Preparation, Characterization of Granulated Sulfur Fertilizers and Their Effects on a Sandy Soils

There is a potential for using sulfur waste in agriculture. The main objective of this study was to design a granular fertilizer based on waste elemental sulfur. Humic acids and halloysite were used to improve the properties and their influence on soil properties. This is the first report on the use of proposed materials for fertilizer production. The following granular fertilizers were prepared (the percentage share of component weight is given in brackets): fertilizer A (waste sulfur (95%) + halloysite (5%)), fertilizer B (waste sulfur (81%) + halloysite (5%) + humic acids (14%)), fertilizer C (waste sulfur (50%) + halloysite (50%)) and fertilizer D (waste sulfur (46%) + halloysite (46%) + humic acids (8%)). Basic properties of the obtained granulates were determined. Furthermore, the effect of the addition of the prepared fertilizers on soil pH, electrolytic conductivity, and sulfate content was examined in a 90-day incubation experiment. Enrichment with humic acids and the higher amount of halloysite increased the fertilizer properties (especially the share of larger granules and bulk density). In addition, it stabilized soil pH and increased the sulfur content (extracted with 0.01 mol·L−1 CaCl2 and Mehlich 3) in the soil.

The Effects of Concentration Gradient of Nitrogen Compounds on the Ammonium-nitrogen and Nitrate-nitrogen Fluxes at Sediment-Water Interface

The incubation experiments focused on altering concentration gradients of nitrogen between sediment and overlying water to examine the diffusion flux of ammonium-nitrogen (NH4+) and nitrate-nitrogen (NO3-) at sediment-water interface. In this study, the diffusion flux can be estimated based on calculating the average of the net change rate of nutrient concentrations in the overlying water. For the incubation experiment of different TN concentrations in the sediment, the results showed that the diffusion flux of ammonia at sediment-water interface is -52.57~84.57 mg·m-2·d-1, and for nitrate diffusion flux, the changing range during the incubation experiment is -110.13~143.25 mg·m-2·d-1. For the incubation experiment of different nitrogen concentrations in the overlying water, the results of NH4+-N diffusion flux in L, M, H treatment were 3.37, -4.94, -3.84 mg·m-2·d-1, respectively. And the average diffusion flux of nitrate in L (0 mg NO3--N, 0 mg NH4+-N), M (0.5 mg NO3--N, 1.5 mg NH4+-N) and H (1 mg NO3--N, 2.5 mg NH4+-N) treatment were 12.30, 10.39 and 7.11 mg·m-2·d-1. Results highlighted that concentrations gradient of nutrients were indeed an important factor affecting the diffusion flux at sediment-water interface. In addition, the diffusion of nutrients at sediment-water interface in aquatic ecosystem is not only controlled by concentration gradients, some other factors such as incoming water, hydrodynamics, dissolved oxygen content, sediment structure, biological disturbance, horizontal migration and diffusion of nutrients and turbulent diffusion caused by wind and wave, are equally important.

Effectiveness of phosphorus control under extreme heatwaves: implications for sediment nutrient releases and greenhouse gas emissions

Eutrophication has been identified as the primary cause of water quality deterioration in inland waters worldwide, often associated with algal blooms or fish kills. Eutrophication can be controlled through watershed management and in-lake measures. An extreme heatwave event, through its impact on mineralization rates and internal nutrient loading (phosphorus—P, and nitrogen—N), could counteract eutrophication control measures. We investigated how the effectiveness of a nutrient abatement technique is impacted by an extreme heatwave, and to what extent biogeochemical processes are modulated by exposure to heatwaves. To this end, we carried out a sediment-incubation experiment, testing the effectiveness of lanthanum-modified bentonite (LMB) in reducing nutrients and greenhouse gas emissions from eutrophic sediments, with and without exposure to an extreme heatwave. Our results indicate that the effectiveness of LMB may be compromised upon exposure to an extreme heatwave event. This was evidenced by an increase in concentration of 0.08 ± 0.03 mg P/L with an overlying water volume of 863 ± 21 mL, equalling an 11% increase, with effects lasting to the end of the experiment. LMB application generally showed no effect on nitrogen species, while the heatwave stimulated nitrification, resulting in ammonium loss and accumulation of dissolved oxidized nitrogen species as well as increased dissolved nitrous oxide concentrations. In addition, carbon dioxide (CO2)-equivalent was more than doubled during the heatwave relative to the reference temperature, and LMB application had no effect on mitigating them. Our sediment incubation experiment indicates that the rates of biogeochemical processes can be significantly accelerated upon heatwave exposure, resulting in a change in fluxes of nutrient and greenhouse gas between sediment and water. The current efforts in eutrophication control will face more challenges under future climate scenarios with more frequent and intense extreme events as predicted by the IPCC.

Enhancement of Cellulose Rich Organic Matter Degradation by Inoculation with Streptomyces sp. Strains

Microbial degradation of organic matter is a vital part of carbon cycle in nature. Actinobacteria play an important role in the decomposition of cellulose rich organic matter (CROM). Streptomyces spp. are abundant in soil, produce various secondary metabolites and secrete extracellular enzymes. The aim of this research was to isolate and select Streptomyces strains with the best cellulose degradation abilities. Out of total 32 actinobacteria isolates, four Streptomyces strains (CA1, CA10, PA2 and PA7) were subjected to morphological, physiological, biochemical characterization and molecular identification. CROM degradation potential of the strains was investigated on straw and beech briquettes as well as on legume based substrate in in vitro condition. Streptomyces strains CA1 and CA10 showed the best cellulose production and starch hydrolysis abilities, followed by strains PA2 and PA7. Strain CA1 was also positive to production of pectinase enzymes. Streptomyces zaomyceticus CA1 and S. tanashiensis CA10 were used as inoculants, which degraded the raw cellulose from 38.38 to 81.69% in the investigated substrates (straw, beech, legume), during a 30-day incubation experiment. CROM inoculation with the selected Streptomyces strains improved and accelerated its degradation in controlled conditions. © 2021 Friends Science Publishers

The Study of Chicken Manure and Steel Slag Amelioration to Mitigate Greenhouse Gas Emission in Rice Cultivation

Organic matter, fertilizers, and soil amendments are essential for sustainable agricultural practices to guarantee soil productivity. However, these materials can increase the emission of greenhouse gases (GHGs) such as CH4 and N2O. Thus, technologies for reducing GHG emissions in concert with the increase in rice production from rice fields are needed. The objectives of this study were to determine the best chicken manure (CM) and steel slag (SS) combination to mitigate CH4, N2O, and CO2 emissions in an incubation experiment, to identify the best CM:SS ameliorant mixture to mitigate CH4 and N2O, and to evaluate dry biomass and grain yield in a pot experiment. A randomized block design was established with four treatments, namely conventional (chemical fertilizer only) and three combinations of different ratios of CM and SS (1:1, 1:1.5, and 1:2.5), with five replications in a pot experiment. CM:SS (1:2.5) was identified as the best treatment for mitigating CH4, N2O, and CO2 in the incubation experiment. However, CM:SS (1:1.5) was the best CM and SS ameliorant for mitigating CH4 and N2O in the pot experiment. The global warming potential of CH4 and N2O revealed that CM:SS (1:1.5) had the lowest value. None of the combinations of CM and SS significantly increased dry biomass and grain yield.

Efficacy of the Nitrification Inhibitor 3,4 Dimethylpyrazol Succinic Acid (DMPSA) when Combined with Calcium Ammonium Nitrate and Ammonium Sulphate—A Soil Incubation Experiment

The efficacy of the new nitrification inhibitor 3,4 dimethylpyrazol succinic acid (DMPSA) was tested with calcium ammonium nitrate (CAN) and ammonium sulphate (AS) fertilisers in an incubation experiment using a sandy loam soil and a sandy textured soil. The experiment was conducted over 80 days. For AS fertiliser, inclusion of DMPSA resulted in significantly less NO3−-N present after 19 days in both soils. In the case of CAN, inclusion of DMPSA resulted in significantly less NO3−-N present after 45 days in the sandy loam soil and after 30 days in the sandy soil. DMPSA is effective nitrification inhibitor when combined with CAN and AS, with a mean reduction of 61% and 58%, respectively, in the average daily nitrification rate over the study period. Over the 80-day incubation period in the sandy loam soil, only 35% NH4+-N was converted to NO3−-N for AS + DMPSA compared to 88% for AS. In the sandy soil, 92% NH4+-N was converted to NO3−-N for AS compared with only 9% for AS + DMPSA by day 80. The results demonstrate that DMPSA is an effective nitrification inhibitor when combined with CAN and AS.

Short lived peaks of stem methane emissions in temperate black alder forest - irrelevant for ecosystem methane budgets?

<p>Tree stems can be a source of the greenhouse gas methane (CH<sub>4</sub>) and locally as regionally important to the overall GHG budget. Stem emissions even hold the potential of narrowing down knowledge gap in the global methane budget. However, assessments of the global importance of stem CH<sub>4</sub> emissions are complicated by a lack of research and high variability between individual ecosystems. Here, we determined the contribution of emissions from stems of mature black alder (<em>Alnus glutinosa</em> (L.) Gaertn.) to overall CH<sub>4</sub> exchange in two temperate peatlands. We measured emissions from stems and soils using closed chambers in a drained and an undrained alder forest over 2 years. Furthermore, we studied the importance of alder leaves as substrate for methanogenesis in an incubation experiment. Stem CH<sub>4</sub> emissions at the undrained alder forest were very variable in time and only persisted for a few weeks during the year. Generally the drained alder forest did not soil nor stem CH<sub>4</sub> emissions. Different upscaling approaches were assessed and all approaches showed that stem CH<sub>4</sub> emissions contributed less than 0.3 % to the total ecosystem CH<sub>4</sub> budget. However, stem CH<sub>4</sub> seem to depend strongly on the hydrological regime and therefore vary strongly between ecosystems. Hence, every ecosystem must be consdidered attentively with respect to their stem CH<sub>4</sub> emissions.</p>

Potential greenhouse gas production by organic matter decomposition in thawing subsea permafrost

<p>Subsea permafrost extends over vast areas across the East Siberian Arctic Ocean shelves and might harbor a large and vulnerable organic matter pool. Field campaigns have observed strongly elevated concentrations of CH<sub>4</sub> in seawater above subsea permafrost that might stem from microbial degradation of thawing subsea permafrost organic matter, from release of CH<sub>4</sub> stored within subsea permafrost, from shallow CH<sub>4</sub> hydrates or from deeper thermogenic/petrogenic CH<sub>4</sub> pools. We here assess the potential production of CH<sub>4</sub>, as well as CO<sub>2</sub> and N<sub>2</sub>O by organic matter degradation in subsea permafrost after thaw. To that end, we employ a set of subsea permafrost drill cores from the Buor-Khaya Bay in the south-eastern Laptev Sea where previous studies have observed a rapid deepening of the ice-bonded permafrost table. Preliminary data from an ongoing laboratory incubation experiment suggest the production of both CH<sub>4</sub> and CO<sub>2</sub> by decomposition of thawed subsea permafrost organic matter, while N<sub>2</sub>O production was negligible. These data will be combined with detailed biomarker analysis to constrain the vulnerability of subsea permafrost organic matter to degradation to greenhouse gases upon thaw.</p>