Soil organic matter in rainfed cropping systems of the Australian cereal belt

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 435 ◽  
Author(s):  
R. C. Dalal ◽  
K. Y. Chan
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Management Practices ◽  
Performance Indicator ◽  
Annual Rainfall ◽  
Soil Productivity ◽  
Organic C ◽  
Soil C ◽  
Eastern Australia

The Australian cereal belt stretches as an arc from north-eastern Australia to south-western Australia (24˚S–40˚S and 125˚E–147˚E), with mean annual temperatures from 14˚C (temperate) to 26˚C (subtropical), and with annual rainfall ranging from 250 mm to 1500 mm. The predominant soil types of the cereal belt include Chromosols, Kandosols, Sodosols, and Vertosols, with significant areas of Ferrosols, Kurosols, Podosols, and Dermosols, covering approximately 20 Mha of arable cropping and 21 Mha of ley pastures. Cultivation and cropping has led to a substantial loss of soil organic matter (SOM) from the Australian cereal belt; the long-term SOM loss often exceeds 60% from the top 0–0.1 m depth after 50 years of cereal cropping. Loss of labile components of SOM such as sand-size or particulate SOM, microbial biomass, and mineralisable nitrogen has been even higher, thus resulting in greater loss in soil productivity than that assessed from the loss of total SOM alone. Since SOM is heterogeneous in nature, the significance and functions of its various components are ambiguous. It is essential that the relationship between levels of total SOM or its identif iable components and the most affected soil properties be established and then quantif ied before the concentrations or amounts of SOM and/or its components can be used as a performance indicator. There is also a need for experimentally verifiable soil organic C pools in modelling the dynamics and management of SOM. Furthermore, the interaction of environmental pollutants added to soil, soil microbial biodiversity, and SOM is poorly understood and therefore requires further study. Biophysically appropriate and cost-effective management practices for cereal cropping lands are required for restoring and maintaining organic matter for sustainable agriculture and restoration of degraded lands. The additional benefit of SOM restoration will be an increase in the long-term greenhouse C sink, which has the potentialto reduce greenhouse emissions by about 50 Mt CO2 equivalents/year over a 20-year period, although current improved agricultural practices can only sequester an estimated 23% of the potential soil C sink.

Three long-term trials end with a quasi-equilibrium between soil C, N, and pH: an implication for C sequestration

Soil Research ◽  
2012 ◽  
Vol 50 (7) ◽  
pp. 527 ◽  
Author(s):  
Mark Conyers ◽  
Philip Newton ◽  
Jason Condon ◽  
Graeme Poile ◽  
Pauline Mele ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Chemical Properties ◽  
C Sequestration ◽  
Soil Chemical Properties ◽  
Quasi Equilibrium ◽  
Soil C ◽  
Eastern Australia ◽  
N Fertility

The aim of this study was to assess the long-term changes in some key soil chemical properties at the completion of three long-term trials in south-eastern Australia and the relationship between those soil properties. From a soil organic matter perspective, the build-up of carbon (%C) requires an accumulation of nitrogen (%N), and the build-up of %C and %N fertility comes at the cost of soil acidity. Rotation, tillage, and stubble practices combine to alter the quantity, quality (C : N), and the depth distribution of organic matter in a soil, but the three soil chemical properties reported here seem to also be in quasi-equilibrium at the three long-term sites. The consequence is that if the build-up of soil organic matter leads to soil acidification, then the maintenance of agricultural production will require liming. The emission of CO2 when limestone reacts with soil acids, plus the C cost of limestone application, will negate a proportion of the gains from C sequestration as organic matter in soil. Such cautionary information was doubtless unforeseen when these three long-term trials were initiated.

scholarly journals Role of Earthworms in Soil Fertility Maintenance through the Production of Biogenic Structures

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Tunira Bhadauria ◽  
Krishan Gopal Saxena
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Management Practices ◽  
Soil Productivity ◽  
Published Data ◽  
Critical Function ◽  
Water Excretion ◽  
Organic C ◽  
Organic Matter Stabilization ◽  
Biogenic Structures

The soil biota benefits soil productivity and contributes to the sustainable function of all ecosystems. The cycling of nutrients is a critical function that is essential to life on earth. Earthworms (EWs) are a major component of soil fauna communities in most ecosystems and comprise a large proportion of macrofauna biomass. Their activity is beneficial because it can enhance soil nutrient cycling through the rapid incorporation of detritus into mineral soils. In addition to this mixing effect, mucus production associated with water excretion in earthworm guts also enhances the activity of other beneficial soil microorganisms. This is followed by the production of organic matter. So, in the short term, a more significant effect is the concentration of large quantities of nutrients (N, P, K, and Ca) that are easily assimilable by plants in fresh cast depositions. In addition, earthworms seem to accelerate the mineralization as well as the turnover of soil organic matter. Earthworms are known also to increase nitrogen mineralization, through direct and indirect effects on the microbial community. The increased transfer of organic C and N into soil aggregates indicates the potential for earthworms to facilitate soil organic matter stabilization and accumulation in agricultural systems, and that their influence depends greatly on differences in land management practices. This paper summarises information on published data on the described subjects.

DYNAMICS OF SOIL MICROBIAL BIOMASS AND WATER-SOLUBLE ORGANIC C IN BRETON L AFTER 50 YEARS OF CROPPING TO TWO ROTATIONS

1986 ◽  
Vol 66 (1) ◽  
pp. 1-19 ◽  
Author(s):  
W. B. McGILL ◽  
K. R. CANNON ◽  
J. A. ROBERTSON ◽  
F. D. COOK
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Environmental Conditions ◽  
Management Practices ◽  
Water Soluble ◽  
Turnover Rates ◽  
Organic Matter Quality ◽  
Organic C ◽  
Microbial N

Amounts and turnover rates of biomass and water-soluble organic C (WSOC) were measured at the Breton plots where records of long-term management of a Gray Luvisolic soil are available. Plots (control, manure, and NPKS) which had been cropped to either a wheat-fallow or a wheat-oats-barley-forage-forage rotation for 50 yr were sampled 13 times during 1981 and 1982. Biomass C and flush of microbial N were measured using the chloroform fumigation technique. Long-term crop yields were used to derive C supply to the plots. Regression analyses were used to relate seasonal fluctuations in environmental conditions to biomass and WSOC dynamics. Reinoculation with soil was unnecessary but Lysobacter sp. formed a greater proportion of isolates following incubation of fumigated soil than of unfumigated samples. Reinoculation with Lysobacter sp. is suggested to provide a more standardized biological assay. The 5-yr rotation contained 38% more N but 117% more microbial N than did the 2-yr rotation, and manured treatments contained twice as much microbial N as did NPKS or control plots. A management effect on soil organic matter quality is indicated. Averge turnover rates of biomass were 0.2–3.9 yr−1; being 1.5–2 times faster in the 2-yr rotation than in the 5-yr rotation. Replenishment of the WSOC component would have to occur 26–39 times yr−1 to supply microbial turnover. Most of the biomass must be dormant because annual C inputs are two orders of magnitude less than maintenance energy requirements. Seasonal variations in biomass were most consistently related to losses during desiccation and regrowth upon moistening. Regrowth appears to be at the expense of native soil organic matter. Management practices and environmental conditions therefore affect amount of organic matter by controlling both input of C and biomass turnover. Key words: Crop rotations, Luvisol, organic matter, biomass, soluble C, Breton plots

scholarly journals The Soil Organic Matter in Connection with Soil Properties and Soil Inputs

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 779
Author(s):  
Václav Voltr ◽  
Ladislav Menšík ◽  
Lukáš Hlisnikovský ◽  
Martin Hruška ◽  
Eduard Pokorný ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Texture ◽  
Management Practices ◽  
Soil Depth ◽  
Operating Conditions ◽  
Hot Water ◽  
Natural Soil ◽  
Soil Productivity ◽  
Linear Regression Models

The content of organic matter in the soil, its labile (hot water extractable carbon–HWEC) and stable (soil organic carbon–SOC) form is a fundamental factor affecting soil productivity and health. The current research in soil organic matter (SOM) is focused on individual fragmented approaches and comprehensive evaluation of HWEC and SOC changes. The present state of the soil together with soil’s management practices are usually monitoring today but there has not been any common model for both that has been published. Our approach should help to assess the changes in HWEC and SOC content depending on the physico-chemical properties and soil´s management practices (e.g., digestate application, livestock and mineral fertilisers, post-harvest residues, etc.). The one- and multidimensional linear regressions were used. Data were obtained from the various soil´s climatic conditions (68 localities) of the Czech Republic. The Czech farms in operating conditions were observed during the period 2008–2018. The obtained results of ll monitored experimental sites showed increasing in the SOC content, while the HWEC content has decreased. Furthermore, a decline in pH and soil´s saturation was documented by regression modelling. Mainly digestate application was responsible for this negative consequence across all soils in studied climatic regions. The multivariate linear regression models (MLR) also showed that HWEC content is significantly affected by natural soil fertility (soil type), phosphorus content (−30%), digestate application (+29%), saturation of the soil sorption complex (SEBCT, 21%) and the dose of total nitrogen (N) applied into the soil (−20%). Here we report that the labile forms (HWEC) are affected by the application of digestate (15%), the soil saturation (37%), the application of mineral potassium (−7%), soil pH (−14%) and the overall condition of the soil (−27%). The stable components (SOM) are affected by the content of HWEC (17%), soil texture 0.01–0.001mm (10%), and input of organic matter and nutrients from animal production (10%). Results also showed that the mineral fertilization has a negative effect (−14%), together with the soil depth (−11%), and the soil texture 0.25–2 mm (−21%) on SOM. Using modern statistical procedures (MRLs) it was confirmed that SOM plays an important role in maintaining resp. improving soil physical, biochemical and biological properties, which is particularly important to ensure the productivity of agroecosystems (soil quality and health) and to future food security.

Impact of long-term cultivation on the status of organic matter and cadmium in soil

2001 ◽  
Vol 81 (3) ◽  
pp. 349-355 ◽  
Author(s):  
D. F. E. McArthur ◽  
P M Huang ◽  
L M Kozak
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Significant Positive Correlation ◽  
Soil Organic C ◽  
Organic C ◽  
Total Soil ◽  
Total Organic C ◽  
Soil Cd ◽  
Cultivated Soils

Research has suggested a link between the bioavailability of soil Cd and total soil organic matter. However, some research suggested a negative relationship between total soil organic matter and bioavailable soil Cd while other research suggested a positive relationship. This study investigated the relationship between soil Cd and both the quantity and quality of soil organic matter as influenced by long-term cultivation. Two Orthic Chernozemic surface soil samples, one from a virgin prairie and the other from an adjacent cultivated prairie, were collected from each of 12 different sites throughout southern Saskatchewan, Canada. The samples were analyzed for total organic C, total Cd, Cd availability index (CAI), and pH. The nature of the soil organic matter was investigated with 13C Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance spectroscopy (13C CPMAS NMR). The total soil Cd, CAI, and total soil organic C of the cultivated soils were significantly lower than those of the virgin soils whereas the opposite trend was observed for the soil pH and the aromaticity of the organic C. The reduced CAI in the cultivated soils was related to the increase in both the soil pH and the aromaticity of the organic C. No relationship was found between the CAI and the soil organic C content, but a significant positive correlation was found between total organic C and total Cd in both the virgin and the cultivated soils. As well, a significant positive correlation was found between the fraction of total Cd removed from the soil after long-term cultivation and the corresponding fraction of organic C removed. Key words: Long-term cultivation, soil organic matter, 13C CPMAS NMR, cadmium

Changes in soil carbon under long-term maize in monoculture and legume-based rotation

2001 ◽  
Vol 81 (1) ◽  
pp. 21-31 ◽  
Author(s):  
E G Gregorich ◽  
C F Drury ◽  
J A Baldock
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Magnetic Resonance ◽  
Soil Carbon ◽  
Crop Residues ◽  
Cropping Systems ◽  
Natural Abundance ◽  
Organic C ◽  
Soil C

Legume-based cropping systems could help to increase crop productivity and soil organic matter levels, thereby enhancing soil quality, as well as having the additional benefit of sequestering atmospheric C. To evaluate the effects of 35 yr of maize monoculture and legume-based cropping on soil C levels and residue retention, we measured organic C and 13C natural abundance in soils under: fertilized and unfertilized maize (Zea mays L.), both in monoculture and legume-based [maize-oat (Avena sativa L.)-alfalfa (Medicago sativa L.)-alfalfa] rotations; fertilized and unfertilized systems of continuous grass (Poa pratensis L.); and under forest. Solid state 13C nuclear magnetic resonance (NMR) was used to chemically characterize the organic matter in plant residues and soils. Soils (70-cm depth) under maize cropping had about 30-40% less C, and those under continuous grass had about 16% less C, than those under adjacent forest. Qualitative differences in crop residues were important in these systems, because quantitative differences in net primary productivity and C inputs in the different agroecosystems did not account for observed differences in total soil C. Cropping sequence (i.e., rotation or monoculture) had a greater effect on soil C levels than application of fertilizer. The difference in soil C levels between rotation and monoculture maize systems was about 20 Mg C ha-1. The effects of fertilization on soil C were small (~6 Mg C ha-1), and differences were observed only in the monoculture system. The NMR results suggest that the chemical composition of organic matter was little affected by the nature of crop residues returned to the soil. The total quantity of maize-derived soil C was different in each system, because the quantity of maize residue returned to the soil was different; hence the maize-derived soil C ranged from 23 Mg ha-1 in the fertilized and 14 Mg ha-1 in the unfertilized monoculture soils (i.e., after 35 maize crops) to 6-7 Mg ha-1 in both the fertilized and unfertilized legume-based rotation soils (i.e., after eight maize crops). The proportion of maize residue C returned to the soil and retained as soil organic C (i.e., Mg maize-derived soil C/Mg maize residue) was about 14% for all maize cropping systems. The quantity of C3-C below the plow layer in legume-based rotation was 40% greater than that in monoculture and about the same as that under either continuous grass or forest. The soil organic matter below the plow layer in soil under the legume-based rotation appeared to be in a more biologically resistant form (i.e., higher aromatic C content) compared with that under monoculture. The retention of maize residue C as soil organic matter was four to five times greater below the plow layer than that within the plow layer. We conclude that residue quality plays a key role in increasing the retention of soil C in agroecosystems and that soils under legume-based rotation tend to be more “preservative” of residue C inputs, particularly from root inputs, than soils under monoculture. Key words: Soil carbon, 13C natural abundance, 13C nuclear magnetic resonance, maize cropping, legumes, root carbon

scholarly journals Spatial patterns in soil organic matter dynamics are shaped by mycorrhizosphere interactions in a treeline forest

2019 ◽  
Vol 447 (1-2) ◽  
pp. 521-535
Author(s):  
Nina L. Friggens ◽  
Thomas J. Aspray ◽  
Thomas C. Parker ◽  
Jens-Arne Subke ◽  
Philip A. Wookey
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Spatial Scales ◽  
Mountain Birch ◽  
Organic C ◽  
Soil C ◽  
Soil Organic Matter Dynamics ◽  
C Stocks ◽  
Organic Matter Dynamics ◽  
Individual Trees

Abstract Aims In the Swedish sub-Arctic, mountain birch (Betula pubescens ssp. czerepanovii) forests mediate rapid soil C cycling relative to adjacent tundra heaths, but little is known about the role of individual trees within forests. Here we investigate the spatial extent over which trees influence soil processes. Methods We measured respiration, soil C stocks, root and mycorrhizal productivity and fungi:bacteria ratios at fine spatial scales along 3 m transects extending radially from mountain birch trees in a sub-Arctic ecotone forest. Root and mycorrhizal productivity was quantified using in-growth techniques and fungi:bacteria ratios were determined by qPCR. Results Neither respiration, nor root and mycorrhizal production, varied along transects. Fungi:bacteria ratios, soil organic C stocks and standing litter declined with increasing distance from trees. Conclusions As 3 m is half the average size of forest gaps, these findings suggest that forest soil environments are efficiently explored by roots and associated mycorrhizal networks of B. pubescens. Individual trees exert influence substantially away from their base, creating more uniform distributions of root, mycorrhizal and bacterial activity than expected. However, overall rates of soil C accumulation do vary with distance from trees, with potential implications for spatio-temporal soil organic matter dynamics and net ecosystem C sequestration.

Soil organic matter as influenced by straw management practices and inclusion of grass and clover seed crops in cereal rotations

Soil Research ◽  
2003 ◽  
Vol 41 (1) ◽  
pp. 95 ◽  
Author(s):  
D. Curtin ◽  
P. M. Fraser
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Management Practices ◽  
Degree Days ◽  
Straw Management ◽  
Soil C ◽  
Total Soil ◽  
C And N ◽  
Second Year ◽  
Seed Crops

In New Zealand, cereal straw has traditionally been burned to facilitate seedbed preparation for the succeeding crop. Because of concerns over the decline of organic matter and the associated deterioration in soil structure, farmers are interested in incorporating crop residues as a means of maintaining organic matter levels. In a 6-year trial on a Wakanui silt loam on the Canterbury Plains, we evaluated the effects of 3 straw management practices (i.e. straw incorporation, burning of straw, and straw removal) on total and labile soil organic matter. A fourth treatment was included to evaluate the local practice of including seed crops (grass and clover) in cereal rotations. The seed crops were grown every second year, the crop sequence being cereal–ryegrass–cereal–clover–cereal–clover. The rate of straw (wheat) decomposition was determined using a litter bag technique, with the bags being buried at a depth of 15 cm for intervals of up to 19 months. In the straw-incorporated treatment, about 25 t/ha of straw (~11 t C/ha) was returned to the soil during the trial. However, there was no significant effect (P > 0.05) of straw management treatments on total soil C (or N), or on labile organic matter pools, although there was a tendency for higher levels of mineralisable C and N where straw was incorporated. Measured straw decomposition rates were consistent with predictions of the Douglas-Rickman residue decomposition model. Under the relatively warm conditions of the Canterbury Plains (thermal time typically >4000 degree-days per year, calculated as the sum of daily degree-days above a base temperature of 0�C), about three-quarters of incorporated straw decomposed within a year. Of the 11 t C/ha of straw-C incorporated, we estimated that only about 1 t C/ha would remain in the soil at the time of sampling. An increase in soil C by this amount would not be detectable (total soil C was about 55 t/ha in the upper 15 cm). Growing seed crops every second year increased several of the labile organic pools (mineralisable C and N, light fraction C and N, microbial biomass) in the 0–7.5 and 7.5 cm soil layers and this may have beneficial effects (e.g. improved N supply) on the succeeding cereal crop. However, the seed crops did not significantly increase total soil organic matter within the 6 years.

Using active fractions of soil organic matter as indicators of the sustainability of Ferrosol farming systems

Soil Research ◽  
1999 ◽  
Vol 37 (2) ◽  
pp. 279 ◽  
Author(s):  
M. J. Bell ◽  
P. W. Moody ◽  
S. A. Yo ◽  
R. D. Connolly
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Management Practices ◽  
Cropping Systems ◽  
Cropping System ◽  
Farming Systems ◽  
Total Carbon ◽  
Critical Concentrations ◽  
Aggregate Breakdown ◽  
Eastern Australia

Chemical and physical degradation of Red Ferrosols in eastern Australia is a major issue necessitating the development of more sustainable cropping systems. This paper derives critical concentrations of the active (permanganate-oxidisable) fraction of soil organic matter (C1) which maximise soil water recharge and minimise the likelihood of surface runoff in these soils. Ferrosol soils were collected from commercial properties in both north and south Queensland, while additional data were made available from a similar collection of Tasmanian Ferrosols. Sites represented a range of management histories, from grazed and ungrazed grass pastures to continuously cropped soil under various tillage systems. The concentration of both total carbon (C) and C1 varied among regions and farming systems. C1 was the primary factor controlling aggregate breakdown, measured by the percentage of aggregates <0·125 mm (P125) in the surface crust after simulated rainfall. The rates of change in P125 per unit change in C1 were not significantly different (P < 0·05) for soils from the different localities. However, soils from the coastal Burnett (south-east Queensland) always produced lower P125 (i.e. less aggregate breakdown) than did soils from the inland Burnett and north Queensland locations given the same concentration of C1. This difference was not associated with a particular land use. The ‘critical’ concentrations of C1 for each region were taken as the C1 concentrations that would allow an infiltration rate greater than or equal to the intensity of a 1 in 1 or 1 in 10 year frequency rainfall event of 30 min duration. This analysis also provided an indication of the risk associated with the concentrations of C1 currently characterising each farming system in each rainfall environment. None of the conventionally tilled Queensland Ferrosols contained sufficient C1 to cope with rainfall events expected to occur with a 1 in 10 frequency, while in many situations the C1 concentration was sufficiently low that runoff events would be expected on an annual basis. Our data suggest that management practices designed both to maximise C inputs and to maintain a high proportion of active C should be seen as essential steps towards developing a more sustainable cropping system.

Management effects on the dynamics and storage rates of organic matter in long-term crop rotations

2004 ◽  
Vol 84 (1) ◽  
pp. 49-61 ◽  
Author(s):  
E. A. Paul ◽  
H. P. Collins ◽  
K. Paustian ◽  
E. T. Elliott ◽  
S. Frey ◽  
...  
Keyword(s):  
Organic Matter ◽  
C Sequestration ◽  
Organic C ◽  
Soil C ◽  
Site Analysis ◽  
Laboratory Incubation ◽  
C And N ◽  
A Site ◽  
Management Effects

Factors controlling soil organic matter (SOM) dynamics in soil C sequestration and N fertility were determined from multi-site analysis of long-term, crop rotation experiments in Western Canada. Analyses included bulk density, organic and inorganic C and N, particulate organic C (POM-C) and N (POM -N), and CO2-C evolved during laboratory incubation. The POM-C and POM-N contents varied with soil type. Differences in POM-C contents between treatments at a site (δPOM-C) were related (r2= 0.68) to treatment differences in soil C (δSOC). The CO2-C, evolved during laboratory incubation, was the most sensitive indicator of management effects. The Gray Luvisol (Breton, AB) cultivated plots had a fivefold difference in CO2-C release relative to a twofold difference in soil organic carbon (SOC). Soils from cropped, Black Chernozems (Melfort and Indian Head, SK) and Dark Brown Chernozems (Lethbridge, AB) released 50 to 60% as much CO2-C as grassland soils. Differences in CO2 evolution from the treatment with the lowest SOM on a site and that of other treatments (δCO2-C) in the early stages of the incubation were correlated to δPOM-C and this pool reflects short-term SOC storage. Management for soil fertility, such as N release, may differ from management for C sequestration. Key words: Multi-site analysis, soil management, soil C and N, POM-C and N, CO2 evolution

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