Significance of pyrolytic temperature, application rate and incubation period of biochar in improving hydro-physical properties of calcareous sandy loam soil.

Biochar is increasingly recognized for its ability to enhance hydro-physical properties of soil, offering promising solutions for improving soil structure, water retention, and overall agricultural productivity. In this study, sandy loam soil was amended at different rates (0, 15, 30, and 60 t ha-1) of biochar produced from olive pomace (Jift) at different pyrolysis temperatures (300, 400, 500, and 600 °C), and incubated for 30, 60, and 90 days. The biochar-amended soils were collected for analysis after each incubation period for infiltration rate, aggregate stability, soil water retention, water repellency, and penetration resistance. At 300 °C, aggregate stability increased with biochar amendments; the highest value (65%) was after 60 days of incubation. At other pyrolysis temperatures, aggregate stability decreased, or no effect of temperature was observed. Also, at 300 °C, the infiltration rate was decreased with biochar application and the lowest value of (0.14 ml/min) was at 90 days of incubation. At other pyrolysis temperatures, the infiltration rate was increased with increased biochar application rate. Water retention was increased with biochar application at 300 °C; however, biochar application did not affect water retention at other pyrolysis temperatures. These results strongly suggest the improvement of soil physical and hydraulic properties following the addition of biochar amendment. Overall, biochar had positive effects on hydro-physical properties. The biochar produced at 300 °C pyrolysis temperature was the most beneficial to agriculturally relevant hydraulic conditions. However, field assessments are necessary to evaluate the long-term effects of biochar on hydro-physical properties.

Evaluation of phytotoxicity effect of olive mill wastewater treated by different technologies on seed germination of barley (Hordeum vulgare L.).

Olive-mill wastewater (OMW) is a by-product effluent of olive oil extraction process that is produced in large amount in the Mediterranean region. OMW is believed to induce phytotoxic effect on organisms including seed germination and plant growth. The objective of this study was to evaluate the impact of untreated and treated OMW with different techniques on seed germination of barley (Hordeum vulgare L.). The following treatments were investigated: (1) tap water (control); (2) OMW treated by aerobic biological technology in a Jacto Reactor (JR); (3) OMW treated by solar fenton oxidation (SFO); (4) OMW treated by microfiltration followed by nanofiltration (MF+NF); (5) OMW treated by microfiltration followed by reverse osmosis (MF+RO) process; (6) diluted OMW with tap water (25 % OMW); (7) diluted OMW with tap water (50 % OMW); (8) diluted OMW with tap water (75 % OMW); and (9) untreated OMW (100 % OMW). A germination test was conducted in an incubator at temperature of 23 (∘)C. In each petri dish, a filter paper was mounted and ten seeds of barley were placed on the filter paper. Five milliliter of water were added to each petri dish. The seed germination was determined by counting the number of germinated seeds to calculate the percentage of germination (G %). Germination rate index (GRI), seed vigor index (SVI), and phytotoxicity index (PI) were also calculated. Then, the dry weights and lengths of the shoots and the roots of the germinated seeds were measured. The results show that 100, 75, and 50 %OMW were very phytotoxic and completely prohibited seed germination. However, phytotoxicity decreased significantly following treatments of OMW with all techniques investigated and by the 25 % OMW dilution, as results of removing the phenols and other phytotoxic organic compounds from the OMW or by diluting it. This was evidenced by relative enhancement of the dry weights and lengths of shoot and root as well as the G %, GRI, SVG, and PI. It was concluded that if OMW will be used for irrigating crops, it has to be first treated or diluted with tap water at a ratio of 1:3 OMW:water at least. The most efficient treatment techniques in reducing the phytotoxicity of OMW were the MF+RO, followed by SFO and JR.

A new method for rapid determination of carbohydrate and total carbon concentrations using UV spectrophotometry.

A new UV spectrophotometry based method for determining the concentration and carbon content of carbohydrate solution was developed. This method depends on the inherent UV absorption potential of hydrolysis byproducts of carbohydrates formed by reaction with concentrated sulfuric acid (furfural derivatives). The proposed method is a major improvement over the widely used Phenol-Sulfuric Acid method developed by DuBois, Gilles, Hamilton, Rebers, and Smith (1956). In the old method, furfural is allowed to develop color by reaction with phenol and its concentration is detected by visible light absorption. Here we present a method that eliminates the coloration step and avoids the health and environmental hazards associated with phenol use. In addition, avoidance of this step was shown to improve measurement accuracy while significantly reducing waiting time prior to light absorption reading. The carbohydrates for which concentrations and carbon content can be reliably estimated with this new rapid Sulfuric Acid-UV technique include: monosaccharides, disaccharides and polysaccharides with very high molecular weight.