Turbidimetric Determination of Anionic Polyacrylamide in Low Carbon Soil Extracts

Concerns over runoff water quality from agricultural lands and construction sites have led to the development of improved erosion control practices, including application of polyacrylamide (PAM). We developed a quick and reliable method for quantifying PAM in soil extracts at low carbon content by using a turbidimetric reagent, Hyamine 1622. Three high-molecular weight anionic PAMs differing in charge density (7, 20, and 50 mol%) and five water matrices, deionized (DI) water and extracts from four different soils, were used to construct PAM calibration curves by reacting PAM solutions with hyamine and measuring turbidity development from the PAM–hyamine complex. The PAM calibration curve with DI water showed a strong linear relationship (r2 = 0.99), and the sensitivity (slope) of calibration curves increased with increasing PAM charge density with a detection limit of 0.4 to 0.9 mg L−1. Identical tests with soil extracts showed the sensitivity of the hyamine method was dependent on the properties of the soil extract, primarily organic carbon concentration. Although the method was effective in mineral soils, the highest charge density PAM yielded a more reliable linear relationship (r2 \u3e 0.97) and lowest detection limit (0.3 to 1.2 mg L−1), compared with those of the lower charge density PAMs (0.7 to 23 mg L−1). Our results suggest that the hyamine test could be an efficient method for quantifying PAM in environmental soil water samples as long as the organic carbon in the sample is low, such as in subsurface soil material often exposed at construction sites

mTOR Controls Ovarian Follicle Growth by Regulating Granulosa Cell Proliferation

We have shown that inhibition of mTOR in granulosa cells and ovarian follicles results in compromised granulosa proliferation and reduced follicle growth. Further analysis here using spontaneously immortalized rat granulosa cells has revealed that mTOR pathway activity is enhanced during M-phase of the cell cycle. mTOR specific phosphorylation of p70S6 kinase and 4E-BP, and expression of Raptor are all enhanced during M-phase. The predominant effect of mTOR inhibition by the specific inhibitor Rapamycin (RAP) was a dose-responsive arrest in the G1 cell cycle stage. The fraction of granulosa cells that continued to divide in the presence of RAP exhibited a dose-dependent increase in aberrant mitotic figures known as anaphase bridges. Strikingly, estradiol consistently decreased the incidence of aberrant mitotic figures. In mice treated with RAP, the mitotic index was reduced compared to controls, and a similar increase in aberrant mitotic events was noted. RAP injected during a superovulation regime resulted in a dose-dependent reduction in the numbers of eggs ovulated. Implications for the real-time regulation of follicle growth and dominance, including the consequences of increased numbers of aneuploid granulosa cells, are discussed

Characterizing Compost Rate Effects on Stormwater Runoff and Vegetation Establishment

Urban development exposes and compacts the subsoil, resulting in reduced infiltration, which often leads to problems with establishing vegetation, increased erosion, and increased runoff volumes. Compost incorporation into these soils can potentially enhance soil physical properties, vegetation establishment, and pollutant removal. The goal of this field study was to determine the efficacy of compost as a soil improvement measure to reduce runoff volume, improve runoff quality, and increase vegetation establishment on a disturbed sandy clay subsoil representing post-development conditions. Two sources of compost were tested: (1) a certified yard waste product at 10%, 30%, and 50% by volume, and (2) an uncertified yard waste product at 30% by volume, both compared to a tilled, no-compost control. Treatment plots were established at Lake Wheeler Road Field Laboratory in Raleigh, NC, and observed for one year. Tilling alone may have been sufficient to reduce runoff quantity as few differences were found between tilled and compost amended plots. Runoff water quality also did not differ according to compost addition. However, the certified compost increased biomass production proportionally to the amount added and compared to the uncertified compost at the same rate. The improved vegetation establishment with compost is important for long-term erosion control and ecosystem services. The results of this study suggest (1) tilling is a viable option to achieve high infiltration rates and reduce runoff volumes, (2) compost incorporation does not reduce nor improve water quality, and (3) compost may yield more robust vegetation establishment

Revegetation of waste fly ash landfills in a semiarid environment

This study investigated vegetation strategies for a fly ash landfill in a semi-arid environment. Ten plant species adapted to the local climate were initially evaluated for their germination characteristics in various mixtures of Tivoli fine sand, fly ash, and cattle manure. Alkali sacaton (native, Sporobolus airoides (Torr.) Torr.), blue grama (native, Bouteloua gracilis (H.B.K.) Lag. Ex Griffiths), a forage sorghum (variety Canex, Sorghum bicolor (L.) Moench), sand bluestem (variety Woodward, Andropogon hallii Hack.), and sideoats grama variety El Reno, Bouteloua curtipendula (michx.) Torr.) were selected for further evaluation. Concurrently, mixtures were evaluated to determine the effects of the soil amendments on soil saturated paste electrical conductivity (EC) and pH. The addition of even 50 g kg-1 fly ash increased EC values above 4.0 dS m-1, indicating salt tolerant species may be needed. Six mixtures were selected for use in a greenhouse study and for further study of moisture retention characteristics. Using an X/Y format, where X is fly ash content and Y is manure content (g kg-1) and the balance of the mixture was Tivoli fine sand, those mixtures were 0/0, 200/0, 200/100, 200/200, 100/100, and 300/100. The addition of manure provided ample quantities of plant nutrients. Alkali sacaton was the only plant specie not adversely affected by the addition of fly ash. For biomass production, height, vigor and leaf tip burn, all remaining species had significantly better growth or ratings with 0/0 as compared to any other mixture. Soil moisture retention characteristics of the Tivoli fine sand can be significantly changed through amendment with fly ash or manure. Sixty cm of Tivoli sand was estimated to have the same available water holding capacity as 45 cm of 200/0, 39 cm of 200/100, 34 cm of 200/200, 47 cm of 100/100, and 33 cm of 300/100.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Exploring Substrate Water Capture in Common Greenhouse Substrates through Preconditioning and Irrigation Pulsing Techniques

Particles in a substrate create a network of pore pathways for water to move through, with size and shape determining the efficacy of these channels. Reduced particle size diversity can lead to increased leachate, poor substrate hydration, and an inefficient irrigation practice. This research examined the hydration characteristics of three greenhouse substrate components at three preconditioned initial moisture contents using subirrigation under five different irrigation durations and three water depths (2 mm, 20 mm, and 35 mm). Sphagnum peatmoss, coconut coir, and aged pine bark were tested at 67%, 50%, and 33% initial moisture (by weight). The objectives were to determine the impact of varying irrigation event durations (5, 10, 20, 30, 60 min) over a 60-min period, and the further influence of water depth and initial moisture, on the water capture abilities of peat, coir, and pine bark. The number of irrigation events depended on the irrigation event time of that experimental unit divided by the total time of 60 min, varying from 12, 6, 3, 2, and 1 event. Hydration efficiency was influenced by initial moisture content (IMC), water depth, pulsing duration, and inherent substrate characteristics (hydrophobicity/hydrophilicity). Initial MC had the largest impact on peat, regardless of water level or irrigation duration. Lower IMCs increased the hydrophobic response of peat, further reducing the amount of water the substrate was able to absorb. Pine bark had a 5–10% decrease in initial hydration between 67%, 50%, and 33% IMC, while coir’s hydrophilic nature reduced any IMC affects. At 50% IMC or less, coir had the highest volumetric water content (VWC) across all substrates, pulsing durations, and water depths. Water depth was found to increase initial hydration and final hydration 6–8% across all substrates. These three materials had altered and varied water capture responses depending on the combination of treatments employed. This work demonstrated the effects of intensity and exposure on substrates and the need for more integrated research for improving water use efficiency on container crops

Contrasting methods for estimating evapotranspiration in soybean

Crop scientists are often interested in canopy rather than leaf water estimates. Comparing canopy fluxes for multiple treatments using micrometeorological approaches presents limitations because of the large fetch required. The goal of this study was to compare leaf-scale to field-scale data by summing soil water evaporation (E) and leaf transpiration (T) versus ET using tower eddy covariance (EC) and scaling leaf transpiration to the canopy level using a two-step scaling approach in soybean [Glycine max (L.) Merr.]. Soybean transpiration represented 89-96% of E + T when combining the soil water evaporation with leaf transpiration on the five measurement days during reproductive growth. Comparing E + T versus ET from the EC system, the E + T method overestimated ET from 0.68 to 1.58 mm. In terms of percent difference, the best agreement between the two methods was 15% on DOY 235 and the worst agreement occurred on DOY 234 (41%). A two-step scaling method predicted average ET within 0.01 mm of the EC ET between 10:00 and 14:15 on an hourly time-step on DOY 227 under uniform sky conditions and average ET within 0.03 mm of the EC ET on DOY 235 under intermittent sky conditions between 10:00 and 15:15. Pooling the scaled-leaf data and comparing them with the measured EC ET data exhibited a strong linear relationship (r = 0.835) after accounting for bias (6%). Findings from this study indicate satisfactory results comparing absolute differences are likely not obtainable by summing leaf transpiration with soil water evaporation to calculate canopy water fluxes. However, scaling leaf transpiration provided a robust measure of canopy transpiration during reproductive growth in soybean under these conditions and merits additional study under different climatic and crop conditions.Leaf gas exchange Eddy covariance Scaling Evapotranspiration Microlysimeters Soybean

Integrating Short Rotation Woody Crops into Conventional Agricultural Practices in the Southeastern United States: A Review

One of the United Nations Sustainable Development Goal’s (SDGs) aims is to enhance access to clean energy. In addition, other SDGs are directly related to the restoration of degraded soils to improve on-farm productivity and land management. Integrating Short Rotation Woody Crops (SRWC) for bioenergy into conventional agriculture provides opportunities for sustainable domestic energy production, rural economic development/diversification, and restoration of soil health and biodiversity. Extensive research efforts have been carried out on the development of SRWC for bioenergy, biofuels, and bioproducts. Recently, broader objectives that include multiple ecosystem services, such as carbon sequestration, and land mine reclamation are being explored. Yet, limited research is available on the benefits of establishing SRWC on degraded agricultural lands in the southeastern U.S. thereby contributing to environmental goals. This paper presents a literature review to (1) synthesize the patterns and trends in SWRC bioenergy production; (2) highlight the benefits of integrating short rotation woody crops into row crop agriculture; and (3) identify emerging technologies for efficiently managing the integrated system, while identifying research gaps. Our findings show that integrating SRWC into agricultural systems can potentially improve the climate of agricultural landscapes and enhance regional and national carbon stocks in terrestrial systems

Elucidation of the calcineurin-Crz1 stress response transcriptional network in the human fungal pathogen <i>Cryptococcus neoformans</i>

<div><p>Calcineurin is a highly conserved Ca²⁺/calmodulin-dependent serine/threonine-specific protein phosphatase that orchestrates cellular Ca²⁺ signaling responses. In <i>Cryptococcus neoformans</i>, calcineurin is activated by multiple stresses including high temperature, and is essential for stress adaptation and virulence. The transcription factor Crz1 is a major calcineurin effector in <i>Saccharomyces cerevisiae</i> and other fungi. Calcineurin dephosphorylates Crz1, thereby enabling Crz1 nuclear translocation and transcription of target genes. Here we show that loss of Crz1 confers phenotypes intermediate between wild-type and calcineurin mutants, and demonstrate that deletion of the calcineurin docking domain results in the inability of Crz1 to translocate into the nucleus under thermal stress. RNA-sequencing revealed 102 genes that are regulated in a calcineurin-Crz1-dependent manner at 37°C. The majority of genes were down-regulated in <i>cna1</i>Δ and <i>crz1</i>Δ mutants, indicating these genes are normally activated by the calcineurin-Crz1 pathway at high temperature. About 58% of calcineurin-Crz1 target genes have unknown functions, while genes with known or predicted functions are involved in cell wall remodeling, calcium transport, and pheromone production. We identified three calcineurin-dependent response element motifs within the promoter regions of calcineurin-Crz1 target genes, and show that Crz1 binding to target gene promoters is increased upon thermal stress in a calcineurin-dependent fashion. Additionally, we found a large set of genes independently regulated by calcineurin, and Crz1 regulates 59 genes independently of calcineurin. Given the intermediate <i>crz1</i>Δ mutant phenotype, and our recent evidence for a calcineurin regulatory network impacting mRNA in P-bodies and stress granules independently of Crz1, calcineurin likely acts on factors beyond Crz1 that govern mRNA expression/stability to operate a branched transcriptional/post-transcriptional stress response network necessary for fungal virulence. Taken together, our findings reveal the core calcineurin-Crz1 stress response cascade is maintained from ascomycetes to a pathogenic basidiomycete fungus, but its output in <i>C</i>. <i>neoformans</i> appears to be adapted to promote fungal virulence.</p></div