Impact of regression methods on improved effects of soil structure on soil water retention estimates

2015 ◽  
Vol 525 ◽  
pp. 598-606 ◽  
Author(s):  
Phuong Minh Nguyen ◽  
Jan De Pue ◽  
Khoa Van Le ◽  
Wim Cornelis
2020 ◽  
Author(s):  
Teamrat Ghezzehei ◽  
Jennifer Alvarez ◽  
Yocelyn Villa ◽  
Rebecca Ryals

<p>The dynamics of soil organic matter is strongly controlled by the hydrophysical environmental factors, including motility, aqueous diffusivity of substrates, gaseous diffusivity, and energetic constraints on microbial physiology. The relationships among these physical factors depend on soil moisture and the architecture of the soil pores. In this regard, the soil water retention curve can serve as a macroscopic signature of pore-size distribution. Therefore, the sensitivity of aerobic and anaerobic microbial activity must be closely associated with the shape of the soil water retention curve. The soil water retention curve is, in turn, strongly dependent on soil texture and structure. Here, we present a physically-based model of aerobic and anaerobic microbial respiration rates. We also present a novel experimental technique for the characterization of the soil-moisture sensitivity of soil microbial activity. The proposed experimental and modeling approaches allow direct coupling of the fate soil organic matter with the nature of soil structure.</p>


Soil Research ◽  
2014 ◽  
Vol 52 (5) ◽  
pp. 443 ◽  
Author(s):  
Phuong Minh Nguyen ◽  
Khoa Van Le ◽  
Wim M. Cornelis

Models of soil water and solute transport require input data of soil hydraulic properties (e.g. soil water retention and hydraulic conductivity curves). Lack of such data, especially in tropical delta regions, has usually been the main constraint for the application of simulation models. Direct field or laboratory measurement of soil water retention is costly, laborious and time-consuming; therefore, indirect estimation from other easily measured soil properties has received great interest. However, indirect estimates are often unreliable. In this study, we hypothesise that including basic descriptive information of soil structure such as aspect of presence or absence of pedality can improve the prediction of the soil water retention characteristic (SWRC). Stepwise multiple linear regression was used to develop point pedotransfer functions (PTFs) to estimate soil water retention at eight pressure potentials (e.g. –1, –3, –6, –10, –20, –34, –100, –1500 kPa). Soil structural information was exploited as a preliminary grouping criterion to test our hypothesis. Soil samples were taken from 160 horizons distributed along the Mekong Delta, Vietnam. The results reveal that SWRC of tropical Mekong Delta soils could be satisfactorily estimated by typical predictors of PTFs (e.g. soil texture, organic carbon content and bulk density). Moreover, incorporating soil structure in developing PTFs did improve the prediction accuracy of SWRC, especially in the wet moisture range. Plastic limit was found to be a promising predictor for SWRC-PTFs of soils having a given degree of structural development.


2017 ◽  
Vol 16 (4) ◽  
pp. 869-877
Author(s):  
Vasile Lucian Pavel ◽  
Florian Statescu ◽  
Dorin Cotiu.ca-Zauca ◽  
Gabriela Biali ◽  
Paula Cojocaru

2021 ◽  
pp. 51495
Author(s):  
Ruth M. Barajas‐Ledesma ◽  
Vanessa N. L. Wong ◽  
Karen Little ◽  
Antonio F. Patti ◽  
Gil Garnier

Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 195 ◽  
Author(s):  
Mirko Castellini ◽  
Anna Maria Stellacci ◽  
Danilo Sisto ◽  
Massimo Iovino

The multi-height (low, L = 3 cm; intermediate, M = 100 cm; high, H = 200 cm) Beerkan run methodology was applied on both a minimum tilled (MT) (i.e., up to a depth of 30 cm) and a no-tilled (NT) bare loam soil, and the soil water retention curve was estimated by the BEST-steady algorithm. Three indicators of soil physical quality (SPQ), i.e., macroporosity (Pmac), air capacity (AC) and relative field capacity (RFC) were calculated to assess the impact of water pouring height under alternative soil management practices. Results showed that, compared to the reference low run, M and H runs affected both the estimated soil water retention curves and derived SPQ indicators. Generally, M–H runs significantly reduced the mean values of Pmac and AC and increased RFC for both MT and NT soil management practices. According to the guidelines for assessment of SPQ, the M and H runs: (i) worsened Pmac classification of both MT and NT soils; (ii) did not worsen AC classification, regardless of soil management parameters; (iii) worsened RFC classification of only NT soil, as a consequence of insufficient soil aeration. For both soil management techniques, a strong negative correlation was found between the Pmac and AC values and the gravitational potential energy, Ep, of the water used for the infiltration runs. A positive correlation was detected between RFC and Ep. The relationships were plausible from a soil physics point of view. NT soil has proven to be more resilient than MT. This study contributes toward testing simple and robust methods capable of quantifying soil degradation effects, due to intense rainfall events, under different soil management practices in the Mediterranean environment.


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