Indexes of plant available organic nitrogen in soils

Rojas, Carlos Fernando

doi:10.31274/rtd-180813-7916

Cited by 5 publications

(1 citation statement)

References 97 publications

(113 reference statements)

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“…Cassmann and Munns (1980) found that the optimum temperature range for N mineralization was from 30 to 35°C. Using the incubation method of Stanford and Smith (1972) for 14 weeks at 20 and 30°C, Rojas (1986) reported that the amoiint of N mineralized was greater at 30°C than that at 20°C in each of 13 Iowa and 7…”

Section: Nitrogen Treinsformations As Affected By Soil Phmentioning

confidence: 99%

Effect of soil pH on phytoavailability of nitrogen in biotechnology by-products and animal manures

Al-Romian

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Section: Nitrogen Treinsformations As Affected By Soil Phmentioning

confidence: 99%

Effect of soil pH on phytoavailability of nitrogen in biotechnology by-products and animal manures

Al-Romian

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Assessment of the Amino Sugar–Nitrogen Test on Iowa Soils: II. Field Correlation and Calibration

et al. 2006

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There has been growing interest in using the amino sugar–nitrogen test (ASNT) to improve N fertilization of corn (Zea mays L.). The ASNT is intended to measure the soil organic N fraction that contributes to plant available N. The objectives of this study were to correlate the ASNT to corn N response measures and calibrate the test to Iowa soils and climatic conditions. Soil samples were collected in the fall, early spring, and late spring at the 0‐ to 15‐cm and 0‐ to 30‐cm sample depths. No significant correlation could be found between the ASNT and relative leaf chlorophyll meter value, relative grain protein, relative grain yield, grain yield response to applied N, and economic optimum N rate (EONR). The ASNT was not able to differentiate sites that were responsive or nonresponsive to N fertilization and could not be calibrated to EONR. There were strong linear correlations between the ASNT and total soil N (TSN), hydrolyzable NH4–N, and hydrolyzable NH4 + amino sugar–N. The ASNT was not significantly correlated to hydrolyzable amino sugar–N. The soils tested in this study had large amounts of hydrolyzable NH4–N relative to hydrolyzable amino sugar–N, which may partially explain the poor results with the ASNT. Also, liberation of a constant proportion of TSN by the ASNT procedure explains the inability of the test to estimate a specific portion of soil N that contributes to plant available N. Based on the results of this work, the ASNT is not recommended in Iowa for estimating corn N responsiveness or adjusting N application rate.

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Effects of redox potential and soil management practices on enzyme activities of soils

Briceño-Salazar

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I43 APPENDIX 144 with organic matter (C and N) contents, and for soils which have received no recent organic substrate amendments activities are poorly correlated with microbial number (Tabatabai, 1977, 1982a; Ladd, 1985). Enzymes related to C, N, P, and S_ cycles in soils Soil enzymes have primarily been involved in the metabolism of carbohydrate-, nitrogen-, phosphorus-containing organic compounds and catalyzing oxidation-reduction processes. Enzymes of special signifi cance in the carbon cycle include amylase, cellulase, glycosidase, and invertase. Metabolism of nitrogenous compounds commonly involves proteinases and peptidases (caseinase, pepsin, and trypsin), deaminases, and araidohydrolases (asparaginase, glutaminase, and urease). Some important enzymes involved in the P cycle include phytase, adenosine triphosphatase, phosphomonoesterase, phosphodiesterase, and pyrophos phatase. The oxido-reductase class of soil enzymes include catalase, dehydrogenase, and peroxidase (Kuprevich and Shcherbakova, 1971). Among the enzymes involved in the sulfur cycle is arylsulfatase. This enzyme is important in the cleavage of sulfate ester bonds in organic matter of soils (Tabatabai and Bremner, 1970a). Among the enzymes involved in carbon metabolism, those acting on glycosyl compounds, including glycoside hydrolases, have been the hydrolases least studied in soils. These enzymes include some important hydrolases like cellulase, amylase, and some glycosidases that catalyze the hydrolysis of disaccharides. Among the glycosidases, a-glucosidase which catalyzes the hydrolysis of aD -glucopyranosides and

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Indexes of plant available organic nitrogen in soils

Cited by 5 publications

References 97 publications

Effect of soil pH on phytoavailability of nitrogen in biotechnology by-products and animal manures

Effect of soil pH on phytoavailability of nitrogen in biotechnology by-products and animal manures

Assessment of the Amino Sugar–Nitrogen Test on Iowa Soils: II. Field Correlation and Calibration

Effects of redox potential and soil management practices on enzyme activities of soils

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