The Forms of Nitrogen in the Organic Matter of Different Horizons of Soil Profiles

Sowden, F. J.

doi:10.4141/cjss58-023

Cited by 49 publications

(25 citation statements)

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“…SOWDEN [1958] used this technique to determine the amide content of four horizons of a podzoL The results for the largely undecomposed organic layer were doubtful, as the recovery of most amino acids following reduction was low, but those for the other three layers suggest that both acids are present as their amides. Thus, the amount of glutamic and aspartic acids after reduction and hydrolysis gives the amide content.…”

Section: Y Amides and Ammoniamentioning

confidence: 99%

Soil Components

1975

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Section: Y Amides and Ammoniamentioning

confidence: 99%

Soil Components

1975

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“…It may play a significant role in mineralization of organic N in soils, because the chemical nature of Z. N. Senwo and M. A. Tabatabai 2576 organic N in soils is such that a large proportion (15 -25%) of the organic N is released as NH 4 þ by acid hydrolysis (6 M HCl). The information available suggests that a portion of the released NH 4 þ is derived from the hydrolysis of amides such as asparagine and glutamine residues of soil organic matter (Sowden 1958;Senwo and Tabatabai 1998). Aspartate is the product of hydrolysis of asparagine by asparaginase in soils (Senwo and Tabatabai 1996).…”

Section: Introductionmentioning

confidence: 99%

Aspartase Activity of Soils Under Different Management Systems

Senwo

Tabatabai

2005

Communications in Soil Science and Plant Analysis

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Recent interest in soil tillage, cropping systems, and residue management has focused on low-input sustainable agriculture. This study was carried out to evaluate the effects of various management systems on aspartase activity in soils. This enzyme [L-aspartate ammonia-lyase, EC 4.3.1.1] catalyzes the hydrolysis of L-aspartate to fumarate and NH 3 . It may play a significant role in the mineralization of organic N in soils. The management systems consisted of three cropping systems [continuous corn (Zea mays L.) (CCCC); corn-soybean [Glycine max (L.) Merr.]-corn-soybean (CSCS); and corn-oat (Avena sativa L.)-meadow-meadow (COMM) fmeadow was a mixture of alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.)] at three long-term field experiments initiated in 1954, 1957, and 1978 in Iowa and sampled in June 1987. The plots received 0 or 180 (or 200) kg ha 21 before corn and an annual application of 20 kg P and 56 kg K ha 21 . The tillage systems (no-tillage, chisel plow, and moldboard plow) were initiated in 1981 in Wisconsin and sampled in May 1991. The crop residue treatments were: bare, normal, mulch, and double (2Â) mulch. The residue in the study was corn stalks. Results showed that, in general, crop rotation in combination with N fertilizer treatments affected aspartase activity in the following order: COMM . CSCS . CCCC. Because of nitrification of the NH 4 þ or NH 4 þ -forming fertilizers, which resulted in decreasing the pH values, N fertilizer application, in general, decreased the aspartase activity in soils in the order: CCCC . CSCS . COMM. The effect of tillage and residue management practices on aspartase activity in soils showed a very wide plow/mulch . moldboard plow/mulch . no-till normal . chisel plow/normal . no-till bare . moldboard plow/normal. Aspartase activity decreased with increasing depth in the plow layer (0 -15 cm) of the no-till/2Â mulch. The decreased activity was accompanied by decreasing organic C and pH with depth. Statistical analyses using pooled data (28 samples) showed that aspartase activity was significantly, linearly correlated with organic C (r ¼ 0.78 ÃÃÃ ) and exponentially with soil pH (r ¼ 0.53 ÃÃ ). The variation in the patterns and magnitudes of activity distribution among the profiles of the four replicated plots was probably due to the spatial variability in soils.

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“…The ammonium in the hydrolyzate for Lithic soil shows higher values than those for Eutrorthox soil. Possibly the cause for this is due to the fact that a considerable part of the ammonium present in the hydrolyzate derives from the clay fixed ammonium, since there is evidence that hydrolysis with 6N HC1 releases a large part of the fixed ammonium (CHENG and KURTZ, 1963;SOWDEN, 1958). From the comparison of the data for fixed ammonium with ammonium in the hydrolyzate of the soils, it is possible to conclude that the higher ammonium content in the hydrolyzate of the Lithic Haplustoll soil fraction may be due to a more intense release of the fixed ammonium of this soil.…”

Section: Forms Of Soil Nitrogenmentioning

confidence: 99%

Process of fixation, imobilization and mineralization of ammonium in soil using N-15

Saravia

Neptune

1976

An. Esc. Super. Agric. Luiz de Queiroz

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RESUMOAs formas de nitrogênio do solo e a maneira em que as mesmas participam dos processos de fixação, imobilização e mineralização do amônio no solo foram avaliadas após diferentes períodos de incubação, utilizando dois solos, um Lithic Haplustoll e um Typic Eutrorthox.As formas analisadas através do conteúdo de nitrogênio e da relação isotópica 15 N/ 14 N foram: amônio trocável, amônio fixado, aminoácidos, hexosaminas, hidroxiaminoácidos, amônio do hidroli¬ sado e nitrogênio total do hidrolisado.Verificou-se que: 1) o método que emprega a extração com KC1 2N para determinar a capacidade de fixação do amônio adicionado, está sujeito a erros provocados pela interferência de outras funções do solo, na fixação de amônio; 2) o aumento no conteúdo de amônio trocável está relacionado com a diminuição dos aminoácidos e do amônio do hidrolisado dos solos e 3) os processos de retenção e liberação do nitrogênio do solo continuam em condições de atividade microbiana nula, sendo as formas mais afetadas aminoácidos e amônio do hidrolisado.

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The Forms of Nitrogen in the Organic Matter of Different Horizons of Soil Profiles

Abstract: A study was made oI the amount of amide-N (as glutamine and asparagine) in soil miterials by rnethylating the organic mateiial with methanolic-HCl, reducing the resulting product with LiBHr and determining the loss of glutamic and aspartic acidi. The

Cited by 49 publications

References 10 publications

Soil Components

Soil Components

Aspartase Activity of Soils Under Different Management Systems

Process of fixation, imobilization and mineralization of ammonium in soil using N-15

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