Improvements in the method for fractional determination of soil organic nitrogen

Organic Nitrogen in a Typic Hapludox Fertilized With Pig Slurry

“…Using this same analytical procedure, Camargo et al (1997) found the proportion of 79.2 % in the 0-20 cm layer of an Ultisol, and Yonebayashi and Hattori (1980) found 78.5 % in alluvial soils with a clayey texture planted to rice. It is important to note that within the organic N fraction hydrolyzed by the method, the N fractions are determined in the forms of NH + 4 -N, hexosamine-N, α-amino-N, amide-N, and unidentified-N ( Table 5).…”

“…For leaf sampling, the center third of 30 leaves located below and opposite the ear in the maize tasseling stage, and 50 flag leaves from the oat plants in the initial flowering stage of the crop were collected in each experimental plot (Tedesco et al, 2004). Fractionation of the organic forms of N was based on the extraction and quantification of the N compounds released by acid hydrolysis, based on the protein degradation technique described by Yonebayashi and Hattori (1980) and modified by Camargo et al (2008).…”

Nutritional Environment of Tropical Peat Soils in Sarawak, Malaysia Based on Soil Solution Composition

“…Na, K, Mg, and Ca contents were measured by AAS. Content of total N was determined photometrically at 220 nm after potassium peroxodisulfate oxidation treatment (Japanese Industrial Standards Committee 1991a), whereas the contents of NH4-N and NOa-N were measured with a N meter (Central Kagaku Co., HC-707N) after steam distillation with successive addition of MgO and Devarda's alloy (Yonebayashi and Hattori 1980). Total P and ortho-phosphate contents were determined by the molybdophosphoric blue method with or without pretreatment with potassium peroxodisulfate (Japanese Industrial Standards Committee 1991b).…”

Burning effects on the distribution of organic N compounds in a 15N labelled forest soil

“…An aliquot of 20 ml of hydrolysate (H1, H2) was steam distilled for 4 min with 10 ml of phosphate-borate buffer (Na 3 PO 4 .10H 2 O 100 g l -1 ; Na 2 B 4 O 7 .10H 2 O 25 g l -1 ). The AS-N content was calculated by subtracting the amount of AM-N + inorganic NH 4 + -N (H1), or that of A-N (H2), from the ammonia distilled under these conditions; the value of AS-N obtained was multiplied by 1.06 because only 93.8% of the amino sugar-N is recovered (Yonebayashi and Hattori, 1980). …”

“…An aliquot of 20 ml of hydrolysate (H1) was steam distilled for 2 min with 200 mg of MgO. The AM-N content was calculated by subtracting the pre-existing inorganic NH 4 + (quantified by the 2 M KCl extraction -steam distillation method) from the ammonia recovered in this first gentle hydrolysis, which only derives from this two sources (Yonebayashi and Hattori, 1980). …”