Soil C balance in a long-term field experiment in relation to the size of the microbial biomass

1996 ◽  
Vol 23 (1) ◽  
pp. 33-37 ◽  
Author(s):  
E. Witter
Keyword(s):  
Microbial Biomass ◽  
Field Experiment ◽  
Soil C ◽  
C Balance ◽  
Soil C Balance ◽  
Term Field

scholarly journals Aliphatic compounds, organic C and N and microbial biomass and its activity in long-term field experiment

2011 ◽  
Vol 51 (No. 6) ◽  
pp. 276-282 ◽  
Author(s):  
T. Šimon
Keyword(s):  
Microbial Biomass ◽  
Field Experiment ◽  
Basal Respiration ◽  
Aliphatic Compound ◽  
Hydrophobicity Index ◽  
Organic C ◽  
Aliphatic Compounds ◽  
C And N ◽  
Term Field

The content of aliphatic compounds, hydrophobicity index, organic C and N content and the microbial biomass and respiration activity were analysed in soil samples originating from different plots of a long-term field experiment (variants: nil, NPK – mineral fertilization: 64.6–100 kg/ha/year, FYM – farmyard manure and FYM + NPK) from three blocks (III, IV and B) with different crop rotation. Samples were taken from 0–200 mm layer in 2002 and 2003 (spring and autumn). The plots without any fertilization had the significantly lowest aliphatic compound content compared to variants fertilized by FYM or FYM + NPK in all the evaluated blocks in both years. The variants fertilized only by mineral NPK without any organic fertilization had the slightly increased aliphatic compound content but they did not exceed significantly the control variants in most cases. The aliphatic compound contents correlated significantly with the organic C contents in 2002 and 2003, as well. The values of the hydrophobicity index showed a similar trend like the data mentioned above. Organic manure increased the soil organic nitrogen content, similarly to the carbon content. In variants fertilized by FYM and FYM + NPK the higher microbial biomass content was found comparing to unfertilized variants. Correlations between aliphatic compound content and biomass differed in spring (2002: r = 0.065, 2003: r = 0.068) and autumn (2002: r = 0.407, 2003: r = 0.529). Organically fertilized variants had increased basal respiration, in autumn 2002 the basal respiration was higher in variants fertilized by mineral NPK, too. The highest specific respiration was recorded in the unfertilised plot in block B (autumn 2002 and 2003), where low microbial biomass exhibited high activity. Increased specific respiration was found also in plots fertilized by FYM and FYM + NPK (block III and IV, autumn samplings). Positive significant correlations between microbial biomass content and basal respiration were found in 2002 (spring: r = 0.716) and 2003 (spring: r = 0.765, autumn: r = 0.671).

Crop straw recycling prevents anthropogenic desilication of agricultural soil–plant systems in the temperate zone – Results from a long-term field experiment in NE Germany

Geoderma ◽  
2021 ◽  
Vol 403 ◽  
pp. 115187
Author(s):  
Daniel Puppe ◽  
Danuta Kaczorek ◽  
Jörg Schaller ◽  
Dietmar Barkusky ◽  
Michael Sommer
Keyword(s):  
Field Experiment ◽  
Agricultural Soil ◽  
Temperate Zone ◽  
Crop Straw ◽  
Ne Germany ◽  
Term Field

Exploring the Vis-NIR wavelength importance in SOC models under field and lab conditions in a long-term field experiment

2021 ◽  
Author(s):  
Javier Reyes ◽  
Mareike Ließ
Keyword(s):  
Field Experiment ◽  
Spectral Response ◽  
Nir Spectroscopy ◽  
Partial Least Square ◽  
Least Square ◽  
Field Conditions ◽  
Partial Least Square Regression ◽  
Preprocessing Technique ◽  
Term Field

<p>Soil organic carbon (SOC) is of particular interest in the study of agricultural systems as an indicator of soil quality and soil fertility. In the use of Vis-NIR spectroscopy for SOC detection, the interpretation of the spectral response with regards to the importance of individual wavelengths is challenging due to the soil’s composition of multiple organic and minerals compounds. Under field conditions, additional aspects affect the spectral data compared to lab conditions. This study compared the spectral wavelength importance in partial least square regression (PLSR) models for SOC between field and lab conditions. Surface soil samples were obtained from a long-term field experiment (LTE) with high SOC variability located in the state of Saxony-Anhalt, Germany. Data sets of Vis-NIR spectra were acquired in the lab and field using two spectrometers, respectively. Four different preprocessing methods were applied before building the models. Wavelength importance was observed using variable importance in projection. Differences in wavelength importance were observed depending on the measurement device, measurement condition, and preprocessing technique, although pattern matches were identifiable, especially in the NIR range. It is these pattern matches that aid model interpretation to effectively determine SOC under field conditions.</p>

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