scholarly journals Quantification of Nitrogen Reductase and Nitrite Reductase Genes in Soil of Thinned and Clear-Cut Douglas-Fir Stands by Using Real-Time PCR

2010 ◽  
Vol 76 (21) ◽  
pp. 7116-7125 ◽  
Author(s):  
David J. Levy-Booth ◽  
Richard S. Winder
Keyword(s):  
Forest Soil ◽  
Real Time ◽  
Real Time Pcr ◽  
Douglas Fir ◽  
N Cycling ◽  
Total Carbon ◽  
Soil Horizon ◽  
Mineral Horizon ◽  
Total N ◽  
C And N

ABSTRACT The abundance of nifH, nirS, and nirK gene fragments involved in nitrogen (N) fixation and denitrification in thinned second-growth Douglas-fir (Pseudotsuga menziesii subsp. menziesii [Mirb.] Franco) forest soil was investigated by using quantitative real-time PCR. Prokaryotic N cycling is an important aspect of N availability in forest soil. The abundance of universal nifH, Azotobacter sp.-specific nifH (nifH-g1), nirS, and nirK gene fragments in unthinned control and 30, 90, and 100% thinning treatments were compared at two long-term research sites on Vancouver Island, Canada. The soil was analyzed for organic matter (OM), total carbon (C), total N, NH4-N, NO3-N, and phosphorus (P). The soil horizon accounted for the greatest variation in nutrient status, followed by the site location. The 30% thinning treatment was associated with significantly greater nifH-g1 abundance than the control treatment in one site; at the same site, nirS in the mineral soil horizon was significantly reduced by thinning. The abundance of nirS genes significantly correlated with the abundance of nirK genes. In addition, significant correlations were observed between nifH-g1 abundance and C and N in the organic horizon and between nirS and nirK and N in the mineral horizon. Overall, no clear influence of tree thinning on nifH, nirS, and nirK was observed. However, soil OM, C, and N were found to significantly influence N-cycling gene abundance.

Detection and quantification of Entomophaga maimaiga resting spores in forest soil using real-time PCR

2007 ◽  
Vol 111 (3) ◽  
pp. 324-331 ◽  
Author(s):  
Louela A. Castrillo ◽  
Lene Thomsen ◽  
Punita Juneja ◽  
Ann E. Hajek
Keyword(s):  
Forest Soil ◽  
Real Time ◽  
Real Time Pcr ◽  
Entomophaga Maimaiga ◽  
Resting Spores ◽  
Detection And Quantification

Effect of storage conditions on losses and crop utilization of nitrogen from solid cattle manure

2015 ◽  
Vol 154 (1) ◽  
pp. 58-71 ◽  
Author(s):  
G. M. SHAH ◽  
G. A. SHAH ◽  
J. C. J. GROOT ◽  
O. OENEMA ◽  
A. S. RAZA ◽  
...  
Keyword(s):  
Arable Land ◽  
Storage Period ◽  
Storage Conditions ◽  
Cattle Manure ◽  
Total Carbon ◽  
N Recovery ◽  
Flux Chamber ◽  
N Losses ◽  
Total N ◽  
C And N

SummaryThe objectives of the present study were to quantify the effects of contrasting methods for storing solid cattle manure on: (i) total carbon (C) and nitrogen (N) balances during storage, and (ii) crop apparent N recovery (ANR) following manure application to arable land, with maize as a test crop. Portions of 10 t of fresh solid cattle manure were stored for 5 months during 2009/10 in three replicates as: (i) stockpiled heaps, (ii) roofed heaps, (iii) covered heaps and (iv) turned heaps at Wageningen University, the Netherlands. Surface emissions of ammonia (NH3), nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) were measured regularly using a static flux chamber connected to a photo-acoustic gas monitor. Total C and N losses during storage were determined through the mass balance method. After storage, the manures were surface-applied and incorporated into a sandy soil, and maize ANR was measured as a proportion of both N applied to the field (ANRF) and N collected from the barn (ANRB).During the storage period, the average losses of initial total N (Ntotal) were 6% from the covered, 12% from the roofed, 21% from the stockpiled and 33% from the turned heaps. Of the total N losses, 2–9% was lost as NH3-N, 1–4% as N2O-N and 16–32% through leaching. However, the greatest part of the total N loss from the four storage methods was unaccounted for and constituted in all probability of harmless dinitrogen gas. Of the initial C content,c. 13, 14, 17 and 22% was lost from the covered, stockpiled, roofed and turned heaps, respectively. Maize ANRFwas highest from covered (39% of the applied N) followed by roofed (31%), stockpiled (29%) and turned manure (20%). The respective values in case of maize ANRBwere 37, 27, 23 and 13%. It is concluded that from a viewpoint of on-farm N recycling the storage of solid cattle manure under an impermeable plastic cover is much better than traditional stockpiling or turning heaps in the open air.

scholarly journals Cycling and retention of nitrogen in European beech (<i>Fagus sylvatica</i> L.) ecosystems under elevated fructification frequency

2021 ◽  
Vol 18 (12) ◽  
pp. 3763-3779
Author(s):  
Rainer Brumme ◽  
Bernd Ahrends ◽  
Joachim Block ◽  
Christoph Schulz ◽  
Henning Meesenburg ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Fagus Sylvatica ◽  
European Beech ◽  
N Deposition ◽  
N Cycling ◽  
Total N ◽  
N Retention ◽  
Leaf Litterfall ◽  
C And N ◽  
Mineral Soils

Abstract. Atmospheric deposition of nitrogen (N) has exceeded its demand for plant increment in forest ecosystems in Germany. High N inputs increased plant growth, the internal N cycling within the ecosystem, the retention of N in soil and plant compartments, and the N output by seepage water. But the processes involved are not fully understood, notably the effect of fructification in European beech (Fagus sylvatica L.) on N fluxes. The frequency of fructification has increased together with air temperature and N deposition, but its impact on N fluxes and the sequestration of carbon (C) and N in soils have been hardly studied. A field experiment using 15N-labeled leaf litter exchange was carried out over a 5.5-year period at seven long-term European beech (Fagus sylvatica L.) monitoring sites to study the impact of current mast frequency on N cycling. Mean annual leaf litterfall contained 35 kg N ha−1, but about one-half of that was recovered in the soil 5.5 years after the establishment of the leaf litter 15N exchange experiment. In these forests, fructification occurred commonly at intervals of 5 to 10 years, which has now changed to every 2 years as observed during this study period. Seed cupules contributed 51 % to the additional litterfall in mast years, which creates a high nutrient demand during their decomposition due to the very high ratios of C to N and C to phosphorus (P). Retention of leaf litter 15N in the soil was more closely related to the production of total litterfall than to the leaf litterfall, indicating the role of seed cupules in the amount of leaf N retained in the soil. Higher mast frequency increased the mass of mean annual litterfall by about 0.5 Mg ha−1 and of litterfall N by 8.7 kg ha−1. Mean net primary production (NPP) increased by about 4 %. Mean total N retention in soils calculated by input and output fluxes was unrelated to total litterfall, indicating that mast events were not the primary factor controlling total N retention in soils. Despite reduced N deposition since the 1990s, about 5.7 out of 20.7 kg N ha−1 deposited annually between 1994 and 2008 was retained in soils, notably at acid sites with high N/P and C/P ratios in the organic layers and mineral soils, indicating P limitation for litter decomposition. Trees retained twice as much N compared to soils by biomass increment, particularly in less acidic stands where the mineral soils had low C/N ratios. These results have major implications for our understanding of the C and N cycling and N retention in forest ecosystems. In particular the role of mast products in N retention needs more research in the future.

Quantification of ammonia-oxidising bacteria in limed and non-limed acidic coniferous forest soil using real-time PCR

2004 ◽  
Vol 36 (12) ◽  
pp. 1935-1941 ◽  
Author(s):  
Anna Hermansson ◽  
Jenny S.K. Bäckman ◽  
Bo H. Svensson ◽  
Per-Eric Lindgren
Keyword(s):  
Forest Soil ◽  
Real Time ◽  
Real Time Pcr ◽  
Coniferous Forest ◽  
Ammonia Oxidising Bacteria

scholarly journals Changes in soil total C and N contents at three chronosequences after conversion from plantation pine forest to dairy pasture on a New Zealand Pumice soil

Soil Research ◽  
2014 ◽  
Vol 52 (1) ◽  
pp. 38 ◽  
Author(s):  
G. P. Sparling ◽  
R. Lewis ◽  
L. A. Schipper ◽  
P. Mudge ◽  
M. Balks
Keyword(s):  
Land Use ◽  
New Zealand ◽  
Radiata Pine ◽  
Soil Horizon ◽  
Moderate Increase ◽  
Plantation Forest ◽  
Time Data ◽  
Total N ◽  
C And N ◽  
Study Sites

The large amounts of carbon (C) and nitrogen (N) sequestered as organic matter in soils have implications for global and national C and N balances and greenhouse gas emissions. Changes in soil management can affect the amount of C and N stored in soil. We investigated the change in land use from radiata pine plantation to ryegrass–white clover dairy pasture on the total C and N content of Taupo Pumice Soil. Samples were taken at three study sites (Atiamuri, Tokoroa and Wairakei) in North Island, New Zealand. Soils were cored to 60 cm depth and subsampled by soil horizon, and bulk density cores were taken from soil pits. A chronosequence of sites was obtained after conversion from pines to pasture. Long-term pastures (40–80 years) and mature pine plantations were included for further comparison. Regression analyses were completed after logarithmic transformation of the time data. The data were highly variable, but significant (P < 0.05) increases in total C and N were found at the Atiamuri and Wairakei sites. However, there was no significant change in the total C content of the profile at the Tokoroa site. Increases in total C and N were greatest in the Ap horizon and were most rapid 1–5 years after conversion. Overall rates of increase in the first 10 years after conversion were 0.167 kg C m–2 year–1 for total C and 0.032 kg N m–2 year–1 for total N, dropping to 0.027 kg C and 0.005 kg N m–2 year–1 for the 10–50-year period. The change in land use from plantation forest to dairy pasture has resulted in a moderate increase or no change in soil storage of C. Compared with total C, increases in total N storage were proportionately greater in all three examples of this Taupo Pumice Soil.

scholarly journals Modeling rhizosphere carbon and nitrogen cycling in Eucalyptus plantation soil

2017 ◽  
Author(s):  
Rafael V. Valadares ◽  
Júlio C. L. Neves ◽  
Maurício D. Costa ◽  
Philip J. Smethurst ◽  
Luiz A. Peternelli ◽  
...  
Keyword(s):  
Root Growth ◽  
Priming Effect ◽  
Mechanistic Model ◽  
Model Performance ◽  
N Cycling ◽  
Total N ◽  
Eucalyptus Plantation ◽  
Eucalyptus Plantations ◽  
C And N ◽  
C And N Cycling

Abstract. Vigorous Eucalyptus plantations produce 105 to 106 km ha−1 of fine roots that probably increase carbon (C) and nitrogen (N) cycling in rhizosphere soil. However, the quantitative importance of rhizosphere priming is still unknown for most ecosystems, for instance Eucalyptus plantations. Therefore, the objective of this work was to propose and evaluate a mechanistic model for predicting rhizospheric C and N cycling in Eucalyptus plantations. The potential importance of the priming effect was estimated for a typical Eucalyptus plantation in Brazil. The process-based model (ForPRAN – Forest plantation rhizospheric available nitrogen) predicts the change in rhizosphere C and N cycling resulting from root growth and consists of two modules: (1) fine root growth, and (2) C and N rhizosphere cycling. The model describes a series of soil biological processes: root growth, rhizodeposition, microbial uptake, enzymatic synthesis, depolymerization of soil organic matter, respiration, mineralization, immobilization, microbial death, microbial emigration and immigration, SOM formation. Model performance was satisfactory quantitatively and qualitatively when compared to observed data in the literature. The input variables that most influenced N gain by rhizospheric mineralization were (in order of decreasing importance): root diameter > rhizosphere thickness > soil temperature > clay content. The priming effect in a typical Eucalyptus plantation producing 42 m3/ha/year of wood, with assumed losses of 40 % of the total N mineralized, was estimated to be 24.6 % of plantation N demand (shoot + roots + litter). The rhizosphere cycling model should be considered for adaptation to other forestry and agricultural production models where the inclusion of such processes offer the potential for improved model performance.

Feldvalidierung einer real-time PCR zum Nachweis von Mycoplasma hyopneumoniae in Nasentupfermaterial von lebenden Schweinen

2005 ◽  
Vol 147 (9) ◽  
pp. 373-379 ◽  
Author(s):  
F. Zeeh ◽  
P. Kuhnert ◽  
R. Miserez ◽  
M. G. Doherr ◽  
W. Zimmermann
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Mycoplasma Hyopneumoniae
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