Total Protein Nitrogen: Evaluation and Comparison of Four Different Methods

Wall, Larry L; Gehrke, Charles W.; Neuner, Terry E; Cathey, Robert D; Rexroad, Paul R

doi:10.1093/jaoac/58.4.811

Cited by 30 publications

(21 citation statements)

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“…The pH was determined using a pH meter (Accumet model AB 15; Fisher Scientific, Pittsburgh, PA), and the EC was determined using an EC meter (model 441; Corning, Corning, NY). The ammonium (NH 4 + ) was determined • February 2017 27 (1) by the nitroprusside-salicylate procedure (Wall et al, 1975), and the nitrate (NO 3 -) concentration was determined using the copperized cadmium reduction procedure (Keeney and Nelson, 1982). The concentrations of P, K, Ca, Mg, sulfate (SO 4 2-), B, Cl, Cu, Fe, Mn, Mo, Na, and Zn were determined using the filtered extract for simultaneous inductively coupled plasma emission spectrometry (Jones, 1977;Munter and Grande, 1981).…”

Section: Methodsmentioning

confidence: 99%

Chemical Properties of Biochar Materials Manufactured from Agricultural Products Common to the Southeast United States

Evans

Jackson

Popp

et al. 2017

hortte

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The use of biochar as a soil amendment has fostered much attention in recent years due to its potential of improving the chemical, physical, and biological properties of agricultural soils and/or soilless substrates. The objective of this study was to evaluate the chemical properties of feedstocks, common in the southeast United States, and their resulting biochar products (after being torrefied) and determine if the chemical properties were within suitable ranges for growers to use the biochar products as root substrate components. Poultry litter biochar produced at 400 °C for 2 hours had a higher total phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), chloride (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), sodium (Na), and zinc (Zn) concentration than biochar made using the same process with mixed hard wood species, miscanthus (Miscanthus capensis), cotton (Gossypium hirsutum) gin trash, switchgrass (Panicum virgatum), rice (Oryza sativa) hull, and pine (Pinus sp.) shavings feedstocks. The pH of the biochar products ranged from 4.6 for pine shaving biochar to 9.3 for miscanthus biochar. The electrical conductivity (EC) ranged from 0.1 dS·m−1 for mixed hardwood biochar to 30.3 dS·m−1 for poultry litter biochar. The cation exchange capacity (CEC) of the biochar products ranged from a low of 0.09 meq/g for mixed hardwood biochar to a high of 19.0 meq/g for poultry litter biochar. The water-extractable nitrate, P, K, Ca, Mg, sulfate, boron, Cl, Cu, Fe, Mo, Na, and Zn were higher in poultry litter biochar than in all of the other types of biochar. The high EC and mineral element concentration of the poultry litter biochar would prevent its use in root substrates except in very small amounts. In addition, the high degree of variability in chemical properties among all of the biochar products would require users to know the specific properties of any biochar product they used in a soil or soilless substrate. Modifications to traditional limestone additions and fertility programs may also need to be tested and monitored to compensate for the biochar pH and mineral nutrient availability. Users should be aware that biochar products made from different feedstocks can have very different chemical properties even if the same process was used to manufacture them.

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Section: Methodsmentioning

confidence: 99%

Chemical Properties of Biochar Materials Manufactured from Agricultural Products Common to the Southeast United States

Evans

Jackson

Popp

et al. 2017

hortte

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“…EC was determined using an EC meter (model 441; Corning, Corning, NY), and the pH was determined using a pH meter (model AB 15; Fisher Scientific, Pittsburgh). NO 3 -N concentration was determined using the copperized cadmium reduction procedure (Keeney and Nelson, 1982) and NH 4 -N was determined by the nitroprusside-salicylate procedure (Wall, et al, 1975). The concentration of P and K was determined using the filtered extract for simultaneous inductively coupled plasma emission spectrometry (Jones, 1977;Munter and Grande, 1981).…”

Section: Methodsmentioning

confidence: 99%

Root Substrate pH, Electrical Conductivity, and Macroelement Concentration of Sphagnum Peat-based Substrates Amended with Parboiled Fresh Rice Hulls or Perlite

Gachukia¹,

Evans²

2008

hortte

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Substrates were formulated by blending parboiled fresh rice (Oryza sativa) hulls (PBH) or perlite with sphagnum peat (peat) to produce root substrates (substrates) that contained 20%, 30%, 40%, 50%, or 60% (by volume) PBH or perlite with the remainder being peat. After 0 (initial mixing), 4, or 8 weeks in a greenhouse environment, samples were taken and pH, electrical conductivity (EC), nitrate (NO3−), ammonium (NH4+), phosphorus (P), and potassium (K) were determined. As the amount of PBH or perlite in the substrate was increased, the pH increased. After 0 and 8 weeks, the pH of substrates containing up to 30% PBH or perlite had a similar pH. However, the rate of pH increase at these sampling times was higher than that of perlite so that substrates containing 40% or more PBH had a higher pH than equivalent perlite-containing substrates. At the week 4 sampling period, all substrates containing PBH had a higher pH than equivalent perlite-containing substrates. For all sampling times, the difference in pH between equivalent PBH and perlite-containing substrates was not high enough to be of practical significance. For all sampling times, EC increased as the amount of perlite was increased. Depending upon sampling time, the EC decreased or remained unchanged as the amount of PBH was increased. For all sampling times and substrates, EC was within acceptable ranges for unused substrates. Substrates containing PBH had higher NO3− levels than equivalent perlite-containing substrates. The NH4+ level of the substrates decreased as the amount of PBH or perlite was increased. The levels of NO3− and NH4+ were within acceptable ranges for unused substrates. Substrate P and K increased as the amount of PBH in the substrate was increased, but the concentration of P and K remained unchanged or decreased as the amount of perlite was increased. None of the differences between equivalent PBH and perlite-containing substrates was high enough to be problematic with respect to crop production and all of the chemical parameters were within acceptable ranges for unused root substrates.

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“…Blood and urinary urea nitrogen were measured enzymatically in duplicate, using a Beckmann urea analyser I1 (Beckmann Instruments). Total urinary nitrogen was measured using the micro-Kjeldahl method [23].…”

Section: Biochemical Analysismentioning

confidence: 99%

Effects of muscarinic blockade on insulin secretion and on glucose‐induced thermogenesis in lean and obese human subjects

Schneeberger

Tappy

Temler³

et al. 1991

Eur J Clin Investigation

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To determine whether hyperinsulinaemia of human obesity is dependent on the activity of the parasympathetic nervous system, and whether activation of the parasympathetic nervous system plays a role in glucose-induced thermogenesis, the metabolic effect of a continuous intravenous glucose infusion [44.4 mumol kg-1 body weight (bw) min-1] with or without atropine infusion was assessed in 11 obese patients and 10 lean controls. Compared with lean controls, obese patients had increased basal and glucose-stimulated plasma insulin and C-peptide concentrations and increased plasma glucose concentrations during glucose infusion. Glucose oxidation during i.v. glucose was lower in obese patients than in lean controls. Glucose-induced thermogenesis was similar in obese patients and in lean controls. Atropine infusion did not affect basal plasma glucose, insulin or free fatty acid concentrations nor glucose-stimulated plasma glucose, insulin, C-peptide, glucagon or free fatty acid concentrations in both groups of subjects. Glucose and lipid oxidation rates and glucose-induced thermogenesis were also unaffected by atropine administration. It is concluded that (1) glucose-stimulated hyperinsulinaemia in human obesity is not dependent on a hyperactivity of the parasympathetic nervous system, which indicates that human obesity is different from most animal models of obesity; (2) glucose-induced thermogenesis is similar in obese and lean subjects when a similar load of glucose is administered; (3) inhibition of the parasympathetic nervous system does not affect the thermic effect of i.v. glucose.

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Total Protein Nitrogen: Evaluation and Comparison of Four Different Methods

Cited by 30 publications

References 0 publications

Chemical Properties of Biochar Materials Manufactured from Agricultural Products Common to the Southeast United States

Chemical Properties of Biochar Materials Manufactured from Agricultural Products Common to the Southeast United States

Root Substrate pH, Electrical Conductivity, and Macroelement Concentration of Sphagnum Peat-based Substrates Amended with Parboiled Fresh Rice Hulls or Perlite

Effects of muscarinic blockade on insulin secretion and on glucose‐induced thermogenesis in lean and obese human subjects

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