Dynamics of soil microbial biomass C, soluble organic C and CO2 evolution after three years of manure application

1998 ◽  
Vol 78 (2) ◽  
pp. 283-290 ◽  
Author(s):  
P. Rochette ◽  
E. G. Gregorich

Application of manure and fertilizer affects the rate and extent of mineralization and sequestration of C in soil. The objective of this study was to determine the effects of 3 yr of application of N fertilizer and different manure amendments on CO2 evolution and the dynamics of soil microbial biomass and soluble C in the field. Soil respiration, soluble organic C and microbial biomass C were measured at intervals over the growing season in maize soils amended with stockpiled or rotted manure, N fertilizer (200 kg N ha−1) and with no amendments (control). Manure amendments increased soil respiration and levels of soluble organic C and microbial biomass C by a factor of 2 to 3 compared with the control, whereas the N fertilizer had little effect on any parameter. Soil temperature explained most of the variations in CO2 flux (78 to 95%) in each treatment, but data from all treatments could not be fitted to a unique relationship. Increases in CO2 emission and soluble C resulting from manure amendments were strongly correlated (r2 = 0.75) with soil temperature. This observation confirms that soluble C is an active C pool affected by biological activity. The positive correlation between soluble organic C and soil temperature also suggests that production of soluble C increases more than mineralization of soluble C as temperature increases. The total manure-derived CO2-C was equivalent to 52% of the applied stockpiled-manure C and 67% of the applied rotted-manure C. Estimates of average turnover rates of microbial biomass ranged between 0.72 and 1.22 yr−1 and were lowest in manured soils. Manured soils also had large quantities of soluble C with a slower turnover rate than that in either fertilized or unamended soils. Key words: Soil respiration, greenhouse gas, soil carbon

2006 ◽  
Vol 57 (8) ◽  
pp. 837 ◽  
Author(s):  
G. M. Lodge ◽  
K. L. King

Studies were conducted at 3 pasture sites in northern New South Wales to examine the effects of grazing treatments over 4 years (spring 1997 to spring 2001) on soil microbial biomass carbon (C), labile C, total C, and total nitrogen (N). These data were collected (0–0.05 m soil depth) at 9 sampling times in 2 replicates of 5 (native pastures) or 4 (a sown pasture) grazing treatments and examined for differences over time using cubic spline analyses. For each site, differences among grazing treatments were also examined in spring 2001 for herbage, litter, and root mass (kg DM/ha), ground cover (%), and perennial grass basal cover (%). Indices were also calculated for the C pool index (CPI), lability index (LI), a carbon management index (CMI), and the microbial quotient. Relationships among microbial biomass C, labile C, total organic C, CPI, LI, CMI, microbial quotient, herbage mass, litter mass, and ground cover were examined by linear regression and correlation analyses. For each of the sites, treatment differences in the linear trend over time for soil microbial biomass C, labile C, total organic C, or total N were not significantly different (P > 0.05). In spring 2001, (4 years after treatments commenced) there were also no significant effects of treatments within sites on soil total organic C and none of the indices (lability of C, CPI, LI, CMI, or the microbial quotient) indicated any distinct trends among treatments. However, in spring 2001, there were significant (P < 0.05) treatment effects at both native pasture sites for herbage mass, litter mass, and ground cover. Similarly, in autumn 2001, herbage mass, root mass, and perennial grass basal cover were lowest (P < 0.05) in the continuously grazed high-stocking rate treatment at the sown pasture site. For all data, microbial biomass C was 10.35% of labile C and labile C was 21.60% of total C. From autumn 1998 to spring 2001, labile C was positively correlated (P < 0.05) with total C (r = 0.72) and in spring 2001, these 2 variables were also highly correlated (r = 0.98).


Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 226
Author(s):  
Anna Walkiewicz ◽  
Piotr Bulak ◽  
Małgorzata Brzezińska ◽  
Mohammad I. Khalil ◽  
Bruce Osborne

Although forest soils play an important role in the carbon cycle, the influence of topography has received little attention. Since the topographical gradient may affect CO2 emissions and C sequestration, the aims of the study were: (1) to identify the basic physicochemical and microbial parameters of the top, mid-slope, and bottom of a forest gully; (2) to carry out a quantitative assessment of CO2 emission from these soils incubated at different moisture conditions (9% and 12% v/v) and controlled temperature (25 °C); and (3) to evaluate the interdependence between the examined parameters. We analyzed the physicochemical (content of total N, organic C, pH, clay, silt, and sand) and microbial (enzymatic activity, basal respiration, and soil microbial biomass) parameters of the gully upper, mid-slope, and bottom soil. The Fourier Transformed Infrared spectroscopy (FTIR) method was used to measure CO2 emitted from soils. The position in the forest gully had a significant effect on all soil variables with the gully bottom having the highest pH, C, N concentration, microbial biomass, catalase activity, and CO2 emissions. The sand content decreased as follows: top > bottom > mid-slope and the upper area had significantly lower clay content. Dehydrogenase activity was the lowest in the mid-slope, probably due to the lower pH values. All samples showed higher CO2 emissions at higher moisture conditions, and this decreased as follows: bottom > top > mid-slope. There was a positive correlation between soil CO2 emissions and soil microbial biomass, pH, C, and N concentration, and a positive relationship with catalase activity, suggesting that the activity of aerobic microorganisms was the main driver of soil respiration. Whilst the general applicability of these results to other gully systems is uncertain, the identification of the slope-related movement of water and inorganic/organic materials as a significant driver of location-dependent differences in soil respiration, may result in some commonality in the changes observed across different gully systems.


2019 ◽  
Author(s):  
Monika Rawat ◽  
Kusum Arunachalam ◽  
Ayyandar Arunachalam ◽  
Juha Alatalo ◽  
Ujjwal Kumar ◽  
...  

Plant-soil interactions are a major determinant of changes in forest ecosystem processes and functioning. We conducted a trait-based study to quantify the contribution of plant traits and soil properties to above- and below-ground ecosystem properties in temperate forest in the Indian Himalayas. Nine plant traits (leaf area, specific leaf area, leaf water content, leaf dry matter content, leaf carbon (C), nitrogen (N), phosphorus (P), leaf C/N, and leaf N/P) and eight soil properties (pH, moisture, available N, P, potassium (K), total C, N, P) were selected for determination of their contribution to major ecosystem processes (above-ground biomass C, soil organic C, soil microbial biomass C, N, and P, and soil respiration) in temperate forest. Among the plant traits studied, leaf C, N, P, and leaf N/P ratio proved to be the main contributors to above-ground biomass, explaining 20-27% of variation. Leaf N, P, and leaf N/P were the main contributors to below-ground soil organic C, soil microbial biomass C, N, and P, and soil respiration (explaining 33% of variation). Together, the soil properties pH, available P, total N and C explained 60% of variation in above-ground biomass, while pH and total C explained 56% of variation in soil organic C. Other soil properties (available P, total C and N) also explained much of the variation in soil microbial biomass C (52%) and N (67%), while soil pH explained some of variation in soil microbial biomass N (14%). Available P, total N, and pH explained soil microbial biomass P (81%), while soil respiration was only explained by soil total C (70%). Thusleaf traits and soil characteristics make a significant contribution to explaining variations in above- and below-ground ecosystem processes and functioning in temperate forest in the Indian Himalayas. Consequently, tree species for afforestation, restoration, and commercial forestryshould be carefully selected, as they can influence the climate change mitigation potential of forest in terms of C stocks in biomass and soils.


1993 ◽  
Vol 23 (7) ◽  
pp. 1286-1290 ◽  
Author(s):  
Hannu Fritze ◽  
Taina Pennanen ◽  
Janna Pietikäinen

Development of humus layer soil microbial biomass C (Cmic) and N (Nmic), fungal biomass (as soil ergosterol content), microbial respiration activity, and the soil organic C (Corg) and N (Ntot) were determined in coniferous forest soils that had received a single prescribed fire treatment at different times over a period of 45 years. The ratio of soil respiration rate to microbial biomass C (qCO2) and the Cmic/Corg and Nmic/Ntot percentages were derived from the measurements taken. All the measured biomass indicators reacted identically to show recovery from prescribed burning within 12 years. A raised metabolic quotient (qCO2) was detected in soils over the first 2 years following the fire treatment, but after the third year it had decreased to a stable level. These observations suggest that during the first few years after fire the soil microflora can be characterized on the basis of simple substrate–decomposer relationships. The first 12 years were characterized by increasing Cmic/Corg and Nmic/Ntot percentages, which then stabilized at mean values of 1.3 and 5.5%, respectively. The observed rise in the Cmic within a large pool of Corg suggested increasing availability of energy-rich C sources. These C sources are probably derived from the organic C input resulting from postfire plant succession.


Agriculture ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 596
Author(s):  
Giancarlo Renella

Recovery of soil fertility after de-sealing of urban soils is still poorly known. This work studied the time-related dynamics of soil physico-chemical and biochemical endpoints of urban soil in the city in Naples (Southern Italy), de-sealed for different time during construction works, that underwent colonization by volunteer plants. The results showed de-sealing decreased the soil bulk density and the soil pH value, increased the electrical conductivity (EC), total organic C (TOC) and extractable carbohydrates (TEC), total and inorganic N contents, soil basal respiration (SBR), soil microbial biomass C (MBC) and soil microbial biomass N (MBN), the substrate induced respiration (SIR) value, and enzyme activities involved in C, N, P and S mineralization. The TEC, total and inorganic N, SBR and microbial biochemical endpoints were higher in the de-sealed soils than those of an arable soil of the same area. The results show that de-sealed urban soils rapidly increase their physical, chemical and biological fertility even with no intervention, especially when they are colonized by volunteer plants.


1993 ◽  
Vol 23 (7) ◽  
pp. 1275-1285 ◽  
Author(s):  
Janna Pietikäinen ◽  
Hannu Fritze

During a 3-year study, soil microbial biomass C and N, length of the fungal hyphae, soil respiration, and the percent mass loss of needle litter were recorded in coniferous forest soil humus layers following a prescribed burning (PB) treatment or a forest fire simulation (FF) treatment (five plots per treatment). Unburned humus from adjacent plots served as controls (PC and FC, respectively). Prescribed burning was more intensive than the forest fire, and this was reflected in all the measurements taken. The amounts of microbial biomass C and N, length of fungal hyphae, and soil respiration in the PB area did not recover to their controls levels, whereas unchanged microbial biomass N and recovery of the length of the fungal hyphae to control levels were observed in the FF area. The mean microbial C/N ratio was approximately 7 in all the areas, which reflected the C/N ratio of the soil microbial community. Deviation from this mean value, as observed during the first three samplings from the PB area (3, 18, and 35 days after fire treatment), suggested a change in the composition of the microbial community. Of the two treated areas, the decrease in soil respiration (laboratory measurements) was much more pronounced in the PB area. However, when the humus samples from both areas were adjusted to 60% water holding capacity, no differences in respiration capacity were observed. The drier humus, due to higher soil temperatures, of the PB area is a likely explanation for the low soil respiration. Lower soil respiration was not reflected in lower litter decomposition rates of the PB area, since there was a significantly higher needle litter mass loss during the first year in the PB area followed by a decline to the control level during the second year. Consistently higher mass losses were recorded in the FC area than in the FF area.


Soil Research ◽  
1998 ◽  
Vol 36 (2) ◽  
pp. 217 ◽  
Author(s):  
M. J. Noonan ◽  
M. Zaman ◽  
K. C. Cameron ◽  
H. J. Di

An open incubation and leaching study was conducted under controlled temperature (25°C) and moisture conditions to measure the N mineralisation rate in soil amended with dairy pond sludge. The dairy pond sludge was applied at 3 different rates equivalent to 0, 200, and 400 kg N/ha. The incubation was conducted at 3 different soil moisture potentials (0, -3, and -13 kPa). Following each 2-week period of incubation, the soil was leached with 2 pore volumes of deionised water to remove the mineralisation products. Mineralisation products in the leachate and enzyme activities, microbial biomass C and N, pH, and water-soluble C in the soil were determined. The incubation lasted 18 weeks. Rapid release of nitrate occurred during the first 6 weeks of incubation, followed by a slow release over the remainder of the incubation period. Although the total amount of N released in the 200 kg N/ha treatment (169 mg N/kg soil) was less than in the 400 kg N/ha treatment (206 mg N/kg soil), when expressed as a percentage of the organic N applied, the amount of N released at the lower rate (18·4%) was greater than that at the higher rate of sludge treatment (13·0%). Rapid nitrification decreased the soil leachate ammonium concentration and the soil pH. Soil microbial biomass, water-soluble C, and deaminase activity were significantly increased after the addition of dairy pond sludge. The increase in soil microbial biomass observed was probably due to the increased water-soluble C and nutrients that stimulated the soil microbial growth. The rapid N release and nitrification rates observed were attributed to the low C : N ratio (12·7), high ammonium content (145 mg N/kg) of the dairy pond sludge used, and the optimum moisture and temperature conditions. The narrow range of soil water potential conditions did not have any significant effect on N release rate or amount.


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