Long term impact of different tillage systems on carbon pools and stocks, soil bulk density, aggregation and nutrients: A field meta-analysis

The estimation of soil wet bulk density (ρn) and dry bulk density (ρb) using the novel digital electromechanical system (DES) has provided information about important parameters for the assessment of soil quality and health with a direct application for agronomists. The evaluation of the DES performance is particularly appropriate for different tillage methods, mulching systems, and fertilizers used to increase soil fertility and productivity, but currently, there is a lack of information, particularly in the arid areas in underdeveloped countries. Therefore, the main aim of this study was the application of a novel digital electromechanical system (DES) to evaluate bulk density, wet (ρn) and dry (ρb), under different soil treatments according to the variations in thermal efficiencies (ηth), microwave penetration depths (MDP), and specific energy consumption (Qcon) in an experimental area close to Baghdad (Iraq). The experimental design consisted of 72 plots, each 4 m2. The agronomic practices included two different tillage systems (disc plough followed by a spring disk and mouldboard plough followed by a spring disk) and twelve treatments involving mulching plastic sheeting combined with fertilizers, to determine their effect on the measured soil ρn and ρb and the DES performance in different soils. The results indicated that soil ρn and ρb varied significantly with both the tillage systems and the mulching systems. As expected, the soil ρn and ρb, MDP, and Qcon increased with an increase in the soil depth. Moreover, the tillage, soil mulching, and soil depth value significantly affected ηth and Qcon. A strong relationship was identified between the soil tillage and MDP for different soil treatments, leading to the changes in soil ρb and the soil dielectric constant (ε’).

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Long-term grazing effects on grassland soil properties in southern British Columbia

Canadian Journal of Soil Science ◽

10.4141/cjss2011-070 ◽

2012 ◽

Vol 92 (4) ◽

pp. 685-693 ◽

Cited By ~ 28

Author(s):

C. R. W. Evans ◽

M. Krzic ◽

K. Broersma ◽

D. J. Thompson

Keyword(s):

British Columbia ◽

Soil Properties ◽

Bulk Density ◽

Aggregate Stability ◽

Soil Bulk Density ◽

Mechanical Resistance ◽

Stocking Rate ◽

Grassland Soil ◽

Grazing Effects

Evans, C. R. W., Krzic, M., Broersma, K. and Thompson, D. J. 2012. Long-term grazing effects on grassland soil properties in southern British Columbia. Can. J. Soil Sci. 92: 685–693. Although grazing effects on soil properties have been evaluated on various temperate grasslands, no study has dealt with these effects in the southern interior of British Columbia. The objective of this study was to determine the effects of spring versus fall season grazing as well as grazing [at a moderate rate of 0.6 animal unit months (AUM) ha−1] versus non-grazing by beef cattle on selected soil properties. Effects were determined 20 and 30 yr after the establishment of the field experiment. Soil properties were determined for the 0- to 7.5-cm, 7.5- to 15-cm, and 15- to 30-cm depths. In comparison with fall grazing, spring grazing had greater soil bulk density, greater mechanical resistance within the top 15 cm of the soil profile, higher pH, and lower polysaccharides. This was true for both 20 and 30 yr of treatment. Grazing effects on aggregate stability were observed only after 30 yr with spring grazing leading to a more stable structure with a mean weight diameter (MWD) of 1.5 mm and 32% and 10% of aggregates in the 2- to 6-mm and 1- to 2-mm size fractions, respectively, compared with a MWD of 1.0 mm and 20% and 6% under fall grazing. Greater soil bulk density, mechanical resistance, and pH were observed under the grazed treatment relative to the control without grazing, but as we used a moderate stocking rate the impacts were not as great as in previous studies, which used heavy stocking rates. Our findings show that long-term grazing at a moderate stocking rate of 0.6 AUM ha−1did not have critical detrimental effects on soil properties as some land managers and ranchers have suggested.

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Short and long-term effects of tillage systems and nutrient sources on soil physical properties of a Southern Brazilian Hapludox

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832008000400008 ◽

2008 ◽

Vol 32 (4) ◽

pp. 1437-1446 ◽

Cited By ~ 29

Author(s):

Milton da Veiga ◽

Dalvan José Reinert ◽

José Miguel Reichert ◽

Douglas Rodrigo Kaiser

Keyword(s):

Physical Properties ◽

Bulk Density ◽

Crop Residues ◽

Total Porosity ◽

Soil Physical Properties ◽

Soil Tillage ◽

Tillage Systems ◽

Nutrient Sources ◽

Over Time

Soil tillage promotes changes in soil structure. The magnitude of the changes varies with the nature of the soil, tillage system and soil water content and decreases over time after tillage. The objective of this study was to evaluate short-term (one year period) and long-term (nine year period) effects of soil tillage and nutrient sources on some physical properties of a very clayey Hapludox. Five tillage systems were evaluated: no-till (NT), chisel plow + one secondary disking (CP), primary + two (secondary) diskings (CT), CT with burning of crop residues (CTb), and CT with removal of crop residues from the field (CTr), in combination with five nutrient sources: control without nutrient application (C); mineral fertilizers, according to technical recommendations for each crop (MF); 5 Mg ha-1 yr-1 of poultry litter (wetmatter) (PL); 60 m³ ha-1 yr-1 of cattle slurry (CS) and; 40 m³ ha-1 yr-1 of swine slurry (SS). Bulk density (BD), total porosity (TP), and parameters related to the water retention curve (macroporosity, mesoporosity and microporosity) were determined after nine years and at five sampling dates during the tenth year of the experiment. Soil physical properties were tillage and time-dependent. Tilled treatments increased total porosity and macroporosity, and reduced bulk density in the surface layer (0.00-0.05 m), but this effect decreased over time after tillage operations due to natural soil reconsolidation, since no external stress was applied in this period. Changes in pore size distribution were more pronounced in larger and medium pore diameter classes. The bulk density was greatest in intermediate layers in all tillage treatments (0.05-0.10 and 0.12-0.17 m) and decreased down to the deepest layer (0.27-0.32 m), indicating a more compacted layer around 0.05-0.20 m. Nutrient sources did not significantly affect soil physical and hydraulic properties studied.

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SOIL BULK DENSITY ESTIMATION FOR TILLAGE SYSTEMS AND SOIL TEXTURES

Transactions of the ASAE ◽

10.13031/2013.17328 ◽

1998 ◽

Vol 41 (6) ◽

pp. 1601-1610 ◽

Cited By ~ 22

Author(s):

Y. Chen ◽

S. Tessier ◽

J. Rouffignat

Keyword(s):

Bulk Density ◽

Density Estimation ◽

Soil Bulk Density ◽

Tillage Systems

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A photogrammetry-based approach for soil bulk density measurements with an emphasis on applications to cosmogenic nuclide analysis

Earth Surface Dynamics ◽

10.5194/esurf-8-995-2020 ◽

2020 ◽

Vol 8 (4) ◽

pp. 995-1020

Author(s):

Joel Mohren ◽

Steven A. Binnie ◽

Gregor M. Rink ◽

Katharina Knödgen ◽

Carlos Miranda ◽

...

Keyword(s):

Bulk Density ◽

Soil Formation ◽

Soil Condition ◽

Soil Bulk Density ◽

Small Scale ◽

Soil Density ◽

Cosmogenic Nuclide ◽

Sampling Campaign ◽

Accuracy And Precision

Abstract. The quantification of soil bulk density (ρB) is a cumbersome and time-consuming task when traditional soil density sampling techniques are applied. However, it can be important for terrestrial cosmogenic nuclide (TCN) production rate scaling when deriving ages or surface process rates from buried samples, in particular when short-lived TCNs such as in situ 14C are applied. Here, we show that soil density determinations can be made using structure-from-motion multi-view stereo (SfM-MVS) photogrammetry-based volume reconstructions of sampling pits. Accuracy and precision tests as found in the literature and as conducted in this study clearly indicate that photographs taken from both a consumer-grade digital single-lens mirrorless (DSLM) and a smartphone camera are of sufficient quality to produce accurate and precise modelling results, i.e. to regularly reproduce the “true” volume and/or density by >95 %. This finding holds also if a freeware-based computing workflow is applied. The technique has been used to measure ρB along three small-scale (<1 km) N–S transects located in the semi-arid to arid Altos de Talinay, northern central Chile (∼30.5∘ S, ∼71.7∘ W), during a TCN sampling campaign. Here, long-term differences in microclimatic conditions between south-facing and north-facing slopes (SFSs and NFSs, respectively) explain a sharp contrast in vegetation cover, slope gradient and general soil condition patterns. These contrasts are also reflected by the soil density data, generally coinciding with lower densities on SFSs. The largest differences between NFSs and SFSs are evident in the lower portion of the respective slopes, close to the thalwegs. In general, field-state soil bulk densities were found to vary by about 0.6 g cm−3 over a few tens of metres along the same slope. As such, the dataset that was mainly generated to derive more accurate TCN-based process rates and ages can be used to characterise the present-day condition of soils in the study area, which in turn can give insight into the long-term soil formation and prevailing environmental conditions. This implies that the method tested in this study may also being applied in other fields of research and work, such as soil science, agriculture or the construction sector.

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Long Term Impact of Tillage Systems, Irrigation and Nitrogen on Soil Properties, Growth, Yield, Nutrient Uptake and Quality of Wheat (Triticum Aestivum L.)

International Journal of Agricultural Science and Research ◽

10.24247/ijasraug201772 ◽

2017 ◽

Vol 7 (4) ◽

pp. 555-566

Author(s):

P. K. Singh et.al., P. K. Singh et.al., ◽

Keyword(s):

Triticum Aestivum ◽

Soil Properties ◽

Nutrient Uptake ◽

Growth Yield ◽

Triticum Aestivum L ◽

Tillage Systems ◽

Long Term Impact

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Soil Bulk Density and Potato Tuber Yield as Influenced by Tillage Systems and Working Depths

Greener Journal of Agricultural Sciences ◽

10.15580/gjas.2014.2.020314087 ◽

2014 ◽

Vol 4 (2) ◽

pp. 046-051 ◽

Cited By ~ 1

Author(s):

K Abrougui ◽

◽

S Chehaibi ◽

H.H Boukhalfa ◽

I Chenini ◽

...

Keyword(s):

Potato Tuber ◽

Bulk Density ◽

Tuber Yield ◽

Soil Bulk Density ◽

Tillage Systems

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HbA1c Change and Diabetic Retinopathy During GLP-1 Receptor Agonist Cardiovascular Outcome Trials: A Meta-analysis and Meta-regression

10.2337/figshare.13100045.v1 ◽

2020 ◽

Author(s):

M. Angelyn Bethel ◽

Rafael Diaz ◽

Noelia Castellana ◽

Indranil Bhattacharya ◽

Hertzel C. Gerstein ◽

...

Keyword(s):

Glycemic Control ◽

Meta Analysis ◽

Cardiovascular Outcome ◽

Data Sources ◽

Sensitivity Analyses ◽

Cardiovascular Outcome Trials ◽

Meta Regression ◽

Long Term Impact

<a>Background: </a>Long-term glycemic control reduces retinopathy risk, but transient worsening can occur with glucose control intensification. GLP-1 receptor agonists (RA) lower glucose, but long-term impact on retinopathy is unknown. GLP-1RA cardiovascular outcome trials (CVOTs) provide long-term follow-up, allowing examination of retinopathy outcomes. Purpose: To examine the associations between retinopathy, HbA1c, systolic blood pressure (SBP) and weight in GLP-1RA CVOTs. Data Sources: Systematic review identified 6 placebo-controlled GLP-1RA CVOTs reporting prespecified retinopathy outcomes. Study Selection: Published trial reports were used as primary data sources. Data Extraction: HbA1c, SBP, and weight data throughout follow-up by treatment group were extracted. Data Synthesis: Random effects model meta-analysis showed no association between GLP-1RA treatment and retinopathy (odds ratio [OR] 1.10; 95% CI 0.93, 1.30), with high heterogeneity between studies (I2=52.2%; Q-statistic p=0.063). Univariate meta-regression showed an association between retinopathy and average HbA1c reduction during the overall follow-up (slope=0.77, p=0.007), but no relationship for SBP or weight. Sensitivity analyses for HbA1c showed a relationship at 3 months (p=0.006) and 1 year (p=0.002). A 0.1% (1.09 mmol/mol) increase in HbA1c reduction was associated with 6%, 14%, or 8% increased ln (OR) for retinopathy at the 3-month, 1-year, and overall follow-up, respectively. Limitations: CVOTs were not powered to assess retinopathy outcomes and differed in retinopathy-related criteria and methodology. The median follow-up of 3.4 years is short compared to the onset of retinopathy. Conclusions: HbA1c reduction was significantly associated with increased retinopathy risk in meta-regression for GLP-1RA CVOTs. The magnitude of HbA1c reduction was correlated with retinopathy risk in people with diabetes and additional cardiovascular risk factors, but the long-term impact of improved glycemic control on retinopathy is unmeasured in these studies. Retinopathy status should be assessed when intensifying glucose-lowering therapy.

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