Available soil nitrogen in relation to fractions of soil nitrogen and other soil properties

Warren, G. P.; Whitehead, David

doi:10.1007/bf02139991

Cited by 33 publications

(24 citation statements)

References 13 publications

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“…These ratios are in accordance with the results of Warren and Whitehead, 27 who reported that the C/N ratio of the macro-organic matter under grass, when living roots are excluded, is generally between 16 and 27 with a mean of about 21. The more narrow C/N ratios in the IF and HF also reflect a more processed state of humification in relation to the LF.…”

Section: Density Fractionation Of Macro-organic Mattersupporting

confidence: 92%

Characterization of soil organic matter fractions from grassland and cultivated soils via C content and δ¹³C signature

Accoe

Boeckx

Cleemput

et al. 2002

Rapid Comm Mass Spectrometry

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Variations in (13)C natural abundance and distribution of total C among five size and density fractions of soil organic matter, water soluble organic C (WSOC) and microbial biomass C (MBC) were investigated in the upper layer (0-20 cm) of a continuous grassland soil (CG, C(3) vegetation), a C(3)-humus soil converted to continuous maize cultivation (CM, C(4) vegetation) and a C(3)-humus soil converted to a rotation of maize cultivation and grassland (R). The amounts of WSOC and MBC were both significantly larger in the CG than in the CM and the R. In the three soils, WSOC was depleted while MBC was enriched in (13)C as compared with whole soil C. The relative contributions to the total C content of C stored in the macro-organic matter and in the size fraction 50-150 microm decreased with decreasing total C contents in the order CG > R > CM, while the relative contribution of C associated with the clay- and silt-sized fraction <50 microm increased. This reflects a greater stability and physical protection against microbial degradation associated with soil disruption (tillage) of the clay- and silt-associated organic C, in relation to the organic C in larger size fractions. The size and density fractions from the CG soil showed significant differences in (13)C enrichment, indicating different degrees of microbial degradation and stability of soil organic C associated with physically different soil organic matter (SOM) fractions. Delta(13)C analysis of the size and density fractions from CM and R soils reflected a decreasing turnover rate of soil organic C with increasing density among the macro-organic matter fractions and with decreasing particle size.

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Section: Density Fractionation Of Macro-organic Mattersupporting

confidence: 92%

Characterization of soil organic matter fractions from grassland and cultivated soils via C content and δ¹³C signature

Accoe

Boeckx

Cleemput

et al. 2002

Rapid Comm Mass Spectrometry

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“…These values are within the range of 1.62-3.17% with a mean of 2.27% reported for the macroorganic matter ( < 6 m m , >0.2mm) separated from 22 grassland soils (Warren and Whitehead, 1988). The higher concentration in the macroorganic matter than in the corresponding root fraction is consistent with the finding (Whitehead et al, 1979) that a sample of roots of perennial ryegrass, after separation and incubation with soil, showed a reduction in N concentration during the first 2-3 weeks from 1.50 to 1.15% but then an increase to about 1.95% after 33 weeks with, of course, a considerable loss in weight.…”

Section: Macro-organic Mattermentioning

confidence: 57%

“…The roots of grasses such as perennial ryegrass are thought to live on average for about one year, though less if the sward is defoliated frequently (Troughton, 1981). The amount of roots plus macro-organic matter tends to increase over a number of years from the time of sowing a sward (Garwood, 1967) but the macro-organic matter, at least after cultivation, is a relatively labile fraction of the total soil organic matter (Warren and Whitehead, 1988). When grass swards are ploughed for re-sowing, either to grass or to an arable crop, there is normally a large increase in the net mineralization of nitrogen and this often results in the leaching of large amounts of nitrate.…”

Section: Introductionmentioning

confidence: 99%

Organic matter and nitrogen in the unharvested fractions of grass swards in relation to the potential for nitrate leaching after ploughing

Whitehead¹,

Bristow²,

Lockyer³

1990

Plant Soil

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The amounts of organic matter in the stubble, litter, root and soil macro-organic matter fractions of two swards of perennial ryegrass that had received normal applications of either fertilizer or cattle urine were, on average for the four fractions, about 3000, 500, 11,500 and 8,800 kg ha -1. The swards had been established 8 or 15 years previously and each was sampled at intervals over a period of about one year. The amounts of N contained in the four fractions were, on average, 68, 12, 249 and 240 kg ha -1, a total of 569 kg N ha-~.With other swards, increasing rates of application of fertilizer N were found to have little effect on the amounts of organic matter in stubble and roots. Concentrations of N in the organic matter of the stubble and roots, however, increased significantly with increasing rate of fertilizer application, though, with stubble, moderate rates of application had little effect.Assessments based on these data, together with other published information, indicate that the amount of N mineralized from the combined stubble, litter, root and macro-organic matter fractions during the first year after ploughing may range from about 40 kg to at least 360 kg N ha -~ depending on the age of the sward and its recent management. The amount mineralized is likely to increase with age of sward, with increasing rate of fertilizer N and with utilisation by grazing rather than cutting.

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“…This suggests that in treatments receiving S Ret and N fertilizer, the MOM fraction may contribute more plant-available N to crop plants compared to whole soil organic matter, as MOM comprises a large proportion of the LFOM (Warren and Whitehead 1988).…”

Section: Soil Biochemical Propertiesmentioning

confidence: 97%

Long-term tillage, straw and N rate effects on quantity and quality of organic C and N in a Gray Luvisol soil

Malhi

Nyborg

Goddard

et al. 2010

Nutr Cycl Agroecosyst

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Long-term use of soil, crop and fertilizer management practices alters some soil properties, but the magnitude of change depends on soil type and climatic conditions. A field experiment with a barley (Hordeum vulgare L.)-wheat (Triticum aestivum L.)-canola (Brassica napus L.) rotation was conducted on a Gray Luvisol (Typic Cryoboralf) loam soil at Breton, Alberta, Canada. Effects of 19 or 27 years (from 1980 to 1998 or 2006 growing seasons) of tillage (zero tillage [ZT] and conventional tillage [CT]), straw management (straw removed [S Rem ] and straw retained [S Ret ]) and N fertilizer rate (0, 50 and 100 kg N ha -1 in S Ret , and 0 kg N ha -1 in S Rem plots) were determined on total organic C (TOC) and N (TON), light fraction organic C (LFOC) and N (LFON), macro organic matter C (MOM-C) and N (MOM-N), microbial biomass C (MB-C), and mineralizable C (C min ) and N (N min ) in the 0-7.5 and 7.5-15 cm or 0-5, 5-10 and 10-15 cm soil layers. Zero tillage and S Ret tended to have higher, and N fertilizer treatment usually had higher mass of TOC, TON, LFOC, LFON, C min and N min in soil compared to the corresponding CT, S Rem and zero-N control treatments, especially in the surface soil layers. Soil MB-C, MOM-C and MOM-N in soil generally tended to be higher with S Ret than S Rem , and also with N fertilizer than zero-N. There was no additional beneficial effect of ZT in increasing MB-C in soil. There were close and significant correlations among most soil organic C or N fractions, except for MB-C which did not correlate with MOM-N, and N min did not correlate with MOM-C. Linear regressions between crop residue C input and soil organic C or N were significant in most cases, except for MB-C and N min . Compared to the 1979 data, all treatments that did not receive N fertilizer (CTS Rem 0, CTS Ret 0, ZTS Rem 0 and ZTS Ret 0) showed a decrease in TOC concentration in the 0-15 cm soil layer over time, with the highest decrease in the CTS Rem 0 treatment. Straw retention and N fertilizer application at 50 and 100 kg N ha -1 under both ZT (ZTS Ret 50 and ZTS Ret 100) and CT (CTS Ret 50 and CTS Ret 100) resulted in a strongest increase in TOC during the first 11 years, and since then the TOC decreased under both N rates but 50 kg N ha -1 rate under CT (CTS Ret 50) showed the strongest negative effect on TOC in soil. In conclusion, elimination of tillage, straw retention and N application all improved organic C and N in soil, and generally differences were more pronounced for light fraction organic C and N, and between the most extreme treatments

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Available soil nitrogen in relation to fractions of soil nitrogen and other soil properties

Cited by 33 publications

References 13 publications

Characterization of soil organic matter fractions from grassland and cultivated soils via C content and δ¹³C signature

Characterization of soil organic matter fractions from grassland and cultivated soils via C content and δ¹³C signature

Organic matter and nitrogen in the unharvested fractions of grass swards in relation to the potential for nitrate leaching after ploughing

Long-term tillage, straw and N rate effects on quantity and quality of organic C and N in a Gray Luvisol soil

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Available soil nitrogen in relation to fractions of soil nitrogen and other soil properties

Cited by 33 publications

References 13 publications

Characterization of soil organic matter fractions from grassland and cultivated soils via C content and δ13C signature

Characterization of soil organic matter fractions from grassland and cultivated soils via C content and δ13C signature

Organic matter and nitrogen in the unharvested fractions of grass swards in relation to the potential for nitrate leaching after ploughing

Long-term tillage, straw and N rate effects on quantity and quality of organic C and N in a Gray Luvisol soil

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Characterization of soil organic matter fractions from grassland and cultivated soils via C content and δ¹³C signature

Characterization of soil organic matter fractions from grassland and cultivated soils via C content and δ¹³C signature