High Carbon Amendments Increase Nitrogen Retention in Soil After Slurry Application—an Incubation Study with Silty Loam Soil

Excess nitrogen (N) after animal slurry application is a persistent problem of intensive agriculture, with consequences such as environmental pollution by ammonia (NH3) and nitrous oxide (N2O) emissions and nitrate (NO3−) leaching. High-carbon organic soil amendments (HCAs) with a large C:N ratio have shown the potential of mitigating unintended N losses from soil. To reduce gaseous and leaching N losses after the application of slurry, a laboratory incubation study was conducted with silt loam soil. We tested the potential of three different types of HCA—wheat straw, sawdust, and leonardite (application rate 50 g C L−1 slurry for each of the three HCAs)—to mitigate N loss after amendment of soil with pig and cattle slurry using two common application modes (slurry and HCA mixed overnight with subsequent addition to soil vs. sequential addition) at an application rate equivalent to 80 kg N ha−1. Compared to the control with only soil and slurry, the addition of leonardite reduced the NH3 emissions of both slurries by 32–64%. Leonardite also reduced the total N2O emissions by 33–58%. Wheat straw reduced N2O emissions by 40–46%, but had no effect on NH3 emission. 15 N labeling showed that the application of leonardite was associated with the highest N retention in soil (24% average slurry N recovery), followed by wheat straw (20% average slurry N recovery). The mitigation of N loss was also observed for sawdust, although the effect was less consistent compared with leonardite and wheat straw. Mixing the slurry and HCA overnight tended to reduce N losses, although the effect was not consistent across all treatments. In conclusion, leonardite improved soil N retention more effectively than wheat straw and sawdust.

Soil Application of Zeolite Affects Inorganic Nitrogen, Water Soluble and Exchangeable Potassium

An incubation study was conducted at college of agriculture, rajendranagar, PJTSAU to evaluate the influence of zeolite application on inorganic nitrogen, water soluble and exchangeable potassium in soil. Clinoptilolite Zeolite was fully mixed with soil (7.5 t ha-1) at the start of the experiment. Nitrogen was applied to soil through urea (200 kg ha-l). The experiment was conducted for 35 days and soil was analyzed for inorganic nitrogen, water soluble and exchangeable potassium at weekly intervals i.e., 1, 7, 14, 21, 28, 35 days of incubation. The results indicated that the treatment with zeolite application showed significantly higher ammoniacal nitrogen from day 1 (136.54 mg kg-l) to day 35 (38.71 mg kg-l) as well as nitrate nitrogen (day 1 – 59.13 mg kg-l; day 35 – 130.13 mg kg-l). Similarly water soluble (day 1 – 92.21 kg ha-l; day 35 – 103.13 kg ha-l) and exchangeable potassium (day 1 – 363.69 kg ha-l; day 35 – 393.94 kg ha-l) was also significantly higher in zeolite applied treatments. Thus, mixing of zeolite into soil improves inorganic nitrogen through reducing leaching losses and also improves water soluble and exchangeable potassium.

Herb-Drug Interaction Between Xiyanping Injection and Lopinavir/Ritonavir, Two Agents Used in COVID-19 Pharmacotherapy

The global epidemic outbreak of the coronavirus disease 2019 (COVID-19), which exhibits high infectivity, resulted in thousands of deaths due to the lack of specific drugs. Certain traditional Chinese medicines (TCMs), such as Xiyanping injection (XYPI), have exhibited remarkable benefits against COVID-19. Although TCM combined with Western medicine is considered an effective approach for the treatment of COVID-19, the combination may result in potential herb-drug interactions in the clinical setting. The present study aims to verify the effect of XYPI on the oral pharmacokinetics of lopinavir (LPV)/ritonavir (RTV) using an in vivo rat model and in vitro incubation model of human liver microsomes. After being pretreated with an intravenous dose of XYPI (52.5 mg/kg) for one day and for seven consecutive days, the rats received an oral dose of LPV/RTV (42:10.5 mg/kg). Except for the t1/2 of LPV is significantly prolonged from 4.66 to 7.18 h (p < 0.05) after seven consecutive days pretreatment, the pretreatment resulted in only a slight change in the other pharmacokinetic parameters of LPV. However, the pharmacokinetic parameters of RTV were significantly changed after pretreatment with XYPI, particularly in treatment for seven consecutive days, the AUC0-∞ of RTV was significantly shifted from 0.69 to 2.72 h μg/mL (p < 0.05) and the CL exhibited a tendency to decrease from 2.71 L/h to 0.94 L/h (p < 0.05), and the t1/2 of RTV prolonged from 3.70 to 5.51 h (p < 0.05), in comparison with the corresponding parameters in untreated rats. After administration of XYPI, the expression of Cyp3a1 protein was no significant changed in rats. The in vitro incubation study showed XYPI noncompetitively inhibited human CYP3A4 with an apparent Ki value of 0.54 mg/ml in a time-dependent manner. Our study demonstrated that XYPI affects the pharmacokinetics of LPV/RTV by inhibiting CYP3A4 activity. On the basis of this data, patients and clinicians can take precautions to avoid potential drug-interaction risks in COVID-19 treatment.

Effect of urea modified hydroxyapatite nano fertilizer on nitrogen release pattern in red soil

A laboratory incubation study was conducted during 2018 at College of Agriculture V.C. Farm, Mandya using CRD design with eight treatments and three replication. Treatments included were T1:100% Nitrogen-Urea (NU), T2 to T4: NU: UHA @ 75:25, 50:50 and 25:75 per cent, respectively and T5 to T7: UHA @ 50, 75 and 100%, respectively, T8: Absolute control. Results revealed that application of 100 per cent N through nano UHA increased the content of ammonical-N at 5 DAI (653.3 μg g-1) but the content decreased at 10 DAI (583.3 μg g-1) and increased to 716.7 μg g-1 at 15 DAI and maintained it upto 20 DAI while, it decreased at 45 DAI. The nitrate –N release was highest (596.7 μg g-1) at 10 DAI in T7 treatment and maintained it upto 20 DAI and decreased at 45 DAI. Similar pattern was observed with the application of 75 and 50 per cent N-UHA treatments (T6 and T5, respectively). The amount of release of ammonical and nitrate N was proportional to the amount N added through UHA at any sampling interval.

Pichia kudriavzevii – A potential soil yeast candidate for improving soil physical, chemical and biological properties

Soil yeasts exhibit an array of beneficial effects to plants viz., plant growth promotion, phosphate solubilization, nitrogen and sulphur oxidation, etc. Yeasts remain as poorly investigated group of microorganisms that represent an abundant and dependable source of bioactive/chemically novel compounds and potential bioinoculants. Hence this study holds the key concept of assessing the performance of soil yeasts with potential plant growth promoting ability in soil quality improvement. Sixteen soil yeast isolates with plant growth promoting traits were assessed for biofilm forming potential and five potential soil yeast isolates were selected and identified through molecular technique. Soil incubation study was performed with these isolates to assess their impact on soil physical, chemical and biological properties. Due to inoculation of soil yeasts, notable changes were observed in soil physical, chemical and biological properties. Among the soil yeast isolates, Pichia kudriavzevii gave better results in soil incubation study.

Soil Mehlich-3 extractable elements as affected by the addition of biochars to a clay soil co-amended with or without a compost

Biochar has potential to sequester carbon and mitigate greenhouse gas emissions, and it may also contribute nutrients for plant growth in temperate climates. Nutrient availability in biochar-amended soil was assessed in a 338-d incubation study. The clay soil prepared with 4% w/w (dry basis) compost or without compost, then amended with wood-based biochar made at different pyrolysis temperatures (maple bark [Acer saccharum] at 400°C [M400], 550°C [M550] and 700°C [M700]) on a dry-rate basis of 5% (w/w). After moistening the soil mixture to 44% volumetric soil water content (equivalent to 70% water-filled pore space), soil mixtures were incubated in the dark at 22°C. Soil was sampled at days 9, 16, 23, 44, 86, 23 170 and 338 of the incubation. Biochar amendment increased the Mehlich-3 P, K, Ca, Mg and Cu concentrations, and reduced the Mehlich-3 Al and Fe concentrations at each sampling date, and M400 had the most significant effect on Mehlich-3 extractable nutrient concentrations. Compost addition also increased the amounts of extractable nutrients. These results suggested that M400 and carbon-rich compost promoted microbial growth and mineralization in amended soil. In addition, soil mixed with compost and amended with biochar had more Mehlich-3 extractable K than when compost or biochar were applied alone, probably due to greater growth and activity of soil K-solubilizing microorganisms. Overall, our study indicated that co-application of wood-based biochar and compost could improve soil fertility in temperate regions by increasing the availability of most plant macronutrients and micronutrients.