Soil microbial biomass, organic C, and soybean physiology in integrated crop–livestock systems with different inputs

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

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Effects of 17-year fertilization on soil microbial biomass C and N and soluble organic C and N in loessial soil during maize growth

Biology and Fertility of Soils ◽

10.1007/s00374-010-0511-7 ◽

2010 ◽

Vol 47 (2) ◽

pp. 121-128 ◽

Cited By ~ 68

Author(s):

Bin Liang ◽

Xueyun Yang ◽

Xinhua He ◽

Jianbin Zhou

Keyword(s):

Microbial Biomass ◽

Soil Microbial Biomass ◽

Microbial Biomass C ◽

Loessial Soil ◽

Organic C ◽

Soil Microbial Biomass C ◽

Soil Microbial ◽

Maize Growth ◽

C And N

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Interpretation of microbial biomass measurements for soil quality assessment in humid temperate regions

Canadian Journal of Soil Science ◽

10.4141/s99-012 ◽

1999 ◽

Vol 79 (4) ◽

pp. 507-520 ◽

Cited By ~ 55

Author(s):

M. R. Carter ◽

E. G. Gregorich ◽

D. A. Angers ◽

M. H. Beare ◽

G. P. Sparling ◽

...

Keyword(s):

Microbial Biomass ◽

Plant Growth ◽

Soil Quality ◽

Soil Microbial Biomass ◽

Spatial And Temporal Variation ◽

Data Set ◽

K Value ◽

Organic C ◽

Soil Microbial ◽

Temperate Soils

Soil microbial biomass (SMB) measurements are often used in soil biological analysis; however, their interpretation can be problematic. In this review, both the limitations and benefits of indirect (both CHCl3 fumigation incubation and fumigation extraction, and substrate-induced respiration) SMB measurements are outlined, along with their value and interpretation as attributes or indicators to assess some soil quality (SQ) functions (e.g., enhance plant growth, maintain aggregation, regulate energy) for mainly humid, temperate soils, with specific emphasis on research conducted in eastern Canada and New Zealand. Indirect SMB methods are subject to limitations analogous to "soil test" procedures (e.g., soil sampling and handling, water content, storage prior to treatment), and also the difficulties with establishing an acceptable "control" and fraction (i.e., k value) of SMB mineralized or extracted. In many cases, such limitations present a need for some degree of standardization (e.g., pre-conditions of 7- to 10-d incubation at 25°C and −0.001 MPa water potential) prior to SMB measurement. However, for SQ assessment, where "comparative" rather than "absolute" values of SMB are often of interest, use of commonly derived k values seem appropriate for surface soils.Soil ecological factors govern SMB and often underlie much of the spatial and temporal variation in SMB. Plant species composition, mainly through net primary productivity and litter quality, can affect SMB measurements along with trophic cascades in soil, where interactions among soil organisms can influence microbial activity. Benefits of SMB measurements relate mainly to the assessment of both soil C turnover and management induced changes in organic matter. The combination of SMB and δ13C to elucidate the transformations and fate of organic C in cropping and soil management systems has also shown that both temporal and spatial redistribution of C inputs, and soil type (i.e., particle size distribution) are dominant factors in turnover and nutrient flow through the SMB.For SQ assessment, SMB is not a useful indicator for the function of soil as a "medium for plant growth" in regard to plant productivity for intensively farmed temperate soils. For the function of soil to "maintain aggregation", where SMB is one agent only of a multi-faceted process, the relationship between SMB and soil aggregation is not always present and tends to be site-specific. In regard to the "regulate energy" soil function, SMB is related to some degree with decomposition and mineralization processes. The main role of SMB for SQ assessment is to serve within a minimum data set of other indicators (e.g., macroorganic C) to monitor soil organic C storage and change. Key words: Soil microbial biomass, humid climate, soil quality

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Miscanthus Biochar had Limited Effects on Soil Physical Properties, Microbial Biomass, and Grain Yield in a Four-Year Field Experiment in Norway

Agriculture ◽

10.3390/agriculture8110171 ◽

2018 ◽

Vol 8 (11) ◽

pp. 171 ◽

Cited By ~ 4

Author(s):

Adam O’Toole ◽

Christophe Moni ◽

Simon Weldon ◽

Anne Schols ◽

Monique Carnol ◽

...

Keyword(s):

Microbial Biomass ◽

Field Experiment ◽

Physical Properties ◽

Soil Microbial Biomass ◽

Soil Physical Properties ◽

Climate Mitigation ◽

Silty Clay ◽

Organic C ◽

Soil Microbial ◽

The Impact

The application of biochar to soils is a promising technique for increasing soil organic C and offsetting GHG emissions. However, large-scale adoption by farmers will likely require the proof of its utility to improve plant growth and soil quality. In this context, we conducted a four-year field experiment between October 2010 to October 2014 on a fertile silty clay loam Albeluvisol in Norway to assess the impact of biochar on soil physical properties, soil microbial biomass, and oat and barley yield. The following treatments were included: Control (soil), miscanthus biochar 8 t C ha−1 (BC8), miscanthus straw feedstock 8 t C ha−1 (MC8), and miscanthus biochar 25 t C ha−1 (BC25). Average volumetric water content at field capacity was significantly higher in BC25 when compared to the control due to changes in BD and total porosity. The biochar amendment had no effect on soil aggregate (2–6 mm) stability, pore size distribution, penetration resistance, soil microbial biomass C and N, and basal respiration. Biochar did not alter crop yields of oat and barley during the four growing seasons. In order to realize biochar’s climate mitigation potential, we suggest future research and development efforts should focus on improving the agronomic utility of biochar in engineered fertilizer and soil amendment products.

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Soil microbial biomass, labile and total carbon levels of grazed sown and native pastures in northern New South Wales

Australian Journal of Agricultural Research ◽

10.1071/ar05337 ◽

2006 ◽

Vol 57 (8) ◽

pp. 837 ◽

Cited By ~ 4

Author(s):

G. M. Lodge ◽

K. L. King

Keyword(s):

Microbial Biomass ◽

Soil Microbial Biomass ◽

Perennial Grass ◽

Ground Cover ◽

Microbial Biomass C ◽

Organic C ◽

Soil Microbial ◽

Labile C ◽

Microbial Quotient ◽

Total Organic C

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).

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Effects of conservation tillage farming on soil microbial biomass, organic matter and earthworm populations, in north-eastern Victoria

Australian Journal of Experimental Agriculture ◽

10.1071/ea9900365 ◽

1990 ◽

Vol 30 (3) ◽

pp. 365 ◽

Cited By ~ 52

Author(s):

PJ Haines ◽

NC Uren

Keyword(s):

Microbial Biomass ◽

Soil Microbial Biomass ◽

Conservation Tillage ◽

Total N ◽

Organic C ◽

Soil Microbial ◽

North Eastern ◽

C And N ◽

Direct Drilling ◽

Earthworm Populations

A long-term field experiment was set up in 1981 in north-eastern Victoria to determine the effects of conservation tillage farming on agronomic and soil properties. Conventional cultivation was compared with direct drilling, and stubbles retained from the previous crop were compared with burning under direct drilling. Wheat was grown continuously over the 7 years of the experiment. Organic carbon (C), total nitrogen (N), soil microbial biomass and earthworm populations were measured. When samples were taken incrementally down the soil profile, there was a significant concentration gradient of organic matter under direct drilling. In the surface 2.5 cm, biomass C and N, and N mineralisation were 35, 30 and 62% greater, respectively, than under conventional cultivation. Direct drilling into retained stubble did not significantly increase organic C or total N. Of the estimated 7.8 t C/ha added to the soil from conserved crop stubbles, 4% was retained in the top 7.5 cm at the time of sampling. Organic C, total N and biomass C and N decreased with depth in both treatments. Microbial biomass varied considerably with season. The biomass of earthworms in the top 10 cm, under direct drilling, was more than twice that of conventional cultivation, while total worm numbers increased significantly (P<0.05), from 123 to 275/m2, when wheat stubble was retained with direct drilling compared to stubble burning.

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Variations in Soil Properties and CO2 Emissions of a Temperate Forest Gully Soil along a Topographical Gradient

Forests ◽

10.3390/f12020226 ◽

2021 ◽

Vol 12 (2) ◽

pp. 226

Author(s):

Anna Walkiewicz ◽

Piotr Bulak ◽

Małgorzata Brzezińska ◽

Mohammad I. Khalil ◽

Bruce Osborne

Keyword(s):

Microbial Biomass ◽

Soil Respiration ◽

Co2 Emissions ◽

Catalase Activity ◽

Soil Microbial Biomass ◽

Total N ◽

Organic C ◽

Soil Microbial ◽

N Concentration ◽

Moisture Conditions

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.

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Grass–legume intercropping in integrated crop-livestock systems: a strategy to improve soil quality and soybean yield in the Brazilian Cerrado

10.21203/rs.3.rs-831197/v1 ◽

2021 ◽

Author(s):

Juliana M. A. S. Moraes ◽

Luiz Gustavo de O. Denardin ◽

Gabriela C. Pires ◽

Evelyn C. Gonçalves ◽

Laércio S. Silva ◽

...

Keyword(s):

Microbial Biomass ◽

Enzymatic Activity ◽

Soil Quality ◽

Pigeon Pea ◽

Brazilian Cerrado ◽

Organic C ◽

Soybean Yield ◽

Soil Microbial ◽

C And N ◽

Livestock Systems

Abstract Aims The integrated crop-livestock systems (ICLS) under no-tillage improves soil fertility of the Brazilian Cerrado. We aimed to evaluate the effect of different grass-legume intercropping compared to single grass cultivation in the off-season of an ICLS on (i) soil organic carbon (C) and nitrogen (N) pools, (ii) soil microbial biomass and activity, (iii) soil enzymatic activity, and (iv) soybean grain yield in succession. Methods The field study was conducted in an on-farm experiment in 2016/17 and 2017/18 cropping seasons. The soybean was cultivated in the summer season, with the subsequent treatments in the off-season, using two grasses (Urochloa ruziziensis and U. brizantha), single or intercropped with Cowpea (Vigna unguiculata) or Pigeon pea (Cajanus cajan). We evaluated soil organic C and N pools, microbial biomass and activity, enzyme activity, and soybean yield. Results Cowpea intercropping yielded 24% more soybeans than grasses single cropped. There was a higher microbial biomass and activity, and enzymatic activity in the soil under grass-legume intercropping. In addition to the lower basal respiration and microbial metabolic quotient (qCO2), the greater microbial quotient (qMIC) and microbial biomass C indicate a higher soil microbial C utilization efficiency under grass-legume intercropping. The soil total organic C and N stocks increased under Pigeon pea intercropping by 16% and 27%, respectively, compared to single grasses. Conclusions Grass-legume intercropping in the pasture phase of ICLS is an additional tool to maximize soybean yields in the short term. The intercropping effects on soybean yield were directly related to soil quality improvements through soil biological and biochemical properties.

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Relative contribution of plant traits and soil properties to the functioning of a temperate forest ecosystem in the Indian Himalayas

10.32942/osf.io/tmzsk ◽

2019 ◽

Author(s):

Monika Rawat ◽

Kusum Arunachalam ◽

Ayyandar Arunachalam ◽

Juha Alatalo ◽

Ujjwal Kumar ◽

...

Keyword(s):

Microbial Biomass ◽

Soil Properties ◽

Temperate Forest ◽

Soil Microbial Biomass ◽

Plant Traits ◽

Microbial Biomass C ◽

Organic C ◽

Soil Microbial Biomass C ◽

Soil Microbial ◽

Leaf N

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.

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