EFFECT OF FERTILIZERRS WITH UREASE AND NITRIFICATION INHIBITORS ON DURUM WHEAT CROP ON YIELD AND QUALITY (Triticum turgidum L. subsp. durum)

Conventional agricultural has a significant role in climate change. For this reason, farmers choose more innovative practices such as fertilizers inhibitors. Durum wheat (Triticum turgidum L. subsp. durum) is the most cultivated winter crop in the Mediterranean basin. The scope of this study is to determine the improvement of the fertilizer yield by adding nitrification (DMPSA) and urease (NBPT) inhibitor in urea in durum wheat crop. Meridiano variety was evaluated for one growing period through 2019–2020 under two basic fertilization (20-20-0 and 12-40-0 (+10S +Zn). The experiments were designed according to split-plot design, 2 main plots (basic fertilization) and 7 subplots (top fertilization). The top fertilization were the various urea combination treatments (urea, urea + urease inhibitor thiophosphoric-triamide (NBPT) (UI), urea + nitrogen inhibitor 3,4- dimethylpyrazole succinic (DMPSA) and control. Nitrogen markers, such as nitrogen use efficiency (NUE), nitrogen harvest index and nitrogen agronomic efficiency (NAE) were used to evaluate nitrogen release. The length of the inflorescences was over 20 cm for all fertilizations. Regarding basic fertilization, larger inflorescences were recorded with 12-40-0 (+10S +Zn). The grain protein content and nitrogen were higher by 1-2% under basic basic fertilization 20-20-0. Grain and biomass production were increased with both fertilizers’ inhibitors (NBPT and DMPSA). Between two inhibitors, urease inhibitor (NBPT) yielded higher than DMPSA.

Recent Efforts in the Discovery of Urease Inhibitor Identifications

: Urease is an attractive drug target for designing anti-infective agents against pathogens such as Helicobacter pylori, Proteus mirabilis, and Ureaplasma urealyticum. In the past century, hundreds of medicinal chemists focused their efforts on explorations of urease inhibitors. Despite the FDA’s approval of acetohydroxamic acid as a urease inhibitor for the treatment of struvite nephrolithiasis and the widespread use of N-(n-butyl)thiophosphoric triamide as a soil urease inhibitor as nitrogen fertilizer synergists in agriculture, urease inhibitors with high potency and safety are urgently needed. Exploration of novel urease inhibitors has therefore become a hot research topic recently. Herein, inhibitors identified worldwide from 2016 to 2021 have been reviewed. They structurally belong to more than 20 classes of compounds such as urea/thioure analogues, hydroxamic acids, sulfonamides, metal complexes, and triazoles. Some inhibitors showed excellent potency with IC50 values lower than 10 nM, having 10000-fold higher potency than the positive control thiourea.

Biochar and urease inhibitor mitigate NH3 and N2O emissions and improve wheat yield in a urea fertilized alkaline soil

In this study, we explored the role of biochar (BC) and/or urease inhibitor (UI) in mitigating ammonia (NH3) and nitrous oxide (N2O) discharge from urea fertilized wheat cultivated fields in Pakistan (34.01°N, 71.71°E). The experiment included five treatments [control, urea (150 kg N ha−1), BC (10 Mg ha−1), urea + BC and urea + BC + UI (1 L ton−1)], which were all repeated four times and were carried out in a randomized complete block design. Urea supplementation along with BC and BC + UI reduced soil NH3 emissions by 27% and 69%, respectively, compared to sole urea application. Nitrous oxide emissions from urea fertilized plots were also reduced by 24% and 53% applying BC and BC + UI, respectively, compared to urea alone. Application of BC with urea improved the grain yield, shoot biomass, and total N uptake of wheat by 13%, 24%, and 12%, respectively, compared to urea alone. Moreover, UI further promoted biomass and grain yield, and N assimilation in wheat by 38%, 22% and 27%, respectively, over sole urea application. In conclusion, application of BC and/or UI can mitigate NH3 and N2O emissions from urea fertilized soil, improve N use efficiency (NUE) and overall crop productivity.

Sources and Doses of Nitrogen Associated with Inoculation with Azospirillum brasilense Modulate Growth and Gas Exchange of Corn in the Brazilian Amazon

The specific objective of the study was to evaluate effect of inoculation with Azospirillum brasilense and nitrogen (N) doses on vegetative growth and gas exchange in Zea mays L. The experimental design adopted was the completely randomized, in a 4 2 2 factorial scheme, in the following way: four doses of N (0 60 120 and 180 kg ha-1 of N), two sources of N (common urea and urease inhibitor-treated urea) and absence and presence of inoculation with A. brasilense, with four replications. The evaluations were made for vegetative growth of the plant (plant height, stem diameter, leaf area, number of leaves, dry mass of stem, root, leaves and aerial part and total dry mass) and photosynthesis, stomatal conductance, transpiration, internal carbon, relationship between internal and external carbon and content of chloroplast pigments. The application of N provided an improvement in plant growth, and, in general, the dose of 180 kg ha-1 N associated with A. brasilense, promoted an increase in stem diameter, photosynthesis, stomatal conductance, transpiration and internal carbon ratio of the corn. The treatment with urease inhibitor, greatly promoted the stem diameter, transpiration, Ci/Ca ratio and chlorophyll (Chl) a, b, total compared to urea treatment. The inoculation of the corn seeds with the bacteria and the use of N fertilization, regardless of the source, promoted an improvement in the vegetative growth of the hybrid, improving the vegetative growth and the physiological responses of corn when applied to the highest dose of 180 kg/ha N. © 2021 Friends Science Publishers

Chelerythrine Chloride: A Potential Rumen Microbial Urease Inhibitor Screened by Targeting UreG

Inhibition of ruminal microbial urease is of particular interest due to its crucial role in regulating urea-N utilization efficiency and nitrogen pollution in the livestock industry. Acetohydroxamic acid (AHA) is currently the only commercially available urease inhibitor, but it has adverse side effects. The urease accessory protein UreG, which facilitates the functional incorporation of the urease nickel metallocentre, has been proposed in developing urease inhibitor through disrupting urease maturation. The objective of this study was to screen natural compounds as potential urease inhibitors by targeting UreG in a predominant ruminal microbial urease. In silico screening and in vitro tests for potential inhibitors were performed using molecular docking and an assay for the GTPase activity of UreG. Chelerythrine chloride was selected as a potential urease inhibitor of UreG with an inhibition concentration IC50 value of 18.13 μM. It exhibited mixed inhibition, with the Ki value being 26.28 μM. We further explored its inhibition mechanism using isothermal titration calorimetry (ITC) and circular dichroism (CD) spectroscopy, and we found that chelerythrine chloride inhibited the binding of nickel to UreG and induced changes in the secondary structure, especially the α-helix and β-sheet of UreG. Chelerythrine chloride formed a pi-anion interaction with the Asp41 residue of UreG, which is an important residue in initiating the conformational changes of UreG. In conclusion, chelerythrine chloride exhibited a potential inhibitory effect on urease, which provided new evidence for strategies to develop novel urease inhibitors targeting UreG to reduce nitrogen excretion from ruminants.

Urease Inhibitors Effects on the Nitrogen Use Efficiency in a Maize–Wheat Rotation with or without Water Deficit

The use of urease inhibitors in irrigated systems decreases both soil ammonium (NH4+) and nitrate (NO3−) availability, and, thus, could be an easy tool to reduce N loss due to ammonia volatilization and NO3− leaching. The main goal of this experiment was to assess the effect of urease inhibitors on N use efficiency, N losses, and their economic impact in a maize-wheat field experiment. In this study, 10 treatments were compared, combining the urea fertilizer with or without urease inhibitor, applied in one or two dressings, and under optimal or sub-optimal irrigation. A single application of urease inhibitor (IN1d), coupled with the conventional urea, helped to reduce the nitrate leaching risk both during the maize period (even when compared to the two dressing treatment) and after harvest. In addition, this improvement was achieved together with an increase in economic benefit, even when compared with the application of the same amount of regular urea split into two dressings. Under low water availability systems, the benefits of applying urease inhibitors increased with respect to the application of regular urea, making this technique a very promising strategy for adaptation to climate change in arid and semiarid regions.

Azospirillum brasilense associated with nitrogen fertilization promotes improvement in macronutrient contents of maize plants

The lack of studies on the benefits of growth-promoting bacteria associated with sources and doses of nitrogen fertilizers in maize in tropical regions has raised many doubts on the use of nitrogen management, as well as recommendation for the adequate dose for maize production. Therefore, the objective of this study was to evaluate the effect of the doses and sources of nitrogen associated with the absence and presence of seed inoculated with Azospirillum brasilense in the contents of N, P, K, Ca, Mg and S in the roots, culm and leaf of maize plants. It was used a completely randomized design, in a 4 x 2 x 2 factorial scheme, consisting of four nitrogen doses (0; 60; 120; and 180 kg ha-1 of N), two sources of N (common urea and urea treated with urease inhibitor) and absence and presence of inoculation with Azospirillum brasilense, with four replications. The results identified that the N doses positively influenced the concentration of N, P, and S in the culm of maize plants. The use of urea with urease inhibitor was not efficient in optimizing nitrogen fertilization, providing similar accumulations of macronutrients to common urea. The inoculation with Azospirillum brasilense promoted a concentration of 10.4% of N in the stem when compared to urea without inoculation. Seed treatment with Azospirillum brasilense at a concentration of 1 g / kg of seed at a dose of 180 kg ha-1 of N provided a higher content of macronutrients in corn, regardless of the sources of common urea or urea treated with a urease inhibitor