard grower practice. Fertilizer N stabilizers improved components of NUE, such as grain N recovery efficiency (GNRE) and partial factor productivity (PFP). A single full rate UAN application did not differ in terms of grain yield each year but did result in less PFP and GNRE in 2015 as compared to the grower standard practice. A timely one‐time full season N rate subsurface banded application of UAN treated with UI and NI to improve NUE could be a viable substitute for the practice of multiple fertilizations. Untreated broadcast urea was inferior to UAN as a N source for corn, but when treated with both a UI and NI, NUE was improved.

Transforming waste to wealth: Impact of food waste‐derived soil amendments and synthetic nitrogen fertilizer on soil dynamics

AbstractApproximately one‐third of all food produced globally goes to waste, highlighting the need for sustainable waste management technologies like composting and anaerobic digestion. These technologies convert food waste into soil amendment products such as compost, liquid digestate (LD) and solid digestate (SD). However, these food waste‐derived soil amendments have relatively low nutrient contents compared with synthetic nitrogen (N) fertilizers such as urea, making their agricultural use challenging. Despite this, food waste‐derived soil amendments can enhance the physical and biological properties of soil, potentially creating synergistic effects when combined with synthetic N fertilizers. This study aimed to investigate effects of food waste‐derived amendments in soil applied at 50 kg ha−1 total N (compost, LD or SD) and synthetic N fertilizer [urea ammonium nitrate (UAN)] at 50 and 100 kg ha−1 total N. Over 56 days of soil incubation, greenhouse gases (CO2, N2O), soil chemistry (–N, –N, pH) and microbial biomass C (MBC) were measured. Results showed that LD + UAN 50 reduced cumulative N2O emissions by 23% compared with UAN 100, despite having the same total N and similar available N rate applied to soil. Replacing UAN with LD in farming practices can supply equivalent available N while lowering N2O emissions, offering a sustainable nutrient strategy. Moreover, applying food waste‐derived soil amendments can enhance N retention in soils, reducing the need for increased applications of synthetic N fertilizers to compensate for N deficits in farming. Food waste‐derived soil amendments can also act as a slower N release compared with UAN, reducing nitrogen run‐off. SD had the highest CO2 emissions, followed by LD and compost. SD + UAN 50 increased MBC levels because of higher carbon content and labile carbon, and available N because of the application of UAN. The major drawback of using SD compared with LD is that the process of evaporating LD to form SD causes high ammonia volatilization (ammonium in solution into ammonia gas) rates, reducing the available N in SD. Therefore, future studies should explore strategies to reduce ammonia volatilization of LD.

Optimization of polyethylene rotomolded tank design for storage of liquid mineral fertilizers by the Taguchi method

In this research, by using the finite element method, the effect of five parameters (density of a liquid mineral fertilizer (ρ), its temperature (T), tank wall thickness (L), spacing of stiffeners (K) and stiffeners height (h)) on the strength of standard polyethylene rotomolded tanks used for storage of liquid mineral fertilizers (LMF) was studied. Using the Taguchi method, it was found that these parameters are ranked according to the degree of their influence (in decreasing order) on: maximum stresses (r>L>h>T>K), maximum stresses in the tank walls (r>L>K>T>h) and deformations of the tank (for DX/DY: r>L>h>T>K and for DZ: r>L>h>K>T). Validation of the FEM strength calculations was carried out, which showed satisfactory convergence of the calculated and experimental values. Generalized equations are derived that describe the effect of all five studied parameters on P, PW and tank deformations (along the X, Y and Z axes). On the basis of the derived equations, a nomogram has been constructed, which makes it possible to choose the optimal wall thickness that will correspond to the LMF density and storage temperature. Applying the optimal wall thickness ensures a guaranteed service life of at least 50 years, minimizing the risk of environmental accidents caused by tank failure and the release of LMF and associated toxic substances into groundwater. This research offers valuable insights for designing safer and more durable storage tanks for liquid mineral fertilizers. As an optimal design of the tank for storing the most common fertilizer UAN-32 (Urea Ammonium Nitrate, 32 % nitrogen), with a density of 1.32 g/cm3 and at storage temperatures up to 40 °C, the following values of structural parameters are recommended: L=10 mm, K=38 mm, and h=4 mm

Stacking nitrogen management practices: Combining double‐slot fertilizer injection with urease and nitrification inhibitors improves yields and reduces ammonia and nitrous oxide emissions

AbstractAmmonia loss following nitrogen fertilization can degrade air quality and impact human health, whereas nitrous oxide (N2O) can contribute to global warming and climate change. Mitigation practices that target only one N‐loss pathway can lead to pollution swamping; hence, practices targeting both N‐losses are required. A 3‐year field study examined fertilizer N‐placement (broadcast urea, single‐slot injection of urea ammonium nitrate [UAN], double‐slot UAN injection) and N‐metabolization inhibitors (with/without urease and nitrification inhibitors) impacts on NH3 and N2O losses and corn yields. Ammonia volatilization was reduced (p < 0.05) by 26% with single‐slot UAN injection (10.6 kg N ha−1) and by 63% with double‐slot UAN injection (5.32 kg N ha−1) compared to broadcast urea (14.3 kg N ha−1). Dual urease and nitrification inhibitors reduced NH3 volatilization (0.84–3.86 kg N ha−1) by 57%–92% compared to no inhibitors (5.32–14.3 kg N ha−1). When no inhibitors were applied, N2O emissions from slot injection (6.43–7.62 kg N ha−1) were 2.6–3.1 times greater than from broadcast urea (2.43 kg N ha−1). Dual inhibitors reduced N2O emissions by 43% from 6.43 to 3.66 kg N ha−1 with double‐slot injection. Double‐slot UAN injection increased corn grain yields (9.73 t ha−1) by 12%–13% compared to single‐slot UAN injection (8.71 t ha−1) and broadcast urea (8.6 t ha−1). Double‐slot UAN injection effectively decreased NH3 losses and increased corn grain yields, but dual N inhibitors were required to also reduce N2O. Hence, combined productivity and environmental benefits were accrued only when fertilizer containing urease and nitrification inhibitors was combined with double‐slot injection.

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.

Value of food waste-derived fertilisers on soil chemistry, microbial function and crop productivity

Food waste management through composting and anaerobic digestion are sustainable waste management processes that can promote sustainable agricultural practices by recycling nutrients, reducing reliance on synthetic fertilisers, and conditioning soils. However, compost and digestate (anaerobic digestate effluent) are low nutrient value fertilisers, limiting their use within agriculture due to the large volumes required for land application. Alternatively, food waste-derived fertilisers could be used alongside chemical fertilisers to improve crop growth further and reduce demand on synthetic fertilisers. Therefore, this study evaluated the impact of food waste-derived fertilisers (compost, liquid digestate (LD), and solid digestate (SD)) on plant growth (Ryegrass) when applied at a rate of 50 kg N·ha−1 in combination with synthetic fertiliser (Urea Ammonium Nitrate (UAN)) at a rate of 0 or 50 kg N·ha−1. Ryegrass growth, soil chemistry, and rhizosphere microbial communities were investigated. SD in combination with UAN yielded the largest shoot biomass, while sole UAN at any application rate was not significantly different from the control. Beneficial plant growth phyla were in higher abundance in all treatments amended with food waste-derived fertilisers, and putative genes encoded for N fixing were found in higher abundances in all soil amendments compared to control. This highlights the value of food waste-derived fertilisers within agriculture. However, while drying would logically reduce costs associated with digestate transport, ammonia volatilisation led to significant N losses, reducing the fertiliser value of SD. Future studies should explore methods to mitigate ammonia valorisation to enhance the final fertiliser value of SD.

Spacing of subsurface poultry litter bands: Influence on maize performance and nitrogen use efficiency

AbstractPoultry litter (PL) is traditionally surface broadcast to no‐till maize (Zea mays L.). PL is nutrient‐dense, and surface‐applied PL nitrogen (N) is vulnerable to losses to the atmosphere and water systems. An application method was developed by USDA‐ARS scientists for shallow subsurface banding PL to reduce ammonia (NH3) volatilization and surface runoff. There is limited information on how this application method will affect conservation and nutrient accessibility in no‐till maize. The objectives were to determine if adjusting PL lateral subsurface band placement in relation to maize rows affects nutrient use and maize yields. Treatments were a nontreated control (NTC), urea ammonium nitrate surface banded (Fert), poultry litter surface broadcast (PLBr), and three subsurface banded PL treatments. The subsurface PL treatments were one (PLSub1), two (PLSub2), or three (PLSub3) bands between maize rows. Treatments receiving N were applied at 180 kg total N ha−1. Nitrogen concentration in V4 aboveground dry matter was higher in PLSub1 than PLSub2. Aboveground dry matter yields for all PLSub treatments were greater than PLBr and comparable to Fert. The PLSub1 and PLSub2 treatments resulted in maize grain yields equivalent to Fert and greater than PLBr and NTC when averaged across years. Few differences were observed in postharvest soil sample nutrient concentrations between PLSub treatments. These results suggest that subsurface banding PL can conserve N and increase no‐till maize yield over traditional surface broadcast PL; however, increasing the frequency of subsurface PL bands did not clearly affect nutrient conservation or accessibility to the maize.

Characterisation and agronomic evaluation of acidified food waste anaerobic digestate products

Raw liquid anaerobic digestate was synthesised into nutrient-dense solid digestates via acidification and evaporation. Acidification retained ammonium in the digestate whilst also donating the anion to free ammonium to form an ammonium salt. Digestate was treated with the addition of sulphuric, nitric, and phosphoric acid resulting in the formation of ammonium sulphate, ammonium nitrate and ammonium phosphate, respectively then evaporated into a solid fertiliser product. FTIR, XRD and SEM-EDS collectively confirm that the addition of acids completely converted the free ammonium in the raw digestate into their respective ammonium salt counterparts. Compounds of potassium chloride, silicon dioxide, calcium carbonate, magnesium ammonium phosphate, sodium nitrate, and sodium chloride were identified in all solid digestate samples. Plant growth and grain yield was higher in urea ammonium nitrate, raw liquid digestate and acidified digestate products compared to control and unacidified solid digestate. Urea ammonium nitrate and ammonium nitrate solid digestate had the highest dry shoot, likely due to the high available nitrogen found in both fertilisers. Overall, acidification and evaporation of liquid digestate can efficiently transform it into a valuable solid fertiliser with a high nutrient density. This process not only has the potential to mitigate handling and storage constraints of low nutrient density digestate in anaerobic digestion facilities but also offers a sustainable alternative to conventional fertilisers.

Selected Carbon and Nitrogen Compounds in a Maize Agroecosystem under the Use of Nitrogen Mineral Fertilizer, Farmyard Manure, Urease, and Nitrification Inhibitors

Carbon and nitrogen compounds in agroecosystems have attracted much attention in recent years due to their key roles in crop production and their impacts on environment quality and/or climate change. Since fertilization profoundly disrupted the C and N cycles, several mitigation and/or adaptation strategies, including the application of farmyard manure (FYM) and/or urease and nitrification inhibitors (UI and NI), have been developed. The aim of this study was to evaluate the contents of soil organic carbon and its fractions, the total and mineral forms of nitrogen, as well as CO2 and N2O emissions under mineral and organic fertilization with and without urease and nitrification inhibitors in a maize agroecosystem. A two-year field study was carried out on Cambisols (silt) in Poland. The experiment scheme included nine treatments: C (the control without fertilization), UAN (Urea Ammonium Nitrate), UAN+UI, UAN+NI, UAN+UI+NI, FYM with N mineral fertilizer base, FYM with N mineral fertilizer base+UI, FYM with N mineral fertilizer base+NI, and FYM with N mineral fertilizer base+UI+NI. It was found that treatments fertilized with cattle FYM were higher sinks and sources of C and N compounds in comparison to the UAN plots. The organic carbon, humic and humin acid, and total nitrogen concentrations, in contrast to ammonium and nitrate nitrogen, were not affected by the inhibitors added. Nitrification and urease inhibitors were effective in decreasing N2O emissions only in treatments that were exclusively applied with UAN and had no significant influence on CO2 emissions.

Long‐term compost use and high frequency low concentration fertigation reduce N2O emissions from a California almond orchard

AbstractUsing compost as an agricultural amendment offers a means to reduce organic waste, as mandated in the US state of California (SB 1383). Compost can improve soil physical characteristics and soil carbon content by increasing soil organic matter. We examined the effect of compost application (7‐year duration) on soil nitrous oxide (N2O) emissions, inorganic nitrogen (N) pools, soil temperature and water content, bulk density, and total carbon (C) and N content. The orchard was composed of Nonpareil cultivars interplanted with Aldrich and Carmel cultivars, all grafted on Nemaguard peach rootstock [Prunus persica (L.) Bratsch]. Its soil was Oakdale sandy loam (coarse‐loamy, mixed, active, thermic Mollic Haploxeralf). Delivering nutrients through the irrigation system, the orchard was fertigated 14 times with urea ammonium nitrate or calcium ammonium nitrate, using high frequency and low concentration (HFLC) fertigation applications (total 195 kg N ha−1). Soil without compost (No Compost) tended to have higher N2O fluxes (up to 2.75‐fold) than soil with compost (Compost). Cumulative measured N2O emissions (i.e., sum of nine sampling events) from Compost were half that from No Compost. Soil pH, electrical conductivity, total C, and N tended to be greater in Compost, and bulk density tended to be lower in Compost than No Compost. No relationships between N2O emissions and soil temperature, volumetric water content, water‐filled pore space, and inorganic N pools occurred in either treatment. Our findings indicate that long‐term applications of compost in perennial crops, in combination with an HFLC nutrient management program, could reduce losses of N as N2O to the atmosphere.

Urea ammonium nitrate placement methods, row patterns, and irrigation effects on corn productivity in a humid subtropical region

AbstractCrop yields are adversely affected by nitrogen (N) losses in humid subtropical regions. This study was conducted to determine whether N dynamics could be manipulated through planting geometry and fertilizer placement. The effects of irrigation (irrigated and rainfed), row pattern (single‐ and twin‐row), and N placement (surface dribble, one knife, two knives, and control) on corn (Zea mays L.) productivity and N use efficiency were investigated at Leland, Mississippi, on a Bosket very fine sandy loam. The total N rate was split into two equal halves of 128 kg N ha−1 at V2 and V6 growth stages. The effects of row pattern and N placement were consistent between irrigated and rainfed environments. There was no interaction between row pattern and N placement nor did row pattern affect corn productivity or N use efficiency parameters. In 2020, when less than 30 mm of rainfall occurred from the first N application through 2 weeks after the last N application, corn grain yield and agronomic N efficiency were not different among placement methods and averaged 11.1 Mg ha−1 and 20.3 kg grain kg−1 fertilizer N, respectively. However, in 2021, applying N with one knife increased corn grain yield by 7% to 14% compared to the two knives and surface dribble application methods; in that year, 235 mm of rainfall occurred from the first N application through 2 weeks after the last N application. Applying N with one knife appears to consistently improve crop productivity and N use efficiency parameters for both irrigated and rainfed environments.

Humic Acid Effects on Reducing Corn Leaf Burn Caused by Foliar Spray of Urea-Ammonium Nitrate at Different Humic Acid/Urea-Ammonium Nitrate Ratios

Humic Acid Effects on Reducing Corn Leaf Burn Caused by Foliar Spray of Urea-Ammonium Nitrate at Different Humic Acid/Urea-Ammonium Nitrate Ratios

Efficiency of using UAN-32 and Sternifag biopreparation on spring wheat grown with No‑till technology

The results of joint application of the biopreparation Sternifag, SP based on the fungus Trichoderma harzianum and urea ammonium nitrate (UAN-32) on spring wheat cultivated using the No-till technology in the northern forest-steppe of the Priobie region are presented. This zone is characterized by a short growing season and a mean annual moisture coefficient of 1.04–1.08. Under such conditions, No-till, or direct seeding, technology can minimize the cost of grain production. When growing crops according to this technology in the conditions of the northern forest-steppe, the sowing dates are postponed, which actualizes the use of biopreparation to accelerate the mineralization of straw residues. In production and stationary experiments on leached chernozem, the joint application of Sternifag and nitrogen fertilizer in autumn of the previous year activated decomposition of plant residues on second wheat by 33.0–49.0%. Application of the biopreparation together with UAN-32 allowed to obtain in the years of research additional 1 ha 1.5 and 0.96 tons of spring wheat grain (43.7–44.4%) due to an increase in the weight of 1000 grains, ear fineness and better preservation of plants for harvesting. Application of biopreparation Sternifag and UAN-32 on spring wheat grown on the basis of No-till technology in the northern forest-steppe of Priobie is economically beneficial. It is accompanied by an increase in profit by 2.0–2.4 times and an increase in the level of profitability of grain production by 27.0–36.0%. Effectiveness of cultivation of the crop on the background of liquid nitrogen fertilizer UAN-32 is lower. In this variant, grain productivity of spring wheat relative to the control increased in 2018, characterized by high humidity, by 1.1 t/ha, in 2020, characterized by June drought, by 0.74 t/ha. The level of profitability of grain production at application of UAN-32 is higher than in the control by 15.0–17.2%.

Does biochar improve nitrogen use efficiency in maize?

AbstractBiochar is promoted as a means of improving soil fertility. Yet, few experiments have investigated its potential to improve nitrogen (N) use efficiency for high‐yielding maize production in the U.S. Midwest. We tested the hypothesis that biochar application increases inorganic soil N availability during maize growth, leading to higher grain yields and N recovery efficiency while reducing the risk of N leaching following harvest. Four N fertilizer rates (0, 90, 179, and 269 kg ha−1 as urea ammonium nitrate [UAN] solution) were applied with or without biochar (10 Mg ha−1) before planting in a two‐year field study. Inorganic soil N concentration was measured during the growing season (0–15 cm), and deep soil cores were obtained following harvest (0–90 cm). Results show that biochar did not affect maize yield, crop N uptake, or N recovery efficiency (by the difference method) across N rates, and there was no biochar by N rate interaction. While biochar lowered soil inorganic N concentrations on several sampling dates, this did not translate into seasonal differences in cumulative soil N availability, although grain yields in the unfertilized control were ~10% lower with biochar, suggesting net N immobilization. Biochar partially reduced the risk of N leaching following harvest by decreasing soil N concentrations at 30–60 cm, but mean concentrations for 0–90 cm were not different. Compared to previous work highlighting the benefits of biochar in arid climates with low soil fertility, we found no evidence of increased crop yield, NRE, or reduced risk of N leaching on Mollisols in a temperate climate.

Evaluating the Use of Postharvest Decomposition Treatments on Peanut Residues for Reducing Subsequent Infection by Nothopassalora personata

The late leaf spot (LLS) pathogen Nothopassalora personata overwinters on peanut residues left in the field. In this study, decomposition treatments were evaluated for their potential use in increasing the rate of decomposition of residues and potentially reducing LLS incidence. Treatments including urea ammonium nitrate (UAN) only, UAN plus a microbial stubble digestor (SD25), or UAN plus an adjuvant (Bond Max, BM), as well as timing of application in fall or spring, were assessed. Fall applications were not effective in reducing or delaying subsequent LLS epidemics. Although there were differences observed among treatments in the spring 2019 test, with UAN plus Bond Max-treated plots having significantly less defoliation from LLS at the end of the growing season, these results were not consistent in the 2020 experiments. Using the litterbag method, no consistent increase in decomposition was observed from treated residues compared with the nontreated control. Based on these results, the examined decomposition treatments were not considered to be useful in increasing the decomposition of peanut residues and subsequently reducing or delaying LLS epidemics. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .