Effect of crop rotations and rotation phase on characteristics of soil organic matter in a Dark Brown Chernozemic soil

Self Cite

. 1997. Tillage and fallow frequency effects on selected soil quality attributes in a coarse-textured Brown Chernozem. Can. J. Soil Sci. 77: 497-505. An 11-yr study was conducted on a coarse-textured Brown Chernozemic soil in the semiarid prairie of southwestern Saskatchewan. Soil was sampled after 3, 7 and 11 yr, and the results were used to assess the influence of fallow frequency and tillage on selected soil quality attributes [e.g., total soil organic C and N, microbial biomass C (MB-C) and microbial biomass N (MB-N), C mineralization (C min ) and N mineralization (N min ), and specific respiratory activity (SRA)] in the 0-to 7.5-cm and 7.5-to 15-cm depths. Although it took 11 yr before we observed significant treatment effects on total organic C or N, effects on C min and N min were observed in 7 yr in the 0-to 7.5-cm depth and by 11 yr, MB and SRA also showed significant treatment effects in this depth. Generally, soil quality attributes were greater in no-tillage (NT) systems than in conventional mechanical tillage (CT) or minimum tillage (MT), and greater in continuous wheat (Triticum aestivum L.) (Cont W) than in fallow-wheat (F-W) systems. With time, the labile constituents tended to increase under the Cont W cropping, but to decrease when F-W was coupled with MT. After 11 yr there was a strong, direct association between the labile attributes (viz., C min , N min and MB-C) in the 0-to 7.5-cm depth and the mean annual straw produced (kg ha -1 yr -1 ) in the four cropping systems tested. Of the soil quality attributes tested, C min and N min were the most sensitive indices to tillage and fallow frequency effects.Key words: Mineralizable C, mineralizable N, microbial biomass, specific respiratory activity, crop residues Campbell, C. A., McConkey, B. G., Biederbeck, V. O., Zentner, R. P., Tessier, S. and Hahn, D. L. 1997. Effets du travail du sol et de la fréquence de la jachère sur certains paramètres de la qualité du sol dans un chernozem brun à texture grossière. Can. J. soil Sci. 77: 497-505. Une étude de 11 ans a été réalisée dans un sol chernozémique brun de texture grossière de la prairie semi-aride du sud-ouest de la Saskatchewan. A partir d'échantillons de sol prélevés après 3, 7 et 11 ans, nous avons évalué l'influence du régime de travail du sol et de la fréquence de la jachère sur quelques paramètres de la qualité du sol notamment la teneur en C et N organiques totaux, C et N d'origine microbienne, minéralisation de C et de N (C min et N min ), ainsi que l'activité respiratoire spécifique (ARS) dans les tranches de profondeur de 0 à 7,5 et de 7,5 à 15 cm. Bien qu'il ait fallu 11 ans avant que les traitements ne causent des effets significatifs sur le C ou le N organiques totaux, des effets ont pu être observés au bout de 7 ans sur C min et sur N min dans la tranche de 0-7,5 cm et au bout de 11 ans sur la biomasse microbienne et sur ARS. D'une manière générale, les valeurs des caractères qualitatifs du sol étaient plus élevées en régime de culture sans travail du sol qu'en régime de travail cla...

Section: Spring 1994 -After 11 Yearscontrasting

confidence: 76%

Tillage and fallow frequency effects on selected soil quality attributes in a coarse-textured Brown Chernozem

Campbell¹,

McConkey²,

Biederbeck³

et al. 1997

Self Cite

“…For example, if a cash-crop farmer, located in the Brown Chernozemic Soil Zone of Saskatchewan (native SOC in adjacent prairie is 50 Mg ha -1 to 30 cm) is currently using a fallow-wheat rotation in conventional tillage, and removes straw for off-farm sale, the SOC stock can be estimated. Soil Carbon native is 50 Mg ha -1 , the Base factor from Table 1 is 1 -(0.24 ± 0.06) = 0.76 ± 0.06, and the Input fac- Campbell et al (1991bCampbell et al ( , 1992Campbell et al ( , 1995Campbell et al ( , 1996aCampbell et al ( , b, 1998Campbell et al ( , 2000aCampbell et al ( , 2001, Larney et al (1997), Bremer et al (1994Bremer et al ( , 2002, Biederbeck et al (1998) …”

Section: Example Of Use Of Ipcc Guidelines Model For Soc Stocks and Cmentioning

confidence: 99%

Influence of agricultural management on soil organic carbon: A compendium and assessment of Canadian studies

VandenBygaart¹,

Gregorich²,

Angers³

2003

310

163

. 2003. Influence of agricultural management on soil organic carbon: A compendium and assessment of Canadian studies. Can. J. Soil Sci. 83: 363-380. To fulfill commitments under the Kyoto Protocol, Canada is required to provide verifiable estimates and uncertainties for soil organic carbon (SOC) stocks, and for changes in those stocks over time. Estimates and uncertainties for agricultural soils can be derived from long-term studies that have measured differences in SOC between different management practices. We compiled published data from long-term studies in Canada to assess the effect of agricultural management on SOC. A total of 62 studies were compiled, in which the difference in SOC was determined for conversion from native land to cropland, and for different tillage, crop rotation and fertilizer management practices. There was a loss of 24 ± 6% of the SOC after native land was converted to agricultural land. No-till (NT) increased the storage of SOC in western Canada by 2.9 ± 1.3 Mg ha -1 ; however, in eastern Canada conversion to NT did not increase SOC. In general, the potential to store SOC when NT was adopted decreased with increasing background levels of SOC. Using no-tillage, reducing summer fallow, including hay in rotation with wheat (Triticum aestivum L.), plowing green manures into the soil, and applying N and organic fertilizers were the practices that tended to show the most consistent increases in SOC storage. By relating treatment SOC levels to those in the control treatments, SOC stock change factors and their levels of uncertainty were derived for use in empirical models, such as the United Nations Intergovernmental Panel on Climate Change (IPCC) Guidelines model for C stock changes. However, we must be careful when attempting to extrapolate research plot data to farmers' fields since the history of soil and crop management has a significant influence on existing and future SOC stocks.

“…Thus, short-term changes in labile soil OM may be useful for predicting long-term changes in soil OM. However, seasonal and rotation-phase variations in labile soil OM (Spycher et al 1983;Bonde and Rosswall 1987) (Campbell et al 1991c(Campbell et al , 1992aJanzen et al 1992). Although C mineralization is often closely related to light fraction (LF) C concentrations (Janzen et al 1992),long turnover times for LF-C have been observed and attributed to the oresence of charcoal (Skjemstad et al 1990).…”

mentioning

confidence: 99%

Sensitivity of total, light fraction and mineralizable organic matter to management practices in a Lethbridge soil

Bremer¹,

Janzen²,

Johnston³

1994

186

in September 1992 to determine the effect of crop management on total, light fraction and mineralizable (10-wk) organic matter contents. Spring wheat was the dominant cropping system; treatments examined include fallow frequency, forage hay production in rotation, manure amendment, N fertilizer application, and native grass. The two latter treatments were infoduced in 1985 Total and light fraction organic matter did not vary among phases of the rotation whereas mineralized C tended to be lowest during and shortly after a fallow phase. When averaged across rotation phases, total, light fraction, and mineralized organic matter were enhanced by reduced fallow frequency, manure additons, hay production and native grass. Highest concentrations of total and labile organic concentrations in the 0-to 7.5-cm soil depth were generally found in the continuously-cropped wheat and native grass treatments. Hay production significantly increased soil organic matter in the 15-to 30-cm soil depth. Nitrogen fertilization did not increase soil organic matter in this study, likely because of minimal yield response over the treatment period.Sensitivity of the various indicators to treatment [ (highest-lowest)