Textural Soil Properties Research Articles

Repeated Solid Digestate Amendment Increases Denitrifying Enzyme Activity in an Acid Clayey Soil

The use of organic fertilizers to replace chemically synthesized fertilizers has assumed an important role in managing plant nutrition and soil fertility. The various organic matrices currently available as organic byproducts and digestates are relatively abundant and have shown promising effects in terms of plant-available nutrients. However, like mineral fertilizers, organic fertilizers must be carefully managed to avoid negative effects on the environment, especially when they are repeatedly applied over time. The aim of the present study was to assess the effect of the single (DIG) and repeated application (DIGP) of solid anaerobic digestates compared to an unamended control (CTR) on the denitrifying enzymatic activity (DEA), which is responsible for nitrous oxide emissions into the atmosphere, and some related soil properties, such as total soluble nitrogen (TSN), nitrate (NO3−-N), extractable carbon (Cextr), microbial biomass carbon (MBC), and basal respiration (Rbas), for a period of ~3 months after application. The application of solid anaerobic digestates progressively boosts N and C concentrations in the soil, with the degree of enhancement directly correlated with the frequency of application over the sampling period. Depending on the textural properties of soils, there was a notable rise in denitrification enzyme activity (DEA), particularly during the DIGP treatment, suggesting that clay soils are highly susceptible to denitrification under suitable conditions. The results of this study recommend the careful management of soils subjected to repeated digestate amendment to prevent the occurrence of conditions conducive to denitrification and the promotion of N2O emissions.

Using Models and Artificial Neural Networks to Predict Soil Compaction Based on Textural Properties of Soils under Agriculture

This study focuses on addressing the challenges associated with labor-intensive soil penetration resistance (SPR) measurements, which are prone to errors due to varying soil moisture levels. The innovative approach involves developing SPR estimation models using artificial neural networks (ANN) for soils with optimal moisture levels determined by van Genuchten (WG) calculations. Sampling and measurements were conducted at 280 points (0–30 cm depth), with an additional 324 samples used for model testing. Considering six scenarios, this study aimed to identify the best estimation model using key soil properties (sand, clay, silt, bulk density, organic carbon, and aggregate stability) in different combinations affecting SPR. Results from all ANN scenarios demonstrated satisfactory SPR estimation performance, with the sand and clay content scenario exhibiting the highest accuracy, characterized by a mean square error (MSE) of 0.0029 and a coefficient of determination (R2) value of 0.9707. This selected scenario were further validated with different test data, yielding an MSE of 0.7891 and an R2 value of 0.67. In conclusion, this study suggests that, by standardizing moisture levels through WG calculations, ANN-based SPR estimation can effectively be applied to soils with specific sand and clay contents.

Identification of culturable microbial functional groups isolated from the rhizosphere of four species of mangroves and their biotechnological potential

This study identified microbial functional groups like total culturable bacteria, potential N2-fixing free living bacteria, N2-fixing hydrocarbonoclastic bacteria, N-assimilating hydrocarbonoclastic bacteria, total fungi, actinobacteria, P-solubilizers, lipolytic microorganisms, and starch, cellulose, pectin and protein degrading microorganisms, isolated from the rhizosphere of four species of mangroves (Red, Black, White, and Button) from the natural protected area at the Terminos Lagoon, Campeche, México. Overall, microbial populations showed significant differences (P<0.05) among the four mangrove species. The rhizosphere of White mangrove showed better chemical and textural soil properties, and harbored the highest microbial populations when compared to the remaining mangrove species. The principal component analysis indicated that two components accounted the 85.3% of the total variation. The most significant textural and chemical soil properties were the major components, CP1 (organic matter and total organic carbon) and CP2 (sand and clay). Microbial populations correlated (P<0.05, Pearson coefficient) with sand and clay particles, and with some soil chemical properties such as organic matter. The total nitrogen and organic carbon significantly correlated with cellulose degraders, while phosphorus with N2-fixing bacteria, total fungi, and with pectin and starch degraders.

Variations in selected physical proprieties of the soils of the sahel savannah as influenced by shleterbelt

Infiltration rate, water content and textural properties of soils in the Sahel region of Nigeria as they are affected by shelterbelts were studied. The study was conducted on three measurement positions (60, 120 and 180 m) within the shelterbelt and the control was the unsheltered area. The site was situated on the southern fringes of the Sahara desert about 53 km from Sokoto metropolis. Infiltration rate was significantly different (P=0.05) when the open soil was compared with the control. Infiltration rate also showed significant difference between (60, 120, 180, m) measurement positions within the shelterbelt. The field capacity showed statistical improvement over the open soil and 60 m measurement position, which is the immediate vicinity of the shelterbelt. But there was no significant difference between 60 and 120 m and 120 and 180 mand 60 and 180 m measurement positions. Permanent wilting point showed significant difference between the open and the protected soil. The field capacity (FC) also showed significant difference between the open soil and the protected soil. But there was no significant difference among the blocks in the protected soil. Differences in sand, silt and clay contents of the protected soil differed significantly from the unprotected soil. The research showed immense benefit of the shelterbelt to soil physical properties.Keywords: Infiltration, water content, textural properties, Sahel, shelterbelt

The variability of soil moisture diffusivity of loamy to silty soils on marl, determined by the hot air method

Various attempts have been made to estimate hydraulic characteristics from textural soil properties, often by testing models on materials with artificial packing. The latter approach prevented soil structure and the arrangement and orientation of soil particles from being taken into account. In this paper the moisture diffusivity (in short “diffusivity”) characteristics of loamy to silty soils with intermediate soil moisture contents are examined. The relationship between diffusivity and soil moisture content was determined by the hot air method on undistributed soil cores from eight different sites in the Ardeche Basin, France. Our objectives were: (1) to obtain reproducible diffusivity values; (2) to distinguish between the natural and procedural variability; (3) to examine the spatial variability; and (4) to discuss whether soil texture can be used to distinguish between the diffusivities of different loamy soils. As for problems of regionalization, it was found that the diffusivity of these soils can be related to the physiographic diversity of the area, rather than to soil texture.