Seasonal trends in selected soil biochemical attributes: Effects of crop rotation in the semiarid prairie

1999 ◽  
Vol 79 (1) ◽  
pp. 73-84 ◽  
Author(s):  
C. A. Campbell ◽  
V. O. Biederbeck ◽  
G. Wen ◽  
R. P. Zentner ◽  
J. Schoenau ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Light Fraction ◽  
Water Soluble ◽  
Microbial Biomass C ◽  
Weather Variables ◽  
Total N ◽  
Organic C ◽  
C And N

Measurements of seasonal changes in soil biochemical attributes can provide valuable information on how crop management and weather variables influence soil quality. We sampled soil from the 0- to 7.5-cm depth of two long-term crop rotations [continuous wheat (Cont W) and both phases of fallow-wheat (F–W)] at Swift Current, Saskatchewan, from early May to mid-October, 11 times in 1995 and 9 times in 1996. The soil is a silt loam, Orthic Brown Chernozem with pH 6.0, in dilute CaCl2. We monitored changes in organic C (OC) and total N (TN), microbial biomass C (MBC), light fraction C and N (LFC and LFN), mineralizable C (Cmin) and N (Nmin), and water-soluble organic C (WSOC). All biochemical attributes, except MBC, showed higher values for Cont W than for F–W, reflecting the historically higher crop residue inputs, less frequent tillage, and drier conditions of Cont W. Based on the seasonal mean values for 1996, we concluded that, after 29 yr, F–W has degraded soil organic C and total N by about 15% compared to Cont W. In the same period it has degraded the labile attributes, except MBC, much more. For example, WSOC is degraded by 22%, Cmin and Nmin by 45% and LFC and LFN by 60–75%. Organic C and TN were constant during the season because one year's C and N inputs are small compared to the total soil C or N. All the labile attributes varied markedly throughout the seasons. We explained most of the seasonal variability in soil biochemical attributes in terms of C and N inputs from crop residues and rhizodeposition, and the influences of soil moisture, precipitation and temperature. Using multiple regression, we related the biochemical attributes to soil moisture and the weather variables, accounting for 20% of the variability in MBC, 27% of that of Nmin, 29% for LFC, 52% for Cmin, and 66% for WSOC. In all cases the biochemical attributes were negatively related to precipitation, soil moisture, temperature and their interactions. We interpreted this to mean that conditions favouring decomposition of organic matter in situ result in decreases in these attributes when they are measured subsequently under laboratory conditions. We concluded that when assessing changes in OC or TN over years, measurements can be made at any time during a year. However, if assessing changes in the labile soil attributes, several measurements should be made during a season or, measurements be made near the same time each year. Key words: Microbial biomass, carbon, nitrogen, mineralization, water-soluble-C, light fraction, weather variables

scholarly journals Assessment of Microbial Biomass Carbon and Nitrogen in Some Tea Soils of Bangladesh

1970 ◽  
Vol 25 (1) ◽  
pp. 21-25
Author(s):  
SM Abdur Rahman ◽  
ARM Solaiman
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Microbial Biomass Carbon ◽  
Microbial Biomass C ◽  
Biomass Carbon ◽  
Total N ◽  
Organic C ◽  
Biomass N ◽  
C And N ◽  
Tea Garden

Microbial biomass carbon (C) and nitrogen (N) and their contribution to soil organic carbon and total N contents were assessed in soils collected from Bilashchara Tea Estate under Bangladesh Tea Research Institute (BTRI), Srimangal of Moulavibazar district, and Sripur Tea Garden under Jaintapur of Sylhet district. Microbial biomass C and N in Bila shchara Tea Estate soils varied from 90.4-144.0 and 20.5-29.0 mg/kg soil, and that of Sripur Tea Garden soils varied from 120.7-362.0 and 26.6-59.5 mg/kg soil, respectively. Within the two tea growing areas biomass C/N ratios ranged from 3.35-6.12. Relationships between biomass C and organic carbon and biomass N and total N were positively correlated. The contribution of biomass C to soil organic C was 1.23%, ranging from 0.9-1.55% and the contribution of biomass N to total N content of the soils ranged from 1.19-2.89%. Keywords: Biomass carbon (C); Biomass nitrogen (N); Organic C; Total N; Tea soilDOI: http://dx.doi.org/10.3329/bjm.v25i1.4850 Bangladesh J Microbiol, Volume 25, Number 1, June 2008, pp 21-25

Seasonal trends in soil biochemical attributes: Effects of crop management on a Black Chernozem

1999 ◽  
Vol 79 (1) ◽  
pp. 85-97 ◽  
Author(s):  
C. A. Campbell ◽  
G. P. Lafond ◽  
V. O. Biederbeck ◽  
G. Wen ◽  
J. Schoenau ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Seasonal Variability ◽  
Crop Management ◽  
Growing Season ◽  
Light Fraction ◽  
Water Soluble ◽  
Organic C ◽  
Seasonal Trends ◽  
Rapid Decomposition ◽  
C And N

Knowledge of the response of soil biochemical attributes to crop management and growing season weather is important for assessing soil quality and fertility. Long-term (38–39 yr) crop rotations on a Black Chernozem at Indian Head, Saskatchewan, were sampled (0- to 7.5-cm depth) between early May and mid-October, 11 times in 1995 and 9 times in 1996. We assessed the effect of cropping frequency [fallow–wheat (Triticum aestivum L.) (F–W) vs. F–W–W, vs. Continuous (Cont) W], fertilizers (unfertilized vs. N + P applied), straw harvesting, legume green-manure (GM) in GM–W–W (unfertilized), and legume-grass hay (H) in F–W–W–H–H–H (unfertilized) systems. Changes in organic C and total N (OC, TN), microbial biomass C (MBC), light fraction C and N (LFC and LFN), mineralizable C and N (Cmin and Nmin), and water-soluble organic C (WSOC) were monitored. Organic C and TN were constant and unaffected by rotation phase during the season, but most of the other more labile soil biochemical attributes varied during the season. Much of this temporal variability was associated with changes in soil moisture, temperature and precipitation, and with rhizodeposition in some cases. Whenever conditions favoured rapid decomposition in situ (e.g., high moisture, temperature and/or precipitation) we obtained lower values for the more labile attributes in subsequent laboratory measurements. Seasonal trends in the more labile attriutes were more pronounced in 1995 (a much wetter year) than in 1996, and the proportion of the variability attributable to weather conditions was greater in 1995 than in 1996 (viz., R2 ranged from 20 to 44% in 1996 and from 37 to 60% in 1995). Seasonal variability was greater in the more fertile treatments [e.g., Cont W (Fert) and F–W–W–H–H–H) than in F–W or Cont W (Unfert). Seasonal variability in LF was unaffected by cropping. Light fraction was lower in 1995 than 1996 because of faster decomposition in 1995 (335 mm of growing season precipitation compared to 157 mm in 1996). Microbial biomass was not influenced by cropping in 1996, but in 1995 it was higher in cropped than in fallow phases of the rotations, suggesting a positive effect of rhizodeposition. Water-soluble organic C was greatest in the more fertile treatments and in cropped than in fallow phases. Mineralizable C and N were greater in cropped than in fallow rotation phases in 1995, but unaffected by cropping in 1996. Further, Cmin and Nmin were higher in 1996 than in 1995, likely due to more rapid decomposition in the wetter 1995. Over the last 10 yr of this experiment LFC and Cmin have increased markedly in the more fertile treatments [e.g., Cont W (Fert), F–W–W–H–H–H], but have hardly changed in the less fertile treatments such as F–W or Cont W (Unfert). In this period the less labile attributes (e.g., OC) have hardly changed in any treatment. Key words: Microbial biomass, carbon, nitrogen, mineralization, water-soluble C, light fraction, weather variables

scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland .VII. Dynamics of nitrogen mineralization potentials and microbial biomass

Soil Research ◽  
1987 ◽  
Vol 25 (4) ◽  
pp. 461 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Microbial Biomass ◽  
Nitrogen Mineralization ◽  
Continuous Cultivation ◽  
Microbial Biomass C ◽  
Total N ◽  
Organic C ◽  
Mineralizable N ◽  
Biomass N ◽  
Potentially Mineralizable N ◽  
C And N

The dynamics of nitrogen mineralization potential (N0) and mineralization rate constant (k) were studied in six major soils which had been used for cereal cropping for up to 20-70 years. In the top 0.1 m layer of virgin soils, N0 varied from 110 � 22 mg kg-1 soil (Riverview) to 217 � 55 mg kg-1 soil (Langlands-Logie), representing about 13% and 11%, respectively, of total N in these soils. Upon cultivation and cropping, N0 declined by 1 7 � 0.5 mg kg-1 yr-1 (Riverview) to 4.8 � 2.0 mg kg -1 yr -1 (Billa Billa). This represented < 20% of total N lost annually from the top layer (0-0.1 m depth) of these soils. The k values varied less than the N0 values, both within and among soils, and were also less affected by cultivation than N0. The mineralizable N in cultivated soil during cropping for periods up to 70 years can be estimated from N0 and k values, taking No as 5% of total N for soils of <40% clay and 15% of total N for soils of >40% clay and k as 0.066 week-1 at 40�C (0.027 week-1 and 0.054 week-1 at 25�C and 35�C, respectively). Organic C and N contained in the 'stabilized' microbial biomass (determined after 30 weeks' pre-incubation) accounted for 1.7-38% of total organic C and 2.0-5.1% of total N in the six soils studied. The microbial biomass C and N declined with cultivation in most soils, biomass N representing 10-23% of the total annual loss of N0. The microbial biomass, urease activity and total N, in addition to a number of other soil properties [e.g. light-fraction (<2 Mg m-3) C, sand-size C, CEC and ESP], were significantly correlated with N0 and k, thus indicating the existence of a myriad of environments for the activity, association and stability of microbial biomass and potentially mineralizable N in soil.

Autumn and spring applications of ammonium nitrate and urea to bromegrass influence total and light fraction organic C and N in a thin Black Chernozem

2002 ◽  
Vol 82 (2) ◽  
pp. 211-217 ◽  
Author(s):  
S S Malhi ◽  
J T Harapiak ◽  
M. Nyborg ◽  
K S Gill ◽  
N A Flore
Keyword(s):  
Ammonium Nitrate ◽  
N Fertilization ◽  
Light Fraction ◽  
Total N ◽  
Organic C ◽  
Soil C ◽  
Soil C And N ◽  
C And N ◽  
Light Fraction Organic C ◽  
Total Organic C

An adequate level of organic matter is needed to sustain the productivity, improve the quality of soils and increase soil C. Grassland improvement is considered to be one of the best ways to achieve these goals. A field experiment, in which bromegrass (Bromus inermis Leyss) was grown for hay, was conducted from 1974 to 1996 on a thin Black Chernozemic soil near Crossfield, Alberta. Total organic C (TOC) and total N (TN), and light fraction organic C (LFOC) and light fraction N (LFN) of soil for the treatments receiving 23 annual applications of 112 kg N ha-1 as ammonium nitrate (AN) or urea in early autumn, late autumn, early spring or late spring were compared to zero-N check. Soil samples from 0- to 5- cm (layer 1), 5- to 10- cm (layer 2), 10- to 15- cm (layer 3) and 15- to 30-cm depths were taken in October 1996. Mass of TOC, TN, LFOC and LFN was calculated using equivalent mass technique. The concentration and mass of TOC and LFOC, TN and LFN in the soil were increased by N fertilization compared to the zero-N check. The majority of this increase in C and N occurred in the surface 5-cm depth and predominantly occurred in the light fraction material. In layer 1, the average increase from N fertilization was 3.1 Mg C ha-1 for TOC, 1.82 Mg C ha-1 for LFOC, 0.20 Mg N ha-1 for TN and 0.12 Mg N ha-1 for LFN. The LFOC and LFN were more responsive to N fertilization compared to the TOC and TN. Averaged across application times, more TOC, LFOC, TN and LFN were stored under AN than under urea in layer 1, by 1.50, 1.21, 0.06 and 0.08 Mg ha-1, respectively. Lower volatilization loss and higher plant uptake of surfaced-broadcast N were probable reasons from more soil C and N storage under AN source. Time of N application had no effect on the soil characteristics studied. In conclusion, most of the N-induced increase in soil C and N occurred in the 0- to 5-cm depth (layer 1) and in the light fraction material, with the increases being greater under AN than urea. Key words: Bromegrass, light fraction C and N, N source, soil, total organic C and N

Management of sugarcane harvest residues: consequences for soil carbon and nitrogen

Soil Research ◽  
2007 ◽  
Vol 45 (1) ◽  
pp. 13 ◽  
Author(s):  
Fiona A. Robertson ◽  
Peter J. Thorburn
Keyword(s):  
Microbial Biomass ◽  
Soil Fertility ◽  
Microbial Activity ◽  
Soil N ◽  
Soil Organic C ◽  
Total N ◽  
Organic C ◽  
Soil Microbial ◽  
C And N

The Australian sugar industry is moving away from the practice of burning the crop before harvest to a system of green cane trash blanketing (GCTB). Since the residues that would have been lost in the fire are returned to the soil, nutrients and organic matter may be accumulating under trash blanketing. There is a need to know if this is the case, to better manage fertiliser inputs and maintain soil fertility. The objective of this work was to determine whether conversion from a burning to a GCTB trash management system is likely to affect soil fertility in terms of C and N. Indicators of short- and long-term soil C and N cycling were measured in 5 field experiments in contrasting climatic conditions. The effects of GCTB varied among experiments. Experiments that had been running for 1–2 years (Harwood) showed no significant trash management effects. In experiments that had been running for 3–6 years (Mackay and Tully), soil organic C and total N were up to 21% greater under trash blanketing than under burning, to 0.10 or 0.25 m depth (most of this effect being in the top 50 mm). Soil microbial activity (CO2 production) and soil microbial biomass also increased under GCTB, presumably as a consequence of the improved C availability. Most of the trash C was respired by the microbial biomass and lost from the system as CO2. The stimulation of microbial activity in these relatively short-term GCTB systems was not accompanied by increased net mineralisation of soil N, probably because of the greatly increased net immobilisation of N. It was calculated that, with standard fertiliser applications, the entire trash blanket could be decomposed without compromising the supply of N to the crop. Calculations of possible long-term effects of converting from a burnt to a GCTB production system suggested that, at the sites studied, soil organic C could increase by 8–15%, total soil N could increase by 9–24%, and inorganic soil N could increase by 37 kg/ha.year, and that it would take 20–30 years for the soils to approach this new equilibrium. The results suggest that fertiliser N application should not be reduced in the first 6 years after adoption of GCTB, but small reductions may be possible in the longer term (>15 years).

Free light fraction carbon and nitrogen, a physically uncomplexed soil organic matter distribution within subtropical grass and leucaena–grass pastures

Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 820 ◽  
Author(s):  
K. A. Conrad ◽  
R. C. Dalal ◽  
D. E. Allen ◽  
R. Fujinuma ◽  
Neal W. Menzies
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Depth ◽  
Light Fraction ◽  
Grass Species ◽  
Pasture Grass ◽  
Total N ◽  
Δ13c And Δ15n ◽  
Organic C ◽  
C And N

Quantifying the size and turnover of physically uncomplexed soil organic matter (SOM) is crucial for the understanding of nutrient cycling and storage of soil organic carbon (SOC). However, the C and nitrogen (N) dynamics of SOM fractions in leucaena (Leucaena leucocephala)–grass pastures remains unclear. We assessed the potential of leucaena to sequester labile, free light fraction (fLF) C and N in soil by estimating the origin, quantity and vertical distribution of physically unprotected SOM. The soil from a chronosequence of seasonally grazed leucaena stands (0–40 years) was sampled to a depth of 0.2m and soil and fLF were analysed for organic C, N and δ13C and δ15N. On average, the fLF formed 20% of SOC and 14% of total N stocks in the upper 0.1m of soil from leucaena rows and showed a peak of fLF-C and fLF-N stocks in the 22-year-stand. The fLF δ13C and fLF δ15N values indicated that leucaena produced 37% of fLF-C and 28% of fLF-N in the upper 0.1m of soil from leucaena rows. Irrespective of pasture type or soil depth, the majority of fLF-C originated from the accompanying C4 pasture-grass species. This study suggests that fLF-C and fLF-N, the labile SOM, can form a significant portion of total SOM, especially in leucaena–grass pastures.

scholarly journals Evaluation some important microbiological parameters of the carbon cycle in chernozem soils profiles

2016 ◽  
pp. 33-39
Author(s):  
János Kátai ◽  
Zsolt Sándor ◽  
Magdolna Tállai ◽  
Ágnes Zsuposné Oáh
Keyword(s):  
Microbial Biomass ◽  
Carbon Cycle ◽  
Large Scale ◽  
Microbial Biomass Carbon ◽  
Close Correlation ◽  
Co2 Production ◽  
Microbial Biomass C ◽  
Soil Profiles ◽  
Organic Carbon Content ◽  
Organic C

Some chemical and microbiological properties of the carbon cycle were investigated in three chernozem soil profiles. The soil profiles originated from a long term fertilization experiment (potato) of the University of Debrecen, Látókép, Kryvyi Rig Botanic Garden (grassland) and a large-scale farm (sunflower) of Ukraine. The results of the organic C-content, total number of bacteria, microscopical fungi, cellulose decomposing bacteria, CO2-production, microbial biomass carbon and saccharase and dehydrogenase activities were compared and evaluated with the help of correlation analyses. Close correlation was found between the organic carbon content and the number of microscopical fungi,, saccharase and dehydrogenase enzymes’ activities, as well as close correlation was found between the dehydrogenase activity and microbial biomass-C and saccharase activity.

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