Reduce Nitrogen Fertilizer Research Articles

The Impact of Azospirallum and Nitrogen on Growth, Yield, and Nitrogen Content in Okra (Abelmoschus esculentus) Leaves.

The objective of this study was to reduce nitrogen fertilizer costs and enhance both growth and nitrogen content in okra by applying lower nitrogen doses in combination with Azospirallum. A simple randomized pot experiment was conducted at Swami Shukdevanand College, Shahjahanpur from October to December 2023. Two control groups were established: one without nitrogen and Azospirallum, and another without nitrogen but with Azospirallum, to compare the effects of Azospirallum alone and in conjunction with different nitrogen doses. Nitrogen levels were assessed in dry leaves at 15, 30, and 45 days after germination (DAG). All nitrogen and Azospirallum treatments resulted in significantly improved growth, yield, and nitrogen content in okra leaves. The highest levels of plant growth, yield, and nitrogen content were observed in plants receiving nitrogen plus Azospirallum. Conversely, the lowest values for these parameters were observed in the control group (no nitrogen, no Azospirallum). Thus, it is recommended to use lower nitrogen doses along with Azospirallum seed inoculation to enhance nitrogen content in okra leaves and subsequently increase crop yield, while also reducing production costs by minimizing nitrogen fertilizer usage.

Crop management strategy redesign enables a reduction in reliance on pesticides: A diachronic approach based on a diversity of French commercial farms

Pesticides are widely used in agriculture to manage pests, weeds and diseases with consequences on ecosystem and human health. Reducing pesticide reliance appears as a necessary step for transitioning to sustainable farming systems. Many non-chemical techniques to control pests, weeds and diseases are individually well documented, but quantitative assessment of how much the reliance on pesticides could be decreased through a holistic approach of cropping system re-design combining several individual techniques was lacking. A diachronic approach was conducted on 913 French commercial farms from the DEPHY network, spanning a diversity of contexts and management strategies. Regression Trees and Random Forest models were run to identify combinations of changes in management strategies associated with the evolution of pesticides reliance over time, in a range of production contexts. The consequences of these changes on pesticide-related risks to human health and the environment were also investigated. Farm reliance on pesticides and pesticide-related risks to human health and the environment were reduced in 65.7% and 60.3% of the farms, respectively. The greatest reductions in pesticide reliance were observed in farms with the highest initial levels of reliance on pesticides. Crop diversification and reduced nitrogen fertilization were often associated with reduced pesticide reliance. This study highlights the value of real farm networks for identifying and promoting combinations of techniques that help reduce pesticide dependency and move towards more sustainable farming systems.

Silicon Fertilizer Addition Can Improve Rice Yield and Lodging Traits under Reduced Nitrogen and Increased Density Conditions

Reducing nitrogen fertilizer application, selecting a reasonable planting density, and adding silicon fertilizer can be used together to decrease excessive nitrogen fertilizer inputs in rice fields, reduce production costs, and ensure stable rice yield. However, the dynamics of the stem and internodes, as well as the changes in the physical and physiological characteristics of rice under a combination of these three strategies, are still unclear. In this study, we aimed to clarify these effects to improve the efficiency of rice production in northeastern China. A 2-year field experiment was conducted using five treatments: a conventional densification treatment (DM), a densification combined with reduced N input (−20%) treatment (DLM), and three densifications combined with reduced N input (−20%) and basal silicon fertilizer treatments (low fertilizer: DLMS1; medium fertilizer: DLMS2; and high fertilizer: DLMS3). This study revealed that the addition of silicon fertilizer improved rice yield compared to that under reduced nitrogen or increased density treatments alone, prevented excessive ineffective tillering after a density increase, and increased the number of productive panicles. Among the treatments, the DLMS3 treatment had the highest yields of 10.53 t/ha and 10.73 t/ha over the 2 years. Reducing nitrogen and increasing density reduced the weight and length of single panicles, while the addition of silicon fertilizer was beneficial for improving stem toughness, improving the physical and physiological characteristics of the plants and panicles, and enhancing plant bending resistance. Among the treatments, DLMS3 had the highest bending resistance, which increased by 440.1 g and 503.8 g compared to the lowest values in the DM treatment in 2020 and 2021, respectively. Nitrogen reduction resulted in the lowest lodging index values, with DLMS3 having the lowest values in both years, which decreased by 19.6% and 22.5% compared to the highest values in DM (2020) and DLM (2021), respectively. This study indicates that the application of 150.0 kg/ha silicon fertilizer in combination with reduced nitrogen and increased density (DLMS3) reduces the lodging index while ensuring rice yield, preventing a tradeoff between yield reduction and lodging due to a density increase or due to nitrogen reduction combined with a density increase and allowing for a reduction in nitrogen fertilizer input, which could ensure a uniform yield and an increase in lodging resistance. These results provide a scientific basis for rice cultivation measures that lead to high yield and lodging resistance while protecting the environment.

The Effect of Soil Microbial Residues-Mediated Nitrogen Conservation and Supply during the Growing Season on Nitrogen Uptake by Wheat

Microbial residue nitrogen can indicate soil quality and is crucial for soil nitrogen retention and supply. However, it is still unclear how the dynamic changes in soil microbial residue nitrogen affect crop nitrogen uptake in agricultural practice. Based on a long-term wheat-maize rotation experiment with different nitrogen application rates (150 kg N ha−1, 200 kg N ha−1, and 300 kg N ha−1), 15N-labeled nitrogen fertilizer was applied during the wheat season to track the dynamics of soil microbial residue nitrogen and its mediated fertilizer nitrogen. The results showed that nitrogen addition was beneficial to the accumulation of microbial residue nitrogen (mainly fungal microbial residue nitrogen). Its contribution rate to soil total nitrogen is 54.87–56.55%, and the fertilizer nitrogen allocated to it accounts for 27.10–47.50% of the remaining fertilizer nitrogen in the soil. Ultimately, 6.77–10.24% of the nitrogen fertilizer applied remained in the soil as microbial residue nitrogen. In addition, microbial residue nitrogen is mainly mineralized during the jointing and filling stages of wheat. In a word, the accumulation and mineralization of soil microbial residue nitrogen during the application of 200 kg N ha−1 better guaranteed the uptake of nitrogen by wheat, which provided a reliable basis for guiding farmland fertility improvement and nitrogen fertilizer reduction in the North China Plain.

Long-term conservation tillage with reduced nitrogen fertilization intensity can improve winter wheat health via positive plant-microorganism feedback in the rhizosphere.

Microbiome-based solutions are regarded key for sustainable agroecosystems. However, it is unclear how agricultural practices affect the rhizosphere microbiome, plant-microorganism interactions and crop performance under field conditions. Therefore, we installed root observation windows in a winter wheat field cultivated either under long-term mouldboard plough (MP) or cultivator tillage (CT). Each tillage practice was also compared at two nitrogen (N) fertilization intensities, intensive (recommended N-supply with pesticides/growth regulators) or extensive (reduced N-supply, no fungicides/growth regulators). Shoot biomass, root exudates and rhizosphere metabolites, physiological stress indicators, and gene expression were analyzed together with the rhizosphere microbiome (bacterial/archaeal 16S rRNA gene, fungal ITS amplicon, and shotgun metagenome sequencing) shortly before flowering. Compared to MP, the rhizosphere of CT winter wheat contained more primary and secondary metabolites, especially benzoxazinoid derivatives. Potential copiotrophic and plant-beneficial taxa (e.g. Bacillus, Devosia, and Trichoderma) as well as functional genes (e.g. siderophore production, trehalose synthase, and ACC deaminase) were enriched in the CT rhizosphere, suggesting that tillage affected belowground plant-microorganism interactions. In addition, physiological stress markers were suppressed in CT winter wheat compared to MP. In summary, tillage practice was a major driver of crop performance, root deposits, and rhizosphere microbiome interactions, while the N-fertilization intensity was also relevant, but less important.

Cumulative transformation characteristics and application reduction potential of soil nitrogen in continuous cropping greenhouse

ABSTRACT Based on the continuous watermelon greenhouses in Daxing District, Beijing, this paper investigated the dynamic transformation characteristics and surplus risk of soil nitrogen in greenhouses of different cropping years and proposed a reasonable nitrogen fertilizer reduction potential for greenhouses of different continuous cropping years. Based on the results, (1) The total nitrogen inputs gradually decreased with the increase of cropping years. The soil nitrogen was accumulated mainly in the 0∼30 cm tillage layer. The nitrogen supply capacity of the soil gradually increased over 20 years (a) of continuous cropping and declined after >20a. (2) The environmental risk levels of soil nitrogen surpluses with different cropping years in the study area had all reached heavy levels and above. The nitrogen fertilizer reduction potential was large, in which the lowest recommended nitrogen application rate was for the greenhouses with 1∼5a of continuous cropping, and the highest was for the greenhouses with 11∼20a of continuous cropping. For watermelon greenhouses with different continuous cropping years, the range of the highest reasonable nitrogen fertilizer reduction potential to ensure the economic benefits of farmers was 74.18% to 87.28%, and the lowest environmentally safe nitrogen fertilizer reduction potential to safeguard environmentally safe conditions was 69.22 to 78.11%.

The Effect of Azolla (Azolla pinnata) Extract on the Growth and Yield of Sweet Corn under Reduced Nitrogen Fertilization Practice

The Effect of Azolla (Azolla pinnata) Extract on the Growth and Yield of Sweet Corn under Reduced Nitrogen Fertilization Practice

Nitrogen fertilizer reduction based on bioorganic fertilizer improves the yield and quality of fresh leaves of alpine tea in summer

Nitrogen fertilizer reduction based on bioorganic fertilizer improves the yield and quality of fresh leaves of alpine tea in summer

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.

The NIN-LIKE PROTINE1 (CsNLP1) transcription factor is involved in modulating the nitrate response in cucumber seedlings

Cucumber is one of the important vegetables cultivated in facilities in China. Due to the deterioration of soil quality in facilities and the low nitrogen use efficiency of existing varieties, it is common to pursue high yield through excessive application of nitrogen fertilizer. Improving crop nitrogen use efficiency is one of the important means to reduce nitrogen fertilizer input. Previous studies have shown that NLP (NIN-like protein) transcription factor family play an important role as transcription factors in regulating plant physiological responses to external nitrogen changes. However, there are few reports on NLPs in cucumber. Here we report that CsNLP1 is a potential candidate to improve cucumber nitrogen use ability. CsNLP1 silencing lines by virus-induced gene silencing (VIGS) showed a significant decrease in the plant biomass, chlorophyll content, nitrogen uptake, total nitrogen content, activities of NR, NIR, GDH, GOGAT and GS, and expression levels of genes involved in nitrogen assimilation and signalling under different nitrogen concentrations. In addition, transfer of CsNLP1 into Arabidopsis nlp7-1 mutant found that the phenotype, nitrate (NO3-) content, NR activity, NIR activity, GDH activity, GOGAT activity and GS activity in transgenic lines could be restored to the wild type level after NO3- treatment. Further study found that CsNLP1 could regulate the expression of NO3- responsive genes such as AtNIR1, AtNIA2, AtNRT1.1 and AtGS2 in plants. Overall, our data indicated that CsNLP1 can affect plant growth, and regulate nitrate assimilation by regulating nitrogen-related genes.

Effectiveness of a 10-year continuous reduction of controlled-release nitrogen fertilizer on production, nitrogen loss and utilization of double-cropping rice

Considerable literature has demonstrated the advantage of controlled-release nitrogen (CRN) fertilizer in improving crop productivity. However, few researches have explored the long-term impacts of using CRN fertilizers as alternative to common urea on production and N utilization in double-cropping paddy. To address this gap, our study utilized a database derived from a 10-year field experiment from 2013 to 2022. During early and late rice seasons, compared to common urea (early rice, 150 kg hm−2; late rice, 180 kg hm−2), CRN fertilizer (150 kg hm−2; 180 kg hm−2) input significantly increased yield by 7.4 %, and 11.7 %, as well as N use efficiency (NUE) from 23.0 % and 24.6 % to 33.0 % and 37.5 %, respectively. CRN application significantly reduced N losses, evidenced by decrease in runoff (23.1 % and 19.4 %), leaching (12.7 % and 12.1 %), ammonia volatilization (28.9 % and 30.2 %), and N2O emissions (10.4 % and 16.1 %). A reduction of 10 % in CRN fertilizer input maintained yield. Compared with normal amount, reducing 10, 20, and 30 % CRN input increased NUE by 7.0–7.6 %, 7.3–7.4 %, and 11.6–12.6 %; reduced runoff loss by 16.1–17.9 %, 27.9–30.7 %, and 35.0–37.2 %; decreased leaching loss by 7.6–12.8 %, 18.1–22.6 %, and 26.5–31.4 %; decreased ammonia volatilization by 9.9–12.3 %, 16.3–22.7 %, and 23.2–29.3 %, and decreased N2O loss by 7.8–13.3 %, 12.8–32.8 %, and 20.3–36.9 %, respectively. Soils with CRN input showed higher total and inorganic N contents than the soils with common urea, and the content increased in parallel with CRN fertilizer input. Soil N content and N runoff loss were significantly related to yield and N uptake, and N runoff and leaching losses were significantly related to NUE. These results support the sustainable use of CRN fertilizers as a viable alternative to common urea, indicating that application rate of 135 and 162 kg N hm−2 of early and late rice, respectively, maintain yield and enhance N utilization in double-season paddy of southern China.

Effect of Reduced Nitrogen Fertilization on the Chemical and Biological Traits of Soils under Maize Crops

The European Commission’s “Farm to Folk” strategy recommends reducing fertilizers by at least 20% by 2030. In this context, the aim of this study was to verify whether a 20 and 40% reduction of nitrogen (N) fertilization rate will be sufficient to maintain soil chemical features, fertility, and yields in monoculture maize cultivation in the no-tillage (NT) system versus the traditional plowing (PL) system. We also examined which tillage system (PL, NT) allows the reduction of fertilization while maintaining good yields of the tested soils. Two fields (10 ha each) were established for PL and NT maize cultivation, and soils (0–20 cm) were sampled twice per year—before maize sowing and after maize harvesting. A broad range of chemical and biological parameters were monitored (i.e., pH, forms of nitrogen, phosphorus and carbon, content of selected macronutrients and humic substances, and respiration activity). It was concluded that the 20% reduction in N fertilization (after 4 years of use) did not have an adverse effect on the soil’s chemical and biological features, which mainly depended on the season of the year. The maize yield seemed to be higher in the PL system, which was mostly the result of the tillage system rather than the N dose. The study will be continued in the next vegetation season to further verify our findings, especially with regard to the maize tillage system and yields.

Water and Nitrogen Balance under Various Water and Fertilizer Regulation Modes

A experiment was conducted at the Jiangxi Province Center Station of Irrigation Experiment from 2019 to 2021 to study the water and nitrogen balance under water and fertilizer regulation modes. The study aimed to propose a recommended mode for paddy fields that could save water, control pollution, reduce gas emission, and improve fertilizer use efficiency. This study examined the impact of different irrigation methods and nitrogen application levels on water saving and emission reduction in paddy fields. The experiment included six treatments, which involved two irrigation methods (intermittent irrigation and flooding irrigation, referred to as W1 and W0, respectively) and three application rates of nitrogen fertilizer (0 kg/ha, 135 kg/ha, 180 kg/ha, referred to as N0, N1 and N2, respectively). The study found that irrigation methods had a significant effect on the amount of irrigation, drainage, leakage, nitrogen load from drainage, soil nitrification potential, and ammonia volatilization. The results showed that compared to flooding irrigation, intermittent irrigation reduced the amount of irrigation, drainage, leakage and nitrogen load from drainage by an average of 25.98%, 16.03%, 8.43% and 10.86%, respectively. However, the study also found that the nitrification potential and ammonia volatilization increased by an average of 6.45% and 4.32%, respectively. Fertilization levels had a significant effect on drainage nitrogen load, early soil nitrification potential and ammonia volatilization. Compared with the treatment of N2 (180 kg N/ha), the drainage nitrogen load under the treatment of N1 (135 kg N/ha) decreased by 10.86% on average, while nitrification potential and ammonia volatilization increased by 38.74% and 3.33%, respectively. In terms of nitrogen output, the amount of nitrogen absorbed by crops was the largest, followed by the nitrogen load from field drainage, then ammonia volatilization, and then denitrification. Considering the goals of water saving, emission reduction, and the efficient utilization of water and fertilizer in paddy fields, the optimal water and fertilizer regulation mode was the W1N1 mode (intermittent irrigation combined with reduced nitrogen fertilizer application rate, 135 kg N/ha).

Excessive synthetic fertilizers elevate greenhouse gas emissions of smallholder-scale staple grain production in China

Smallholder farmers produce one-third of the world's food and over 80% of China's; therefore, they must be at the forefront of developing a sustainable food system. Greenhouse gas (GHG) emissions from these farms cannot be ignored. In this study, we created an agricultural environmental impact evaluation framework for China based on a localized database through an extensive survey. The survey was based on face-to-face interviews by 120 investigators with 1015 smallholders in 100 villages within Chinese major agricultural regions. The GHG emissions of each smallholder farmer's staple grain production was assessed on a case-by-case basis. Structural equation models were used to analyze the influence paths of production behavior. The results showed that GHG emissions from smallholder grain production exceeded average global levels. Despite some regional differences, synthetic fertilizers were the main source of GHG emissions from all farm inputs. Increased farm size can reduce nitrogen fertilizer use. The GHG emissions can be reduced by 203.59–279.90 Tg CO2eq, and profits would increase by 62.05–92.42 billion CNY in China, when all smallholders are managed in the same way as the top 25% or 10% of outstanding producers without applying higher nitrogen fertilizer application than the national recommendation. It is urgent and necessary for smallholders to change production practices to reduce their reliance on fertilizers to achieve climate goals.

Enhancing Rhizobium–Legume Symbiosis and Reducing Nitrogen Fertilizer Use Are Potential Options for Mitigating Climate Change

This review article explores the impact of nitrogen fertilizers on the symbiotic relationship between Rhizobium bacteria and legume plants. Nitrogen fixation has the potential to address the global protein shortage by increasing nitrogen supply in agriculture. However, the excessive use of synthetic fertilizers has led to environmental consequences and high energy consumption. To promote sustainable agriculture, alternative approaches such as biofertilizers that utilize biological nitrogen fixation have been introduced to minimize ecological impact. Understanding the process of biological nitrogen fixation, where certain bacteria convert atmospheric nitrogen into ammonia, is crucial for sustainable agriculture. This knowledge helps reduce reliance on synthetic fertilizers and maintain soil fertility. The symbiotic relationship between Rhizobium bacteria and leguminous plants plays a vital role in sustainable agriculture by facilitating access to atmospheric nitrogen, improving soil fertility, and reducing the need for chemical fertilizers. To achieve optimal nitrogen fixation and plant growth, it is important to effectively manage nitrogen availability, soil conditions, and environmental stressors. Excessive nitrogen fertilization can negatively affect the symbiotic association between plants and rhizobia, resulting in reduced soil health, altered mutualistic relationships, and environmental concerns. Various techniques can be employed to enhance symbiotic efficiency by manipulating chemotaxis, which is the ability of rhizobia to move towards plant roots. Plant-specific metabolites called (iso)flavonoids play a crucial role in signaling and communication between legume plants and rhizobia bacteria, initiating the symbiotic relationship and enhancing nitrogen fixation and plant growth. Excessive nitrogen fertilizer application can disrupt the communication between rhizobia and legumes, impacting chemotaxis, root exudation patterns, nodulation, and the symbiotic relationship. High levels of nitrogen fertilizers can inhibit nitrogenase, a critical enzyme for plant growth, leading to reduced nitrogenase activity. Additionally, excessive nitrogen can compromise the energy demands of nitrogen fixation, resulting in decreased nitrogenase activity. This review discusses the disadvantages of using nitrogenous fertilizers and the role of symbiotic biological nitrogen fixation in reducing the need for these fertilizers. By using effective rhizobial strains with compatible legume cultivars, not only can the amounts of nitrogenous fertilizers be reduced, but also the energy inputs and greenhouse gas emissions associated with their manufacturing and application. This approach offers benefits in terms of reducing greenhouse gas emissions and saving energy. In conclusion, this paper provides a comprehensive overview of the current understanding of the impact of nitrogen fertilizers on the symbiotic relationship between Rhizobium and legume plants. It also discusses potential strategies for sustainable agricultural practices. By managing nitrogen fertilizers carefully and improving our understanding of the symbiotic relationship, we can contribute to sustainable agriculture and minimize environmental impact.

A Strategy for Reducing Nitrogen Fertilizer Application Based on Application of Biochar: A Case in Northeast China Black Soil Region (Mollisols)

A Strategy for Reducing Nitrogen Fertilizer Application Based on Application of Biochar: A Case in Northeast China Black Soil Region (Mollisols)

Irrigation practices affect relationship between reduced nitrogen fertilizer use and improvement of river and groundwater chemistry

In the last decades, the intensification of agricultural practices has deeply altered nitrogen (N) and water cycles. Climate change and drought events are expected to further increase the human impacts on the hydrological and biogeochemical cycles, and these impacts are gaining the attention of the scientific community. Here we show how the Chiese River watershed (Lombardy Region, Italy) represents an interesting opportunity to analyse the effects of traditional irrigation practices on N contamination in the context of water scarcity. During summer, flood irrigation is mostly sustained by groundwater withdrawal. Additional water withdrawals from the river contribute to the dry out of the Chiese River. The use of wells for irrigation over permeable and fertilized soils and the percolation of nitrate (NO3-) from the vadose zone to groundwater result in the accumulation of NO3- in groundwater and limited N losses via denitrification due to dominant oxic conditions. These practices contrast other measures targeting the reduction of N excess over arable land. In the Chiese River watershed, the N surplus from Soil System Budget calculations decreased by 43% since the early 2000 s but NO3- concentration in groundwater remained high and stable (up to 98.0 mg NO3- L−1). The dried-out Chiese River gains groundwater and NO3- concentration at the river mouth approaches 32.2 mg NO3- L−1. Our results suggest how the mismanagement of the watershed (overabundant fertilization and flood irrigation using groundwater) increases the N concentration both in the river and groundwater, leading to the violation of both Nitrate and Water Framework directives. We anticipate our assay to be a starting point for the conversion of the northern Po Plain to more efficient irrigation and fertilization practices to contrast severe droughts driven by climate change like the one who struck the Po Plain in summer 2022.

Study on N application and N reduction potential of farmland in China.

The frequent occurrence of extreme weather in recent years poses a significant threat to food production. Ensuring food production and rationalizing the use of agricultural resources require addressing the problem of the improper application of chemical fertilizers. Several effective measures have been implemented in China to reduce agricultural non-point source pollution. Among them, the reduction of excessive nitrogen fertilizer application proves to be the most effective approach in controlling surface pollution from cultivation. Currently, it is crucial to clarify and quantify crop nutrient fertilizer requirements while evaluating the potential for reducing nitrogen fertilizer usage in China. Nitrogen requirements for major crops grown in China were assessed based on the theory of crop nutrient balance, assuming constant grain production as a guarantee. In this paper, we analyze the potential for nitrogen reduction through short-term, medium-term, and long-term scenario predictions. The results show that in the next 3 years, China has a reduction potential of 34.98%, but this potential is not sustainable. Over the next 10 years, there is a reduction potential of 15.04%, with most provinces experiencing a balanced state of soil nitrogen cycling. Hainan, Beijing, Shaanxi, and Fujian have higher reduction potential, with possible reductions of 69.95%, 64.14%, 60.72%, and 54.10%, respectively. However, there are still provinces in China where nitrogen fertilizer is insufficient, leading to soil nitrogen consumption. Specifically, Heilongjiang, Jiangxi, and Shandong Provinces need to increase their nitrogen fertilizer applications by 87.00%, 35.97%, and 8.31%, respectively. The long-term scenario analysis over the next 30 years shows a reduction potential of 40.96%. Among the regions analyzed, Hainan, Beijing, Shaanxi, Fujian, and Ningxia have higher nitrogen fertilizer reduction potentials, with values of 78.97%, 78.48%, 74.25%, 67.87%, and 67.72%, respectively. However, Heilongjiang Province still needs to increase nitrogen fertilizer application by 44.20% to address soil nitrogen depletion. Conversely, Tibet and Qinghai, with high organic fertilizer yields, lower chemical fertilizer usage, and low nitrogen loss coefficients, are well-suited for organic agriculture development. For areas with high organic fertilizers usage and a risk of fertilizer loss, we recommend implementing the organic-inorganic mixed fertilization planting mode.

Effect of Dopamine on Growth, Some Biochemical Attributes, and the Yield of Crisphead Lettuce under Nitrogen Deficiency

Nitrogen (N) represents the most important nutrient for plant growth and productivity, but extreme and ineffective usage of N fertilizer results in boosted plant production expenditures and environmental contamination. For the world’s sustainable food production and environmental profits, there has been increased research interest in reducing the use of N fertilization along with improving plant N deficiency (ND) tolerance. Dopamine (DA), a potential antioxidant, mediates several physio-biochemical processes in plants under normal or stressful conditions. However, their roles in increasing ND tolerance in crisphead lettuce are not well-documented. We investigate the role of DA concentration (0.50 and 100 µM) on the growth and yield of crisphead lettuce plants under ND. Under normal conditions (100% recommended N fertilizer dose), DA (50 and 100 μM) application significantly enhanced growth, chlorophyll concentration, N%, antioxidant enzymes activity, as well as yield and its components, decreased nitrate accumulation and oxidative biomarkers compared to untreated plants (0 μM DA). ND significantly decreased plant growth and yield attributes as well as evoked oxidative impairment and nitrate accumulation as compared to 100% recommended N fertilizer dose in the absence of DA. However, within ND conditions, the application of DA concentrations significantly mitigated ND-induced oxidative burst and improved plant growth, chlorophyll concentration, N%, nitrate concentration, peroxidase, catalase, superoxide dismutase, total soluble solid, vitamin C, dry matter %, and total sugars, over 0 μM DA treated plants. Current findings highlighted that exogenous application of 100 μM DA could reinforce the crisphead lettuce plant’s resilience to ND by minimizing reactive oxygen species accumulation and promoting enzymatic antioxidants alongside growth, yield, and quality improvement. The beneficial effects of DA in lessening ND’s drastic impacts on crisphead lettuce resulted from upregulating antioxidant enzyme activity, impairment of oxidative biomarkers, and maintaining chlorophyll levels. The current findings open pioneering prospects to reduce nitrogen fertilization by DA application without any drastic effect on plant productivity. But further research is needed to fully understand DA effects and their mechanisms in inducing ND tolerance in different plant species, including crisphead lettuce.

Changes in the mycobiome structure in response to reduced nitrogen fertilization in two cropping systems of maize

Nitrogen (N) is an essential element for plant productivity; hence, it is abundantly applied to the soil in the form of organic or chemical fertilizers, which consequently have a negative impact on the environment. Therefore, the main objective of our study was to investigate the structure and richness of the soil mycobiome in response to reduced nitrogen fertilization under two cropping systems: plowing (P) and no-till (NT). Moreover, the scope of the study perfectly falls into the EU “From Field to Table” strategy, which recommends a 20 % reduction of nitrogen fertilization of agricultural soils by 2030.In our study, the samples were collected twice during a single growing season: before maize sowing (without fertilization) and after harvesting the crop (four different fertilization rates). The mycobiome structure was identified based on the next generation sequencing (NGS) technique.Overall, our research has proved that the cropping system is important in terms of the formation of the fungal mycobiome structure and relative abundance. In addition, we confirmed that soil properties have a significant impact on fungal communities. We determined that a 20 % lower nitrogen fertilization rate (92.0 kg N ha−1) had a positive effect on the abundance of fungal communities. Moreover, the highest biodiversity at each of the taxonomic levels tested (phylum, class, genus) in the NT system and at the class and genus levels in the P system was also evidenced at the 20 % lower N fertilization rate. We also recommended potential indicators confirming the positive impact of reduced fertilization in two cropping systems: plowing – Epicoccum, Metarhizium, Mycosphaerella, and Paraconiothyrium and no-till – Peziza, Podospora, Metarhizium, Trechispora, and Umbelopsis.