Comparison of microbial C, N-flush and ATP, and certain enzyme activities of different textured soils subject to gradual drying

Soil Research ◽  
1988 ◽  
Vol 26 (1) ◽  
pp. 217 ◽  
Author(s):  
AW West ◽  
GP Sparling ◽  
TW Speir ◽  
JM Wood
Keyword(s):  
Soil Texture ◽  
Clay Loam ◽  
Fe Method ◽  
Wide Range ◽  
Loam Soil ◽  
Substrate Induced Respiration ◽  
C And N ◽  
Microbial C ◽  
The Relationship ◽  
Microbial N

A clay loam, a silt loam and a sand soil were gradually dried from field moisture content to air-dryness at 25�C in the laboratory. Microbial C measured by substrate-induced respiration (SIR), fumigation-incubation (FI) and fumigation-extraction (FE), microbial N-flush measured by FI and FE, microbial ATP content, and soil phosphatase and sulfatase activities were monitored throughout a drying period of approx. 60 h achieved over 16 days. All the microbial and enzyme variables declined as the gravimetric soil water content ( W) decreased to air-dryness. In general, the relationship between microbial C or N-flush and W was linear, but was exponential between ATP or phosphatase and W. Soil texture appeared to affect the rates of decline and also the amounts of the microbial and enzyme variables remaining in air-dry soil; e.g., the lowest rate of microbial C decline and the largest amount remaining at air-dryness occurred in the clay loam soil. Sulfatase activity was not significantly affected by soil drying. Agreement between the SIR and FE estimates of microbial C was good (r = 0.92***). These two methods were applicable over a wide range of water contents. Microbial N-flush, estimated by the FE method, also showed a consistent trend and correlated highly with microbial C estimated by SIR or FE. In contrast, microbial C and N-flush estimated by the FI method were not significantly correlated with W or any of the other variables. ATP and phosphatase activity appeared to relate more closely to microbial activity (CO2 respiration/microbial C) than microbial mass. The reliability of the methods to measure the biomass and the influence of soil texture, water and carbon contents on microbial survival are discussed.

Dynamics of microbial-C, N-flush and ATP, and enzyme activities of gradually dried soils from a climosequence

Soil Research ◽  
1988 ◽  
Vol 26 (3) ◽  
pp. 519 ◽  
Author(s):  
AW West ◽  
GP Sparling ◽  
TW Speir ◽  
JM Wood
Keyword(s):  
Annual Rainfall ◽  
Silt Loam ◽  
Strongly Correlated ◽  
Total Change ◽  
Moisture Regimes ◽  
Substrate Induced Respiration ◽  
C And N ◽  
Microbial C ◽  
Soil Phosphatase ◽  
Microbial N

Three silt loam soils from a climosequence (1000-2700 mm annual rainfall) were gradually dried from field moisture content to air-dryness at 25�C in the laboratory. Microbial C measured by substrate-induced respiration (SIR), fumigation-incubation (FI) or fumigation-extraction (FE), microbial N-flush measured by FI and FE, microbial ATP content and soil phosphatase and sulfatase activities were monitored throughout the drying period (approx. 60 h). All indices declined as the gravimetric soil water content (W) decreased until reaching air-dryness. Significant declines in the biomass sometimes occurred only following a large decrease in W, dependent on the soil. In general, when microbial C and N-flush declined, the rates of decline were linearly correlated with W. However, ATP and soil phosphatase were exponentially related to W. When expressed as a ratio of the total change in microbial indices against the total change in W for the whole drying period, the ratios were consistent between the soils. Agreement between the SIR and FE estimates of microbial C, whilst significant (r = 0 58***), was poor, especially for the low rainfall soil, although the FE C- and N-flushes correlated well (r = 0-76***). In contrast, the FI C- and N-flushes correlated very poorly (r = 0.30**) and were not significantly correlated with W or the other indices. ATP and soil phosphatase activity were strongly correlated (r = 0.89***). The reliability of the methods and the influence of soil moisture regimes on microbial survival are discussed.

The relationship between soybean cyst nematode seasonal population dynamics and soil texture

Nematology ◽  
2004 ◽  
Vol 6 (4) ◽  
pp. 511-525 ◽  
Author(s):  
Felicitas Avendaño ◽  
Francis J. Ierce ◽  
Haddish Melakeberhan
Keyword(s):  
Population Dynamics ◽  
Soil Texture ◽  
Soybean Cyst Nematode ◽  
Reproductive Potential ◽  
Cyst Nematode ◽  
Stable Relationship ◽  
Wide Range ◽  
The Relationship ◽  
Seasonal Population ◽  
Seasonal Population Dynamics

Abstract The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, cyst population densities at planting and at harvest have been related to soil texture but the seasonal mechanisms by which these correlations are established are less well known. The purpose of this work was to analyse the relationship of SCN life stages and reproductive potential (number of eggs per cyst) with soil texture. Cyst population density was positively correlated with sand and negatively correlated with clay and silt percentage in the soil within the ranges of 45-80% sand, 8-23% clay, and 8-43% silt in one field, but not in the other at five sampling times. The relationship between soil texture and juvenile stages in roots was weak. The stable relationship between SCN spatial and seasonal population dynamics and soil properties provides further support for potential delineation of management zones in SCN infested fields with a wide range of soil textures.

scholarly journals Preferential protein depolymerization as a preservation mechanism for vascular litter decomposing in <i>Sphagnum</i> peat

2019 ◽  
Author(s):  
Hendrik Reuter ◽  
Julia Gensel ◽  
Marcus Elvert ◽  
Dominik Zak
Keyword(s):  
Protein Content ◽  
Litter Breakdown ◽  
N Dynamics ◽  
N Content ◽  
Sphagnum Peat ◽  
Elemental Analyses ◽  
Microbial Carbon ◽  
C And N ◽  
Microbial C ◽  
Microbial N

Abstract. Nitrogen (N) dynamics in Phragmites australis litter due to anaerobic decomposition in three anoxic wetland substrates were analyzed by elemental analyses and infrared spectroscopy (FTIR). After 75 days of decomposition, a relative accumulation of bulk N was detected in most litters, but N accumulated less when decomposition took place in a more N-poor environment. FTIR was used to quantify the relative content of proteins in litter tissue and revealed a highly linear relationship between bulk N content and protein content. Changes in bulk N content thus paralleled and probably were governed by changes in litter protein content. Such changes are the result of two competing processes within decomposing litter: enzymatic protein depolymerization as a part of the litter breakdown process and microbial protein synthesis as a part of microbial biomass growth within the litter. Assuming microbial homeostasis, DNA signals in FTIR spectra were used to calculate the amount of microbial N in decomposed litter which ranged from 14 to 42 % of the total litter N for all leaf samples. Microbial carbon (C) content and resultant calculated carbon-use efficiencies (CUEs) indicate that microbial N in litter accumulated according to predictions of the stoichiometric decomposition theory. Subtracting microbial C- and N-contributions from litter, however, revealed decomposition site dependent variations in the percentual amount of remaining, still unprocessed plant N compared to remaining plant C, an indicator for preferential protein depolymerization. For all leaf litters, the coefficient of preferential protein depolymerization (α), which relates N-compound depolymerization to C-compound depolymerization, ranged from 0.74–0.88 in a nutrient-rich detritus mud to 1.38–1.82 in Sphagnum peat, the most nutrient-poor substrate in this experiment. Preferential protein depolymerization leads to a gradual N depletion of decomposing litter which we propose as a preservation mechanism for vascular litter decomposing in Sphagnum peat.

scholarly journals A novel three-point hitch dynamometer to measure the draft requirement of mounted implements

2011 ◽  
Vol 57 (No. 4) ◽  
pp. 128-136 ◽  
Author(s):  
M. Askari ◽  
M.H. Komarizade ◽  
A.M. Nikbakht ◽  
N. Nobakht ◽  
R.F. Teimourlou
Keyword(s):  
Field Tests ◽  
Design Concept ◽  
Force Sensing ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Wide Range ◽  
Loam Soil ◽  
High Degree ◽  
Moldboard Plow

An adjustable three-point hitch dynamometer with a draft capacity of 50 kN was developed to measure forces on the tractor and mounted implements. The design concept of the dynamometer was based on two linkage frames mounted between tractor links and the implement. The force sensing elements were comprised of a loadcell that was installed between the frames. The system provides variable width and height of the dynamometer links to satisfy a wide range of implement dimensions. All mounted tillage implements at categories II and III such as plows, cultivators and harrows were able to be tested by this dynamometer excluding mounted implements powered by power take-off (PTO). The dynamometer was calibrated and several field tests were conducted to measure the force required to pull a moldboard plow in a clay loam soil. The calibration showed a high degree of linearity between the draft requirements and the dynamometer outputs. Field tests showed that it was able to function effectively as intended without any mechanical problems.

CO2 Emissions and Maize Biomass Production Using Digestate Liquid Fraction in Two Soil Texture Types

2017 ◽  
Vol 60 (4) ◽  
pp. 1325-1336 ◽  
Author(s):  
Carmelo Maucieri ◽  
Maurizio Borin
Keyword(s):  
Biomass Production ◽  
Soil Texture ◽  
Sandy Loam ◽  
Liquid Fraction ◽  
Emission Peak ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Primary Tillage ◽  
Loam Soil

Abstract. The aim of this work was to evaluate the effects of soil texture and primary tillage type on soil CO2 emission and maize biomass production after digestate liquid fraction (DLF) spreading. The study was conducted in 2014 in two open fields at Terrasa Padovana (farm 1) and Bovolenta (farm 2) in the Veneto Region of Italy. Soil CO2 emission after digestate spreading was evaluated by comparing the effect of soil texture (sandy loam vs. clay loam) at farm 1 and the effect of long-term primary tillage management (&gt;10 years) (ripping vs. plowing) in clay loam soil at farm 2. Unamended soil was considered the control at both farms. DLF was supplied before maize ( L.) sowing at a dose equal to 170 kg total nitrogen ha-1 using a splash-plate technique. DLF spreading determined a CO2 emission peak 1 h after spreading at both farms, with median emission values of 8.93 and 4.35 g m-2 h-1, respectively, from the sandy loam and clay loam soils at farm 1. At farm 2, primary tillage type did not exert a significant effect on CO2 emission peak, with a median value of 5.85 g m-2 h-1. About three days after DLF distribution, soil CO2 fluxes were less than 1 g m-2 h-1. The first soil harrowing and the first rainfall event after spreading determined significantly higher CO2 emissions from amended plots than from unamended plots for a few hours. At farm 1, soil CO2 emission during the maize growing season was significantly higher in the amended plots (+1.7 times) than in the unamended plots, which showed a median emission value of 0.29 g m-2 h-1; soil texture and tillage exerted no significant influence. Maize yield at dough stage was not significantly influenced by DLF at farm 1, with 22.7 ±1.6 Mg ha-1 and 18.7 ±2.8 Mg ha-1 in the clay loam and sandy loam soils, respectively. At farm 2, the distribution of DLF increased maize biomass production by +17% with respect to the unamended treatment that produced 18.0 ±2.4 Mg ha-1. Although the results reported in this article concern data from only one year, and further long-term experiments are needed to confirm our findings, they indicate that CO2 emissions after digestate distribution are lower in a clay loam soil than in a sandy loam soil and are not affected by primary tillage type. Keywords: Clay loam soil, Digestate splash-plate spreading, Plowing, Ripping, Sandy loam soil.

Evidence of a union between organic carbon and water content in soil

2016 ◽  
Vol 96 (3) ◽  
pp. 305-316 ◽  
Author(s):  
Hida R. Manns ◽  
Gary W. Parkin ◽  
Ralph C. Martin
Keyword(s):  
Organic Carbon ◽  
Water Content ◽  
Soil Texture ◽  
Principal Component ◽  
Research Centre ◽  
Least Squares Regression ◽  
Wide Range ◽  
Single Field ◽  
The Relationship

Soil organic matter, comprising ∼58% soil organic carbon (SOC), is attributed with increased water holding capacity in the surface horizon of agricultural soil. This paper addresses the role of SOC as a component of a common functional unit in soil from analysis within a single field and over multiple fields. Soil data measured on the fields during the SMAPVEX12 satellite prelaunch algorithm development campaign exhibited high correlation among SOC, field-mean soil water content (SWC), bulk density, and soil texture. The analysis extended over a wide range of soil texture and wetness in the top 5 cm of soil over 50 agricultural fields covering ∼400 km2 of southern Manitoba. Data collected over a much smaller area from Ontario silt loam soils at the Elora Research Centre demonstrated a similar correlation between SOC and SWC in intensive field sampling. This intercorrelation of SOC and SWC is examined with partial least-squares regression, principal component analysis, and geostatistical semivariograms. A model is proposed to interpret the feedback process between SOC and SWC to explain the persistent correlation. Further work to substantiate the strengths and limits of the relationship between SOC and SWC may be beneficial for estimating SWC for remote sensing, agriculture, hydrology, and ecosystem function.

Effects of gamma irradiation on soil biological communities and C and N pools in a clay loam soil

2016 ◽  
Vol 108 ◽  
pp. 352-360 ◽  
Author(s):  
Shixiu Zhang ◽  
Shuyan Cui ◽  
Xiaoming Gong ◽  
Liang Chang ◽  
Shuxia Jia ◽  
...  
Keyword(s):  
Gamma Irradiation ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Biological Communities ◽  
Loam Soil ◽  
C And N ◽  
C And N Pools

Soil microbial biomass and microbial and mineralizable N in a clear-cut chronosequence on northern Vancouver Island, British Columbia

1995 ◽  
Vol 25 (10) ◽  
pp. 1595-1607 ◽  
Author(s):  
Scott X. Chang ◽  
Gordon F. Weetman ◽  
Caroline M. Preston
Keyword(s):  
Microbial Biomass ◽  
Vancouver Island ◽  
Old Growth ◽  
Clear Cutting ◽  
Old Growth Forest ◽  
Mineralizable N ◽  
Old Growth Forests ◽  
C And N ◽  
Microbial C ◽  
Microbial N

We studied the dynamics of microbial biomass and nitrogen in old-growth forests and in 3- and 10-year-old plantations established after clear-cutting and slash burning of old-growth western red cedar (Thujaplicata Donn ex D. Don)–western hemlock (Tsugaheterophylla (Raf.) Sarg.) stands on northern Vancouver Island. Ten-year-old plantations, after initially growing well, were experiencing declining growth rates. Three forest floor layers: F (fermentation), woody F (Fw), and H (humus) were sampled four times in May, July, August, and October of 1992. Moisture content was significantly greater in the old-growth forests than in the plantations for F on July 16 (p < 0.05) and Fw (p < 0.10), but was not significantly different for H. Microbial biomass C and N were relatively constant throughout the sampling period, resulting in nonsignificant date effects. Microbial C content was in the order: old-growth forests > 10-year-old plantations > 3-year-old plantations. Microbial N content was significantly greater in the old-growth forest than in the young plantations for both F (p < 0.001) and H (p < 0.05) but was not different between the plantations. Therefore, the hypothesis that the microbial biomass acted as a net sink in the 10-year-old plantations by immobilizing N into the microbial N pool is rejected. Microbial C/N ratios were greater (p < 0.05) in the 10-year-old plantations than in the old-growth forests and in the 3-year-old plantations in H and on July 16 in F, indicating that microbial competition for N was probably a factor in the growth declining in the 10-year-old plantations. Extractable C and N and mineralizable N were generally higher in the old-growth forests than in the 3-year-old plantations and higher in the 3-year-old than in the 10-year-old plantations. As a result of better nutritional conditions, tree and understory foliage in the 3-year-old plantations had higher N concentrations and lower C/N ratios than in the 10-year-old plantations. Trees in the 10-year-old plantations displayed chlorotic symptoms and slow growth which were not observed in the 3-year-old plantations.

scholarly journals Dynamics of C and N in a clay loam soil amended with biochar and corn straw

2019 ◽  
Author(s):  
George O. Odugbenro ◽  
Zhihua Liu ◽  
Yankun Sun
Keyword(s):  
Microbial Biomass ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Clay Loam ◽  
Corn Straw ◽  
Clay Loam Soil ◽  
Mineral N ◽  
Total N ◽  
Loam Soil ◽  
C And N

An incubation study was conducted to determine the influence of biochar and corn straw on CO2-C emission, soil organic C, microbial biomass C and N, total N, and mineral N (NH4+-N and NO3--N) in a clay loam soil. Six treatments viz., CK (Control); S (Soil + 1% straw); B1 (Soil + 0.5% biochar); B2 (Soil + 2% biochar); SB1 (Soil + 1% straw + 0.5% biochar); SB2 (Soil + 1% straw + 2% biochar) were tested with three replications. Results showed that straw addition to soil with or without biochar increased CO2-C emission while sole-biochar addition (2%) reduced it. Straw and biochar also increased the soil microbial biomass C and N but greatest increase in microbial biomass N (111.9 µg g-1) was recorded by biochar-straw combination. SOC and total N significantly increased following biochar and straw additions which suggest that organic amendments can improve soil chemical properties. Additionally, for soil mineral N, biochar reduced NH4+-N and NO3--N concentrations while straw increased NH4+-N concentration but greatly reduced that of NO3--N.

scholarly journals Plasticity in response to soil texture affects the relationships between a shoot and root trait and responses vary by population

2021 ◽  
Vol 48 (2) ◽  
pp. 199-204
Author(s):  
Alicia J. Foxx ◽  
Siobhán T. Wojcik
Keyword(s):  
Soil Texture ◽  
Root Traits ◽  
Plant Population ◽  
Population Variation ◽  
Root Tip ◽  
Plant Selection ◽  
Shoot Height ◽  
Loam Soil ◽  
The Relationship ◽  
Two Populations

Abstract The relationships between shoot and root traits can inform plant selection for restoration, forestry, and agriculture and help to identify relationships that inform plant productivity and enhance their performance. But the strength of coordination between above- and belowground morphological and physiological traits varies due to differences in edaphic properties and population variation. More assessments are needed to determine what conditions influence these relationships. So, we tested whether plant population and soil texture affect the relationship between shoot and root traits which have important ecological ramifications for competition and resource capture: shoot height and root tip production. We grew seedlings of two populations of Bromus tectorum due to is fast growing nature in a growth chamber in loam soil, sand, and clay. We found variation in height by plant population and the substrate used (R2 = 0.44, p < 0.0001), and variation in root tip production by the substrate used (R2 = 0.33, p < 0.0001). Importantly, we found that relationships between shoot height and root tip production varied by soil texture and population (R2 = 0.54, p < 0.0001), and growth in sand produced the strongest relationship and was the most water deficient substrate (R2 = 0.32). This shows that screening populations under several environments influences appropriate plant selection.

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