Search Results (127)

Climate change has intensified the increase in irrigated crops to solve frequent droughts, but part of the stress continues due to heat waves, and for these systems, there is a lack of in-depth discussion about their damage and strategies to minimize this damage. The damage caused by high temperatures may be exacerbated in crops with a nutritional disorder of nitrogen, but optimized management of this nutrient can help mitigate the effects of this stress. This merits further debate, as it would be a sustainable strategy without risk to the environment and at the same time could induce greater plant tolerance to heat stress. This review will address the relevance of rising temperatures and their isolated effects on crop nutrition and productivity and the role of optimized nitrogen use in mitigating this stress and propose future perspectives for this research that could help researchers improve thermotolerance. Nitrogen plays an essential role in plant metabolism, inducing the production of proteins from photosynthesis, boosting primary and secondary plant metabolism and, consequently, the production and defense systems of the plant. Studies indicate that adequate nitrogen supplementation can increase plant resilience to high temperatures, improving water use efficiency and promoting the synthesis of heat shock proteins. In addition, new strategies in nitrogen fertilizer management, such as the use of nitrification inhibitors and biofertilizers, have demonstrated greater efficiency in the use of nitrogen, reducing environmental losses, and, consequently, they could have an impact on stress mitigation. Although nitrogen can mitigate the negative effects of heat waves on plants, there are still gaps in the knowledge about the underlying biochemical and physiological mechanisms involved and whether the doses of N used in research are really optimal for maximizing the plant’s defense system against stress. The future outlook is that optimal N management will become important not only to guarantee high yields but also to minimize heat wave losses by strengthening the plant’s defense mechanisms to deal with this stress. In the context of climate change, a better understanding of the benefits of N will help to better manage heat stress towards more sustainable agriculture. Full article

Excessive N loss through leaching and volatilization is a major concern in modern agriculture, reducing N use efficiency, groundwater contamination, and environmental degradation. To address these issues, this research evaluates the impact of N fertilizers containing nitrification inhibitors (NIs), which restrict the conversion of ammonium (NH₄⁺) into nitrate (NO₃⁻), thereby enhancing N retention in the soil. This study examines the effects of different N fertilizer applications on the yield and nutrient dynamics of winter barley (Hordeum vulgare L.) Field experiments were conducted to compare the effects of a one-time and split application of granular N fertilizers ENSIN (with NIs) and DASA (without NIs) on winter barley yield and N dynamics. The highest grain yield was observed with a single ENSIN application (8.35 Mg.hm⁻²), followed by a divided DASA application (7.97 Mg.hm⁻²), both significantly outperforming the control (no N). The most efficient N use was recorded for the single ENSIN application, yielding 27.4 kg of grain per kg of applied N. Agrochemical analyses were conducted to assess soil NH₄⁺ and NO₃⁻ content throughout the vegetation period, and lysimetric methods were used to determine leaching losses. The results highlight the potential of NIs to improve nutrient uptake efficiency, reduce N loss, and enhance sustainable barley production. Through optimizing fertilizer application strategies, this study contributes to the development of more sustainable agricultural practices that improve crop yield while minimizing environmental impacts, particularly in reducing N runoff and groundwater contamination. Full article

The use of nitrification inhibitors (NIs) with nitrogen fertilizers represents an effective strategy to reduce nitrogen loss. In addition, nitrification inhibitors are widely applied to improve agricultural yield. However, it is necessary to continue investigating the crop-specific agricultural practice. In this study, a nitrapyrin-based nitrification inhibitor was used to assess its effects on Brassica oleracea L. var. botrytis growth and on the environment. In a pot experiment, cauliflower plants were grown in fertilized soils based on calcium nitrate (SF) and SF + nitrapyrin. At the end of the experiment, the content of nitrogen compounds in soil and percolation water and the cauliflower yield were determined, and the plant tissues were characterized by Fourier-transform infrared spectroscopy. The application of the NI significantly reduced nitrogen losses, increasing nutrient availability in the soil and the element’s absorption in the plant. Co-application of fertilizers and NIs reduced ${NO}_3^{-}$ leaching from 925 to 294 mg/L. Plant tissue characterization by FTIR spectroscopy highlighted variations in the functional groups in response to the application of NIs. These results suggest that applying nitrogen fertilizer in combination with nitrapyrin can mitigate nitrate pollution and improve element absorption and plant growth. Our research has shown that application methods and cropping systems need to be studied to maximize the effectiveness of nitrapyrin-based NIs. Full article

Nitrous oxide (N₂O) is a potent greenhouse gas, and agriculture represents more than fifty percent of total anthropogenic emissions. The production of N₂O in soil is biogenic through nitrification, denitrification, chemonitrification, nitrifier denitrification, etc., which are processes influenced by the soil pH, temperature, moisture, oxygen concentration, organic carbon, and soil nitrogen. Higher N₂O emissions from the soil result in lower nitrogen use efficiency and higher environmental pollution in terms of global warming. Therefore, an understanding of different pathways for N₂O production in soil and the affecting factors is essential to mitigate N₂O emissions from soil to the atmosphere. Nitrification inhibitor application has been reported in many studies, but the impact of nitrification inhibitors in different perennials (orchards) and biennials (rice, wheat, maize, etc.) is not lacking. In this study, we develop an understanding of different N₂O production pathways and different influencing factors. The role of the different nitrification inhibitors was also developed to achieve low N₂O emissions from soils to the atmosphere. Full article

Plant invasions play a significant role in global environmental change. Traditionally, it was believed that invasive plants absorb and utilize nitrogen (N) more efficiently than native plants by adjusting their preferred N forms in accordance with the dominant N forms present in the soil. More recently, invasive plants are now understood to optimize their N acquisition by directly mediating soil N transformations. This review highlights how exotic species optimize their nitrogen acquisition by influencing soil nitrogen dynamics based on their preferred nitrogen forms, and the various mechanisms, including biological nitrification inhibitor (BNI) release, pH alterations, and changes in nutrient stoichiometry (carbon to nitrogen ratio), that regulate the soil nitrogen dynamics of exotic plants. Generally, invasive plants accelerate soil gross nitrogen transformations to maintain a high supply of NH₄⁺ and NO₃⁻ in nitrogen-rich ecosystems irrespective of their preference. However, they tend to minimize nitrogen losses to enhance nitrogen availability in nitrogen-poor ecosystems, where, in such situations, plants with different nitrogen preferences usually affect different nitrogen transformation processes. Therefore, a comprehensive understanding requires more situ data on the interactions between invasive plant species’ preferential N form uptake and the characteristics of soil N transformations. Understanding the combination of these processes is essential to elucidate how exotic plants optimize nitrogen use efficiency (NUE) and minimize nitrogen losses through denitrification, leaching, or runoff, which are considered critical for the success of invasive plant species. This review also highlights some of the most recent discoveries in the responses of invasive plants to the different forms and amounts of N and how plants affect soil N transformations to optimize their N acquisition, emphasizing the significance of how plant–soil interactions potentially influence soil N dynamics. Full article

Nitrogen (N) fertilizer incorporation of efficiency enhancer is a well-established practice aiming at reducing N loss while enhancing crop yield. However, the effect of different kinds of fertilizer efficiency enhancer on N use efficiency (NUE) and gas loss are rarely compared and poorly comprehended. Here, we conducted a field experiment involving the combination of urease and nitrification inhibitor (NI), the biological inhibitor eugenol (DE) and the bioploymer poly-glutamic acid (PG) and their combinations (NI + PG, NI + DE, PG + DE) to evaluate their effects on crop yield, NUE, NH3 volatilization and greenhouse gas emissions (GHGs). Results indicated that NI, DE, PG and their combinations significantly enhanced the crop yield, N uptake and NUE. NI, DE and PG are all effective in reducing NH₃ volatilization and N₂O emission, averagely decreased by 11.13%, 6.83%, 8.29%, respectively, and by 11.15%, 4.32%, 8.35%, respectively, while have no significant effects on CO₂-C and CH₄-C fluxes, except PG significantly increases CO₂-C emission and thus global warming potential. The combination of these three efficiency enhancers has no multiply effect on maize yield, NUE and gas loss. These findings help to screen the fertilizer efficiency enhancer that can be more effectively utilized in agricultural practices and contribute to their application strategies within agricultural systems. Full article

The application of nitrification inhibitors (NIs) is an effective way to reduce soil nitrogen (N) losses and increase crop N uptake. Yet, the efficacy of NIs commonly varies with dosages, crop systems and soil environmental conditions. Hence, clarifying the suitable type and dosage of NIs is extremely important for structuring the best N management regime at a regional scale. Here, based on microcosm experiments, we evaluated the influence of three widely used NIs [Dicyandiamide, DCD; 3,4-Dimethylpyrazole phosphate, DMPP; 2-chloro-6-(trichloromethyl) pyridine, Nitrapyrin] on the nitrification activity of an intensively cultivated greenhouse soil. The results showed that both DCD and DMPP imposed a transient inhibition on nitrification (less than five days) regardless of the dosages applied, and, on the contrary, Nitrapyrin presented a persistent suppression, with a longer duration of the inhibition action by a higher dosage. Accordingly, the incorporation of Nitrapyrin at 2% of the applied N rate (w/w) is a recommendable dosage for local intensive greenhouse production. Further, we assessed the influence of various dosages of Nitrapyrin incorporation (0%, 0.25%, 0.5%, 2% and 5%) on the abundance and community of three groups of soil ammonia oxidizers [i.e., ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and completely ammonia-oxidizing bacteria (Comammox Nitrospira)] by qPCR and high-throughput amplicon sequencing. Nitrapyrin incorporation strongly lowered both the AOB and Comammox Nitrospira abundances and their community richness even at the lowest dosage. Nitrapyrin incorporation also significantly altered the community structure of all of the tested ammonia oxidizers, and the average relative abundance of some major community members (i.e., the Nitrososphaerales Clade Nitrososphaera, Nitrososphaerales Clade A, Nitrosospira briensis Clade, Nitrosospira multiformis Clade, Comammox Nitrospira Clade A.2 and Comammox Nitrospira Clade A-associated) obviously responded to Nitrapyrin incorporation. Overall, our findings indicated that AOB and Comammox Nitrospira were more sensitive to Nitrapyrin incorporation as compared with AOA. The results obtained here highlight the importance of optimizing the type and dosage of NIs for N fertilization management in intensive greenhouse vegetable production. Nitrapyrin incorporation inhibits soil nitrification probably by suppressing the Nitrosospira multiformis Clade in the AOB community at the level tested herein. Full article

Urease and nitrification inhibitors represent ways to reduce nitrogen losses; their presence modifies microbial and enzymatic activity in the soil, affecting pH and organic matter (OM), which in turn affects the mobility of heavy metals. To evaluate the effect of urea with inhibitors, pH, OM content, and pseudo-total and mobile metal content (Cu, Cd, Ni, Pb, Cr, Zn, and Mn) were determined in soil samples fertilized with six different urea variants with inhibitors. The modification in the pseudo-total content of heavy metals following fertilization (%) was as follows: Cu (−39.26 ÷ −8.82), Cd (10.74 ÷ 15.40), Ni (5.76 ÷ 18.84), Pb (−13.30 ÷ 12.46), Cr (−15.55 ÷ 11.60), Zn (35.10 ÷ 162.76), and Mn (−1.32 ÷ 12.17). The pH was situated in the range of 7.05 to 7.17, while OM content showed an average increase of 16%. The determined pollution indicators revealed an accumulation of Zn in the soil. The results showed a trend of accumulation of bioavailable heavy metals, with the greatest increase for Mn (43%). Only in the case of Zn, there was a decrease in mobile content with the lowest value when applying two urease inhibitors and one nitrification inhibitor. Inhibitors modify the OM content and soil pH, influencing the mobility and bioavailability of heavy metals. Full article

Agricultural soils are major anthropogenic sources of N₂O emissions. The application of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) has been proved to be an effective management measure to mitigate N₂O emissions. However, the influence mechanism of DMPP on the mitigation of soil N₂O emissions under different irrigation regimes remains unclear. Therefore, a lysimeter experiment was conducted to study the effects of irrigation level (lower irrigation limits of 75%, 65%, and 55% of field capacity (FC), signed as WH, WM, and WL) and DMPP addition (0% and 1% of N application, signed as D0 and D1) on N₂O emissions, soil environmental factors such as ammonium nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃⁻-N), water-filled pore space (WFPS), soil temperature, and the abundances of N₂O-related genes (AOA amoA, AOB amoA, nirS, and nirK). The results showed that soil N₂O emissions increased with the increasing of irrigation level. The efficiency of DMPP mitigating N₂O emissions varies depending on irrigation regime. Compared to D0, D1 strongly decreased cumulative N₂O emissions by 11.27%, 18.96%, and 15.05% in the WL, WM, and WH conditions, respectively. Meanwhile, D1 caused an obvious reduction in the AOB amoA gene by 29.73%, 47.02%, and 22.41%, respectively, but there was no significant effect on the AOA amoA gene. D1 was effective in decreasing nirS and nirK genes except in the WL condition; the percentages of reduction were 48.45%, 40.84% and 37.18%, 44.97% in the WM and WH conditions, respectively. In addition, D1 caused an increase in NH₄⁺-N content and a decrease in NO₃⁻-N content, WFPS, and soil temperature in all irrigation regimes. A higher significant correlation was observed between N₂O emissions and NH₄⁺-N and AOB amoA in the WL and WM conditions, while a significant correlation was observed between N₂O emissions and NO₃⁻-N, nirK, and nirS in the WH condition. It was revealed that with the increase in irrigation level, the main source of N₂O emissions might change from nitrification to denitrification. Overall, our study indicated that in the WL and WM conditions, the mitigation of N₂O emissions by DMPP was primarily attributable to the inhibition of the AOB amoA gene, whereas the inhibition of nirS and nirK genes was likely the dominant mechanism in the WH condition. The findings of this study will provide a theoretical basis for the application of a nitrification inhibitor for drip-irrigated winter wheat fields in the North China Plain. Full article

Agro-industrial residues have transitions from being an environmental problem to being a cost-effective source of biopolymers and value-added chemicals. However, the efficient extraction of the desired products from these residues requires pretreatments. Fungal biorefinery is a fascinating approach for the biotransformation of raw materials into multiple products in a single batch. In this study, the ability of Trichoderma asperellum R to convert fruit scrap and green waste into value-added chemicals was tested in solid-state and in nonsterile conditions. A solid-state fermentation protocol for a tray bioreactor was developed using spawn as the inoculum for nonsterile substrates. T. asperellum R drove the fermentation of both substrates, shaping the metabolites that were enriched in the secondary plant metabolites. Strain R showed cellulase activity only when inoculated on fruit scraps, resulting in increased amounts of polysaccharides in the crude extract. This extract was also enriched in vanillic acid and limonoid, which are intriguing compounds due to the increasing interest in their potential as biological nitrification inhibitors or food additives. Finally, trimethoxybenzaldehyde, an interesting chemical building block, was identified in the extracts of the Trichoderma-guided fermentation. The overall results showed that the application of T. asperellum R has potential as a driver to facilitate the extraction of bioactive substances from nonsterile recalcitrant substrates. Full article

The preference of potato plants for specific nitrogen (N) form changes with growth stage. Potato plants prefer nitrate N before tuber formation, while they favor ammonium N after tuber formation. However, few studies have focused on N species management in potato production. In this study, 2-year field experiments were conducted from 2020 to 2021 in Inner Mongolia, China, under drip irrigation with four N treatments: (1) CK (no N was used), (2) conventional farming practices (F) (urea was the only N source applied for potato growth), (3) nitrate N supplied before tuber formation and ammonium N with nitrification inhibitor supplied after tuber formation (N-NI), and (4) nitrate N supplied before tuber formation and frequent, low-dose ammonium N applied after tuber formation (Opt). The results demonstrated that, compared with the F, the Opt treatment facilitated potato N uptake, with a 33–40% increase in plant N accumulation, and significantly increased potato growth, which ultimately resulted in a yield increase of 12–20% and an increase of 11–22 percentage units in NUE. In addition, the Opt treatment reduced the soil N residual by ~14% after harvest. Compared with the N-NI, the Opt treatment did not result in a decrease in tuber yield or NUE. Therefore, supplying nitrate N before tuber formation and frequent, low-dose ammonium N after tuber formation can result in a better match between the supply and demand of potato plants for N forms without the use of nitrification inhibitors, improving both potato yield and NUE, which is of substantial agronomic and environmental value. Full article

Studies of the impact of nitrification inhibitors (NIs), specifically DMPP and DMPSA, on N₂O emissions during “hot moments” have produced conflicting results regarding their effectiveness after rewetting. This study aimed to clarify the effectiveness of NIs in reducing N₂O emissions by assessing residual DMP concentration and its influence on ammonia-oxidizing bacteria (AOB) in two pot experiments using calcareous (Soil C, Calcic Haploxerept) and acidic soils (Soil A, Dystric Xerochrepts). Fertilizer treatments included urea (U), DMPP, and DMPSA. The experiments were divided into Phase I (water application to dry period, 44 days) and Phase II (rewetting from days 101 to 121). In both phases for Soil C, total N₂O emissions were reduced by 88% and 90% for DMPP and DMPSA, respectively, compared with U alone. While in Phase I, the efficacy of NIs was linked to the regulation of AOB populations, in Phase II this group was not affected by NIs, suggesting that nitrification may not be the predominant process after rewetting. In Soil A, higher concentrations of DMP from DMPP were maintained compared to Soil C at the end of each phase. Despite this, NIs had no significant effect due to low nitrification rates and limited amoA gene abundance, indicating unfavorable conditions for nitrifiers. The study highlights the need to optimize NIs to reduce N₂O emissions and improve nitrogen efficiency, while understanding their interactions with the soil. This knowledge is necessary in order to design fertilization strategies that improve the sustainability of agriculture under climate change. Full article

Greenhouse gas and NH₃ emissions are exacerbated by the inappropriate timing and excessive application of nitrogen (N) fertilizers in wheat cultivation in China. In this study, the impacts on N₂O, CO₂, and NH₃ emissions of a delayed and reduced N application regime on the Huang-Huai-Hai Plain were investigated. The treatments comprised the control (N₀), conventional N at 270 kg N ha⁻¹ (N₂₇₀) and optimized N application of 180 kg N ha⁻¹ (N₁₈₀), N₁₈₀ + biochar at 7.5 t ha⁻¹ (N₁₈₀B_7.5), N₁₈₀ + biochar at 15 t ha⁻¹ (N₁₈₀B₁₅), N₁₈₀ + DMPP (a nitrification inhibitor; N₁₈₀D), N₁₈₀D + biochar at 7.5 t ha⁻¹ (N₁₈₀DB_7.5), and N₁₈₀D + biochar at 15 t ha⁻¹ (N₁₈₀DB₁₅). Reduced N application (N₁₈₀) lowered N₂O and NH₃ emissions. Biochar application resulted in a 4–25% and 12–16% increase in N₂O and NH₃ emissions, respectively. Application of DMPP significantly decreased N₂O emissions by 32% while concurrently inducing a 9% increase in NH₃ emissions. Co-application of DMPP and biochar significantly reduced the activity of nitrification enzymes (HAD, NOO), resulting in a reduction of 37–38% in N₂O emissions and 13–14% in NH₃ emissions. No significant differences in CO₂ emissions were observed among the various N treatments except the N₀ treatment. Application of DMPP alone did not significantly affect grain yield. However, biochar, in combination with DMPP, effectively increases grain yield. The findings suggest that the N₁₈₀DB₁₅ treatment has the potential to reduce emissions of N₂O and NH₃ while concurrently enhancing soil fertility (pH, SOC) and wheat yield. Full article

While previous studies have suggested that biochar, nitrification inhibitors, and urease inhibitors may reduce soil greenhouse gas emissions, their effectiveness in soils irrigated with alternative water resources remains unclear. To compensate for this, reclaimed water and livestock wastewater were utilized as alternative water resources alongside groundwater control. Nitrapyrin and N-(n-butyl) thiophosphoric triamide and biochar were applied to the soil either individually or in combination, and a no-substance treatment (NS) was included for comparison. The results revealed that reclaimed water and livestock wastewater irrigation exacerbated the global warming potential. Compared to the NS, all exogenous substance treatments suppressed nitrous oxide (N₂O) emissions while increasing carbon dioxide (CO₂) emissions, and affecting methane (CH₄) emissions varied across treatments irrespective of the water types. Interestingly, the additional biochar reduced the inhibitory effect of the inhibitors on the greenhouse effect. Using nitrification inhibitors reduced the global warming potential by 48.3% and 50.1% under reclaimed water and livestock wastewater irrigation, respectively. However, when nitrification inhibitors were applied in combination with biochar, the global warming potential was increased by 52.1–83.4% compared to nitrification inhibitors alone, and a similar trend was also observed in the scenario of urease inhibitors, with increases ranging from 8.8 to 35.1%. Therefore, the combined application of biochar and inhibitors should be approached cautiously, considering the potential for increased greenhouse gas emissions. Full article

In order to increase nutrient input and alleviate the poor growth of blueberry (Vaccinium corymbosum L.) in neutral soil with strong nitrification, the application of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) as an enhanced efficiency fertilizer is a strategy to reduce nitrogen (N) loss and improve N supply. However, few studies have systematically investigated the effect of DMPP application on blueberry and its soil condition in detail so far. In this study, a pot experiment was conducted to elucidate the effect of DMPP at four gradient levels including 0.5% (w/w applied-N) DMPP (DL), 1% DMPP (DM), 2% DMPP (DH), and no DMPP (CK) on the dynamics of soil mineral N (NH₄⁺-N and NO₃⁻-N), soil chemical properties, as well as the agronomic characteristics and physiological indexes of blueberry plants in the neutral soil–blueberry system. The addition of DMPP significantly increased the retention of soil ammonium nitrogen and the content of total mineral nitrogen. qPCR analysis showed that DMPP inhibited the ammoxidation process mainly by reducing the abundance of the ammonia-oxidizing bacteria (AOB) amoA gene rather than the ammonia-oxidizing archaea (AOA) amoA gene. No significant inhibitory effect of DMPP was observed for the nitrite dehydrogenase gene nxrA and nitrite reductase gene nirS. Soil NH₄⁺-N and available phosphorus content were both enhanced with the DMPP application rates both in bulk and rhizosphere soil. Applying 1% DMPP to the neutral soil for blueberry was sufficient to safely inhibit soil nitrification, not only increasing ammonium nitrogen content by 10.42% and 26.79%, but also enhancing available phosphorus content by 9.19% and 22.41% compared with CK in bulk and rhizosphere soil, respectively. Moreover, 1% DMPP addition increased the nitrogen and phosphorus concentration of blueberry leaves by 12.17% and 26.42%, respectively, compared with CK. The total branch length and the dry weight of blueberry plant were also increased by 16.8% and 33.1%, respectively. These results provide valuable agronomic information for the application of DMPP in blueberry cultivation. Fertilization applied with 1% DMPP has great economic potential to improve both nitrogen and phosphorus absorption of blueberry so as to promote the vegetative growth of blueberry. Full article