Electrical Conductivity Measurements in Agriculture: The Assessment of Soil Salinity

Soil salinity is an important issue constraining the productivity of irrigation agriculture around the world. The standard method for soil salinity assessment is based on a laboratory method that is cumbersome and gives rise to limitations for data-intensive works. The use of sensors for the assessment of the apparent electrical conductivity (EC) of soils offers a way to overcome these constraints. These sensors are based on three electromagnetic phenomena, namely, electrical resistivity, electromagnetic induction, and reflectometry. Each class of sensors presents its own advantages and drawbacks. In the following chapter, these are presented along with the most popular commercial EC sensors used in nowadays agriculture, equations for the assessment of soil salinity on basis sensor measurements, some examples of application, and present and future development trends

A Modified Version of RothC to Model the Direct and Indirect Effects of Rice Straw Mulching on Soil Carbon Dynamics, Calibrated in Two Valencian Citrus Orchards

The mulching of agricultural soils has been identified as a viable solution to sequester carbon into the soil, increase soil health, and fight desertification. This is why it is a promising solution for carbon farming in Mediterranean areas. Models are used to project the effects of agricultural practices on soil organic carbon in the future for various soil and climatic conditions, and to help policy makers and farmers assess the best way to implement carbon farming strategies. Here, we modified the widely used RothC model to include mulching practices and their direct and indirect effects on soil organic matter input, soil temperature changes, and soil hydraulic balance. We then calibrated and tested our modified RothC (RothC_MM) using the dataset collected in two field mulching experiments, and we used the tested RothC_MM to estimate the expected soil carbon sequestration due to mulching by the year 2050 for the Valencian Community (Spain). Our results show that RothC_MM improved the fit with the experimental data with respect to basic RothC; RothC_MM was able to model the effects of mulch on soil temperature and soil water content and to predict soil organic carbon (SOC) and CO2 observations taken in the field

Assessing the environmental sustainability of irrigation with oil and gas produced water in drylands

Produced water (PW) is the largest by-product of the oil and gas industry. Its management is both economically and environmentally costly. PW reuse for irrigation offers an alternative to current disposal practices while providing water to irrigators in drylands. The aim of this investigation was to evaluate the environmental effects of irrigation with PW. The SALTIRSOIL_M model was used to simulate the irrigation of sugar beet with 15 PWs of a wide range of qualities in four climates of different aridity and on four contrasting soil types. The impacts on soil salinity, sodicity and pH as well as on crop yield and drainage water salinity were estimated. Well-drained soils with low water content at field capacity (Arenosol) are less sensitive to salinisation while a relatively high gypsum content (Gypsisol) makes the soil less vulnerable to both sodification and salinisation. On the contrary, clayey soils with higher water content at field capacity and lower gypsum content must be avoided as the soil structural stability as well as a tolerable soil electrical conductivity for the crop cannot be maintained on the long-term. Soil pH was not found to be sensitive to PW quality. Drainage water quality was found to be closely linked to PW quality although it is also influenced by the soil type. The impact of drainage water on the aquifer must be considered and reuse or disposal implemented accordingly for achieving sustainable irrigation. Finally, increasing aridity intensifies soil and drainage water salinity and sodicity. This investigation highlights the importance of adapting the existing irrigation water quality guidelines through the use of models to include relevant parameters related to soil type and aridity. Indeed, it will support the petroleum industry and irrigators, to estimate the risks due to watering crops with PW and will encourage its sustainable reuse in water-scarce areas

Field Comparison of Electrical Resistance, Electromagnetic Induction, and Frequency Domain Reflectometry for Soil Salinity Appraisal

By using different physical foundations and technologies, many probes have been developed for on-site soil salinity appraisal in the last forty years. In order to better understand their respective technical and practical advantages and constraints, comparisons among probes are needed. In this study, three different probes, based on electrical resistance (ER), electromagnetic induction (EMI), and frequency domain reflectometry (FDR), were compared during a field survey carried out in a large salt-threatened agricultural area. Information about the soil bulk electrical conductivity (σb) at different depths was obtained with each of the probes and, additionally, other soil properties were also measured depending on the specifications of each instrument and, moreover, determined in samples. On average, the EMI and FDR techniques could be regarded as equivalent for σb measurement, whereas ER gave higher σb values. Whatever the case, EMI, and also ER, had to be supplemented with information about soil clay, organic matter, and water mass fractions to attain, despite this effort, poor soil salinity estimations by means of multiple linear regression models (R2 < 0.5). On the contrary, FDR needed only probe data to achieve R2 of 0.7, though root mean standard error (RMSE) was still 1.5 dS m−1. The extra measurements and calculations that modern electrical conductivity contact probes integrate, specifically, those based on FDR, remarkably increase their ability for soil salinity appraisal, although there is still room for improvement

DSS-SALTIRSOIL: Un sistema de ayuda a la decisión en internet para la obtención de recomendaciones de gestión del riego y el cultivo en tierras amenazadas por salinización

En el presente trabajo se presenta un ejemplo de utilización del sistema de ayuda a la decisión DSS-SALTIRSOIL para la recomendación del riego en una plantación de caqui “Rojo Brillante” en la zona de riegos del Magro de la Ribera del Xúquer (Valencia). De acuerdo con la simulación realizada con datos de la zona representativos de su meteorología (año 2010), suelo (franco arcilloso), calidad de agua (2.3 dS/m) y manejo del riego (goteo) y el cultivo, se esperaría una pérdida del 15% de producción como consecuencia de la salinización. Un incremento de la dotación anual de riego de 140 mm, o una disminución de la salinidad hasta 2.0 dS/m reducirían dicha pérdidas a tan solo un 10% en dicho año de meteorología media. No obstante, la simulación del periodo 2000-2015 indica que una disminución de 100 mm en la precipitación anual media supone una amenaza de pérdida de producción de más del 20% en promedio. En consecuencia una solución satisfactoria a los problemas de salinidad en el cultivo del caqui en la zona pasa necesariamente por usar aguas de riego de salinidad más baja (< 2.0 dS/m), o bien por un cambio del patrón del caqui a uno más tolerante a la salinidad como es el D. virginiana

A semi-empirical model to predict the EM38 electromagnetic induction measurements of soils from basic ground

Electromagnetic induction (EMI) measurements (σb*) are widely used for the survey of several soil attributes, among which basic properties such as salinity (σe),water content (θw), clay (wc), organic matter (wom) and bulk density (ρb) standout. In usual practice, purely empirical models relating one of these properties to σb* are calibrated at selected sites. However, this calibration is site and time specific and has to be repeated time and again. In order to understand where the variability of the EMI empirical models comes from, it is necessary to know how the different soil properties contribute to them and, with this aim, a more physically based relationship between σb* and, at least, σe, θw, wc, wom and ρb was developed in this work, additionally including soil temperature (t). It was calibrated and cross-validated with the data from one survey carried out in a wide agricultural irrigation area in SE Spain, taking σb* measurements with the Geonics EM38 in the horizontal and vertical dipole modes and at various heights over the ground. Then, it was externally validated with the data from a second survey carried out 4 years later in the same area but in a different season. In the calibration, R2 and root mean square error (RMSE) were 0.84 and 0.18 dS m−1(41%), respectively, forthe vertical dipole orientation and 0.90 and 0.11 dS m−1(39%) for the horizontalone. In the external validation, R2 and RMSE were 0.80 and 0.24 dS m−1(44%),respectively, for the vertical dipole orientation and 0.90 and 0.13 dS m−1(38%) for the horizontal one. Therefore, because the performance of the model barely worsened as time passed by, it can be considered to represent the underlying physicalprocess and, therefore, to increase our understanding of how the soil EMI signalsare generated, with potential benefits for the planning and comparability of EMI soil measurements, specifically with the EM38, among different areas

Global Research Trends in the Latarjet Procedure: A Bibliometric and Visualized Study

Background and Objectives: Latarjet is among the procedures indicated to treat shoulder instability, producing excellent results, including low instability rates and high patient satisfaction. The aim of this study was to report the characteristics of scientific articles that address the subject of the Latarjet procedure through the use of bibliometric analysis. Materials and Methods: Bibliographic searches were performed for original articles published in journals indexed by the Web of Science database until 2021, with no language restrictions. Results: A total of 668 articles published in 87 journals were included. The first publication was in 1981; the most registered publications were in 2018 and 2021 (89 articles), with an annual percentage growth rate of 11.9. Provencher MT was the author with the most published articles, and the institutional affiliation with the most original articles was the Steadman Philippon Research Institute. The most cited article was a study by Burkhart and Beer, and the scientific journal with the most publications on the subject was the Journal of Shoulder and Elbow Surgery. Most published studies included keywords such as dislocation, instability, and meta-analysis. Conclusion: There has been a sustained increase in original articles on the Latarjet procedure. However, the greatest growth in articles has occurred during the last decade, demonstrating the considerable interest among the world scientific community.Revisión por pare

Critical nitrogen dilution curve and dry matter production parameters for several Mediterranean vegetables

Inadequate nitrogen fertilizing practices lead to low nitrogen uptake efficiency (NUE), which increases water NO3− pollution, as well as N2O emissions to the atmosphere. In order to increase the NUE and decrease the N losses as NO3− and N2O from the soil-plant system, accurate data about optimum crop N concentrations and dry matter production throughout the growing season are still needed for many vegetables typically grown under Mediterranean climate. For this reason, several N fertilization trials were set up for globe artichoke, carrot, cauliflower, chard, chinese cabbage, early potato, leek, lettuce, onion, red cabbage, romanesco, and spinach, under the semiarid Mediterranean conditions of the Valencian Community (Eastern Spain) during several years. The fresh and dry matter weight (W), as well as the nitrogen concentration in the dry matter (%N) in both the marketable and non-marketable crop parts, was measured between 3 and 7 times throughout their respective growing seasons. The a and b coefficients of the average N dilution curve (%N = a W − b), for which all %N and W data were used, and the critical N dilution curve (%Nc = a Wc−b), for which only the minimun %N for maximum W data were used if available, in addition to the dry/fresh yield matter ratio (DM) and the harvest index (HI), were calculated for all these crops. No significant differences were observed between the average and critical N dilution curve coefficients in this work. Interestingly, the coefficients of both N dilution curves differed from the ones found in the literature with the exception of those obtained for similar cultivars, e.g., early potatoes, and under similar climatic conditions, i.e., Mediterranean. Besides, there were neither differences of DM and HI among the several N fertilization treatments. Therefore, due to the absence of changes in the N dilution curve and dry matter production coefficients for the different N supplies, all these parameters were estimated on the basis of the whole dataset, i.e., regardless of the N input. The use of the critical nitrogen dilution curve coefficients and dry matter production parameters presented in this work should contribute to better fit the N fertilizer additions to N demands of these vegetables under Mediterranean conditions, mainly, by their use through simulation models. Therefore, the NUE in horticulture should increase and the N losses as NO3− to inland and sea waters in these environments, and as N2O to the atmosphere should decrease

Auxins seem promising as a tuning method for balancing sugars with acidity in grape musts from cv. Tempranillo, but not defoliation or application of magnesium to leaves

[EN] Global warming boosted by climate change affects grape quality, with increasing total soluble solids (TSS) content and decreasing total acidity (TA). However, current wine preferences increasingly include moderate alcohol content, higher acidity and the preservation of primary aromas reminiscent of grapes. Therefore, we hypothesised that applying phytohormones or mineral nutrients to leaves or carrying out defoliation can improve grape must properties in the face of climate warming and in accordance with current oenological trends. The effects of these three viticultural strategies were assessed independently from one another during three growing seasons in a Vitis vinifera L. cv. Tempranillo vineyard in northern Spain. Specifically, three 1-naphtaleneacetic acid (NAA) treatments, two early defoliations (ED; moderate and severe) and two foliar fertilisations with magnesium (Mg) were applied. Treatment with NAA was the most encouraging strategy for decreasing must TSS while increasing TA: it had slight effects on TSS in general and also slight effects on TA when applied close to veraison. The effects of the Mg treatments and moderate ED had null to slightly adverse effects. Finally, severe ED was clearly counter-productive. This study contributes to understanding the effects of both auxin and early defoliation treatments on grape must TSS, acidity and even yeast assimilable nitrogen (YAN) at harvest time. The favourable effects of NAA application are shown to be consistent though slight. Therefore, according to these results, the application of auxins may be an adequate choice for balancing sugars with acidity in grape musts. However, the results also suggest that more research needs to be undertaken to better characterise the effects of auxin treatments on grape must properties at harvest. In particular, different types of auxins, rates, concentrations and number of applications should be tested in the quest for more marked effects.SIThe authors are most grateful to both Consejo Regulador de la Denominación de Origen Ribera del Duero and Bodega and Viñedos Martín Berdugo, S.L., for assisting with this research project