scholarly journals The Effect of Increasing Topsoil Disturbance on Surface-Active Invertebrate Composition and Abundance under Grazing and Cropping Regimes on Vertisols in North-West New South Wales, Australia

Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 237
Author(s):  
Johnson N. Nkem ◽  
Lisa Lobry de Bruyn ◽  
Kathleen King
Keyword(s):  
Conventional Tillage ◽  
Soil Disturbance ◽  
Agricultural Management ◽  
Catchment Scale ◽  
North West ◽  
South Wales ◽  
Management Regimes ◽  
Consistent Manner ◽  
Surface Active ◽  
The Impact

Agricultural intensification practices involve varying degrees of disturbance to the soil ecosystem. This study evaluated six agricultural management regimes with increasing levels of topsoil disturbance, on the composition and abundance of surface-active invertebrates on Vertisols at a sub-catchment scale. Two grazing (native and introduced pastures), and four cropping (combining short and long fallow, with zero and conventional tillage) management regimes were examined. Surface-active invertebrates were collected seasonally with pitfall traps over 2 years (8 seasons), and identified to order, while ants (Formicidae) that comprised 47% of total invertebrates collected, were identified to genera. Season had a significant effect on ant abundance and number of genera recorded with higher abundance and twice the number of genera in summer than all other seasons. Ants, particularly Iridomyrmex, were mainly active in summer, while other invertebrates especially Coleoptera, were more active in winter. Surface-active invertebrates were 30% more abundant in grazing than cropping land use types. Native pasture, with little surface soil disturbance, recorded the highest number of invertebrates, mainly ants, compared to other agricultural management regimes. Coleoptera and Dermaptera were higher in abundance under conventional tillage compared with those agricultural management regimes that disturb the topsoil less. Optimizing surface-active invertebrate activity on Vertisols for most taxa will require reducing topsoil disturbance. However, the research findings also suggest that the impact of agricultural management regimes on invertebrate activity was difficult to predict with any certainty as the three main ant genera, and most abundant invertebrate collected, did not respond in a consistent manner.

Evaluation of olive grove management on various soils at the micro-catchment scale with the AnnAGNPS model to quantify their impacts on organic carbon

2020 ◽  
Author(s):  
Encarnación Taguas ◽  
Ronald L. Bingner ◽  
Henrique Momm ◽  
Robert R. Wells ◽  
Martin Locke
Keyword(s):  
Organic Carbon ◽  
Sandy Loam ◽  
Experimental Studies ◽  
Life Time ◽  
Conventional Tillage ◽  
Catchment Scale ◽  
Maximum Increase ◽  
Small Catchment ◽  
Silty Loam ◽  
The Impact

<p>Soil organic carbon (SOC) stock changes are crucial to identify the risk of desertification in fragile areas such as the Mediterranean Basin and to fulfill environmental protection global conventions. In Spain, 48% of the world’s olive oil is produced with 2.6 Mha dedicated to the crop and there is clear concern over the carbon balance in the context of climate change and the resulting loss of productivity. In this work, 108 scenarios were prepared with the model AnnAGNPS in a small catchment of extensive olive groves by considering the impact of soil type and management using 6 different soil types (with textures sandy, S; sandy loam, Slo; loam, L; clay loam, Clo; silty loam clay, SiLoC; clay, C), 3 different managements (no till, NT; conventional tillage, CT, and cover crop, SC), 3 types of fertilization (two organic with different rates, F2 and F3,  and another inorganic F1) and 2 contrasting reach organic carbon half-life time (0.1 day-730 days). The consistency of the simulated values of annual OC attached to the sediments and of variations of ground SOC (h=200 mm) were evaluated and compared in the context of the region of Andalusia.</p><p>There were significant differences of annual values of the sediment OC for the scenarios of soil and management with a range variation between 0.0 kg.ha<sup>-1</sup> and 368.9 kg.ha<sup>-1</sup>. In addition, S and SC showed the lowest variability intervals while Clo and NT had the highest sediment OC and variation ranges. For the SOC pools, the effects of soil and fertilization types were more evident than of the management. The combination C-SC-F3 presented the maximum increase of SOC (0.150 mg OC.g<sup>-1</sup>soil.y<sup>-1</sup>) while the combination Slo-NT-F1 presented the minimum (0.080 mg OC.g<sup>-1</sup>soil.y<sup>-1</sup>). Despite specific calibrations needed to quantify OC balances, the consistency of the hydrological and erosive parameterization based on the abundance of experimental studies supports the use of AnnAGNPS for simulating the OC loss in agricultural catchments.</p>

The potential for sown tropical perennial grass pastures to improve soil organic carbon in the North-West Slopes and Plains of New South Wales

Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 726 ◽  
Author(s):  
G. D. Schwenke ◽  
M. K. McLeod ◽  
S. R. Murphy ◽  
S. Harden ◽  
A. L. Cowie ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
New South ◽  
Conventional Tillage ◽  
Tropical Pastures ◽  
Total N ◽  
Organic C ◽  
North West ◽  
South Wales ◽  
Native Pastures

Sown tropical perennial grass pastures may be a means to restore soil organic carbon (C) lost by cropping with conventional tillage to the levels originally present in native grass pastures. To assess this, total organic carbon and related soil properties were measured under sown tropical pastures, conventionally cultivated cropping, and native pastures on 75 Chromosols and 70 Vertosols to 0.3 m depth in the New South Wales North-West Slopes and Plains region of Australia. The impact of several perennial pasture species on soil organic carbon was also assessed in a 6-year-old, sown pasture experiment on a previously cropped Chromosol. Soil cores in 0.1-m segments to 0.3 m were analysed for total organic carbon, total nitrogen (N), pH, and phosphorus (Colwell-P). Mid-infrared scans were used to predict the particulate, humus, and resistant fractions of the total organic carbon. Bulk density was used to calculate stocks of C, N, and C fractions. In Chromosols, total organic carbon in the surface 0–0.1 m was greater under sown tropical pastures (23.1 Mg ha–1) than conventional tillage cropping (17.7 Mg ha–1), but still less than under native pastures (26.3 Mg ha–1). Similar land-use differences were seen for particulate and resistant organic C, and total N. The proportional differences between land uses were much greater for particulate organic C than other measures, and were also significant at 0.1–0.2 and 0.2–0.3 m. Subsurface bulk density (0.1–0.2 m) was lower under sown tropical pastures (1.42 Mg m–3) than conventionally tilled cropping (1.52 Mg m–3). For Vertosols, total organic carbon in the surface 0–0.1 m was greater under sown tropical pastures (19.0 Mg ha–1) and native pastures (20.5 Mg ha–1) than conventional tillage cropping (14.0 Mg ha–1). Similar land-use effects were seen for the particulate and humus organic C fractions, and total N. In the sown pasture species experiment, there was no significant difference in total N, total organic carbon, or any C fraction between soils under a native-grass species mixture, two improved tropical grass species, or a perennial pasture legume. Regular monitoring is required to better discern whether gradual changes are being masked by spatial and temporal variation. The survey results support previous research on Vertosols within the New South Wales North-West Slopes and Plains that show sown tropical grass pastures can improve total organic carbon. Improvements in total organic carbon on Chromosols have not previously been documented, so further targeted soil monitoring and experimentation is warranted for the region.

scholarly journals The use of total luminescence spectroscopy in the investigation of the effects of different rice management practices on humic substances of a planosol

2009 ◽  
Vol 33 (5) ◽  
pp. 1147-1152 ◽  
Author(s):  
Rodrigo Nogueira Olendzki ◽  
Andréia Christina Ignácio ◽  
Antonio Salvio Mangrich
Keyword(s):  
Humic Substances ◽  
Management Practices ◽  
Conventional Tillage ◽  
Agricultural Management ◽  
Emission Wavelength ◽  
Luminescence Spectroscopy ◽  
Reduced Tillage ◽  
C Stocks ◽  
Management Techniques ◽  
The Impact

In the Earth's carbon cycle, C stocks in the soil are higher than in vegetation and atmosphere. Maintaining and conserving organic C concentrations in the soil by specific management practices can improve soil fertility and productivity. The aim of this study was to evaluate the impact of agricultural management techniques and influence of water regime (flooded or drained) on the structure of humic substances by excitation/emission matrix fluorescence. Six samples of a Planosol (Planossolo by the Brazilian System of Soil Classification) were collected from a rice field. Humic substances (HS) were extracted from flooded and drained soil under different agricultural management techniques: conventional tillage, reduced tillage and grassland. Two peaks at a long emission wavelength were observed in the EEM spectra of HA whereas those of the corresponding FA contained a unique fluorophore at an intermediate excitation/emission wavelength pair (EEWP) value. The fluorescence intensity measured by total luminescence (FI TL) of HA was lower than that of the corresponding FA. A comparison of all samples (i.e., the HA values compared to each other) revealed only slight differences in the EEWP position, but the FI TL values were significantly different. In this soil, anoxic conditions and reduced tillage (little plowing) seem to favor a higher degree of humification of the soil organic matter compared with aerated conditions and conventional tillage.

The Global Uptake of Conservation Agriculture and the Impact on Water-Related Ecosystem Services

2018 ◽  
pp. 689-708
Author(s):  
Amir Kassam ◽  
David Coates
Keyword(s):  
Ecosystem Services ◽  
Crop Production ◽  
Conservation Agriculture ◽  
Conventional Tillage ◽  
Soil Disturbance ◽  
Related Services ◽  
Alternative Crop ◽  
Current Spread ◽  
The Impact ◽  
Production Approach

Conventional tillage agriculture has a built-in propensity for soil erosion and land degradation leading to loss of ecosystem services that are required to sustain agricultural production as well as minimize off-farm impacts. It is associated with suboptimal crop and land productivity. The global uptake of Conservation Agriculture (CA), which is a recognized flagship alternative crop production approach, is built upon three practical interlinked principles of: no or minimum mechanical soil disturbance (‘no-till’), soil cover management, and diversified cropping. The current spread of CA globally is 180 M ha of annual cropland (12.5 per cent), increasing annually at 10 M ha. Knowledge of how CA positively affects ecosystem services at the field and landscape level, with emphasis on water-related services and food security, shows that CA has the potential to meet, or exceed, most of the current shortfall in projected global agricultural water demand by 2050.

Soil carbon is only higher in the surface soil under minimum tillage in Vertosols and Chromosols of New South Wales North-West Slopes and Plains, Australia

Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 680 ◽  
Author(s):  
M. K. McLeod ◽  
G. D. Schwenke ◽  
A. L. Cowie ◽  
S. Harden
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Soil Carbon ◽  
Carbon Stock ◽  
Management Practices ◽  
New South ◽  
Conventional Tillage ◽  
Minimum Tillage ◽  
North West ◽  
South Wales

Reduced carbon stock levels in Australian soil due to cropping provide a significant opportunity for carbon sequestration, and the recent initiative to consider soil carbon in domestic emissions trading requires a scientific assessment of soil carbon levels under a range of cropping soil management practices. Some of the previous research in southern and western New South Wales (NSW) showed that the rate of carbon decline in cropping soils is slowed under minimum tillage when the stubble is also retained. However, such comparison is rare in the NSW North-West Slopes and Plains region, particularly on the red soils (Chromosols) which are one of the major soil types in the region. We surveyed 50 dryland Chromosols, 72 dryland Vertosols, and 25 irrigated Vertosols on commercial farms across this region to examine the effects of conventional tillage, minimum tillage, and irrigation on total soil organic carbon. Samples of 0.1 m segments to 0.3 m depth were analysed for total organic carbon and other soil properties. Mid-infrared scans were used to predict the particulate, humus, and resistant soil organic carbon fractions. Bulk density was used to calculate total organic carbon stock for each segment, and equivalent soil mass (ESM) for 0–0.3 m. In Vertosols, for 0–0.3 m ESM, total organic carbon and particulate organic carbon were not different between management practices, whereas humic organic carbon and resistant organic carbon were consistently lower under conventional tillage. However, in 0–0.1 m, total organic carbon was greater under minimum tillage (15.2 Mg ha–1) than conventional tillage (11.9 Mg ha–1) or irrigation (12.0 Mg ha–1), reflecting less soil surface disturbance under minimum tillage. In Chromosols, only total organic carbon was higher under minimum tillage than conventional tillage in the 0–0.3 m ESM (39.8 v. 33.5 Mg ha–1) and in 0–0.1 m (19.7 v. 16.9 Mg ha–1). The strong influences of rainfall, temperature, bulk density, texture, and management history on soil carbon stocks suggested that these environmental and management factors require further consideration when gauging soil carbon sequestration potential under current and novel tillage practices in key regional locations.

Sediment yields and turbidity records from small upland subcatchments in the Warragamba Dam Catchment, southern New South Wales

Soil Research ◽  
2002 ◽  
Vol 40 (4) ◽  
pp. 557 ◽  
Author(s):  
J. L. Armstrong ◽  
D. H. Mackenzie
Keyword(s):  
Water Supply ◽  
New South ◽  
New South Wales ◽  
Large River ◽  
Catchment Scale ◽  
Sediment Yields ◽  
Stream Monitoring ◽  
South Wales ◽  
Order Of Magnitude ◽  
The Impact

Accelerated rates of soil erosion, following European settlement in Australia, pose a major threat to river ecosystems and water supply storages with agricultural catchments, such as Warragamba Dam (the main water supply dam for Sydney). Sediment yields from 1988 to 1999 have been determined by stream monitoring for 6 small grazing catchments located near Goulburn in southern New South Wales, in the outer Warragamba catchment. Average specific sediment yields were 0.07 t/ha.year from 3 small catchments of around 10 ha, where the drainage lines were not continuously gullied, and the drainage lines were undisturbed. Sediment yields from larger gullied catchments of 29, 52, and 510 ha were at least an order of magnitude higher than from the ungullied catchments at around 1 t/ha.year. Gullies continue to be the dominant source of sediment from these subcatchments despite indications that yields from gullies in the Southern Tablelands are much less than in the first few decades following settlement and are gradually declining as gullies move towards a stable vegetated state. Measured sediment yields from this study are comparable with yields for southern New South Wales determined using other methods, such as radionuclide and farm dam survey techniques. The impact of soil conservation works, such as sediment trapping and grade stabilisation works, on sediment yields can be mixed depending on the activity of the gully being treated and the mobility of the bed sediments. Turbidity levels from runoff events from the gullied catchments were an order of magnitude higher than from the ungullied catchments. For the Warragamba catchment turbidity levels are scale dependent; at the farm paddock scale turbidities are generally low where the land use is grazing, they increase dramatically at the subcatchment scale where active gullies dominate the drainage network, and then drop back again at the large river catchment scale. Turbidity is positively correlated with sediment concentration, so works that reduce sediment loads will also reduce the turbidity of water leaving the subcatchment. However, the link between high turbidity levels in small upland catchments and downstream water quality in large complex river basins is tenuous.

The Impact of Bioconjugation on the Interfacial Activity of a Protein Biosurfactant

2018 ◽  
Author(s):  
Hossam H Tayeb ◽  
Marina Stienecker ◽  
Anton Middelberg ◽  
Frank Sainsbury
Keyword(s):  
Polyethylene Glycol ◽  
Colloidal Stability ◽  
Point Mutations ◽  
Pharmaceutical Formulations ◽  
Industrial Processes ◽  
Parent Molecule ◽  
Site Specific ◽  
Interfacial Activity ◽  
Surface Active ◽  
The Impact

Biosurfactants, are surface active molecules that can be produced by renewable, industrially scalable biologic processes. DAMP4, a designer biosurfactant, enables the modification of interfaces via genetic or chemical fusion to functional moieties. However, bioconjugation of addressable amines introduces heterogeneity that limits the precision of functionalization as well as the resolution of interfacial characterization. Here we designed DAMP4 variants with cysteine point mutations to allow for site-specific bioconjugation. The DAMP4 variants were shown to retain the structural stability and interfacial activity characteristic of the parent molecule, while permitting efficient and specific conjugation of polyethylene glycol (PEG). PEGylation results in a considerable reduction on the interfacial activity of both single and double mutants. Comparison of conjugates with one or two conjugation sites shows that both the number of conjugates as well as the mass of conjugated material impacts the interfacial activity of DAMP4. As a result, the ability of DAMP4 variants with multiple PEG conjugates to impart colloidal stability on peptide-stabilized emulsions is reduced. We suggest that this is due to constraints on the structure of amphiphilic helices at the interface. Specific and efficient bioconjugation permits the exploration and investigation of the interfacial properties of designer protein biosurfactants with molecular precision. Our findings should therefore inform the design and modification of biosurfactants for their increasing use in industrial processes, and nutritional and pharmaceutical formulations.

Impact and Challenges of Centres for Education and Community Action in Cameroon’s North West Region

2018 ◽  
Vol 8 (2) ◽  
pp. 51-74
Author(s):  
Fonteh Athanasius Amungwa
Keyword(s):  
Rural Development ◽  
Economic Crisis ◽  
Formal Education ◽  
Community Education ◽  
Sampling Technique ◽  
Community Action ◽  
Structured Interviews ◽  
North West ◽  
West Region ◽  
The Impact

This paper examines the impact of community education and challenges facing Centres for Education and Community Action as a rural development strategy in Cameroon. The study was conducted in the North-West Region of Cameroon, employing field observations, semi-structured interviews with key informants using a convenient sampling technique and through elaborate review of documents. These research instruments were blended into what is termed triangulation and the data collected was analysed descriptively. The main focus of qualitative analysis is to understand the ways in which people act and the accounts that people give for their actions. This paper posits that extreme dependence on the provision of Western formal education cannot solve the problems of a rapidly changing society like Cameroon, which is facing a long-term economic crisis and persistent unemployment issues of graduates. Consequently, education should be redefined in the context of the prevailing economic crisis to make it responsive to the aspirations of rural communities. Findings showed that community education had contributed towards rural development immensely but has suffered many challenges due to neglect of the field in the policy agenda. This paper recommends the integration of community education with formal education to facilitate group and community betterment in particular and rural transformation in general.

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