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

1990 ◽  
Vol 30 (3) ◽  
pp. 365 ◽  
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.

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).

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

Forests ◽  
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.

Soil microbial biomass, metabolic quotient, and carbon and nitrogen mineralisation in 25-year-old Pinus radiata agroforestry regimes

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 491 ◽  
Author(s):  
S. Saggar ◽  
C. B. Hedley ◽  
G. J. Salt
Keyword(s):  
Carbon Dioxide ◽  
Microbial Biomass ◽  
Pinus Radiata ◽  
Soil Microbial Biomass ◽  
Negative Influence ◽  
Metabolic Quotient ◽  
Decomposition Rates ◽  
Organic C ◽  
Soil Microbial ◽  
C And N

To understand the effects of agroforestry on soil biological processes we assessed the conditions in Pinus radiata plantations of 50, 100, 200, and 400 stems/ha after 25 years of growth, and in a grassland. Agroforestry resulted in a 15–25% decline in soil organic C and N compared with grassland, and had a significant negative influence on soil microbial biomass. There was less microbial C and N in soils under 50–400 stems/ha of P. radiata than in soils under grassland (0 stems/ha). Soil carbon decomposition and microbial activity were measured by trapping the carbon dioxide produced by incubating soils over a 60-week period. The results showed that soil C decomposition rates were ~1.5 times as much (c. 15 mg CO2-C/kg soil) in soil from grassland as in that from plots with 50 or100 stems/ha (c. 10 mg CO2-C/kg soil), and were further reduced to one half (c. 5.5 mg CO2-C/kg soil) in the plots with 200 or 400 stems/ha. The soils under P. radiata gave off less carbon dioxide per unit of biomass (the metabolic quotient) than soils under grassland. These shifts in microbial biomass and its metabolic quotients appear to be associated with differences in the quantity and ‘quality’ of inputs and soil organic matter decomposition rates, and to reflect the land use change from grassland to forest. Given the general ability of soil microbial biomass to recolonise depopulated areas after tree harvest, we see no problem in restoring populations of these soil organisms vital in controlling nutrient cycling after tree felling, provided adequate adjustments to soil pH are made.

Relationships between C and N availability, substrate age, and natural abundance 13C and 15N signatures of soil microbial biomass in a semiarid climate

2009 ◽  
Vol 41 (8) ◽  
pp. 1605-1611 ◽  
Author(s):  
Jeff S. Coyle ◽  
Paul Dijkstra ◽  
Richard R. Doucett ◽  
Egbert Schwartz ◽  
Stephen C. Hart ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Natural Abundance ◽  
N Availability ◽  
Soil Microbial ◽  
Semiarid Climate ◽  
C And N ◽  
Substrate Age

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
Keyword(s):  
Microbial Biomass ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Soil Microbial Biomass ◽  
N Fertilizer ◽  
Microbial Biomass C ◽  
Organic C ◽  
Soil Microbial ◽  
Manure Amendments ◽  
Soluble C

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

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

C and N availability affects the 15 N natural abundance of the soil microbial biomass across a cattle manure gradient

2006 ◽  
Vol 57 (4) ◽  
pp. 468-475 ◽  
Author(s):  
P. Dijkstra ◽  
O. V. Menyailo ◽  
R. R. Doucett ◽  
S. C. Hart ◽  
E. Schwartz ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Natural Abundance ◽  
Cattle Manure ◽  
N Availability ◽  
Soil Microbial ◽  
C And N ◽  
N Natural Abundance

Seasonal dynamics of soil microbial biomass C and N in different habitats in Zhalong Wetland

2014 ◽  
Vol 34 (13) ◽  
Author(s):  
张静 ZHANG Jing ◽  
马玲 MA Ling ◽  
丁新华 DING Xinhua ◽  
陈旭日 CHEN Xuri ◽  
马伟 MA Wei
Keyword(s):  
Microbial Biomass ◽  
Seasonal Dynamics ◽  
Soil Microbial Biomass ◽  
Microbial Biomass C ◽  
Soil Microbial Biomass C ◽  
Soil Microbial ◽  
Zhalong Wetland ◽  
C And N

Nitrogen- and sulfur-deposition-altered soil microbial community functions and enzyme activities in a boreal mixedwood forest in western Canada

2013 ◽  
Vol 43 (9) ◽  
pp. 777-784 ◽  
Author(s):  
Ya-Lin Hu ◽  
Kangho Jung ◽  
De-Hui Zeng ◽  
Scott X. Chang
Keyword(s):  
Microbial Community ◽  
Microbial Biomass ◽  
Soil Microbial Community ◽  
Oil Sands ◽  
Soil Microbial Biomass ◽  
Soil Microbial ◽  
C And N ◽  
Boreal Mixedwood Forest ◽  
The Impact ◽  
S Deposition

Chronic nitrogen (N) and (or) sulfur (S) deposition to boreal forests in the Athabasca oil sands region (AOSR) in Alberta, Canada, has been caused by oil sands mining and extraction/upgrading activities. It is important that we understand the response of microbial community function to chronic N and S deposition as microbial populations mediate soil carbon (C) and N cycles and affect ecosystem resilience. To evaluate the impact of N and (or) S deposition on soil microbial community functions, we conducted a simulated N and S deposition experiment in a boreal mixedwood forest with the following four treatments: control (CK), N addition (+N, 30 kg N·ha−1 as NH4NO3), S addition (+S, 30 kg S·ha−1 as NaSO4), and N plus S addition (+NS, 30 kg N·ha−1 + 30 kg S·ha−1), from 2006 to 2010. Nitrogen and (or) S deposition did not change soil organic carbon, total N, dissolved organic C and N, or soil microbial biomass C and N. Soil microbial community-level physiological profiles, however, were strongly affected by 5 years of N and (or) S addition. Soil β-glucosidase activity in the +NS treatment was greater than that in the +S treatment, and S addition decreased soil arylsulfatase; however, urease and dehydrogenase activities were not affected by the simulated N and (or) S deposition. Our data suggested that N and (or) S deposition strongly affected soil microbial community functions and enzymatic activities without changing soil microbial biomass in the studied boreal forest.

Sign in / Sign up

Export Citation Format

Share Document