An Automated Total Protein Nitrogen Method

Wall, Larry L; Gehrke, Charles W.

doi:10.1093/jaoac/58.6.1221

Cited by 48 publications

(27 citation statements)

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“…Crude protein for calibration samples was determined by measuring total N content using the micro‐Kjeldahl technique outlined by Wall and Gerke (1975) and then multiplying N percentages by 6.25. Acid detergent fiber and NDF for calibration samples were determined using the methods described by Van Soest and Robertson (1980)…”

Section: Methodsmentioning

confidence: 99%

Yield, Quality, and Persistence of Grazing‐ and Hay‐Type Alfalfa under Three Harvest Frequencies

2002

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ble. Kust and Smith (1961) reported that 'Vernal' alfalfa ideally would be harvested three times (at about 42-d Producers in the lower Midwest often plant grazing-type alfalfa intervals) before 1 September in Wisconsin as a compro-(Medicago sativa L.) cultivars assuming they can withstand frequent hay harvests. However, little research has examined the long-term mise among forage yield, quality, and stand persistence. effects of frequent hay harvests on grazing-type compared with hay-However, harvesting four or more times during the type alfalfa. Our objective was to determine how cultivar-type and growing season or after 1 September reduced yields the harvest frequency change long-term alfalfa yields, quality, and stand following year by 30 to 78%. Subsequent studies by persistence. 'Alfagraze' (grazing-type), 'Pioneer 5373' (modern, Matches et al. (1970), Brink and Marten (1989), Brown multipest resistant hay-type), and 'Cody' (older hay-type) alfalfa were et al. (1990), and Sheaffer et al. (2000) have shown that seeded on 1 Apr. 1994, near Mt. Vernon, MO. Cultivars were main alfalfa should be harvested every 30 to 35 d during the plots, and four, five, or six harvests before 15 September (42, 34, and growing season to maximize forage yield, quality, and 28 d between harvests, respectively) were subplots in a randomized stand persistence. complete block in a split-plot arrangement. Cumulatively, over 5 yr, Research from Georgia suggests that harvesting al-Pioneer 5373 produced 6% (2.8 Mg ha Ϫ1 ) more forage than Alfagraze and 10% (5.0 Mg ha Ϫ1 ) more than Cody. Alfalfa harvested four times falfa frequently during the growing season may be less yielded 7% (0.8 Mg ha Ϫ1 ) more per year than when harvested five detrimental for grazing-type cultivars than for traditimes, and 28% (3.1 Mg ha Ϫ1 ) more than when harvested six times.tional hay-types Bouton, 1991, 1992).Alfagraze and the hay-types yielded equally when harvested six times. Brummer and Bouton (1991) found that Alfagraze, a Alfagraze usually had equal or lower detergent fiber, and equal or cultivar selected under continuous grazing pressure, was greater crude protein (CP) concentrations than other cultivars. Harmorphologically different than modern hay-types, being vesting more frequently improved forage quality but had little impact more decumbent and having many, thin stems compared on plant density. We concluded that a grazing-type, like Alfagraze, with modern hay-types. They suggested that these mordoes not show a yield or persistence advantage over a modern hayphological traits made grazing-type alfalfa cultivars toltype under frequent hay harvest regimes in the lower Midwest. Howerant of frequent harvests. Subsequent research with ever, the grazing-type used in this study often had superior forage quality.

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Section: Methodsmentioning

confidence: 99%

Yield, Quality, and Persistence of Grazing‐ and Hay‐Type Alfalfa under Three Harvest Frequencies

2002

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“…The total content of crude protein (%N 3 6.25) in the basal diet was determined following the Kjeldahl procedure for nitrite-free samples (procedure 2.057; AOAC 1980). A modified Technicon autoanalyzer with block digestor procedure (Kjeldahl) was used for nitrogen extraction to determine the total protein content (%N 3 6.25) in fecal samples (Walls and Gehrke 1975). Fecal samples were digested in concentrated sulfuric acid and 30% hydrogen peroxide for 1 h in a block digestor, and the nitrogen content determined colorimetrically in an autoanalyzer (Alpkem, Clackamas, Oregon).…”

Section: Technical Notementioning

confidence: 99%

Validation of a Fecal Collection Method for Determination of Apparent Digestibility Coefficients of Diets in Gulf of Mexico Sturgeon

2007

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Apparent digestibility coefficients (ADCs) of dry matter, energy, and crude protein in the diet of Gulf of Mexico sturgeon Acipenser oxyrinchus desotoi were determined by two methods, dissection and hand stripping of feces from the lower spiral valve-rectal area of the digestive tract. Hand stripping resulted in ADC values of 58, 69, and 85% and the dissection method resulted in values of 54, 64, and 78% for dietary dry matter, energy, and crude protein, respectively. No significant differences in the ADC values obtained between the two methods were observed. Gulf of Mexico sturgeon are protected in the Gulf Coast region of the United States and listed as a threatened species under the U.S. Endangered Species Act. The hand stripping method is recommended over dissection for Gulf of Mexico sturgeon since it is an accurate and reliable procedure that does not require killing the fish.

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“…Nitrogen and K were determined in the digestate resulting from a H2SO4 + selenized granule (Hengar Granules; Hengar Co., Philadelphia, PA, USA) wet digestion on an aluminum block. Nitrogen was determined colorimetrically (Wall & Gehrke, 1975) and K by atomic absorption. Phosphorus was quantified in tissue ashed in a muffle furnace.…”

Section: Collection Of Datamentioning

confidence: 99%

Relationship of colonization and sporulation by VA mycorrhizal fungi to plant nutrient and carbohydrate contents*

Douds

Schenck

1990

New Phytologist

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SUMMARYVesicular-arbuscular (VA) mycorrhizal fungi typically produce spores either within roots of a host plant or in the soil. Experiments were conducted to examine the effects of plant nutrition, as measured by tissue N, P, K, and soluble sugar concentrations, upon colonization of roots of Paspalum notatum Flugge and sporulation within roots by Glomus intraradix Schenck & Smith and in the soil by Acaulospora longula Spain & Schenck and Gigaspora margarita Becker & Hall. Plants receiving a balanced nutrient solution without P consistently had the greatest percentage root length colonized by VA mycorrhizal fungi. Glomus intraradix produced more spores per root weight under conditions of nonmycotrophy, when plants received either water only or KHgPO^ only in the nutrient-poor soil used in these experiments. Gigaspora margarita and A. longula produced more spores in the soil when plants received the balanced nutrient solution without P. Similarly contrasting responses were seen when sporulation inside and outside the roots was correlated to plant nutrient and soluble sugar concentrations. The P-tolerant, intraradical-sporulating, VA mycorrhizal fungus G. intraradix sporulated heavily when N:P ratios of host tissue were imbalanced toward P. Acaulospora longula and G. margarita produced more spores in the soil when plant tissue N:P ratios were imbalanced toward N.

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An Automated Total Protein Nitrogen Method

Cited by 48 publications

References 0 publications

Yield, Quality, and Persistence of Grazing‐ and Hay‐Type Alfalfa under Three Harvest Frequencies

Yield, Quality, and Persistence of Grazing‐ and Hay‐Type Alfalfa under Three Harvest Frequencies

Validation of a Fecal Collection Method for Determination of Apparent Digestibility Coefficients of Diets in Gulf of Mexico Sturgeon

Relationship of colonization and sporulation by VA mycorrhizal fungi to plant nutrient and carbohydrate contents*

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