Nitrogen Accumulation in Oyster (Crassostrea gigas) Slurry Exposed to Virucidal Cold Atmospheric Plasma Treatment

Viral contamination of edible bivalves is a major food safety issue. We studied the virucidal effect of a cold atmospheric plasma (CAP) source on two virologically different surrogate viruses [a double-stranded DNA virus (Equid alphaherpesvirus 1, EHV-1), and a single-stranded RNA virus (Bovine coronavirus, BCoV)] suspended in Dulbecco’s Modified Eagle’s Medium (DMEM). A 15 min exposure effectuated a statistically significant immediate reduction in intact BCoV viruses by 2.8 (ozone-dominated plasma, “low power”) or 2.3 log cycles (nitrate-dominated, “high power”) of the initial viral load. The immediate effect of CAP on EHV-1 was less pronounced, with “low power” CAP yielding a 1.4 and “high power” a 1.0 log reduction. We observed a decline in glucose contents in DMEM, which was most probably caused by a Maillard reaction with the amino acids in DMEM. With respect to the application of the virucidal CAP treatment in oyster production, we investigated whether salt water could be sanitized. CAP treatment entailed a significant decline in pH, below the limits acceptable for holding oysters. In oyster slurry (a surrogate for live oysters), CAP exposure resulted in an increase in total nitrogen, and, to a lower extent, in nitrate and nitrite; this was most probably caused by absorption of nitrate from the plasma gas cloud. We could not observe a change in colour, indicative for binding of NOx to haemocyanin, although this would be a reasonable assumption. Further studies are necessary to explore in which form this additional nitrogen is deposited in oyster flesh.

Impacts of Fertilization Optimization on Ammonia Volatilization, Soil Nitrification, Denitration Intensity From Wheat Fields and Nitrogen Utilization Under Water-saving Irrigation

Scholars have proposed the practice of split N fertilizer application (SNFA), which has proven to be an effective approach for enhancing N use efficiency. However, the effect of SNFA on NH3 volatilization, nitrification and denitration in soil, remain largely unknown. As such, the current study assessed soil NH3 volatilization, nitrification and denitrification intensities, abundance of nitrogen cycle-related funetional genes, and invertase activity for different treatments. We applied a rate of 240 kg·ha-1 of N, and the following fertilizer ratios of the percent base to that of topdressing under water-saving irrigation: N1 (basal/dressing, 100%/0%), N2 (basal/dressing, 70%/30%), N3 (basal/dressing, 50%/50%), N4 (basal/dressing, 30%/70%), and N5 (basal/dressing, 0%/100%). N3 treatment resulted in a significant decrease in rate of NH3 volatilization. This treatment also significantly reduced nitrification and denitrification intensities, primarily owing to the reduced functional genes abundance involved in the nitrogen cycle (Amoa-AOB, nirK and nirS) and reduced invertase activity (urease, nitrate reductase, nitrite reductase) in wheat-land soil. 15N tracer studies further demonstrated that N3 treatments significantly increased the grain nitrogen accumulation by 9.50-28.27% compared with that under other treatments. This increase was primarily due to an increase in the amount of N absorbed by wheat from soil and fertilizers, which was caused by an enhancement in total N uptake (7.2-21.81%). Collectively, these results suggest that the N3 treatment (basal/dressing, 50%/50%) improves N uptake by wheat, reduces the soil NH3 volatilization rate, and has the potential to reduce the amount of N2O generated by nitrification and denitrification.

The effect of the growth regulator “Tsirkon” and microfertilizer “Akvamiks ST” on blue lupine productivity

Исследования выполнялись в 2018–2020 годах на опытном поле ВНИИ люпина – филиала ФГБНУ ФНЦ «ВИК им. В. Р. Вильямса» в почвенно-климатических условиях юго-западной части Нечернозёмной зоны. В статье представлены результаты исследований применения новых для люпина узколистного препаратов: регулятора роста «Циркон» и микроудобрения «Аквамикс СТ». Дана оценка их совместного действия на показатели роста, фотосинтез, азотфиксацию, урожайность, качество зерна люпина узколистного сорта Витязь. Совместное использование препаратов усиливало развитие растений, о чём свидетельствует увеличение в вариантах опыта массы клубеньков на растении на 7,0–24,1%, площади листьев — на 22,5–29,4%, сбора сухой массы — на 10,5–28,9%. В среднем за годы исследований бόльшими значениями фотосинтетического потенциала характеризовались варианты, включающие предпосевную обработку семян совместно регулятором роста и микроудобрением. Превышение над контролем находилось в пределах от 22,1 до 30,2%. Обработки препаратами оказывали положительное влияние на накопление азота клубеньками. Максимальным накоплением характеризовался вариант с комплексной обработкой семян регулятором и микроудобрением с последующим опрыскиванием регулятором роста по вегетации. Превышение над контролем составило 5,7%. Условия вегетации в годы исследований не благоприятствовали полной реализации процесса азотфиксации, тем не менее использование «Аквамикса СТ» и «Циркона» способствовало повышению коэффициента азотфиксации. В вариантах опыта этот показатель был выше контроля в среднем на 20,7%. Применение регулятора роста «Циркон» и микроудобрения «Аквамикс СТ» стимулировало рост урожайности семян во всех вариантах. В среднем за годы исследований достоверными прибавками характеризовались варианты, включающие предпосевную комплексную обработку семян «Цирконом» и «Аквамиксом СТ», но максимальной она была в варианте с дополнительной обработкой растений в фазе бутонизации регулятором роста — выше контроля на 24,1%. The investigation took place in the south-west of the Non-Chernozem region in 2018–2020. The article reports on the effectiveness of the growth regulator “Tsirkon” and microfertilizer “Akvamiks ST”. The following parameters of blue lupine “Vityaz” were evaluated: growth, photosynthetic activity, nitrogen fixation, productivity, and grain quality. Combination of “Tsirkon” with “Akvamiks ST” positively affected plant development, increased nodule mass by 7.0–24.1%, leaf area — by 22.5–29.4%, dry mass yield — by 10.5–28.9%. Seed treatment with growth regulator as well as application of the microfertilizer led to a higher photosynthetic activity of lupine plants by 22.1–30.2%. The preparations had positive effect on nitrogen accumulation. The highest N content was observed under seed and plant treatments with the growth regulator combined with the application of microfertilizer. The increase in N concentration amounted to 5.7%. Even though weather conditions did not favor N fixation, application of “Tsirkon” with “Akvamiks ST” improved this process by 20.7%. “Tsirkon” and “Akvamiks ST” increased seed productivity in all the variants. The highest productivity occurred under the additional plant treatment with the growth regulator exceeding the control by 24.1%.

Growth and nitrogen accumulation assessment of banana (Musa acuminata) after exposure to hydroquinone in a charcoal-ultisol mix

The present study investigates plant growth and nitrogen accumulation assessment of young banana plant (Musa acuminata) after exposure to hydroquinone (a mutagen) in a charcoal-ultisol mix. Charcoal was obtained from the wood of Pentaclethra macrophylla aerobically, and was crushed into a smooth powdered form. This was mixed with an ultisol obtained from the University of Benin Botanic garden. Different levels of the soil-charcoal mix were prepared as follows; 100% charcoal, 75% charcoal-25% soil, 50% charcoal-50% soil, 25% charcoal- 75% soil, and 100% sand. The charcoal-ultisol mix was then amended with 5ppm hydroquinone one week before propagating young banana suckers. Results showed that sprouting began fifteen days after propagation. There were also different changes in plant height in the various soil treatments; the lowest was reported in the 75-25 charcoal ultisol mix (10.50cm), compared to 45.83cm in plants sown in 100% charcoals. Foliar yield was lowest in the 75-25 charcoal-ultisol mix (8.55 grams per plant), compared to 29.15 grams per plant in the 100% charcoal. The below ground morphological characteristics test plant revealed that there were significant differences between the growth parameters. Nitrate nitrogen, Ammonia Nitrogen and total nitrogen were significantly accumulated on the leaves of plant. However, higher nitrogen accumulation in the leaves was found in treatment with high charcoal percentage.