Artificial recharge – measurement of soil infiltration in Rožnov pod Radhoštěm

The purpose of this study is to evaluate the potential for infiltration in a study area – Rožnov pod Radhoštěm, the Czech Republic. The results are important for the future design of an artificial recharge structure as a method to store water underground in times of water surplus. A total of six measurements of infiltration were made using a double ring infiltrometer on selected prospective sites for the future application of artificial recharge. The results of infiltration tests were analysed based on the Philip`s model. The steady soil infiltration rates ranged from 28 cm∙h-1 to 70.38 cm∙h-1and the cumulative soil infiltration ranged from 58 cm to 68 cm

Controls on spatial and temporal variations in sand delivery to salmonid spawning riffles

Fine sediment infiltration into gravel interstices is known to be detrimental to incubating salmonid embryos. Infiltration into spawning riffles can show large spatial variations at the scale of a morphological unit and over time, with significant implications for embryo survival. Furthermore, some process-based infiltration studies, and incubation-to-emergence models assume that fines are delivered to redds via suspension rather than bedload. This process-based 12-month study examined spatial patterns of predominantly sand infiltration into gravels in an upland trout stream, using infiltration baskets. An assessment of Rouse numbers for infiltrated sand indicated that it was transported predominantly as bedload at flow peaks. Clear temporal and spatial patterns existed, with highest rates of infiltration strongly associated with higher discharges (r2 = 0.7, p < .05). Seasonal variations in the delivery of different grain sizes were also a feature, with enhanced contributions of 0.5–2 mm sediment during elevated winter flows and 0.125–0.5 mm sediment during spring and summer; the latter is potentially harmful to the later stages of embryo incubation. Clear spatial patterns were also evident across riffles, with highest rates of infiltration tending to occur in areas of lower relative roughness—the areas competent to transport sand for longer periods. Incubation-to-emergence models should take into consideration spatial patterns of fine sediment dynamics at the pool–riffle scale, to improve prediction

Residual effects of fallows on selected soil hydraulic properties in a kaolinitic soil subjected to conventional tillage (CT) and no tillage (NT)

Improved fallows have been used to reduce time required for soil fertility regeneration after cropping in low input agricultural systems. In semi-arid areas of Southern Africa, Acacia angustissima and Sesbania sesban are among some of the more widely used improved fallow species. However the residual effects of improved fallows on soil hydraulic properties during the cropping phase is not known. The aim of this study was to quantify the residual effects of fallows and tillage imposed at fallow termination on soil hydraulic properties (infiltration rates, hydraulic conductivity and soil porosity) during the cropping phase. Treatments evaluated were planted fallows of Acacia angustissima, Sesbania sesban and natural fallow (NF) and continuous maize as a control. Steady state infiltration rates were measured using a double ring infiltrometer and porosity was calculated as the difference between saturated infiltration rates and tension infiltration measurements on an initially saturated soil. Unsaturated hydraulic conductivity (K-o) and mean pore sizes of water conducting pores were measured using tension infiltrometer at tensions of 5 and 10 cm of water on an initially dry soil. While there was no significant difference in steady state infiltration rates from double ring infiltrometer measurements among the fallow treatments, these were significantly higher than the control. The steady state infiltration rates were 36, 67, 59 and 68 mm h(-1) for continuous maize, A. angustissima, S. sesban and NF respectively. Tillage had no significant effect on steady state infiltration rate. Pore density at 5 cm tension was significantly higher in the three fallows than in maize and varied from 285-443 m(-2) in fallows, while in continuous maize the pore density was less than 256 m(-2). At 10 cm tension pore density remained significantly higher in fallows and ranged from 4,521-8,911 m(-2) compared to 2,689-3,938 m(-2) in continuous maize. Unsaturated hydraulic conductivities at 5 cm tension were significantly higher in fallows than in continuous maize and were 0.9, 0.7, 0.8 cm and 0.5 cm h(-1) for A. angustissima, S. sesban, NF and continuous maize, respectively. However there were no significant treatment differences at 10 cm tension. Fallows improved infiltration rates, hydraulic conductivity and soil porosity relative to continuous maize cropping. Through fallowing farmers can improve the soils hydraulic properties and porosity, this is important as it affects soil water recharge, and availability for plant growt

Saving fuel with non-inversion tillage

The mouldboard plough is the traditional and proven method of preparing a seedbed for drilling and controlling arable weeds. However there is a downside; trials have shown deterioration in structural stability, losses of soil organic matter, poor moisture retention and infiltration rates (Riley et al 2008). Farmers have long been aware of these adverse impacts of mouldboard ploughing, but concerns over the greenhouse gas emissions associated with tractor usage have prompted a fresh look at cultivations. ORC researchers, Oliver Crowley, Jemima Showering and Thomas F. Döring consider the case for non-inversion tillage

Surface Water Infiltration in Loess Soils of the Lower Mississippi River Valley: An Emphasis on Land Use

The Alluvial Aquifer is the shallowest and most heavily used groundwater aquifer in the Lower Mississippi River Valley, particularly in the Delta region of eastern Arkansas. However, the Alluvial Aquifer is being depleted faster than the rate of recharge, primarily due to excessive withdrawals for irrigated crop production. Since extensive irrigation in the highly agriculturally productive Delta region of eastern Arkansas has been a main culprit in the groundwater depletion issues the region faces, a better understanding of how ecological factors and/or agricultural best management practices could possibly increase infiltration, to consequently increase recharge, are needed in order to either slow down or reverse the declining aquifer levels through the Delta region of eastern Arkansas. Therefore, the objective of this study was to evaluate the effects of landuse on surface water infiltration into alluvial and loessial soils in the Delta region of eastern Arkansas. Landuse combinations of interest included conventional and no-tillage agricultural practices, deciduous and coniferous forests, and native/natural grasslands. Replicate infiltration measurements were conducted using a double-ring infiltrometer, with a 15-cm inner-ring diameter, across multiple sites representing each of the five landuses. Despite the initial soil water content being greater (P \u3c 0.05) in the grassland than in all other ecosystems, the overall infiltration rate into the deciduous forest ecosystem (1.2 cm hr-1) was greater (P \u3c 0.05) than all other landuse types, which did not differ and averaged 0.10 cm hr-1. In addition, though the slope of the relationship between the natural logarithm of the infiltration rate versus the mid-point of time was unaffected (P \u3e 0.05) by landuse, the intercept parameter differed (P \u3c 0.05) among landuses. Results of this study demonstrated that landuse significantly affects infiltration processes in the fine-textured loessial and alluvial soils in the Delta region of eastern Arkansas; thus, further research is warranted into factors that can increase surface infiltration and potentially groundwater recharge

A model for estimating time-variant rainfall infiltration as a function of antecedent surface moisture and hydrologic soil type

Recent research indicates that the use of remote sensing techniques for the measurement of near surface soil moisture could be practical in the not too distant future. Other research shows that infiltration rates, especially for average or frequent rainfall events, are extremely sensitive to the proper definition and consideration of the role of the soil moisture at the beginning of the rainfall. Thus, it is important that an easy to use, but theoretically sound, rainfall infiltration model be available if the anticipated remotely sensed soil moisture data is to be optimally utilized for hydrologic simulation. A series of numerical experiments with the Richards' equation for an array of conditions anticipated in watershed hydrology were used to develop functional relationships that describe temporal infiltration rates as a function of soil type and initial moisture conditions

Do Outcomes of Arthroscopic Subscapularis Tendon Repairs Depend on Rotator Cuff Fatty Infiltration?

Background:Rotator cuff fatty infiltration has been correlated with poorer radiographic and clinical outcomes in supraspinatus and infraspinatus tendon repairs, but this has not been well-studied in subscapularis tendon repairs. Purpose:To evaluate the influence of preoperative rotator cuff fatty infiltration on postoperative outcomes for patients undergoing arthroscopic subscapularis tendon repair. Study Design:Cohort study; Level of evidence, 3. Methods:Patients who underwent arthroscopic subscapularis repair between 2010 and 2016 were retrospectively identified, and demographic data and surgical findings were recorded. The extent of fatty infiltration was determined on preoperative magnetic resonance imaging by the Fuchs modification of the Goutallier classification. At the most recent follow-up, patients completed the Patient-Reported Outcomes Measurement Information System for Upper Extremity (PROMIS-UE) computer adaptive test and a postoperative visual analog scale for pain. The distribution of fatty infiltration was compared between patients undergoing subscapularis tendon repair versus subscapularis tendon repair combined with a posterior cuff repair. Outcomes were compared for patients using Goutallier grade 0-1 versus grade ≥2 changes in each rotator cuff muscle. Multivariate linear regression analysis was performed to evaluate the influence of muscle quality, as well as demographic factors, on PROMIS-UE scores. Significance was defined as P < .05. Results:There were 140 shoulders included (mean age, 61.8 years; 42.1% female; mean follow-up, 51.7 months). The prevalence of Goutallier grade 2 changes or higher was significantly greater in patients with multitendon repair relative to isolated subscapularis tendon repair. For the overall group of all patients undergoing subscapularis tendon repair, whether in isolation or as part of a multitendon repair, PROMIS-UE scores were significantly lower for patients with infraspinatus muscle grade 2 or higher Goutallier changes relative to grade 0 or 1. After adjustment for age, body mass index, patient sex, and fatty infiltration in other rotator cuff muscles, poor infraspinatus muscle quality remained the only significant predictor for lower PROMIS-UE scores. Conclusion:Patients undergoing arthroscopic subscapularis tendon repair with poor infraspinatus muscle quality had worse patient-reported outcomes. This was true whether subscapularis tendon repair was isolated or was performed in conjunction with supraspinatus and infraspinatus tendon repairs

The Miner's Dilemma

An open distributed system can be secured by requiring participants to present proof of work and rewarding them for participation. The Bitcoin digital currency introduced this mechanism, which is adopted by almost all contemporary digital currencies and related services. A natural process leads participants of such systems to form pools, where members aggregate their power and share the rewards. Experience with Bitcoin shows that the largest pools are often open, allowing anyone to join. It has long been known that a member can sabotage an open pool by seemingly joining it but never sharing its proofs of work. The pool shares its revenue with the attacker, and so each of its participants earns less. We define and analyze a game where pools use some of their participants to infiltrate other pools and perform such an attack. With any number of pools, no-pool-attacks is not a Nash equilibrium. With two pools, or any number of identical pools, there exists an equilibrium that constitutes a tragedy of the commons where the pools attack one another and all earn less than they would have if none had attacked. For two pools, the decision whether or not to attack is the miner's dilemma, an instance of the iterative prisoner's dilemma. The game is played daily by the active Bitcoin pools, which apparently choose not to attack. If this balance breaks, the revenue of open pools might diminish, making them unattractive to participants

Propriedades físicas e infiltração de água de um Latossolo Vermelho Amarelo (Oxisol) do noroeste do estado de São Paulo, Brasil, sob três condições de uso e manejo

This study presents the results obtained in a field experiment carried out at Glicério, Northwest of São Paulo state, Brazil, whose objective was to analyze changes of selected soil physical properties and water infiltration rates on a Yellow-Red Latosol, under three different management conditions. The experimental design was arranged as completely randomized split-block with twelve treatments, which corresponded to four depths (0-0.05 m; 0.05-0.10 m; 0.10-0.20 m and 0.20-0.40 m) and three conditions of soil use and management with four replications. The soil surface conditions were: conventional tillage (one disking with moulboard plus two levelling passes with harrow), nine months before starting filed experiences; recent conventional tillage (also one disking with moulboard plus two levelling passes with harrow) and native forest. The conventional tillage areas were cropped for about fifteen years with annual cultures. The considered soil general physical properties were: macroporosity, microporosity, total porosity, bulk density, soil moisture and penetration resistance and, in addition; soil water infiltration rates were also recorded. According to our results, differences on general soil physical properties and infiltration rates appeared when both tilled sub-treatments and native forest were compared. Both, plots recently prepared by conventional tillage and those prepared by tillage but left nine months in rest, presented a statistically significant decrease of constant (final) water infiltration rates of 92.72% and 91.91% when compared with native forest plots