Fertilizer Efficiency Research Articles

Preparation of nutrient hydrogels with core-shell structure for seed germination and seedling growth in high temperature saline environment.

Drought and soil degradation are the key factors in desertification control. How to improve the utilization efficiency of water and fertilizer has always been the focus of research in desert areas. The conventional hydrogel-loaded fertilizer is not suitable because of the high salinity and large temperature difference in sandy land. Therefore we prepared a novel temperature/pH-responsive core-shell structured hydrogel and loaded urea in three ways: in situ polymerization, encapsulation, and immersion, and germination and seedling growth experiments on Artemisia absinthium and Cabbage (Brassica campestris L. ssp. chinensis Makino) seeds. The results showed that the immersion hydrogel SAP4 (PCP-g-PAA/P(DMAEMA-co-AMPS))/urea had the best repetitive swelling performance, achieving 163.89 % of the original water absorption performance after 16 repetitions and the highest nitrogen release of 151.37 mg at 40 days. For A. desertorum, the treatment group applying the in situ composite hydrogel SAP2 (PCP-g-PAA/P(DMAEMA-co-AMPS)/urea) had the highest germination rate of 70 %; for B. campestris, the treatment groups applying SAP2, the encapsulated hydrogel SAP3 (PCP-g-PAA/urea/P(DMAEMA-co-AMPS)) and SAP4 hydrogels had higher germination rates, with SAP3 having a 100 % germination rate. This phenomenon suggests that the three urea-loaded temperature/pH-responsive core-shell structured hydrogels we have prepared are very promising as an aid to seed germination and seedling growth.

Enhancing Regional Topsoil Total Nitrogen Mapping Through Differentiated Fusion of Ground Hyperspectral Data and Satellite Images Under Low Vegetation Cover

Total nitrogen in soil (STN) serves as a crucial indicator of soil nutrient content and provides an essential nitrogen source necessary for crop growth. Precisely inversion of STN content is crucial for the sustainable management of soil resources and the advancement of agricultural development, particularly to achieve efficient fertilization—reduction in fertilizer usage without compromising yield or increase in yield while maintaining the total fertilization amount. Spectroscopy technology is regarded as an ideal non-destructive method for nutrient detection. However, due to the weak spectral signals of STN and its spatial heterogeneity, hyperspectral imaging technology presents significant potential for high-resolution measurements and precise characterization of STN heterogeneity. In this paper, the STN content was selected as the study subject, and three aspects of soil spectral feature enhancement, multi-source remote sensing data differentiated fusion, and STN content inversion model construction were studied. Therefore, a differentiated fusion of enhanced multispectral image bands (DFE_MSIBs) method combined with Random Forest (RF) algorithms was developed for spectral inversion of STN content. The findings demonstrate the following: 1. The enhanced spectral characteristics and differentiated fusion method not only strengthen the relationship between STN and Sentinel-2A MSI data but also enhance the precision of regional STN inversion models. 2. For the differentiated fusion of enhanced multispectral image bands (DFE_MSIBs) method combined with Random Forest (RF) algorithms, the R2 was 0.95, RMSE was 0.10 g/kg, and LCCC was 0.89. 3. Compared to the unfused model, the average R2 value was increased by 0.02, the average RMSE was decreased by 0.01 g/kg, and the average LCCC was increased by 0.03. These findings hold practical significance for utilizing multi-source remote sensing data in STN mapping and precision fertilization in agricultural fields.

Preparation of Lignin-Based Slow-Release Nitrogen Fertilizer

Slow-release nitrogen fertilizer technology is essential for sustainable agriculture, reducing field pollution and enhancing fertilizer efficiency. Lignin, a natural polymer derived from agricultural and forestry waste, offers unique benefits for slow-release fertilizers due to its biocompatibility, biodegradability and low cost. Unlike conventional biochar-based fertilizers that often rely on simple pyrolysis, this study employs hydrothermal activation to create a lignin-based slow-release nitrogen fertilizer (LSRF) with enhanced nutrient retention and controlled release capabilities. By incorporating porous carbon derived from industrial alkaline lignin, this LSRF not only improves soil fertility, but also reduces nitrogen loss and environmental contamination, addressing key limitations in existing fertilizer technologies. We studied the hydrothermal carbonization and chemical activation of IAL, optimizing the conditions for producing LSRF by adjusting the ratios of PC, IAL and urea. Using BET, SEM and FT-IR analyses, we characterized the PC, finding a high specific surface area of 1935.5 m2/g. A selected PC sample with 1923.51 m2/g surface area and 0.82 cm3/g pore volume and yield (37.59%) was combined with urea via extrusion granulation to create the LSRF product. Soil column leaching experiments showed that LSRF effectively controls nutrient release, reducing nitrogen loss and groundwater contamination, ensuring long-term crop nutrition. This research demonstrates LSRF’s potential in improving fertilizer efficiency and promoting sustainable agriculture globally.

Energy efficiency and economic analysis of mechanized vs conventional cotton production system: A comparative study under rainfed vertisols of Tamil Nadu

Energy efficiency plays a pivotal role in optimizing input use and improving the sustainability of agricultural practices, especially in energy-intensive crops like cotton. Due to its high economic importance, cotton cultivation has been in the need of the hour in developing mechanized cultivation practices aimed at improving production efficiency. This study evaluated energy consumption and performed an economic analysis of mechanized versus conventional cotton production under rainfed vertisols in Tamil Nadu. Among the various inputs, fertilizer application consumed the most energy in both systems, followed by labor energy differences between the 2 methods. Mechanized cultivation drastically reduced labor energy requirements (174.2 MJ/ha) compared to manual methods (2215.6 MJ/ha), highlighting the potential for labor savings. Mechanized cultivation also showed more efficient use of non-renewable energy sources, whereas conventional methods relied more on renewable energy inputs, highlighting the trade-offs between the 2 systems. Mechanized cultivation significantly reduced production costs (Rs. 74290/ha) compared to conventional methods (Rs. 140440/ha), largely due to a 47.8 % reduction in labor costs, demonstrating its economic viability. This study suggests that improving the energy efficiency of mechanized cotton production should prioritize efficient fertilizer use and reducing diesel fuel consumption through enhanced machinery performance.

Slow-Release Fertilisers Control N Losses but Negatively Impact on Agronomic Performances of Pasture: Evidence from a Meta-Analysis

High nitrogen (N) losses and low nitrogen utilisation efficiency (NUE) of conventional-nitrogen fertilisers (CNFs) are due to a mismatch between N-delivery and plant demand; thus, slow-release N fertilisers (SRNFs) are designed to improve the match. A quantitative synthesis is lacking to provide the overall assessment of SRNFs on pasture. This meta-analysis analyses application rate and type of SRNFs on N losses and agronomic performances with 65 data points from 14 studies in seven countries. Standardized mean difference of SRNFs for nitrate leaching losses and N2O emission were −0.87 and −0.69, respectively, indicating their effectiveness in controlling losses. Undesirably, SRNFs had a more negative impact on dry matter (DM) yield and NUE than CNFs. Subgroup analysis showed that SRNF type and application rate had an impact on all tested parameters. The biodegradable coating-type of SRNF outperformed other types in controlling N losses and improving agronomic performances. High application rates (>100 kg N ha−1) of SRNFs are more effective in controlling N losses. In conclusion, SRNFs are more conducive to controlling N losses, but they showed a negative impact on yield and NUE in pasture. Further studies are recommended to assess the efficacy of SRNFs developed using advanced technologies to understand their impact on pastoral agriculture.

Effect of Magnesium Sulfate and Rhizosphere Microorganisms on the Growth and Biosynthesis of Cymbopogon nardus L. Essential Oil

Background: Citronella oil from Cymbopogon nardus L. is used in various fields, including health, industry and pharmaceuticals. Efforts to increase the content and quality of essential oils in this research were made with the application of magnesium sulfate. Rhizosphere microorganisms, which act as biological fertilizers, are applied to assist in the absorption of nutrients. This research aims to determine the interaction between the type of rhizosphere microorganisms and the dose of MgSO4 on growth, essential oil yield and essential oil content in C. nardus. Methods: The research was carried out from February to August 2023. The research used a randomized block design arranged factorially with three replications. The first factor is the type of rhizosphere microorganisms (without RM, PGPR and AMF) and the second factor is the MgSO4 fertilizer dose (0, 190, 285 and 280 kg ha-1). Result: Providing MgSO4 fertilizer can increase the growth and yield of essential oils of C. nardus. The application of PGPR and AMF can increase efficiency of MgSO4 fertilization. Treatment without administering rhizosphere microorganisms required a higher dose of MgSO4 compared to PGPR and AMF treatments. To increase growth variables and essential oil quality, treatment without rhizosphere microorganisms requires MgSO4 of 380 kg ha-1, while PGPR and AMF only require MgSO4 at a dose of 190-285 kg ha-1.

Nano-fertilizers: The future of nutrient approaches for cereals

Nanotechnology offers a promising solution to address the nutrient demands of cereals, which are nutrient-intensive crops typically reliant on large amounts of inorganic fertilizers. These large quantities of nutrients are supplied to the crop by applying a huge amount of inorganic fertilizer as a soil application led to a decline in environmental systems, particularly affecting the soil health, lesser use efficiency of fertilizers and water resources contamination. In this context, nanotechnology serves as a potential solution. The huge demand for nutrients in cereal crops is met by nano-fertilizers. The nano-fertilizers are now playing a promising role in fulfilling the nutrient requirement of the crops by replacing the normal conventional fertilizers not only for cereals but also for other agricultural crops. The mechanism of action of nano-fertilizers is that they are smaller than the pore size of plant cell walls, allowing them to easily enter and reach the plasma membrane. Nano-fertilizers have 100 times greater surface area than conventional fertilizers, allowing them to easily interact with plant surfaces and increase the absorption of nutrients. Therefore, the nutrient-use efficiency of the crop is increased and shown a positive effect on the physiological and growth parameters of cereal crops, resulting in enhanced yield and improved drought tolerance. This review discussed, the effects and efficiency of nano-fertilizers on cereal crop growth and the correlation between physiological, qualitative, quantitative traits with nano-form of application in detailed manner. This review concludes that nano-fertilizers are the potential nutrient source for cereal crops like rice (Oryza sativa L.), wheat (Triticum aestivum L.), maize (Zea mays) etc. and they are going to be a promising resource for nutrient management in agricultural crops.

Efficiency of nitrogen fertilizers in newly implanted coffee crops

A vigorous and productive coffee crop is the result of adequate nutritional management from its young stage. High yields demand greater investments, especially in fertilization, making nutritional management indispensable. Hence, this study evaluated the growth of coffee crop formation, soil acidity and economic aspects using different fertilizers. The experiment was conducted at Pedra Bela site, Ouro Fino, Brazil, between November 2022 and June 2023. Experimental design consisted of randomized blocks with nine treatments and four replications, totaling 36 plots. Treatments included conventional urea, conventional urea via drench, ammonium nitrate, ammonium sulfate, urea + S0 + polymers, urea + NBPT, urea formaldehyde, organomineral CPMULT and coffee straw. Plant height, stem diameter, number of plagiotropic branches, defoliation percentage, soil pH, and costs were the variables evaluated. Treatment with ammonium nitrate achieved superior results in terms of pH growth within the range considered ideal for coffee crops compared with the other treatments. It also resulted in the highest number of plagiotropic branches, less defoliation and was the most cost-effective. As for soil acidity, ammonium nitrate and organomineral fertilizers promoted values within what is considered ideal for coffee cultivation.

ASSESSMENT OF SMALL HOLDERS FARMERS' ADOPTION OF CLIMATE-SMART AGRICULTURE PRACTICES IN BORNO STATE, NIGERIA

The study assessed smallholder farmers’ adoption of Climate-Smart Agriculture practices in Borno State, Nigeria. Identified socio-economic characteristics of the respondents, assessed the respondents’ adoption of climate-smart agriculture practices and investigated the constraint by respondents in adopting climate-smart agriculture practices. Both primary and secondary sources were used. Multi-stage sampling procedure was employed to select 200 respondents as the sample size. Descriptive statistics such as frequency, percentages, mean, standard deviation and likert type scale were used. The findings indicated that, majority (67.5%) of the respondents were within the prime working age of 20-49 years with a mean age of 43 years. Majority (75.5%) were male, 63.5% married with 43.0% had 7-9 persons per household. However, more than half (56%) of the respondents had no formal education, and 56% earn less than 50,000 Naira annually. The study also found that 58% had more than 10 years of farming experience, but only 30% were members of association. Conservation agriculture practices such as reduced tillage, crop residue management, and crop rotation/intercropping were rated 1st with the highest (x = 4.29) implying strong agreement to adoption of conservation agriculture practices. The climate smart agricultural practices highly adopted by the respondents include; water retention and erosion control technique (89%) and efficient fertilizer application technique (79.5%), moderately adopted practices; home garden (63%) and compost making/green manuring (58%), whereas least adopted practices; early warning system (20.0%) and use of more efficient cooking stove (17%). The most severe constraint identified include lack of awareness and limited information about climate smart agriculture practices (x=1.87), as well as limited access to credit (x=1.80). High cost of labor for climate smart agriculture and policy inconsistencies (x=1.32, 1.44) were identified as not severe constraint compared to others. The study recommended that Extension agents and Research institute should create more awareness on impact of adopting Climate Smart Agriculture (CSA) practices and improve easy accessibility to weather and climate information through provision of mobile-based platforms or community radio broadcasts that deliver timely and relevant information.

Optimizing Nitrogen Management in Maize (Zea mays L.) Using Urease and Nitrification Inhibitorss

ABSTRACT Nitrogen (N) is essential for plant growth, and in conventional agriculture, it is usually supplied through fertilization. However, N can be lost through various pathways, reducing its availability to plants and decreasing fertilizer efficiency. This study examined the effects of split urea application and fertilizers containing the nitrification inhibitor 3.4-dimethylpyrazole phosphate (DMPP) and the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT). The fertilizers with inhibitors were applied at both full (100%) and reduced (75%) levels of the standard rate. Conducted over two years, the field trial aimed to assess the capacity of these treatments to mitigate N loss and meet the N requirements of maize effectively. The results of the study revealed that NBPT maintained the required N levels in the soil by meeting the N requirement of maize. On the other hand, DMPP caused N losses due to increasing ammonium levels in the soil during early plant growth stages. NBPT provided the best results in terms of plant yield and N content, whereas DMPP showed lower performance in these parameters. Reduced NBPT doses increased N use efficiency but were less effective in terms of yield compared to full doses. According to the result of the economic analysis, split urea treatment gave better results compared to all treatments. In conclusion, NBPT increased both yield and N use efficiency by regulating N release.

Long-Term Effects of Nitrogen Sources on Yields, Nitrogen Use Efficiencies, and Soil of Tilled and Irrigated Corn

Although corn is the most important and nitrogen (N)-fertilized crop, there is a lack of long-term data on the effects of organic and inorganic N fertilizers on the N balance and losses for corn systems under different tillage approaches. From 2012 to 2023, we assessed the effects of the N source on the grain yields from cultivated continuous corn receiving irrigation at a site with minimal erosion in Fort Collins, Colorado, USA, and compared these effects to no-till (NT) and strip till (ST) systems receiving inorganic N. An N balance accounting for N and carbon (C) sequestration found a system nitrogen use efficiency (NUESys) for organic N fertilizer (manure) with a tillage of 86.6%, which was higher than the NUESys of 62.6% with inorganic N fertilizer (enhanced efficiency fertilizer, EEF). Conventional tillage with manure use is a good management practice that contributed to higher grain yields (2 of 11 years), C sequestration (p < 0.05), soil organic N content (p < 0.05), and soil phosphorus (P) content than inorganic N fertilizer with tillage (p < 0.05). The tilled systems, whether receiving organic or inorganic N fertilizer, had higher yields and grain N content than the NT and ST systems receiving inorganic N fertilizer (p < 0.05). The grain production of the cultivated system receiving organic N fertilizer did not decrease with time, while the yields of the cultivated system receiving inorganic N fertilizer decreased with time (p < 0.05), suggesting that cultivated systems receiving organic N fertilizer may be more sustainable and better able to adapt to a changing climate. Additionally, a combination of manure (30% of N input) with EEF (70% of N input) contributed to a synergistic effect that increased the agronomic productivity (harvested grain yields).

Foliar Fertilization Improves the Nitrogen Nutrition of Sugarcane

Increasing the recovery of N fertilizer (RNf) is the main challenge in managing nitrogen fertilization in sugarcane. This study aimed to evaluate the efficiency of complementary foliar fertilization in managing nitrogen nutrition in sugarcane. Four fertilization managements, combining soil (5.0 and 4.5 g plot−1 of N) and foliar (1.0 and 1.5 g plot−1 of N) fertilization in up to two application events (0.5 + 0.5 and 0.75 + 0.75 g plot−1 of N), were compared with conventional fertilization (6.0 g plot−1 of N in soil). The change from 6.0 g plot−1 to 4.5 g plot−1 of N reduced the RNf by 46% before the first foliar fertilization. The RNf (26%) was similar between managements after the first foliar fertilization. After the second foliar fertilization, the RNf was 38% higher than that for conventional management. The accumulation of N in the aerial part of sugarcane was similar between managements until the first foliar fertilization. After the second foliar fertilization, the accumulation of N increased by 3.5% with foliar fertilization. The biomass accumulated by the managements was similar before and after the first and second foliar fertilization. The splitting of foliar fertilization increased the accumulation of N and RNf by 22% and 24%, respectively. The fertilization management with 4.5 g plot−1 of N applied to the soil, with two applications of 0.75 g plot−1 of N on the leaf, obtained greater accumulations of N and RNf. Foliar fertilization increases the efficiency of fertilization and improves the N nutrition of sugarcane.

The combination of metformin and high glucose increased longevity of Caenorhabditis elegans a DAF-16/FOXO-independent manner: cancer/diabetic model via C. elegans.

Sedentary lifestyles and diets with high glycemic indexes are considered to be contributing factors to the development of obesity, type 2 diabetes in humans. Metformin, a biguanide medication commonly used to treat type 2 diabetes, has been observed to be associated with longevity; however, the molecular mechanisms underlying this observation are still unknown. The effects of metformin and high glucose, which have important roles in aging-related disease such as diabetes and cancer, were studied in lin-35 worms because they are associated with cancer-associated pRb function in mammals and have a tumour suppressor property. According to our results, the negative effect of high glucose on egg production of lin-35 worms was greater than that of N2 worms. High glucose shortened lifespan and increased body length and width in individuals of both strains. Metformin treatment alone extended the lifespan of N2 and lin-35 worms by reducing fertilization efficiency. However, when metformin was administered in the presence of high glucose, the lifespan of lin-35 worms was clearly longer compared to N2 worms. Additionally, we conclude that glucose and metformin in lin35 worms can extend life expectancy through a DAF-16/FOXO-independent mechanism. Furthermore, the results of this study will provide a new perspective on extending mammalian lifespan through the model organism C. elegans.

Use Efficiency, Reduction Potential, and Effects of Fertilizers on Carbon Emissions in China’s Major Citrus Regions

Enhancing the efficiency of fertilizer utilization and advancing fertilizer reduction efforts constitutes a pivotal initiative for augmenting the quality and productivity of the citrus industry; this constitutes an indispensable prerequisite for attaining green and sustainable development. Utilizing panel data from seven prominent mandarin-producing regions and seven prominent tangerine-producing regions in China spanning from 2002 to 2022, this study employed the stochastic frontier analysis (SFA) method to develop a translog production function model for precisely measuring the fertilizer use efficiency for mandarins and tangerines. Employing the calculated optimal fertilizer use rates, we further ascertained the fertilizer reduction potential for mandarin and tangerine; then, we estimated the associated carbon emission reduction potential within these key citrus regions. The research revealed the following findings: the overall level of citrus fertilizer use efficiency in China is comparatively low, with the mean values for mandarin and tangerine fertilizer use efficiency being merely 0.4403 and 0.3887, respectively, indicating substantial room for improvement by approximately 60%; substantial potential exists for decreasing fertilizer use in China’s citrus industry, with average reduction potentials of 66.27% for mandarins and 64.83% for tangerines, signifying a notable redundancy in fertilizer application within major citrus-producing areas. The magnitude of carbon emission reduction potential through the diminution of citrus fertilizer use is tremendous. When optimal fertilizer rates are applied, the average carbon emission reductions resulting from fertilizer reduction in mandarins and tangerines amount to 815.8681 kg/hm2 and 602.3551 kg/hm2, respectively. The average carbon reduction potential for mandarins and tangerines reach levels of 55.9673% and 61.1299%, respectively, both surpassing the threshold of 55%. Significant differences exist in the technical efficiency of fertilizer input, reduction potential, and carbon emission mitigation potential among major citrus-producing regions. Citrus orchards in Guangdong exhibit higher potential for fertilizer reduction but demonstrate a relatively low level of technical efficiency. In contrast, Hunan Province shows an opposite trend, necessitating the development of region-specific strategies. Therefore, to minimize citrus fertilizer use and augment the technical efficiency of citrus fertilizer, it is imperative to comprehensively integrate and promote the “three new” technologies aimed at reducing fertilizer use and enhancing its efficiency within the citrus industry; implement a regional coordinated development strategy for citrus fertilizer reduction; and intensify policy guidance, publicity, and training efforts related to citrus fertilizer reduction, efficiency enhancement, and carbon emissions reduction.

Predictive Models for the Implementation of Targeted Reproductive Management in Multiparous Cows on Automatic Milking Systems

Targeted reproductive management (TRM) aims to improve the fertility efficiency of the dairy herd by applying group-level management strategies based on expected reproductive performance. Key to the utility of TRM is the accuracy with which an animal's reproductive performance can be predicted. Automatic milking systems (AMS) allow for the collection of data relating to milk quantity, quality, and robot visit behavior throughout the transition period. In addition to this, auxiliary data sources such as rumination and activity monitors, as well as historical cow-level data are often readily available. The utility of this data for the prediction of fertility has not been previously explored. The objective of this study was first, to assess the accuracy with which the likelihood of expression of oestrus between 22 and 65 d in milk (DIM) and conception to first insemination between 22 and 80 DIM could be predicted using data collected by AMS from 1 to 21 DIM. Our second objective was to assess the change in model performance following the addition of 2 auxiliary data sources. Using data derived solely from the AMS (RBT data set) a binary random forest classification model was constructed for both outcomes of interest. The performance of these models was compared with models constructed using AMS data in conjunction with 2 auxiliary sources (RBT+ data set). Expression of oestrus was classified with an area under the receiver operator curve (AUC-ROC) of 0.6 and 0.65, conception to first insemination with an AUC-ROC of 0.56 and 0.62 for the RBT and RBT+ data sets respectively. No statistically significant improvement in classification accuracy was achieved by the addition of auxiliary data sources. This is the first study to report the utility of data collected by AMS for the prediction of reproductive performance. Though the performance described is comparable with previously reported models, their utility for the implementation of TRM is limited by poor classification accuracy within key sub-groups. Of note within this study is the failure of the addition of auxiliary data sources to increase the accuracy of prediction over models built using AMS data alone. We discuss the advantages and limitations the integration of additional data sources imposes on model training and deployment and suggest alternative methods to improve performance while preserving model parsimony.

Can additives or controlled release coating improve the nitrogen use efficiency of urea fertiliser

A plot trial was undertaken to determine whether tactical use of nitrogen (N) fertiliser applied with or without coating or biostimulant improved herbage yield and N use efficiency. A randomised complete block design was used to compare no fertiliser (CON), frequent low rates of urea (FL), infrequent moderate rates of urea (IM), IM with controlled release (IM+CR), IM with Progibb (IM+PG), IM with Agrisea (IM+AS), or IM with N-Boost (IM+NB) on irrigated, grazed perennial ryegrass and white clover dairy pastures in Canterbury. The total annual N applied in all fertilised treatments was 190 kg N/ha. The use of fertiliser increased annual herbage yield (16.9±0.44 vs 14.5 t DM/ha/y; P<0.05). Combining urea with a coating or biostimulant altered the distribution of pasture growth, but did not affect net annual production or herbage quality. Due to the lack of response and greater application costs with liquid versus granule products, these results highlight the need to consider expected responses to different fertiliser regimes when adopting practices to achieve economic benefits and N efficiency.

Unprecedented N2O production by nitrate-ammonifying Geobacteraceae with distinctive N2O isotopocule signatures.

Dissimilatory nitrate reduction to ammonium (DNRA), driven by nitrate-ammonifying bacteria, is an increasingly appreciated nitrogen-cycling pathway in terrestrial ecosystems. This process reportedly generates nitrous oxide (N2O), a strong greenhouse gas with ozone-depleting effects. However, it remains poorly understood how N2O is produced by environmental nitrate-ammonifiers and how to identify DNRA-derived N2O. In this study, we characterize two novel enzymatic pathways responsible for N2O production in Geobacteraceae strains, which are predominant nitrate-ammonifying bacteria in paddy soils. The first pathway involves a membrane-bound nitrate reductase (Nar) and a hybrid cluster protein complex (Hcp-Hcr) that catalyzes the conversion of NO2- to NO and subsequently to N2O. The second pathway is observed in Nar-deficient bacteria, where the nitrite reductase (NrfA) generates NO, which is then reduced to N2O by Hcp-Hcr. These enzyme combinations are prevalent across the domain Bacteria. Moreover, we observe distinctive isotopocule signatures of DNRA-derived N2O from other established N2O production pathways, especially through the highest 15N-site preference (SP) values (43.0‰-49.9‰) reported so far, indicating a robust means for N2O source partitioning. Our findings demonstrate two novel N2O production pathways in DNRA that can be isotopically distinguished from other pathways.IMPORTANCEStimulation of DNRA is a promising strategy to improve fertilizer efficiency and reduce N2O emission in agriculture soils. This process converts water-leachable NO3- and NO2- into soil-adsorbable NH4+, thereby alleviating nitrogen loss and N2O emission resulting from denitrification. However, several studies have noted that DNRA can also be a source of N2O, contributing to global warming. This contribution is often masked by other N2O generation processes, leading to a limited understanding of DNRA as an N2O source. Our study reveals two widespread yet overlooked N2O production pathways in Geobacteraceae, the predominant DNRA bacteria in paddy soils, along with their distinctive isotopocule signatures. These findings offer novel insights into the role of the DNRA bacteria in N2O production and underscore the significance of N2O isotopocule signatures in microbial N2O source tracking.

Field trial guidelines for evaluating enhanced efficiency fertilizers

AbstractThere are many fertilizer additives and alternatives that aim to increase plant nutrient use efficiency and reduce nutrient losses to the environment, here referred to collectively as enhanced efficiency fertilizers (EEFs). However, there is often insufficient published scientific field trial results across a variety of locations, climates, soils, cropping systems, and management scenarios to prove their efficacy and conditions for use. Guidelines for common minimum datasets and data stewardship in evaluating the agronomic performance and environmental impact of EEFs are needed for researchers to follow. Such guidelines will improve hypothesis testing centered on product efficacy and provide producers with guidance on how these technologies function and perform when integrated with other management practices within the 4R Nutrient Stewardship Framework. A scientific committee was formed to develop a set of protocol guidelines for evaluating EEFs in replicated, plot‐based field trials on an international scale. The guidelines are composed of experimental design and core metadata, crop and soil analyses, environmental loss measurements, and data stewardship, and include both recommended and required components to allow for flexibility and adaptability depending on the trial location, objectives, infrastructure capacity, product type, and depth of understanding of the potential EEF efficacy. This approach will ensure consistency and compatibility in experimental design and data collection to support data integration, analysis, and reuse leading to large‐scale impact and end‐user confidence.

Bacillus-inoculated organomineral fertilizer in soybean crop during short-term: comparing sources and doses with mineral fertilizer

Bacillus species and organomineral fertilizers can improve various crop responses. The objective of this study was to evaluate the efficiency of organomineral fertilizer with B. subtilis and B. licheniformis, in comparison to mineral fertilizer, on soybean growth, leaf nutrient content, grain yield, and soil characteristics. Two soybean field experiments (305 km apart) were set up in southeastern Brazil. Two sources of fertilizers (inoculated granulated organomineral, 5-26-0 + 0-0-32 N-P2O5-K2O, and coated mineral fertilizer, 10-52-0 + 0-0-60 N-P2O5-K2O), and four doses of P plus K (no fertilizer, 50, 75, 100 kg ha−1 of each P2O5 and K2O) were applied. At 60 days after sowing, plant height and leaf analysis were assessed. Weight of 1000 seeds, grain yield, and soil analysis were evaluated (120 days after sowing). In both fields, there was interaction between source and P plus K dose factors for soybean grain yield. In Site 1, the highest grain yield (4,543.69 kg ha−1) was observed for 100 kg ha−1 of P2O5 and K2O dose of coated mineral fertilizer; in Site 2, the highest grain yield (4,638.55 kg ha−1) was observed for 75 kg ha−1 of P2O5 and K2O dose of organomineral fertilizer. These factors also affected N, P, and K leaf contents. Less effects were observed on plant height, weight of 1000 seeds, and soil characteristics. Inoculated organomineral fertilizer can be used for total or partial supply of nutrients without a clear difference from mineral fertilization. Smaller doses of inoculated organomineral fertilizer could be used without compromising soybean grain yield.

Application of magnesium-containing fertilizers by priming method for regulation of physiological processes in winter wheat

The studing the efficiency of new magnesium-containing fertilizer “AktiMax” use for priming soft winter wheat seeds of the “Skipetr” variety. The effect of the fertilizer is compared with the negative (no fertilizer) and positive (“Novosil”) controls. During the study, the optimal concentration 2.6 ml/l of the solution for processing by the selected method is found, which is equivalent to 20% of the recommended by the manufacturer (13 ml/l). At treating with a solution of this concentration, a slight decrease in seed germination is observed, and growth parameter records taken after 7 days showed an increase in leaf length by 15–20%. A slight decrease in the number of roots (by 10%) and branching of the root system is observed, which is presumably due to the availability of the fertilizer components. The effect fertilizer on the photosynthetic apparatus, carbon dioxide assimilation and transpiration rate when use in a range of concentrations is studied. On average, the transpiration activity increased by 2 times in the variant with the working concentration and by 1.8 times in the variant with one fifth of the working concentration. A slight increase in the efficiency of non-photochemical fluorescence quenching is revealed in plants at the “AktiMax” application. The efficiency of seed priming method use to stimulate the rate of winter wheat development is demonstrated that leads to reduction of unfavorable outcomes risks.