Efficiency Of Nitrogen Fertilization Research Articles

Enhanced efficiency nitrogen fertilizers (EENFs) can reduce nitrous oxide emissions and maintain high grain yields in a rain-fed spring maize cropping system

ContextEnhanced efficiency nitrogen fertilizers (EENFs) have provided opportunities for the simultaneous mitigation of nitrous oxide (N2O) emissions and increases in crop productions. However, the practice of combining EENFs with optimal fertilization under conditions of misaligned water and fertilizer inputs in rain-fed spring maize systems remains inadequately understood. ObjectiveThis study aims to determine the factors controlling N2O emissions under the soil climatic conditions in rain-fed plastic mulching cropping systems treated with different nitrogen (N) fertilization rates and EENFs, and to determine the most effective N fertilization measure to reduce N2O emissions while maintaining crop yields. MethodsA 3-year field experiment was conducted in a spring maize system located in the semiarid rain-fed region of the Loess Plateau, applying two types of EENFs: a nitrification inhibitor dicyandiamide (DCD) and a slow-release fertilizer (SRF). It comprised five fertilization treatments: unfertilized (CK), conventional N rate (CON, 200 kg N ha−1), optimal N rate (OPT, 160 kg N ha−1), OPT with the addition of DCD (OPT+DCD), and OPT using SRF (OPT-SRF). ResultsThe average annual cumulative N2O emissions over the 3-year experimental period ranged from 0.74 to 1.87 kg N2O-N ha–1. Fertilizer N contributed 26−60% to annual N2O emissions. The highest N2O fluxes (50–161 μg N2O-N m–2 h–1) typically occurred within the initial 10 days following fertilization, likely induced by strong nitrification processes, constituting 12–19% of the annual N2O emissions during this brief period. In comparison to the CON treatment, the OPT, OPT+DCD, and OPT-SRF treatments resulted in significant reductions in annual N2O emissions of 24%, 46%, and 34%, respectively, without causing any significant decrease in maize grain yields. The application of DCD led to increased ammonium (NH4+-N) concentrations while reducing nitrate (NO3–-N). Conversely, using SRF resulted in a decrease in both NH4+-N and NO3–-N concentrations. ConclusionsUsing EENFs at the ideal fertilization rate significantly curtailed yearly N2O emissions without adversely affecting maize yields in a rain-fed plastic mulching spring maize system prevalent in the Loess Plateau. Most N2O emissions occurred post-fertilization, with rainfall events further influencing these emissions. ImplicationsOur findings recommend the incorporation of nitrification inhibitors, such as DCD, as the most effective fertilizer measure for reducing N2O emissions in the rain-fed region of the Loess Plateau.

Effects of Different Organic Fertilizer Substitutions for Chemical Nitrogen Fertilizer on Soil Fertility and Nitrogen Use Efficiency of Foxtail Millet

Conventional fertilizer management can destroy the structure of soil. Replacing chemical fertilizers with organic fertilizers can improve soil quality and nitrogen use efficiency. We aimed to study the effects of organic fertilizer substitutions for chemical nitrogen fertilizer on soil fertility and nitrogen use efficiency in order to clarify the effectiveness of the available nutrient management measures in improving soil quality and increasing foxtail millet yield. A field experiment was carried out over two consecutive years, and a total of six treatments were set up: no fertilizer (CK), chemical nitrogen fertilizer alone (N), the substitution of 25% of chemical nitrogen fertilizer with bio-organic fertilizer (N25A1), the substitution of 25% of chemical nitrogen fertilizer with fermented mealworm manure (N25B1), the substitution of 50% of chemical nitrogen fertilizer with bio-organic fertilizer (N50A2), and the substitution of 50% of chemical nitrogen fertilizer with fermented mealworm manure (N50B2). The results of this study show the following: (1) Compared with chemical nitrogen fertilizer, the substitution of organic fertilizer for nitrogen fertilizer reduced the bulk density and solid phase of the soil, and it increased the total porosity, water content, liquid phase, and gas phase of the soil. (2) Compared with nitrogen fertilizer, the use of an organic fertilizer increased the contents of nitrate nitrogen, ammonium nitrogen, and total nitrogen in the soil by 13.59~52.56%, 4.47~18.27%, and 4.40~12.09%, respectively. The content of alkaline nitrogen increased by 1.70~32.37%, and the contents of soil available potassium, available phosphorus, and organic matter also increased. (3) The activities of sucrase, urease, glutaminase, and asparaginase were improved by replacing chemical nitrogen fertilizer with organic fertilizer. The N25 treatments performed better than the N50 treatments, and fermented mealworm manure performed better than biological organic fertilizer. (4) A moderate application of organic fertilizer (N25) can increase the grain yield, ear weight, grain weight, and 1000-grain weight of foxtail millet, whereas excessive application of organic fertilizer (N50) can reduce foxtail millet yield. (5) Replacing chemical nitrogen fertilizer with organic fertilizer can improve the agronomic use efficiency, physiological efficiency, biased productivity, harvest index, and apparent use efficiency of nitrogen fertilizer. In this study, the substitution of 25% of chemical nitrogen fertilizer with fermented mealworm manure was the best combination for restoring crop productivity and soil quality.

Nitrogen: from discovery, plant assimilation, sustainable usage to current enhanced efficiency fertilizers technologies – A review

ABSTRACT From 1913 onwards, the global situation changed from a scenario of nitrogen (N) scarcity to an abundance of ammonia (NH 3 ) produced synthetically via the Haber-Bosch process. Several N compounds have been synthesized since then, with urea becoming the main source of N, accounting for 55 % of current N consumption. However, N efficiency in agroecosystems is low and, normally, N recovery in cultivated plants is less than 50 %. This occurs because a large amount of reactive N is lost to the environment, inducing various forms of pollution, threatening human and environmental health, in addition to causing a negative economic impact on the farmer. The main processes responsible for low N efficiency are NH 3 volatilization, leaching, and N denitrification. Considering global NH 3 volatilization losses of 14 %, it can be assumed that up to 8.6 million Mg of urea are lost every year in the form of NH 3 . For each ton of NH 3 produced, 1.9 to 3.8 Mg of CO 2 is emitted into the atmosphere. Therefore, increasing N use efficiency (NUE) without compromising yield is a necessity and a challenge for crop improvement programs and current management systems, in addition to reducing greenhouse gas emissions. In this context, enhanced efficiency fertilizers (EEFs), which contain technologies that minimize the potential for nutrient losses compared to conventional sources, are an alternative to increasing the efficiency of nitrogen fertilization. Currently, EEFs are classified into three categories: stabilized, slow-release, and controlled-release. This study aims to understand the technologies used to produce EEFs and the factors that govern their availability to plants. This review covers the following topics: the discovery of N, N dynamics in the soil-atmosphere system, N assimilation in plants, strategies to increase NUE in agrosystems, NH 3 synthesis, NH 3 volatilization losses, N fertilizer technologies, the importance of characterization of EEFs, conventional nitrate or ammonium-based fertilizers to reduce gaseous losses of NH 3 and future prospects for the use of N fertilizers in agriculture.

Can Foliar-Applied Omeprazole Improve the Yield, Assimilation, Recovery and Nitrogen Use Efficiency in Bean Plants?

The low efficiency of nitrogen (N) fertilizers is a frequent problem in agriculture that impacts the environment. Omeprazole (OMP) has been reported to promote N uptake and assimilation in tomato, basil, and corn. However, information about the effect of omeprazole on N assimilation, recovery, and N use efficiency parameters for bean plants is limited. Therefore, the objective of the present study was to determine the effect of foliar applications of OMP at 0, 1, 10, and 100 µM on nitrogen assimilation, growth, yield, nitrogen use efficiency parameters, and recovery percentage in green bean plants. Green bean plants cv. Strike grown in pots were used. Biomass, yield, nitrate reductase activity, photosynthetic pigments concentration, soluble amino acids and protein concentrations, total nitrogen concentration, nitrogen use efficiency parameters, and nitrogen recovery were analyzed. The results obtained indicate that the application of OMP at 1 µM increased yield and biomass, promoted N assimilation through higher NR enzyme activity, higher amino acid concentration, higher N use efficiency coefficient, and allowed a more efficient nitrogen recovery percentage.

Efficiency of neem (Azadirachta indica) as a nitrification inhibitor under laboratory conditions

The use of nitrification inhibitors is a technology that can increase the efficiency of nitrogen fertilization, and synthetic and natural products can be used for this purpose. However, the use of these products is still poorly studied in tropical regions. The objective of this work was to evaluate the nitrification of nitrogen, under laboratory conditions, with urea covered with doses of neem leaf or cake, using DMPP (3,4-dimethylpyrazole phosphate) for comparison. The treatments consisted of a 2 x 4 + 2 factorial scheme, with the first factor represented by neem sources (leaf and cake), used to cover the urea and the second factor by neem doses, these doses being 0, 10 , 20 and 40% of the total applied N (200 mg kg-1, using urea as a N source) and two additional treatments: control (soil without nitrogen fertilizer) and urea + DMPP. Ammonium and nitrate contents were evaluated right after incubation (time 0) and on the 7th, 15th, 30th, 60th and 90th day after the start of incubation. For the ammonium content in the soil, there was influence of source and dose on the fifteenth day of incubation, with linear increments for both sources; and for nitrate levels, there was a significant effect (p<0.01) of neem doses on the 7th and 15th days of incubation, with a reduction in levels depending on the doses for the two sources tested. Significant differences (p<0.01) were found between additional and factorial treatments and between additional treatments for ammonium levels from the 7th to the 90th day of incubation. There was no significant interaction, in any of the dates, between neem sources and doses for ammonium and nitrate contents in the soil. Covering the urea with neem leaf and cake was efficient in reducing the levels of nitrate in the soil up to 15 days after incubation, resulting in higher levels of ammonium in the soil until this date. However, DMPP was more efficient in reducing nitrification, promoting inhibition up to 60 days of incubation.

Effect of NBPT-DCD (Urease and Nitrification Inhibitor) on Nitrogen Loss, N Uptake and Oil Palm Yields (Elaeis guineensis Jacq.) bn Typic Dystrudepts Soil

Incorporating N-(n-butyl) thiophosphoric triamide (NBPT) as a urease inhibitor and Dicyandiamide (DCD) as a nitrification inhibitor can enhance the efficiency of nitrogen (N) fertilization. The main aim of the study was to evaluate the impact of urease and nitrification inhibitors (NBPT and DCD) on N loss in urea fertilizer, N absorption, and oil palm (Elaeis guineensis Jacq.) yield. Researchers conducted the field trial using a single-factor, completely randomized design (CRD) with three replications. The experimental treatments included nitrogen (N) fertilization with 5 different levels. The levels were: 100% urea (2.75 kg/plant/year: 1.50 kg/plant in rotation 1 and 1.25 kg/plant in rotation 2) (N0), 80% urea + NBPT-DCD (2.20 kg/plant/year: 1.20 kg/plant in rotation 1 and 1.0 kg/plant in rotation 2) (N1), 60% urea + NBPT-DCD (1.65 kg/plant/year: 0.90 kg/plant in rotation 1 and 0.75 kg/plant in rotation 2) (N2), Urea dosage of 80% (2.20 kg/year: 1.20 kg/plant in rotation 1 and 1.00 kg/plant in rotation 2) (N3), and Urea dosage of 60% (1.65 kg/plant/year: 0.90 kg/plant in rotation 1 and 0.75 kg/plant in rotation 2) (N4). The findings revealed that the application of Urea in combination with NBPT-DCD (inhibitors of urease and nitrification) led to a reduction in N loss by 30.33-37.48% and an increase in N absorption compared to Urea without NBPT-DCD. Oil palm trees grew on Typic Dystrudept soil. The plants received 2.20 kg of urea treatment per plant. The researchers combined Urea with NBPT-DCD. These trees had better outcomes than others. They had less N volatilization and better N absorption. They also had higher fresh fruit bunch productivity. The others received N fertilization but not NBPT-DCD.

The impact of Klebsiella quasipneumoniae inoculation with nitrogen fertilization on baby corn yield and cob quality

In response to the escalating costs and diminishing efficiency of nitrogen fertilizers, the agricultural community is actively seeking sustainable alternatives that leverage natural nitrogen sources derived from biological N-fixation processes to enhance crop yield. This study investigates the combined effects of Klebsiella quasipneumoniae inoculation and varying nitrogen fertilizer doses on soil fertility, nutrient availability, and the yield and quality parameters of baby corn (Zea mays. L). The study involved the application of five nitrogen levels (0, 75, 150, 225, and 300 kg N ha-1) in conjunction with Klebsiella quasipneumoniae inoculum on HM-4 variety of baby corn, employing a comprehensive experimental design with five treatments and four replications. All treatments demonstrated increased ear count and weights of ear, silk, husk, edible cob, and biomass compared to the control. The study highlights the potential of Klebsiella quasipneumoniae inoculation in synergy with reduced nitrogen fertilizer to enhance total N contents in soil and positively impact baby corn yield and cob quality parameters. Optimal results were achieved with a 50% reduction in nitrogen fertilizer (150 kg N ha-1), emphasizing the importance of integrated nutrient management. The findings contribute valuable insights to sustainable agriculture, offering a promising strategy for increased baby corn production, improved nutritional quality, and environmental conservation. This integrated approach, involving microbial inoculation and nitrogen management, emerges as a key element in modern agricultural practices, promoting both productivity and nutritional content in baby corn crops.

Controlled-Release Nitrogen Mixed with Common Nitrogen Fertilizer Can Maintain High Yield of Rapeseed and Improve Nitrogen Utilization Efficiency.

Field experiments were conducted to study the effects of different proportions of controlled-release nitrogen fertilizer mixed with quick-acting nitrogen fertilizer on the yield and nitrogen utilization efficiency of direct-seeding rapeseed. Using a conventional nitrogen application rate of 180 kg ha-1 as a control, a total of 5 types of available nitrogen fertilizers and different proportions of controlled-release nitrogen fertilizers were mixed for fertilizer treatment. The proportion of available nitrogen fertilizer used was 135 kg ha-1, and the addition ratios of the five types of controlled-release nitrogen fertilizers were 0%, 30%, 50%, 70%, and 100%, respectively (i.e., the proportion of controlled-release nitrogen to the total nitrogen application amount). These ratios were represented as N135R0, N135R1, N135R2, N135R3, and N135R4, respectively. The results showed that there was no significant difference in the number of pods per plant, the number of seeds per pod, or the grain yield under the treatment of controlled-release nitrogen fertilizer mixed with quick-acting nitrogen fertilizer for proportions of 30-50% (N135R1~R3) when compared with the control, and a stable yield was achieved. Mixing controlled-release nitrogen fertilizer under reduced nitrogen application can significantly improve the apparent utilization rate of rapeseed nitrogen fertilizer, but it first increases and then decreases with the increase of the controlled-release nitrogen mixing ratio, reaching its highest under the N135R2 treatment. The agronomic utilization efficiency and partial productivity of nitrogen fertilizer first increased and then decreased with the increased proportion of controlled-release nitrogen, and both reached their highest utilization with the N135R2 treatment. The mixed treatment of controlled-release nitrogen did not affect soil urease activity, but significantly increased soil sucrase activity. The mixed treatment of controlled-release nitrogen also increased soil microbial biomass nitrogen and carbon content. Especially in the flowering stage, the soil microbial biomass nitrogen and carbon content was significantly higher under a controlled-release nitrogen mixing ratio of 30-50%. At the same time, it had a similar effect on soil inorganic nitrogen content. Therefore, a controlled-release nitrogen mixing treatment provided sufficient nitrogen for the key growth period of rapeseed. Under the condition of reducing the amount of nitrogen fertilizer by 25% based on the amount of nitrogen fertilizer applied to conventional rapeseed, the application of controlled-release urea mixed with common nitrogen fertilizer mixed at a ratio of 30-50% can be an effective way to maintain grain yield levels and improve nitrogen utilization efficiency.

NITROGEN FERTILIZERS ROLE IN GRAIN CROPS PRODUCTIVITY IN SOUTH-EAST KAZAKHSTAN

Seeking to improve the efficiency of nitrogen fertilizers for grain crops led to conducting this study on developing methods using 15N in 2015–2017 at the Kazakh Research Institute of Agriculture, Almalybak Village, Almaty Region, Southeastern Kazakhstan. Nitrogen use efficiency using the stable isotope 15N in microfield experiments revealed that the assimilation of nitrogen fertilizers by grain crops largely depends on the norms, timing, fertilization method, and varietal parameters of the concerned crop. Based on morphophysiological methods of monitoring plant development conditions, the nitrogen fertilizers’ role based on the development has been affirmative, with the optimal timing of their application also determined. Results show that grain crops use nitrogen productively with partial application at the beginning of tillering and tubing, respectively, and stages III and V of organogenesis. With the use of nitrogen fertilizers, the significant varietal differences were evident. The help of an isotope label established the accurate nitrogen utilization coefficients of fertilizers based on the options ranging from 14.7% to 32.2%. Using the isotope method provides an opportunity for further development of practicing the most efficient techniques of applying fertilizers, which is an imperative method for determining the effectiveness of nitrogen fertilizers.

Use of shrimp farming waste in the production of biomaterials for sustainable agriculture and mitigation of environmental damage

AbstractBackgroundDue to the environmental degradation caused by shrimp farming in Brazilian mangrove ecosystems, it is of great importance to develop techniques capable of inserting waste into the production chain, strengthening the premise of sustainable shrimp farming development due to its economic and social impact. In this work, solid residues from shrimp farming were used as a slow‐release fertilizer (SRF) in formulations that also contain chitosan, montmorillonite, and urea.ResultsFertilizer granules produced without (FERT A) and with additional layers (FERT B) were characterized by elemental analysis (Carbon, Hydrogen, Nitrogen), obtaining values of 14.4%–18.4% for carbon, 5.6%–6.9% for hydrogen, and 12.3%–19.3% for nitrogen. The fertilizers had low C/N ratios of around 1.0–1.50, compared to a value of 0.87 for urea, the nitrogen fertilizer most widely used in Brazilian agriculture. Release tests in water showed the same release pattern in the first 5 min for FERT A and FERT B, with <10% urea release. After 30 min, the release from the fertilizers progressively increased, reaching >60% after 1 day and a maximum of 95%–97% after 15 days. In the first 3 days of incubation in the soil, the releases of nitrogen from FERT A, FERT B, and conventional urea presented different patterns, with values of 32%, 10%, and 90%, respectively. After incubation for 25 days, FERT A and FERT B presented nitrogen releases lower than 78%, confirming the slow release of the nutrient from these fertilizers. Degradation experiments showed that the fertilizers were biodegradable in the soil, with degradation exceeding 60% after 30 days, indicating that they could be applied to the soil without leaving residues.ConclusionsThe fertilizer granules produced are SRFs that have the potential to increase the efficiency of nitrogen fertilization, reducing the frequency of applications and minimizing nitrogen losses in the soil. In addition, they enable the reuse of shrimp farming waste, producing a new material of agricultural interest.

Sustainable management of water, nitrogen and biochar resources for soybean growth considering economic, environmental and resource use efficiency aspects: An integrated modeling approach

Intensive soybean production requires that water and fertilizer are collaboratively managed in an accurate and efficient manner, while biochar application offers a sustainable approach for protecting land, alleviating water scarcity, and increasing crop yield. The purpose of this study was to carry out a multifactor coupling orthogonal experiment of irrigation, nitrogen and biochar in the soybean growing season in 2021 and 2022 via plot treatment, linking the effect of irrigation and nitrogen on soybean yield with the carbon sequestration and emission reduction properties of biochar. A dynamic regulation model with multi-dimensional objective synergy for soybean yield, water footprint (WF), carbon footprint (CFP), water use efficiency (WUE) and partial productivity of nitrogen fertilizer (PFPN) based on the comprehensive regulation framework of experimental-simulation-optimization was constructed. This model was used to explore the optimal irrigation, nitrogen and biochar application patterns and their synergistic effects on yield and environmental benefits. The results showed that soybean yield and PFPN were affected by irrigation, nitrogen application affected WF and WUE, and biochar application affected CFP. Irrigation significantly affected the soil water content and consequently the WF while enhancing the crop yield and PFPN. Compared to the I1 treatment, the I0 treatment reduced water consumption, and the addition of nitrogen (N0 and N1) contributed to higher crop yields and WUE. The addition of biochar significantly increased crop yield, WUE and PFPN while mitigating the impact of nitrogen fertilizer application on greenhouse gas emissions. Based on the three-factor interaction, the yield, WF, CFP, WUE, and PFPN in 2022 increased by 3.03%, 3.51%, 2.17%, 1.59%, and 7.61%, respectively, compared to those in 2021. In addition, combined with water and nitrogen application, biochar application reduced CFP while increasing soybean yield, WUE and PFPN. A multiobjective optimization model demonstrated that when the amounts of irrigation, nitrogen, and biochar in 2021 and 2022 were 178.4 mm, 104.6 kg/hm2, and 8650.8 kg/hm2 and 153.7 mm, 93.7 kg/hm2, and 8063.4 kg/hm2, respectively, the synthetic degrees of yield, WF, CFP, WUE, and PFPN reached 0.866 and 0.872, respectively. The coordinated regulation of irrigation, nitrogen, and biochar reached a high-quality coordinated level that was 14.39% and 7.13% higher in 2021 and 2022 than the best I0N0B1 treatment, respectively. In this study, a combination of experiment-simulation-optimization is used to propose optimal irrigation, nitrogen and biochar regulation methods that synergize soybean yield, resource use efficiency and environmental benefits, which are of theoretical value for promoting green and efficient soybean production in black soil areas.

Comparison of the efficiency of nitrogen fertilizers during the autumn and spring tillering of winter wheat (Triticum aestivum L.)

An important direction of modern agrotechnologies of crop production is the greening of intensive technologies and energy conservation, this contributes to the use of biological preparations that can increase yields, improve grain quality, increase profitability by saving mineral fertilizers and protective equipment. Therefore, field experiment was conducted during 2019-2021 in the dry-steppe zone of chestnut soils of the Volgograd region. The scheme of the experiment included four sites with late-autumn; early-spring; late-spring application dates and control, without the use of nitrogen fertilizers. All records and surveys were carried out according to the methodology of the state variety testing of agricultural crops: calculation of germination, determination of tillering coefficient, determination of the weight of aboveground biomass of plants, the density of productive stems. As a result of studying the issue conducted in various weather conditions of the test years, it was established that the period of application of nitrogen fertilizers had a significant impact on the growth, development and yield of experimental crops. The highest yield indicators were recorded at the time of early spring application of nitrogen fertilizers @ 38.0, 30.8 and 40.2 q/ha in 2020, 2021 and 2022, respectively. With the delay in the application of nitrogen fertilizers in the spring, the yield decreased by 8-13% during the observation period, and 32.94 28.2 and 35.8 q/ha in 2020, 2021 and 2022, respectively. The introduction of nitrogen fertilizers in autumn, as close as possible to the end of the growing season, led to a decrease in yield by only 2-4% and amounted to 36.5, 29.8 and 39.5 q/ha in 2020, 2021 and 2022, respectively.

Assessing fertilizer nitrogen sources and application timing for water‐seeded rice systems

AbstractIn California's water‐seeded rice systems, both high yields and nitrogen (N) use efficiency are achieved when the pre‐plant N fertilizer (usually aqueous‐ammonia [aqua‐N]) is injected into a dry seedbed before flooding and planting. However, there are situations where applying N fertilizer in this manner is not possible. The objective of this study was to evaluate alternative N management practices by testing different N sources and application times. In 2020, we tested 13 treatments and in 2021, six more treatments were added. The following N sources were evaluated: urea, ammonium sulfate, and three enhanced efficiency nitrogen fertilizers (EENFs). Application times for the EENFs, urea, and ammonium sulfate were one day after flooding and 2 weeks after flooding. Urea and ammonium sulfate were also applied in a four‐way split. In 2021, additional treatments were added with aqua‐N, ammonium sulfate, and urea applied before flooding, and urea applications at 3, 4, and 5 weeks after flooding. Grain yield and agronomic nitrogen use efficiency (ANUE) were used for comparison. All fertilizer N treatments increased grain yields relative to the zero‐N control, which averaged 5093 kg ha−1. Applying aqua‐N or urea preplant to a dry soil resulted in the highest yields and ANUE. The EENF fertilizers performed similarly to or worse than urea applied alone. If the field was already flooded, splitting urea applications was the best option. Only one split N treatment was evaluated in this study; this warrants further research on fine‐tuning the best N splits for these systems.

Evaluation of Nitrogen Release Characteristics and Enhanced Efficiency of a Novel Synthetic Slow-Release Nitrogen Fertilizer

Evaluation of Nitrogen Release Characteristics and Enhanced Efficiency of a Novel Synthetic Slow-Release Nitrogen Fertilizer

Estimating Fertilizer Nitrogen-Use Efficiency in Transplanted Short-Day Onion

Efficient nitrogen (N) fertilizer applications in onion (Allium cepa L.) can reduce input costs and improve fertilizer-use efficiency, while maintaining high yields and quality. Understanding the N requirements of onion at different growth stages is necessary to enhance fertilizer N-use efficiency (FNUE). In a two-year study (2021 and 2022), the FNUE of onions was determined at five stages of development (at transplant, vegetative growth, bulb initiation, bulb swelling and bulb maturation). The FNUE was estimated by substituting a conventional N fertilizer (ammonium nitrate) with a 5% enriched 15N ammonium nitrate at a rate of 22.4 kg·ha−1 N, at one of five application times corresponding to a stage of development. All onions received a season total of 112 kg·ha−1 N. Marketable yield of onions was significantly greater in 2022 compared to 2021 and FNUE was affected by application timing in both years. In 2021, the FNUE at transplant was 8.9%, increasing to 26.4% and 35.28% at vegetative growth and bulb initiation stages, respectively. At bulb swelling and bulb maturation stages, FNUE was greater than 95%. In 2022, the FNUE at transplant was 25.2%. This increased to 75.7% and 103% at vegetative growth and bulb initiation stages, respectively. Results suggest that the application of fertilizer N at transplant is inefficient due to limited plant uptake ability, while N applications during bulb initiation and swelling were the most efficient.

Combination effects of microbial inoculation and N fertilization on maize yield: A field study from southern Brazil

The use of inoculants based on diazotrophic microorganisms is an alternative to decrease the dosage and increase the efficiency of nitrogen fertilizers, especially in grains that are demanding and nutrient-responsive crops. Cyanobacteria is photosynthetic and nitrogen fixing prokaryote; however, there has been little focus on Anabaena cylindrica and Nostoc muscorum as biofertilizers in the presence of added nitrogen sources. The purpose of this study was to explore the maize yield in two crop seasons in Londrina, Brazil under different nitrogen rates (topdress, 0–130 kg ha−1; sowing, 20–150 kg ha−1) and microbial inoculants (A. cylindrica, N. muscorum and Azospirillum brasilense), in randomized block design with factorial arrangement 4 × 4. Different phytometric characteristics (e.g. height of plant and spike insertion; stem diameter; area idex and chlorophyll content of leaf; Nitrogen (N), Phosphorous (P) and Potassium (K) contents in leaf) and grain yield (such as quantity of rows ear−1, grains row−1, grains ear−1, ear plant−1, grain N content, weight 1000 grains−1, grain yield) were evaluated. The phytometric characteristics and maize yield were not altered by the interaction between N rates and inoculants, demonstrating that N rates do not interfere with cyanobacteria performance. The inoculation with A. cylindrica favored the development and yield performance of maize and resulted in an increase in grain biomass of 912 kg ha−1 (20.46%) in the crop season 1 and 1020 kg ha−1 (21.11%) in season 2 crop, related to the control. The use of above inoculants was favorable in the responses of maize growth and yield components, particularly when combined with an adequate dose of N. The results demonstrated the potential of microbial inoculants in the improvement of maize crop yield.

Evaluating How Enhanced Efficiency Nitrogen Fertilizers Improve Agricultural Sustainability: Greenhouse Multi-Phase Tracking System

The vast consumption of nitrogen-based fertilizers is a significant source of environmental pollutants in all phases. While enhanced-efficiency nitrogen fertilizers (EENFs) improve N-use efficiency and reduce environmental impact, their performance depends on local conditions. Here, we present a relatively simple soil–fertilizer–plants greenhouse setup for the multi-phase tracking of N species of the effects of EENFs. We compared the environmental and agronomic performance of three urea-based EENFs (urea embedded with urease inhibitors, 2-month, and 4-month controlled release urea) and the common split surface application of the granulated urea. We tested the fertilizer applications on basil seedlings for three consecutive growing cycles. The analyses carried out included nitrogen recovery in plant biomass, soil, drainage, and NH3 and N2O emissions. This multi-phase research indicates that tested EENFs perform better than the standard surface-applied urea. The four-month controlled-release urea fertilizer matched the basil N demand the best, significantly increasing yield and improving nitrogen use efficiency while reducing NO3− leaching and NH3 and N2O emissions. The presented soil–fertilizer–plants experimental setup provides a relatively easy-to-handle system for the comprehensive tracking of N dynamics, including plant response. It allows stakeholders to estimate and improve fertilization sustainability.

Agrobiological methods of fertility rehabilitation of degraded irrigated lands of the south-east of Kazakhstan

The results of the research open up fundamentally new directions in the use of water resources, in the study of the fertility of saline and secondarily saline lands, in the development of agrobiological and agro-reclamation methods for their improvement, in the development of effective methods for the environmental sustainability of irrigated agriculture. The developed system will significantly reduce costs and allow the widespread introduction of drip irrigation technology over large areas and in many farms in the region. The developed system of irrigated agriculture can be the basis for the adaptation of agriculture in the Ili-Balkhash basin to global climate change with the introduction of a drip irrigation system for rice, diversification of crop production with the introduction of new salt- and drought-resistant crops, and the development of effective methods of amelioration of secondary saline lands. The results of the conducted studies show that in the experimental area under the studied crops, before drip irrigation, there was a slight salinity. Thus, the dense residue under crops varies in the arable 0-20 cm layer within 0.15-0.39 %, and in the subarable 20-40 cm layer in the range of 0.13-0.58 %. After drip irrigation, the content of dense residue under the studied crops slightly increased to 0.34-1.48 % in the arable layer to 0.12 -0.88 %, that is, to the level of low and medium salinity. The results of studies on the study of various methods of irrigating rice on takyr-like soils indicate an increase in rice yields with drip irriga tion. In 2021, with drip irrigation with mulching film, the rice grain yield was 38.5 c/ha. The introduction of 100 kg of ammophos during the row sowing of rice increases the grain yield by 42.2 c/ha. With drip irrigation without a film, the greatest efficiency of nitrogen fertilizers is manifested. With double fertilization with irrigation water of 30 kg/ha in the phase of tillering and panicle ejection, the yield of rice increases by 45.7 c/ha. 651-478 c/ha of green mass of Sudanese grass and 325-287 c/ha of sorghum were obtained, with drip irrigation the soybean grain yield was 51.5 c/ha, which indicates the high ameliorative properties of these crops for cultivation on saline and secondarily saline soils of Akdalinsky irrigation array for fodder purposes. The best reclamation crops for cultivation in saline takyr-like soils of the Akdala irrigation array are soybean, Sudanese grass and sorghum.

Effects of climate change on streamflow and nitrate pollution in an agricultural Mediterranean watershed in Northern Spain

Predicting water quality and quantity response to climate change in a watershed is very difficult due to the complexity and uncertainties in estimating and understanding future hydrological conditions. However, hydrological models could simplify the processes and predict future impacts of agricultural activities. This study aimed to evaluate the applicability of the Soil Water Assessment Tool (SWAT) model for climate change prediction of streamflow and nitrate load in an agricultural Mediterranean watershed in northern Spain. The model was first evaluated for simulating streamflow and nitrate load under rainfed agricultural conditions in the Cidacos River watershed in Navarre, Spain. Then, climate change impact analysis on streamflow and nitrate load was conducted in the short-term (2011–2040), medium-term (2041–2070), and long-term (2071–2100) future projections relative to the historical baseline period (1971–2000) under the RCP4.5 and RCP8.5 CO2 emission scenarios. The model evaluation showed a good model performance result during calibration (2000–2010) and validation (2011–2020) for streamflow (NSE = 0.82/0.83) and nitrate load (NSE = 0.71/0.68), indicating its suitability for adoption in the watershed. The climate change projection results showed a steady decline in streamflow and nitrate load for RCP4.5 and RCP8.5 in all projections, with the long-term projection scenario of RCP8.5 greatly affected. Autumn and winter saw a considerable drop in comparison to spring and summer. The decline in streamflow was attributed to the projected decrease in precipitation and increase in temperatures, while the nitrate load decline was consistent with the projected streamflow decline. Based on these projections, the long-term projection scenarios of RCP8.5 indicate dire situations requiring urgent policy changes and management interventions to minimize and mitigate the resulting climate change effects. Therefore, adapted agricultural management practices are needed to ensure sustainable water resource utilization and efficient nitrogen fertilizer application rates in the watershed to reduce pollution.

The influence of different doses and ratios of mineral fertilizers on the yield of winter rye in the Urals

Winter rye is an important crop of the Non-Chernozem belt of Russia, the productivity of which depends on the use of fertilizers. The paper presents data on the agronomic and economic efficiency of cultivating Falenskaya 4 winter rye under conditions of long-term use of mineral fertilizers. The studies were carried out in 2019-2021 in Perm Region on sod-podzolic heavy loamy soil in a long-term stationary experiment based on a reduced factorial design (6x6x6) with a wide range of doses and NPK ratios. The highest yield in 2019 was obtained in N30P120K120 variant (3.07 t/ha), the highest payback of mineral fertilizers by grain was noted in N90 and N30P30K30 variants (6.00 and 5.69 kg of grain). The highest yield and payback of grain in the conditions of 2021 and for two years of research in average was obtained in the variant N90: in 2021, 3.01 t/ha and 13.96 kg of grain, for 2 years average – 2.95 t/ha and 9.82 kg of grain. The efficiency of nitrogen fertilizers has been proved by a regression equation for two years average, phosphoric and potash fertilizers did not have a significant effect. The rise in the yield increase occurred up to a nitrogen dose of 90 kg/ha and amounted to 0.42 t/ha at N90. The highest payback by grain was noted among nitrogen treatments – by N30 (7.3 kg of grain), with each increase in doses by 30 kg/ha, this indicator decreased linearly by 1.3 kg. The highest profitability over the years of research was obtained in the variant without fertilizers– 60 %, over two years in average. The profitability of using N90 was higher compared with the control only in 2021 – 50 % versus 43 %. All the studied doses of nitrogen used separately provided positive profitability, but the most cost-effective was the use of N30 and N60 – profitability was 52 and 45 %, respectively.