Soil and vegetation of ungrazed crested wheatgrass and native rangelands

2000 ◽  
Vol 80 (3) ◽  
pp. 411-417 ◽  
Author(s):  
K. Broersma ◽  
M. Krzic ◽  
D. J. Thompson ◽  
A. A. Bomke
Keyword(s):  
Species Diversity ◽  
Soil Quality ◽  
Soil Aggregates ◽  
Plant Cover ◽  
Size Fraction ◽  
Aggregate Stability ◽  
Penetration Resistance ◽  
Slight Reduction ◽  
Crested Wheatgrass ◽  
Soil C

Seeding of introduced forage grasses, such as crested wheatgrass [Agropyron cristatum (L.) Gaertn. and A. desertorum (Fisch.) Schult.], can lead to the reduction of species diversity and soil quality. This study evaluated the effects of crested wheatgrass on soil and vegetation relative to native rangeland dominated by bluebunch wheatgrass [Pseudoroegneria spicata (Pursh) Scribn. & Smith] under ungrazed conditions. Three sites consisting of adjacent ungrazed stands of crested wheatgrass and native vegetation were sampled in June 1997. Total plant cover was 37% on native and 24% on crested wheatgrass rangeland. Species richness was lower for crested wheatgrass than for native rangeland. Quantities of root biomass and most soil properties were similar for the two rangelands. Native rangeland had a more stable soil structure with 1.7 mm mean weight diameter (MWD) and 38% of soil aggregates in the 2–6 mm size fraction compared to 1.4 mm MWD and 28% of soil aggregate in the 2–6 mm size fraction on crested wheatgrass rangeland. Greater soil penetration resistance was observed at the 6 and 7.5 cm depths for crested wheatgrass rangeland. Crested wheatgrass did not invade adjacent native rangelands and only a slight reduction in soil quality was observed on crested wheatgrass rangelands. Key words: Crested wheatgrass, soil C, soil N, penetration resistance, aggregate stability, species diversity

Labile soil carbon fractions as indicators of soil quality improvement under short-term grassland set-aside

Soil Research ◽  
2020 ◽  
Vol 58 (4) ◽  
pp. 364
Author(s):  
Jason M. Lussier ◽  
Maja Krzic ◽  
Sean M. Smukler ◽  
Katarina R. Neufeld ◽  
Chantel J. Chizen ◽  
...  
Keyword(s):  
Soil Quality ◽  
Quality Indicators ◽  
Crop Production ◽  
Low Cost ◽  
Size Fraction ◽  
Aggregate Stability ◽  
Aggregate Size ◽  
Soil Quality Indicators ◽  
Short Term ◽  
Soil C

Grassland set-asides (GLSA) are fields that are taken out of intensive annual crop production and seeded with a mixture of grasses and legumes for one to four years to improve soil quality. The objectives of this study were to evaluate (i) the relationships among soil organic carbon (SOC), permanganate oxidisable C (POXC), dilute-acid extractable polysaccharides (DAEP) and aggregate stability to determine if they may be used as proxies for one another, (ii) whether these indicators could be used to predict aggregate stability, (iii) if differences in soil quality after short-term GLSAs, detected with aggregate stability, could instead be detected with POXC or DAEP and (iv) potential use of diffuse Fourier transform spectroscopy (FT-MIR) to predict POXC, DAEP and aggregate stability in the Fraser River Delta region of British Columbia, Canada. There were strong relationships among SOC, POXC and DAEP, but the relationship between DAEP and SOC (R2 = 0.60, P < 0.0001) was less strong than that observed between POXC and SOC (R2 = 0.71, P < 0.0001). All three soil C fractions were significantly predicted with the 2–6 mm aggregate size fraction but the correlations for DAEP (R2 = 0.43) and POXC (R2 = 0.36) were stronger than that for SOC (R2 = 0.29). Predictions of soil quality indicators using FT-MIR produced R2 = 0.92 for POXC, R2 = 0.93 for DAEP and R2 = 0.62 for the 2–6 mm aggregate size fraction. These results suggest that FT-MIR holds promise as a low-cost method to determine labile soil C fractions that are better proxy soil quality indicators for aggregate stability than SOC.

scholarly journals Enzymatic biofilm detachment causes a loss of aggregate stability in a sandy soil

2016 ◽  
Author(s):  
F. Büks ◽  
M. Kaupenjohann
Keyword(s):  
Organic Matter ◽  
Soil Quality ◽  
Extracellular Polymeric Substances ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Agricultural Practices ◽  
Enzyme Treatment ◽  
Rooting Depth ◽  
Experimental Proof ◽  
Biofilm Detachment

Abstract. The stability of soil aggregates against shear and compressive forces as well as water caused dispersion is an integral marker of soil quality. High stability results in less soil compactibility and erodibility, enhanced water retention, a dynamic water transport and aeration regime, increased rooting depth and protection of soil organic matter (SOM) against microbial degradation. For decades the importance of biofilm extracellular polymeric substances (EPS) regarding aggregate stability has been canonical because of its distribution, geometric structure and ability to link primary particles. However, experimental proof is still missing. This lack is mainly due to methodological reasons. Thus, the objective of this work is to develop a method of enzymatic biofilm detachment for studying the effects of EPS on soil aggregate stability. The method combines an enzymatic pre-treatment with different activities of α-glucosidase, β-galactosidase, DNAse and lipase, which preserves aggregate structure, with a subsequent sequential ultrasonic treatment for disaggregation and density-fractioning. Soil organic carbon (SOC) releases of treated samples were compared to an enzyme-free control. To test the effectivity of biofilm detachment the ratio of bacterial DNA from sessile and suspended cells after enzymatic treatment was measured by quantitative real-time PCR. Although the enzyme treatment was not sufficient for total biofilm removal, our results confirm, that EPS stabilizes soil aggregates predominantly by a strong intra-aggregate fixation, and enzymatic biofilm digestion caused a shift of occluded particulate organic matter (POM) to more fragile binding patterns. This suggests that an effect of agricultural practices on soil microbial populations could influence aggregate stability and thereby soil quality.

scholarly journals Enzymatic biofilm digestion in soil aggregates facilitates the release of particulate organic matter by sonication

SOIL ◽  
2016 ◽  
Vol 2 (4) ◽  
pp. 499-509 ◽  
Author(s):  
Frederick Büks ◽  
Martin Kaupenjohann
Keyword(s):  
Organic Matter ◽  
Soil Quality ◽  
Particulate Organic Matter ◽  
Extracellular Polymeric Substances ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Enzyme Treatment ◽  
Rooting Depth ◽  
Experimental Proof ◽  
Biofilm Detachment

Abstract. The stability of soil aggregates against shearing and compressive forces as well as water-caused dispersion is an integral marker of soil quality. High stability results in less compaction and erosion and has been linked to enhanced water retention, dynamic water transport and aeration regimes, increased rooting depth, and protection of soil organic matter (SOM) against microbial degradation. In turn, particulate organic matter is supposed to support soil aggregate stabilization. For decades the importance of biofilm extracellular polymeric substances (EPSs) regarding particulate organic matter (POM) occlusion and aggregate stability has been canonical because of its distribution, geometric structure and ability to link primary particles. However, experimental proof is still missing. This lack is mainly due to methodological reasons. Thus, the objective of this work is to develop a method of enzymatic biofilm detachment for studying the effects of EPSs on POM occlusion. The method combines an enzymatic pre-treatment with different activities of α-glucosidase, β-galactosidase, DNAse and lipase with a subsequent sequential ultrasonic treatment for disaggregation and density fractionation of soils. POM releases of treated samples were compared to an enzyme-free control. To test the efficacy of biofilm detachment the ratio of bacterial DNA from suspended cells and the remaining biofilm after enzymatic treatment were measured by quantitative real-time PCR. Although the enzyme treatment was not sufficient for total biofilm removal, our results indicate that EPSs may attach POM within soil aggregates. The tendency to additional POM release with increased application of enzymes was attributed to a slight loss in aggregate stability. This suggests that an effect of agricultural practices on soil microbial populations could influence POM occlusion/aggregate stability and thereby carbon cycle/soil quality.

Farmer perceptions of soil quality and their relationship to management-sensitive soil parameters

2007 ◽  
Vol 22 (4) ◽  
pp. 271-281 ◽  
Author(s):  
J.B. Gruver ◽  
R.R. Weil
Keyword(s):  
Soil Quality ◽  
Structural Parameters ◽  
Aggregate Stability ◽  
Farming Systems ◽  
Soil Parameters ◽  
Study Region ◽  
Individual Parameter ◽  
Soil C ◽  
Percent Difference ◽  
Level Of Agreement

AbstractA critical step in the quantification of soil quality (SQ) is the selection of SQ benchmarks. The benchmarks used in this study were SQ ratings made by 32 farmer collaborators representing a range of farming systems, scales of operation and geographic locations in the Mid-Atlantic region of USA. Soils from 45 pairs of sites identified by their farmers as having good and poor SQ were sampled over three seasons and analyzed for 19 soil parameters. Farmer judgments of SQ were based on many factors, most commonly soil organic matter, crop performance, soil water availability and erosion history. Selected individual soil parameters were normalized and integrated into an additive SQ index (SQI). Three additional indices were developed using discriminant analysis. The level of agreement between individual parameters, SQIs and farmer SQ ratings was evaluated using paired t-tests and mean percent difference values. The additive SQI was found to have the highest level of agreement with farmer SQ ratings (P<0.0001), demonstrating that a linear combination of soil parameters can be assembled that is more in agreement with holistic SQ criteria, such as farmer SQ ratings, than individual soil parameters. Extractable C from microwave (MW) sterilized soil (a measure of microbial biomass) was the individual parameter that best agreed with farmer SQ ratings (P<0.0001). Five additional soil C parameters, as well as aggregate stability, also agreed well with farmer SQ ratings (all P values <0.0005). The three parameters with the highest ratio of mean percent difference to coefficient of variation (an indication of parameter reliability) were extractable C from MW sterilized soil, anthrone reactive C and macroaggregate stability (14.2, 7.7 and 3.7, respectively). Mineral fertility parameters (pH, Ca, Ca:Mg ratio, P and K) were not significantly related to farmer SQ ratings (P values >0.05). The strong relationships observed between soil C parameters, soil structural parameters and farmer SQ ratings suggest that efforts to improve SQ in the study region should focus on monitoring and enhancement of soil C and soil structure.

scholarly journals Aggregate structure and stability linked to carbon dynamics in a south Chilean Andisol

2005 ◽  
Vol 2 (1) ◽  
pp. 203-238 ◽  
Author(s):  
D. Huygens ◽  
P. Boeckx ◽  
O. Van Cleemput ◽  
R Godoy ◽  
C. Oyarzún
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Carbon Dynamics ◽  
C Mineralization ◽  
Physical Protection ◽  
Soil C

Abstract. The extreme vulnerability of soil organic carbon to climate and land use change emphasizes the need for further research in different terrestrial ecosystems. We have studied the aggregate stability and carbon dynamics in a chronosequence of three different land uses in a south Chilean Andisols: a second growth Nothofagus obliqua forest (SGFOR), a grassland (GRASS) and a Pinus radiata plantation (PINUS). The aim of this study was to investigate the role of Al as soil organic matter stabilizing agent in this Andisol. In a case study, we linked differences in carbon dynamics between the three land use treatments to physical protection and recalcitrance of the soil organic matter (SOM). In this study, C aggregate stability and dynamics were studied using size and density fractionation experiments of the SOM, δ13C and total carbon analysis of the different SOM fractions, and mineralization measurements. The results showed that electrostatic attractions between and among Al-oxides and clay minerals are mainly responsible for the stabilization of soil aggregates and the physical protection of the enclosed soil organic carbon. Whole soil C mineralization rate constants were highest for SGFOR and PINUS, followed by GRASS. In contrast, incubation experiments of isolated macro organic matter fractions showed that the recalcitrance of the SOM decreased in another order: PINUS > SGFOR > GRASS. We concluded that physical protection of soil aggregates was the main process determining whole soil C mineralization. Land use changes affected soil organic carbon dynamics in this south Chilean Andisol by altering soil pH and consequently available Al.

scholarly journals Changes in Soil Aggregate Stability Induced by Mineral Nitrogen Fertilizer Application

2017 ◽  
Vol 65 (5) ◽  
pp. 1477-1482 ◽  
Author(s):  
Martin Brtnický ◽  
Jakub Elbl ◽  
Helena Dvořáčková ◽  
Jindřich Kynický ◽  
Jan Hladký
Keyword(s):  
Soil Quality ◽  
Nitrogen Fertilizer ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Fertilizer Application ◽  
Soil Aggregate ◽  
Significant Deterioration ◽  
N Application ◽  
Soil Aggregate Stability ◽  
The Stability

The stability of soil aggregates is one of the most important characteristics of the soil affecting the overall soil quality and its health. In locality Březová nad Svitavou, experiment to reveal the effect of nitrogen dose on the stability of soil aggregates of Rendzina soil was carried out. The aim was to detect changes in soil aggregate stability after 4 and 5 years from the beginning of the experiment. There were tested 7 variants, prepared in triplicate. The results revealed that the stability of soil aggregates decreases with increasing amounts of applied N. Effect of N application was not statistically significant in the fourth but in the fifth year of the experiment. The results also revealed a significant deterioration in the stability of soil aggregates in the fifth year compared to the fourth year of the experiment.

scholarly journals Aggregate stability and penetration resistance after mobilization of a dystrocohesive Ultisol

2017 ◽  
Vol 21 (11) ◽  
pp. 752-757 ◽  
Author(s):  
Uilka E. Tavares ◽  
Mario M. Rolim ◽  
Djalma E. Simões Neto ◽  
Elvira M. R. Pedrosa ◽  
Adriana G. Magalhães ◽  
...  
Keyword(s):  
Soil Aggregates ◽  
Aggregate Stability ◽  
Penetration Resistance ◽  
Soil Tillage ◽  
Soil Fraction ◽  
Soil Penetration Resistance ◽  
Before And After ◽  
The Impact ◽  
The City ◽  
Coarse Soil

ABSTRACT Evaluation of mobilized soil profiles can provide important information on soil compaction reduction processes. In this context, the objective of this study was to evaluate alterations in soil penetration resistance and the impact on the aggregate stability of a cohesive Ultisol cultivated with sugarcane. The experiment was carried out at the Carpina Sugarcane Experimental Station (EECAC/UFRPE), located in the city of Carpina, PE. Penetration resistance, mobilized area and depth, and percentage of soil aggregates were evaluated before and after soil tillage. Soil mobilization improved soil aggregate uniformity and decreased penetration resistance in the 0-0.20 m layer. Coarse soil fraction, moisture and organic carbon positively contributed to the increase in soil mobilization.

Changes in soil quality following humping/hollowing and flipping of pakihi soils on the West Coast, South Island New Zealand

2007 ◽  
pp. 265-270 ◽  
Author(s):  
S.M. Thomas ◽  
M.H.Beare C.D. Ford ◽  
V. Rietveld
Keyword(s):  
Organic Matter ◽  
Soil Quality ◽  
West Coast ◽  
Land Development ◽  
Hot Water ◽  
Limited Information ◽  
The West ◽  
Organic Matter Quality ◽  
Pasture Production ◽  
Soil C

Humping/hollowing and flipping are land development practices widely used on the West Coast to overcome waterlogging constraints to pasture production. However, there is very limited information about how the resulting "new" soils function and how their properties change over time following these extreme modifications. We hypothesised that soil quality will improve in response to organic matter inputs from plants and excreta, which will in turn increase nutrient availability. We tested this hypothesis by quantifying the soil organic matter and nutrient content of soils at different stages of development after modification. We observed improvements in soil quality with increasing time following soil modification under both land development practices. Total soil C and N values were very low following flipping, but over 8 years these values had increased nearly five-fold. Other indicators of organic matter quality such as hot water extractable C (HWC) and anaerobically mineralisable N (AMN) showed similar increases. With large capital applications of superphosphate fertiliser to flipped soils in the first year and regular applications of maintenance fertiliser, Olsen P levels also increased from values

SOIL C AND N AS INDICATORS OF VINEYARD SOIL QUALITY IN THE RAVNI KOTARI REGION OF CROATIA

2020 ◽  
Author(s):  
Sonia C. Clemens ◽  
◽  
Mia Brkljaca ◽  
Delaina Pearson ◽  
C. Brannon Andersen
Keyword(s):  
Soil Quality ◽  
Soil C ◽  
Vineyard Soil ◽  
Soil C And N ◽  
C And N

scholarly journals Dynamics of Soil Organic Carbon and Labile Carbon Fractions in Soil Aggregates Affected by Different Tillage Managements

2021 ◽  
Vol 13 (3) ◽  
pp. 1541
Author(s):  
Xiaolin Shen ◽  
Lili Wang ◽  
Qichen Yang ◽  
Weiming Xiu ◽  
Gang Li ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
No Tillage ◽  
Labile Carbon ◽  
Carbon Fractions ◽  
Soil Aggregate Stability ◽  
Positive Effects

Our study aimed to provide a scientific basis for an appropriate tillage management of wheat-maize rotation system, which is beneficial to the sustainable development of agriculture in the fluvo-aquic soil areas in China. Four tillage treatments were investigated after maize harvest, including rotary tillage with straw returning (RT), deep ploughing with straw returning (DP), subsoiling with straw returning (SS), and no tillage with straw mulching (NT). We evaluated soil organic carbon (SOC), dissolved organic carbon (DOC), permanganate oxidizable carbon (POXC), microbial biomass carbon (MBC), and particulate organic carbon (POC) in bulk soil and soil aggregates with five particle sizes (>5 mm, 5–2 mm, 2–1 mm, 1–0.25 mm, and <0.25 mm) under different tillage managements. Results showed that compared with RT treatment, NT treatment not only increased soil aggregate stability, but also enhanced SOC, DOC, and POC contents, especially those in large size macroaggregates. DP treatment also showed positive effects on soil aggregate stability and labile carbon fractions (DOC and POXC). Consequently, we suggest that no tillage or deep ploughing, rather than rotary tillage, could be better tillage management considering carbon storage. Meanwhile, we implied that mass fractal dimension (Dm) and POXC could be effective indicators of soil quality, as affected by tillage managements.

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