scholarly journals Microbiological characterization of land set-aside before and after Roundup desiccation

2011 ◽  
Vol 57 (No. 2) ◽  
pp. 88-94 ◽  
Author(s):  
M. Růžková ◽  
L. Růžek ◽  
K. Voříšek ◽  
P. Vráblík ◽  
D. Musilová

Luvic chernozem (set-aside from 1996) was evaluated. The first period, before Roundup desiccation (2002–2003), was characterized by black, spontaneous and controlled fallows (mowed with the removal of plant biomass or mulched); the following period (2003–2004) by black fallow with repeated Roundup applications; and the last period (2004–2006) involved re-grassing by a mowed Lolium multiflorum Lam. monoculture. The characterization included microbial biomass, available organic carbon, basal respiration, metabolic quotient, biomass-specific available organic carbon, arylsulfatase activity, soil organic matter carbon and total nitrogen. Mulching of pure cultures of grasses and legumes contributed to a high soil organic matter accumulation. Repeated Roundup desiccation caused a strong (highly significant) decrease of arylsulfatase activity (–28%), however highly significant increase of microbial biomass (+69%) and nitrate-nitrogen (+86%) were determined. The subsequent re-grassing compensated the changes described. The soil biological properties were best preserved on mulched fallow with Lotus corniculatus L. and Festuca pratensis L., also in regard to contamination with weeds.

1969 ◽  
Vol 100 (2) ◽  
pp. 123-140
Author(s):  
Ian C. Pagán-Roig ◽  
Joaquín A. Chong ◽  
José A. Dumas ◽  
Consuelo Estévez de Jensen

The objective of this work was to measure the effects of repeated short-term organic amendments that we termed soil treatment management cycles (STMC) on physical and biological properties of a San Antón series soil. Each STMC lasted 60 days and consisted of incorporating 5% organic matter from coffee pulp compost; the planting, growth and incorporation of an intercrop of four green manure species; and the application of mycorrhizae and compost tea. The treatments were labeled: CL0, CL1, CL2 and CL3; where CL0 was the control, CL1 received one STMC, CL2 and CL3 received two and three STMC, respectively. The STMC intended to mimic the overall effect of a sustainable agricultural system, not to measure the individual effects of the practices. All treatments (CL1, CL2, CL3) showed an increase in soil organic matter (p≤0.05). When compared to the CL0 control, saturated hydraulic conductivity increased and bulk density decreased in all soils. Soil macroporosity was significantly increased by CL2 and CL3. Soil aggregate stability increased in CL1, CL2 and CL3 plots. Microbial biomass C increased in treatment CL3, and microbial biomass N increased in CL2 and CL3. The production of stable aggregates was correlated to humic acid content and positively influenced all other physical parameters assessed in this study. The STMC had a positive impact on soil properties by increasing the soil organic matter as well as the humic acid fraction. Soil macroporosity, defined as porosity with radius > 38 µm, was significantly increased by treatments CL2 and CL3. All of the organic matter fractions, including total organic matter, humic acid content, microbial biomass C and microbial biomass N were significantly increased by one or more STMC.


2011 ◽  
Vol 8 (6) ◽  
pp. 12179-12195
Author(s):  
N. Singh ◽  
S. Abiven ◽  
M. S. Torn ◽  
M. W. I. Schmidt

Abstract. Pyrogenic Carbon (PyC), the residue of an incomplete combustion of plant biomass, is considered as a carbon (C) sink due to its assumed stability in soil. Our meta-analysis of studies on PyC degradation challenges the assumption that PyC persist in soil for several thousand years. The turnover time for PyC estimated here ranges from decadal to centennial time scales, and is not slower than decomposition of bulk Soil Organic Matter (SOM) and differs with initial biomass, pyrolysis temperature and climate. Thus, using PyC as a strategy for offsetting carbon emissions requires caution and further research.


2016 ◽  
Author(s):  
Stephan John ◽  
Gerrit Angst ◽  
Kristina Kirfel ◽  
Sebastian Preusser ◽  
Carsten W. Mueller ◽  
...  

Abstract. Radiocarbon (14C) analysis is an important tool that can provide information on the dynamics of organic matter in soils. Radiocarbon concentrations of soil organic matter (SOM) however, reflect the heterogeneous mixture of various organic compounds and are affected by different chemical, biological, and physical soil parameters. These parameters can vary strongly in soil profiles and thus affect the spatial distribution of the apparent 14C age of SOM considerably. The heterogeneity of SOM and its 14C signature may be even larger in subsoil horizons, which are thought to receive organic carbon inputs following preferential pathways. This will bias conclusions drawn from 14C analyses of individual soil profiles considerably. We thus investigated important soil parameters, which may influence the 14C distribution of SOM as well as the spatial heterogeneity of 14C distributions in soil profiles. The suspected strong heterogeneity and spatial variability, respectively of bulk SOM is confirmed by the variable 14C distribution in three 185 cm deep profiles in a Dystric Cambisol. The 14C contents are most variable in the C horizons because of large differences in the abundance of roots there. The distribution of root biomass and necromass and its organic carbon input is the most important factor affecting the 14C distribution of bulk SOM. The distance of the soil profiles to a beech did not influence the horizontal and vertical distribution of roots and 14C concentrations. Other parameters were found to be of minor importance including microbial biomass-derived carbon and soil texture. The microbial biomass however, may promote a faster turnover of SOM at hot spots resulting in lower 14C concentration there. Soil texture had no statistically significant influence on the spatial 14C distribution of bulk SOM. However, SOM in fine silt and clay sized particles (< 6.3 µm) yields slightly higher 14C concentrations than bulk SOM particularly at greater soil depth, which is in contrast to previous studies where silt and clay fractions contained older SOM stabilized by organo-mineral interaction. 14C contents of fine silt and clay correlate with the microbial biomass-derived carbon suggesting a considerable contribution of microbial-derived organic carbon. In conclusion, 14C analyses of bulk SOM mainly reflect the spatial distribution of roots, which is strongly variable even on a small spatial scale of few meters. This finding should be considered when using 14C analysis to determine SOM.


2017 ◽  
Vol 68 (1) ◽  
pp. 41-55
Author(s):  
Taru Sandén ◽  
Georg J. Lair ◽  
Jeroen P. van Leeuwen ◽  
Guðrún Gísladóttir ◽  
Jaap Bloem ◽  
...  

Summary In order to study the soil aggregate distributions and soil organic matter (SOM), we sampled top- and subsoils in four intensively farmed croplands (two organic (Org-OB and Org-LA), and two conventional (Con-OB and Con-LA)) on Haplic Chernozems located in Marchfeld in the east of Vienna (Austria). Soil structure and SOM quantity, quality and distribution between free and occluded particulate organic matter and aggregate size fractions (<20 µm, 20-250 µm, 250-5000 µm) were studied by following a density fractionation procedure with low-energy ultrasound treatment. The relation of the soil physicochemical (e.g., particle size distribution, pH, organic carbon, total nitrogen) and biological properties (e.g., fungal biomass, active fungi) with stable soil aggregate size fractions and SOM was studied. The mean weight diameter (MWD) showed no significant difference between all studied sites and was between 3.8 mm and 10.0 mm in topsoils and between 6.7 mm and 11.9 mm in subsoils. In topsoils, the contents of calcium-acetate-lactate (CAL)-extractable P, active fungal biomass, dithionite-extractable Fe and sand were significantly positively correlated with the amount of the macroaggregates and with the MWD. We observed that most soil organic carbon, depending on soil texture, was stored in the microaggregate size classes <20 µm and 20-250 µm.


2021 ◽  
Vol 770 ◽  
pp. 145307
Author(s):  
Mohammad Bahadori ◽  
Chengrong Chen ◽  
Stephen Lewis ◽  
Sue Boyd ◽  
Mehran Rezaei Rashti ◽  
...  

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1386
Author(s):  
Michael Stotter ◽  
Florian Wichern ◽  
Ralf Pude ◽  
Martin Hamer

Cultivation of Miscanthus x giganteus L. (Mis) with annual harvest of biomass could provide an additional C source for farmers. To test the potential of Mis-C for immobilizing inorganic N from slurry or manure and as a C source for soil organic matter build-up in comparison to wheat (Triticum aestivum L.) straw (WS), a greenhouse experiment was performed. Pot experiments with ryegrass (Lolium perenne L.) were set up to investigate the N dynamics of two organic fertilisers based on Mis at Campus Klein-Altendorf, Germany. The two fertilisers, a mixture of cattle slurry and Mis as well as cattle manure from Mis-bedding material resulted in a slightly higher N immobilisation. Especially at the 1st and 2nd harvest, they were partly significantly different compared with the WS treatments. The fertilisers based on Mis resulted in a slightly higher microbial biomass C and microbial biomass N and thus can be identified as an additional C source to prevent nitrogen losses and for the build-up of soil organic matter (SOM) in the long-term.


2013 ◽  
Vol 37 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Adriana Rodolfo da Costa ◽  
Juliana Hiromi Sato ◽  
Maria Lucrécia Gerosa Ramos ◽  
Cícero Célio de Figueiredo ◽  
Géssica Pereira de Souza ◽  
...  

Phosphorus fertilization and irrigation increase coffee production, but little is known about the effect of these practices on soil organic matter and soil microbiota in the Cerrado. The objective of this study was to evaluate the microbiological and oxidizable organic carbon fractions of a dystrophic Red Latossol under coffee and split phosphorus (P) applications and different irrigation regimes. The experiment was arranged in a randomized block design in a 3 x 2 factorial design with three split P applications (P1: 300 kg ha-1 P2O5, recommended for the crop year, of which two thirds were applied in September and the third part in December; P2: 600 kg ha-1 P2O5, applied at planting and then every two years, and P3: 1,800 kg ha-1 P2O5, the requirement for six years, applied at once at planting), two irrigation regimes (rainfed and year-round irrigation), with three replications. The layers 0-5 and 5-10 cm were sampled to determine microbial biomass carbon (MBC), basal respiration (BR), enzyme activity of acid phosphatase, the oxidizable organic carbon fractions (F1, F2, F3, and F4), and total organic carbon (TOC). The irrigation regimes increased the levels of MBC, microbial activity and acid phosphatase, TOC and oxidizable fractions of soil organic matter under coffee. In general, the form of dividing P had little influence on the soil microbial properties and OC. Only P3 under irrigation increased the levels of MBC and acid phosphatase activity.


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