650 research outputs found
An assessment of the BEST procedure to estimate the soil water retention curve: A comparison with the evaporation method
No full textThe Beerkan Estimation of Soil Transfer parameters (BEST) procedure is an attractive, easy, robust, and inexpensive way for a complete soil hydraulic characterization but testing the ability of this procedure to estimate the water retention curve is necessary as relatively little information is available in the literature. In this investigation the soil water retention curve was predicted for four differently textured soils by applying three existing BEST algorithms (i.e., slope, intercept and steady) and the results compared with those measured by the standard Wind evaporation method. A sensitivity analysis of the infiltration constants, beta and gamma, was also carried out and their impact on the estimated retention curve scale parameter, h(g), was evaluated. BEST-slope underestimated the soil water retention for three of the four soils under consideration, providing relatively low root mean squared differences between estimated and measured data (0.0261 cm(3)cm(-3) <= RMSD <= 0.0483 cm(3)cm(-3)). For one site (PAL, sandy-loam soil), BEST-steady provided the lowest RMSD value (0.0893 cm(3)cm(-3)) among the considered algorithms, but the water retention was systematically overestimated as a consequence of a relatively higher difference between field and lab saturated soil water contents. A specific calibration performed for beta and gamma highlighted that: i) the water retention estimations by BEST-slope were more sensitive to beta than those obtained by BEST-intercept and BEST-steady; ii) with the exception of PAL soil, the lowest RMSD values were obtained with BEST-slope. Estimation of the soil water retention curve was not significantly worse when reference values of infiltration constants (beta = 0.6 and gamma = 0.75) were used as detected by negligible differences in RMSDs as compared to calibrated beta and gamma. Therefore, it was concluded that the BEST slope algorithm yielded predictions of water retention closer to the laboratory estimated ones than the alternative BEST algorithms (i.e. BEST-intercept and-steady). For these algorithms, the less accurate estimates of the water retention data were attributed to h(g) overestimations due to the independence of the retention curve scale parameter from gamma
Compost Amendment Impact on Soil Physical Quality Estimated from Hysteretic Water Retention Curve
No full textCapacity-based indicators of soil physical quality (SPQ) and pore distribution parameters were proposed to assess the effects of compost amendment but their determination was limited to desorption water retention experiments. This study also considered the pore size distribution obtained from adsorption experiments to establish the effectiveness of compost amendment in modifying the physical and hydrological attributes of a sandy loam soil. Repacked soil samples with different compost to soil ratios, r, were subjected to a wetting-drying cycle, and the water retention data were fit to the van Genuchten model to obtain the pore volume distribution functions. The soil bulk density was minimally affected by the wetting-drying cycle but a significant negative correlation with r was obtained. The sorption process involved larger and more heterogeneous pores than the desorption one thus resulting in an estimation of the air capacity SPQ indicators (P-mac and AC) that were higher for the wetting-water retention curve (WWRC) than the drying one (DWRC). The opposite result was found for the water storage SPQ indicators (PAWC and RFC). In general, SPQ indicators and pore distribution parameters were generally outside the optimal range but estimates from the DWRC were closer to the reference values. The water entry potential increased and the air entry potential decreased with an increase in the compost rate. Significant correlations were found between the SPQ indicators estimated from the DWRC and r but the same result was not obtained for the WWRC. It was concluded that compost addition could trigger positive effects on soil hydrological processes and agronomic service as both water infiltration during wetting and water storage during drying are favored. However, the effectiveness of the sorption process for evaluating the physical quality of soils needs further investigation
Application of Multivariate Analysis Techniques for Selecting Soil Physical Quality Indicators: A Case Study in Long-Term Field Experiments in Apulia (Southern Italy)
No full textLong-term field experiments and multivariate analysis techniques represent research tools that may improve our knowledge on soil physical quality (SPQ) assessment. These techniques allow us to measure relatively stable soil conditions and to improve soil quality judgment, thereby reducing uncertainties. A monitoring of SPQ under long-term experiments, aimed at comparing crop residue management strategies (burning vs. incorporation of straw, FE1) and soil management (minimum tillage vs. no tillage, FE2), was established during the crop growing season of durum wheat. The relationships between five SPQ indicators (bulk density [BD], macroporosity [PMAC], air capacity [AC], plant available water capacity [PAWC], and relative field capacity [RFC]) were evaluated, and two techniques of multivariate analysis (principal component analysis and stepwise discriminant analysis) were applied to select key indicators for SPQ assessment. According to the used indicators, an SPQ from optimal to intermediate (i.e., not definitely poor) was detected in 65% of the observations in FE1 and in 54% in FE2. The main results showed a significant negative relationship between RFC and AC, and multivariate analysis identified RFC as a key SPQ indicator, mainly in FE2. Plant available water capacity and BD showed the highest discriminating capability in the FE1 dataset. The highest scores of RFC assessment were highlighted for burning and minimum tillage treatments (+1 and +2). An optimal AC range, derived from optimal RFC limits, was obtained and was suggested to better assess the AC of agricultural soils (0.10 ≤ AC ≤ 0.26 cm3 cm-3). © 2019 The Author(s)
Temporal variability of physical quality of a sandy loam soil amended with compost
No full textCompost can enhance the soil's ability to retain water, resulting in an overall improvement of soil physical quality (SPQ). The purpose of this study was to evaluate the temporal variability of physical and hydraulic properties of a sandy loam soil amended with a compost obtained from orange juice processing wastes and garden cleaning. The soil water retention curve of repacked soil samples at varying compost to soil ratios, r, was determined at the time of compost embedding (M0) and after six months (M6), and twelve months (M12). Indicators of SPQ linked to soil water retention curve such as air capacity (AC), macroporosity (Pmac), plant available water capacity (PAWC), relative field capacity (RFC) and Dexter S-index (S), were estimated. The effect of compost addiction of the pore volume distribution function was also evaluated.
The elapsed time from compost application influenced all SPQ indicators but the maximum beneficial effects of compost amendment were achieved within approximately the first six months. Indicators linked the macro- and mesoporosity (Pmac and AC) decreased with r whereas indicators linked to plant water availability (PAWC and RFC) increased with r. The combined effect of time and rate was statistically observed only for Pmac, PAWC and S.
Compost addiction reduced the soil compaction and modified the pore system, as the fraction of structural porosity (i.e., macropores) decreased and the fraction of textural porosity (i.e., micropores) increased. It was concluded that even a single application of compost could have a significant impact on soil water retention and microstructure with positive implications for soil health, precision agriculture and crop productivity
Impact of vermicompost addition on water availability of differently textured soils
No full textVermicompost is an organic material that is abundant in humic acids and nutrients. It is obtained through the bio-oxidation and stabilization processes carried out by earthworms. It has been proven to bring several benefits to different soil properties, including bulk density, soil structure, and plant available water capacity (PAWC). This investigation was conducted to fill the knowledge gap in some critical factors related to vermicompost application, specifically the short-term influence of a single vermicompost application with increasing doses on soil wettability and physical quality of differently textured soils. Water repellency of vermicompost and soil/vermicompost mixtures was investigated at different moisture contents by the water drop penetration time test, whereas physical quality was assessed by 35 soil indicators related to bulk density, soil water retention curve, and pore size distribution function.Despite vermicompost showed from strong to severe hydrophobicity at moisture content lower than the field capacity, amended soils were at the most slightly water repellent thus indicating that, under field conditions, the hydrophobicity attributable to soil amendment with vermicompost could be considered negligible. Soil physical quality was effectively affected by vermicompost addiction with different outcomes depending on soil texture. Indicators linked to PAWC generally increased at increasing the vermicompost rate in the coarse soils whereas no significant effect was observed for intermediate and fine soils. For example, plant available water capacity of coarse-textured soils increased from an average initial value of 0.056 cm3 cm−3 to an optimal value of 0.15 cm3 cm−3 when a vermicompost addition dose of about one-third by volume (34 %) was applied. In the finest soil, drainable porosity significantly increased from an initial value of 0.09 cm3 cm−3 to 0.23 cm3 cm−3 when the maximum vermicompost dose (43 %) was applied thus indicating that amendment could be effective in enhancing water and air circulation
Sustainable Agriculture and Soil Conservation II
No full textThe use of sustainable soil conservation practices has become more and more widespread in recent decades due to the growing awareness that soil, a non-renewable resource delivering multiple ecosystem services, is increasingly being menaced by various processes, such as erosion, pollution, loss of organic matter, desertification, salinization, loss of biodiversity, and many others [...
Advances in Ecohydrology for Water Resources Optimization in Arid and Semi-Arid Areas
No full textConserving water resources is a current challenge that will become increasingly urgent in future due to climate change. The arid and semi-arid areas of the globe are expected to be particularly affected by changes in water availability. Consequently, advances in ecohydrology sciences, i.e., the interplay between ecological and hydrological processes, are necessary to enhance the understanding of the critical zone, optimize water resources’ usage in arid and semi-arid areas, and mitigate climate change. This Special Issue (SI) collected 10 original contributions on sustainable land management and the optimization of water resources in fragile environments that are at elevated risk due to climate change. In this context, the topics mainly concern transpiration, evapotranspiration, groundwater recharge, deep percolation, and related issues. The collection of manuscripts presented in this SI represents knowledge of ecohydrology. It is expected that ecohydrology will have increasing applications in the future. Therefore, it is realistic to assume that efforts to increase environmental sustainability and socio-economic development, with water as a central theme, will have a greater chance of success
Mirko Breyer, Publisher from Križevci
No full textU tekstu se donosi kratak prikaz života i djela križevačkog nakladnika Mirka Breyera. Mirko Breyer bio je pr\>ak hrvatske bibliografije, bibliofil, knjižar-nakladnik i antikvar. Obilježio je početak dvadesetog stoljeća svojim kulturnim radom. Autor donosi dio objavljene i dio neobjavljene građe o Mirku Breyeru.The text is a short overview of the life and work of a Križevci publisher Mirko Breyer. Mirko Breyer was a pioneer of Croation bibliography, a bibliophile, bookseller, publisher and antiquarian. He marked the beginning of the 20th century with his cultural work. The author presents parts of published as well as unpublished material on Mirko Breyer, with his bibliography
Soilwater conservation : Dynamics and impact
No full textHuman needs like food and clean water are directly related to good maintenance of healthy and productive soils. A good understanding of human impact on the natural environment is therefore necessary to preserve and manage soil and water resources. This knowledge is particularly important in semi-arid and arid regions, where the increasing demands on limited water supplies require urgent efforts to improve water quality and water use efficiency. It is important to keep in mind that both soil and water are limited resources. Thus, wise use of these natural resources is a fundamental prerequisite for the sustainability of human societies. This Special Issue collects 15 original contributions addressing the state of the art of soil and water conservation research. Contributions cover a wide range of topics, including (1) recovery of soil hydraulic properties; (2) erosion risk; (3) novel modeling, monitoring and experimental approaches for soil hydraulic characterization; (4) improvement of crop yields; (5) water availability; and (6) soil salinity. The collection of manuscripts presented in this Special Issue provides more insights into conservation strategies for effective and sustainable soil and water management
Use of BEST Procedure to Assess Soil Physical Quality in the Baratz Lake Catchment (Sardinia, Italy)
No full textConversion of Mediterranean maquis and/or natural forest into agro-pastoral lands is a cause of soil degradation in many Mediterranean areas. Indicators of soil physical quality (SPQ) quantitatively linked to soil hydraulic properties are a valuable tool to assess the effect of land use changes. In this investigation, the Beerkan Estimation of Soil Transfer parameters (BEST) procedure for soil hydraulic characterization was used to estimate SPQ indicators. Four areas of the Baratz Lake watershed, Sardinia, Italy, characterized by both typical natural vegetation (holm oak [Quercus ilex L.] forest and high maquis) and degraded vegetation (grassland established after fire or clearing of the maquis) were considered. The SPQ was assessed by either independently measured soil physical attributes, like soil bulk density, organic C content, saturated hydraulic conductivity, and sorptivity, and capacitive and dynamic indicators calculated from the water retention curve estimated by the BEST procedure. Measured and estimated SPQ indicators unanimously showed that clearing of the maquis caused a severe deterioration of SPQ associated with soil compaction, organic matter loss, and decrease of macropore volume and soil aeration capacity as well as reduced water circulation. A different and unexpected result was obtained for the fire-affected area, where the SPQ was comparable to that of the neighboring oak forest area. We deduced that vegetation restoration after fire passage contributed to maintain a high organic matter content and to mitigate rain compaction effects. We concluded that SPQ indicators derived by applying the BEST procedure are suitable to detect land degradation in the natural environments studied
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