Browsing by Author "Kumar, Sandeep"

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    Biochar Surface Oxygenation by Ozonization for Super High Cation Exchange Capacity
    Kharel, Gyanendra; Sacko, Oumar; Feng, Xu; Morris, John R.; Phillips, Claire L.; Trippe, Kristin; Kumar, Sandeep; Lee, James W. (2019-10-07)
    Biochar cation exchange capacity (CEC) is a key property central to better retention of soil nutrients and reduction of fertilizer runoff. This paper reports a breakthrough process to improve biochar CEC value by a factor of nearly 10 through biochar surface oxygenation by ozonization. The CEC value of the untreated biochar was measured to be anywhere between 14 and 17 cmol/kg. A 90 min dry ozonization treatment resulted in an increased biochar CEC value of 109-152 cmol/kg. Simultaneously, the biochar ozonization process resulted in a reduction of biochar pH from 9.82 to as low as 3.07, indicating the formation of oxygen-functional groups including carboxylic acids on biochar surfaces. Using the technique of X-ray photoelectron spectroscopy (XPS), the formation of oxygen-functional groups including carboxylic acids on biochar surfaces have been observed at a nanometer molecular scale following the ozonization treatment. The molar O/C ratio (0.31:1) on ozonized biochar surface as analyzed by XPS was indeed significantly higher than that (0.16:1) of the control biochar surface. The molar O/C ratio from the elemental analysis data also showed an increase from the nonozonized sample (0.077:1) to the dry-ozonized sample (0.193:1). Fourier-transform infrared (FTIR) spectroscopy analysis also showed an increase in the content of oxygen-functional groups in the form of carbonyl groups on biochar surfaces upon ozonization, which can also produce certain amount of oxygenated biochar molecular fragments that may be solubilized by liquid water, potentially leading to greater effects upon application of biochar in soil.
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    Conversion of open pasture to hardwood silvopasture enhanced soil health of an ultisol
    Poudel, Sanjok; Bansal, Sangeeta; Podder, Swarup; Paneru, Bidur; Karki, Sangita; Fike, John H.; Kumar, Sandeep (Springer, 2022-12)
    Black walnut (Juglans nigra) and honeylocust (Gleditsia triacanthos) have gained particular interest for use in silvopastures and other temperate agroforestry systems. However, measures of soil health indicators in these deciduous hardwood silvopastures over time have received limited attention. This study assessed soil health indicators in 25-year-old black walnut- (BSP) and honeylocust-based silvopastures (HSP) and compared with those from adjacent open pasture (OP) systems. Soil samples collected from 0 to 10 cm depth were analyzed for soil organic matter (OM), carbon and nitrogen fractions, glomalin-related soil protein, soil enzymatic activities, and microbial community structure. The soil OM content in HSP (64 g kg(-1)) was greater (p < 0.05) than BSP and OP (55 g kg(-1)). The BSP soils had about 45% and 52% more (p < 0.05) microbial biomass carbon and nitrogen than OP soils. The HSP soils had 60% greater (p < 0.05) microbial biomass nitrogen than OP soils. The BSP supported greater (p < 0.05) beta-glucosidase and urease activities than the HSP and OP treatments, while greater (p < 0.05) beta-glucosidase activity was measured in HSP than OP. Total phospholipid-derived fatty acid and actinomycetes abundance were greater (p < 0.001) in OP compared to BSP and HSP while the arbuscular mycorrhiza fungi abundance was greater (p < 0.05) in OP than in HSP. These findings indicate that black walnut and honeylocust trees in the silvopastures with proper management can improve certain soil health parameters over time depending on tree characteristics and the age of the system.
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    Linking soil microbial community structure to potential carbon mineralization: A continental scale assessment of reduced tillage
    Rieke, Elizabeth L.; Cappellazzi, Shannon B.; Cope, Michael; Liptzin, Daniel; Mac Bean, G.; Greub, Kelsey L. H.; Norris, Charlotte E.; Tracy, Paul W.; Aberle, Ezra; Ashworth, Amanda; Banuelos Tavarez, Oscar; Bary, Andy, I; Baumhardt, R. L.; Borbon Gracia, Alberto; Brainard, Daniel C.; Brennan, Jameson R.; Briones Reyes, Dolores; Bruhjell, Darren; Carlyle, Cameron N.; Crawford, James J. W.; Creech, Cody F.; Culman, Steve W.; Deen, Bill; Dell, Curtis J.; Derner, Justin D.; Ducey, Thomas F.; Duiker, Sjoerd W.; Dyck, Miles F.; Ellert, Benjamin H.; Espinosa Solorio, Avelino; Fonte, Steven J.; Fonteyne, Simon; Fortuna, Ann-Marie; Foster, Jamie L.; Fultz, Lisa M.; Gamble, Audrey, V; Geddes, Charles M.; Griffin-LaHue, Deirdre; Grove, John H.; Hamilton, Stephen K.; Hao, Xiying; Hayden, Zachary D.; Honsdorf, Nora; Howe, Julie A.; Ippolito, James A.; Johnson, Gregg A.; Kautz, Mark A.; Kitchen, Newell R.; Kumar, Sandeep; Kurtz, Kirsten S. M.; Larney, Francis J.; Lewis, Katie L.; Liebman, Matt; Lopez Ramirez, Antonio; Machado, Stephen; Maharjan, Bijesh; Martinez Gamino, Miguel Angel; May, William E.; McClaran, Mitchel P.; McDaniel, Marshall D.; Millar, Neville; Mitchell, Jeffrey P.; Moore, Amber D.; Moore, Philip A.; Mora Gutierrez, Manuel; Nelson, Kelly A.; Omondi, Emmanuel C.; Osborne, Shannon L.; Osorio Alcala, Leodegario; Owens, Philip; Pena-Yewtukhiw, Eugenia M.; Poffenbarger, Hanna J.; Ponce Lira, Brenda; Reeve, Jennifer R.; Reinbott, Timothy M.; Reiter, Mark S.; Ritchey, Edwin L.; Roozeboom, Kraig L.; Rui, Yichao; Sadeghpour, Amir; Sainju, Upendra M.; Sanford, Gregg R.; Schillinger, William F.; Schindelbeck, Robert R.; Schipanski, Meagan E.; Schlegel, Alan J.; Scow, Kate M.; Sherrod, Lucretia A.; Shober, Amy L.; Sidhu, Sudeep S.; Solis Moya, Ernesto; St Luce, Mervin; Strock, Jeffrey S.; Suyker, Andrew E.; Sykes, Virginia R.; Tao, Haiying; Trujillo Campos, Alberto; Van Eerd, Laura L.; Verhulst, Nele; Vyn, Tony J.; Wang, Yutao; Watts, Dexter B.; William, Bryan B.; Wright, David L.; Zhang, Tiequan; Morgan, Cristine L. S.; Honeycutt, C. Wayne (Pergamon-Elsevier, 2022-05)
    Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal community structure and potential microbial drivers of Cmin in soils maintained under various degrees of physical disturbance. Potential carbon mineralization, 16S rRNA sequences, and soil characterization data were collected as part of the North American Project to Evaluate Soil Health Measurements (NAPESHM). Results showed that type of cropping system, intensity of physical disturbance, and soil pH influenced microbial sensitivity to physical disturbance. Furthermore, 28% of amplicon sequence variants (ASVs), which were important in modeling Cmin, were enriched under soils managed with minimal physical disturbance. Sequences identified as enriched under minimal disturbance and important for modeling Cmin, were linked to organisms which could produce extracellular polymeric substances and contained metabolic strategies suited for tolerating environmental stressors. Understanding how physical disturbance shapes microbial communities across climates and inherent soil properties and drives changes in Cmin provides the context necessary to evaluate management impacts on standardized measures of soil microbial activity.