Soil Physical Quality Indicators and Refinement of the Evaluation Method through the Srelative

This study aimed to verify the efficiency of indicators of measure of physical attributes’ alterations and to refine the Srelative determination method in order to increase its sensitivity to soil physical alterations. Soils under Ficus carica L. cultivation (with 0, 20, 40 and 60% of liquid bovine biofertilizer in the irrigation depth) and under forest were used. Parameters evaluated included soil granulometry, soil bulk and particle density, soil water retention curve (SWRC), porosity and the indices S and Srelative. The experimental design was completely randomized with four replicates. For Srelative refinement, with the SWRC containing only textural porosity, the soil was dispersed in water and with the addition of 1 N sodium hydroxide (with and without removal of sodium through washing). An ANOVA was performed for 0, 20, 40 and 60% of biofertilizer in 0-10, 10-20 and 20-30 layers; Dunnett test was used to compare the mean values of S-index and Srelative-index. With respect to four methods to obtain the Srelative-index the means were compared by Tukey test. Tests of line parallelism and intercept were performed for the regressions between each of the soil physical variables and Srelative-index obtained. It was found that S and Srelative indices were sensitive to soil physical alterations caused by the application of the biofertilizer; Srelative-index was sensitive to variation in soil bulk density and total porosity and the Srelative-index obtained from the method of soil dispersion in water is more sensitive to soil physical alterations in comparison to Srelative-index obtained through ADFE.

Study of the technical performance of localized irrigation and its environmental and agroeconomic impact in the first areas of collective reconversion at the irrigated perimeter of the Tadla - Beni Moussa perimeter of the west – Morocco

The evaluation of the performance of the localized irrigation system involved a selected sample of farmers to reflect the diversity of the study area. The hydraulic diagnosis revealed the absence of apparent malfunctioning anomalies of the installations studied (Coefficient of Distribution Uniformity ≥ 90% with average application efficiencies and overall of 90.54 and 86.83% respectively). In terms of the combined use of surface and underground irrigation water this new technique has saved about 30% compared to conventional irrigation. The agro-economic evaluation revealed that the crops practiced have high value-added and optimize the value of irrigation water. The environmental impact has resulted in an average drawdown of the static level of groundwater of 2.59 m due mainly to the new irrigation method introduced, which limited the percolation of water to the aquifer. The drip-to-drip transition resulted in an increase in salinity relative compared to the reference situation (+ 0.59 %, or 0.01 mS / cm) but to different degrees depending on the prospecting soil horizon. The practice of fertilization remains the major and probable cause of soil salinization of aquifers. The effect of soluble salts on the soil was investigated through the risks associated with sodium, which showed that the soil permeability problem does not arise at this time (SAR ≤ 15). The residual sodium carbonate remains less than 1.25 meq / l thus not causing soil dispersion.

Field trial and modelling of different strategies for remediation of soil salinity and sodicity in the Lower Murray irrigation areas

Rising saline groundwatertables and drought in the Lower Murray Reclaimed Irrigation Area (LMRIA) has created soil salinity and sodicity conditions, which has resulted in a decline in agricultural production. A 2 month field experiment was conducted at Mobilong irrigation area using a randomised block design with trial plots (4m2) in each of the three blocks containing the following six treatments: (1) control (not irrigated), (2) irrigation (River Murray water) only, (3) gypsum application (1.5 kg/m2) and irrigation, (4) limestone application (1.5 kg/m2) and irrigation, (5) seawater (source of dissolved Ca2+) application (100mm depth) and irrigation and (6) acid (pH 3) drainage (to dissolve CaCO3 in soil to release Ca2+) application (100mm irrigation water depth) and irrigation. Soil electrical conductivity (EC), pH, exchangeable cations (Ca2+, Mg2+, Na+, K+), exchangeable sodium percentage (ESP) and saturated hydraulic conductivity were measured. The decrease in EC was greatest in the irrigation only treatment followed by the gypsum and limestone treatments. At the end of the trial, the EC in the irrigation only treatment was about one-quarter of the control, in which the EC increased. The seawater and acid drainage treatments reduced the soil EC relative to the control but the EC was 2–3dS/m higher than the irrigation, gypsum and limestone treatments at the end of the trial. The gypsum, irrigation only and limestone treatments approximately doubled the exchangeable Ca relative to the control and exchangeable Na was reduced. Unsaturated water and solute transport model (HYDRUS-UNSATCHEM) simulations were able to represent the general trends in the field results. The results suggest that only River Murray water irrigation and drainage could be effective for the management of soil salinity and sodicity in the LMRIA but further research is required to establish the threshold electrolyte concentration to prevent soil dispersion.

Highly ordered surfactant micelles function as the extraction matrix for direct electrochemical detection of halonitrobenzenes at the ppb level

Electrochemical detection of halonitrobenzenes in complex samples like soil dispersion was accomplished using surfactant micelles as the extraction matrix.