The Assessment of Water Retention Efficiency of Different Soil Amendments in Comparison to Water Absorbing Geocomposite

Soil amendments are substances added to the soil for moisture increment or physicochemical soil process enhancement. This study aimed to assess the water conservation efficiency of available organic soil amendments like bentonite, attapulgite, biochar and inorganics like superabsorbent polymer, and nonwoven geotextile in relation to the newly developed water absorbing geocomposite (WAG) and its biodegradable version (bioWAG). Soil amendments were mixed with loamy sand soil, placed in 7.5 dm3 pots, then watered and dried in controlled laboratory conditions during 22-day long drying cycles (pot experiment). Soil moisture was recorded in three locations, and matric potential was recorded in one location during the drying process. The conducted research has confirmed that the addition of any examined soil amendment in the amount of 0.7% increased soil moisture, compared to control, depending on measurement depth in the soil profile and evaporation stage. The application of WAG as a soil amendment resulted in higher soil moisture in the centre and bottom layers, by 5.4 percent point (p.p.) and 6.4 p.p. on day 4 and by 4.5 p.p. and 8.8 p.p. on day 7, respectively, relative to the control samples. Additionally, an experiment in a pressure plate extractor was conducted to ensure the reliability of the obtained results. Soil density and porosity were also recorded. Samples containing WAG had water holding capacity at a value of −10 kPa higher than samples with biochar, attapulgite, bentonite, bioWAG and control by 3.6, 2.1, 5.7, 1 and 4.5 percentage points, respectively. Only samples containing superabsorbent polymers and samples with nonwoven geotextiles had water holding capacity at a value of −10 kPa higher than WAG, by 14.3 and 0.1 percentage points, respectively. Significant changes were noted in samples amended with superabsorbent polymers resulting in a 90% soil sample porosity and bulk density decrease from 1.70 g∙cm−3 to 1.14 g∙cm−3. It was thus concluded that the water absorbing geocomposite is an advanced and most efficient solution for water retention in soil.

Impact of Foliar-Applied Dormancy-Breaking Chemicals on Budburst and Metabolic Changes in Chemical Constituents of Leaves and Fruits of Malus sylvestris "Ein Shamer"

This study was carried out during the two successive seasons of 2016 and 2017 to investigate the impact of dormex, dormex plus mineral oil, dormex plus potassium nitrate, dormex plus calcium nitrate and dormex plus thiourea on bud break, growth, yield and some chemical constituents of Malus sylvestris "Ein Shamer". The trees were grown in loamy sand soil, and sprayed with six treatments (dormex (4%), (dormex (2%) plus mineral oil (2.5%),(dormex (2%) plus potassium nitrate (4%),(dormex (2%) plus calcium nitrate (4%) and (dormex (2%) plus thiourea (1%) and control. Generally, it was found that all studied growth parameters , date of flower bud break, percentage of bud break, fruit-setting ,fruit weight, fruit size, fruit number/tree, yield/tree (kg) and some chemical constituents of leaves (total chlorophyll ,total carbohydrates, total protein, nitrogen, phosphorous and potassium contents) and some chemical constituents of fruits (total soluble solids(T.S.S.), T.S.S/ acid ratio, vitamin C, water content %, total free amino acids, total carbohydrates, total sugars and reducing sugars) were increased with the application of the different treatments. The best results were obtained from the treatments of dormex at 4% followed by (dormex (2%) plus mineral oil (2.5%). On the contrary, the same treatments decreased total acidity and total phenols in fruits as compared to the control. It could be recommended to use dormex at 4% and (dormex (2%) plus mineral oil (2.5%) for improving bud break, growth, yield and chemical constituents of apple trees or fruits.

Effect of Integrated Potassium Application on Growth, Yield and Micronutrient Uptake by Forage Maize (Zea mays L.)

A pot experiment was conducted during kharif season of 2019 to carry out the study on “Interactive effect of potash (K2O), potassium mobilizing bacteria (KMB) and FYM on forage yield, nutrient uptake by forage maize and soil fertility in a loamy sand soil of middle Gujarat”. Application of K2O @ 60 kg ha-1, KMB and FYM recorded significantly the highest plant height of forage maize at harvest over respective control. Crop fertilized with K2O @ 60 kg ha-1 and KMB gave significantly the highest green forage and dry matter yield. The results indicated that application of K2O @ 60 kg ha-1, potassium mobilizing bacteria recorded significantly the highest uptake of N, P, K, Fe and Zn by crop at harvest. Significantly the highest uptake of N, K and Cu were found with application of FYM @10 t ha-1. Significantly the highest K uptake by maize as well as higher P and Zn uptake by maize were observed due to interaction effect of K × KMB (60 kg K2O ha-1 with KMB). In case of N and Cu uptake by maize were noted the Significantly higher due to interaction effect of K × KMB (30 kg K2O ha-1 with KMB) and K × KMB × FYM (60 kg K2O ha-1 with KMB and FYM), respectively. The integrated use of potassium fertilizers along with KBM or in combination with FYM significantly improved the maize grain and nutrient uptake.

Guidelines for surfactant selection to treat petroleum hydrocarbon-contaminated soils

The present study determined the most effective surfactants to remediate gasoline and diesel-contaminated soil integrating information from soil texture and soil organic matter. Different ranges for aliphatic and aromatic hydrocarbons (> C6–C8, > C8–C10, > C10–C12, > C12–C16, > C16–C21, and > C21–C35) in gasoline and diesel fuel were analyzed. This type of analysis has been investigated infrequently. Three types of soils (silty clay, silt loam, and loamy sand) and four surfactants (non-ionic: Brij 35 and Tween 80; anionic: SDBS and SDS) were used. The results indicated that the largest hydrocarbon desorption was 56% for silty clay soil (SDS), 59% for silt loam soil (SDBS), and 69% for loamy sand soil (SDS). Soils with large amounts of small particles showed the worst desorption efficiencies. Anionic surfactants removed more hydrocarbons than non-ionic surfactants. It was notable that preferential desorption on different hydrocarbon ranges was observed since aliphatic hydrocarbons and large ranges were the most recalcitrant compounds of gasoline and diesel fuel components. Unlike soil texture, natural organic matter concentration caused minor changes in the hydrocarbon removal rates. Based on these results, this study might be useful as a tool to select the most cost-effective surfactant knowing the soil texture and the size and chemical structure of the hydrocarbons present in a contaminated site.

Phytochemical Properties of Roselle (Hibiscus sabdariffa, L.) Plants Grown under Bio and Mineral Fertilizers in Different Types of Soil

The aim of this study was to clarify the phytochemical property evaluation of Roselle plants grown under bio Azotobacterine (Azotobacterchroococcum) and phosphorein (Bacillus polymyxa) and mineral (N, P and K fertilizers at the rates of 25, 50 and 100% from the doses recommended by Ministry of Agriculture) fertilizers applied in different types of soil. Samples of Roselle plants were obtained from different soils (clay soil at Dar El-Ramad farm, sandy loam and saline loamy sand soil at Demo farm, Faculty of Agriculture) at El-Fayoum governorate conditions. Moreover, some of the phytochemical properties (N, P and K percentage in roselle herb and its uptake, photosynthetic pigments (chlorophyll A, chlorophyll B and carotenoids), anthocyanin pigment and pH value) of roselle plants (Hibiscus sabdariffa, L.) under different soils were determined. The data obtained showed that, bio and mineral (NPK) fertilizers increased the above compositions of roselle plants under different soils of experiment. The maximum increase of these compositions was obtained by the treatment clay soil × 100% NPK + bio fertilizers, followed by clay soil × 50% NPK + bio fertilizers as compared to saline loamy sand soil × non fertilizer treatment, although, the differences between these treatments and mineral fertilizer at the rate of 100% NPK alone were insignificantly. Therefore, it is economically and environmentally recommended to inoculate roselle seeds with mixture of Azotobacter + Bacillus and fertilize these inoculated plants with 50% NPK for improve chemical compositions (N, P and K percentage in roselle herb and its uptake, photosynthetic pigments (chlorophyll A, chlorophyll B and carotenoids), anthocyanin pigment and pH value) of roselle plants under clay soil. Key words: Roselle, Hibiscus sabdariffa L., nitrogen, phosphorus, potassium, biofertilization, soil type, salinity, chemical composition.

Effects of the Denitrification Inhibitor “Procyanidins” on the Diversity, Interactions, and Potential Functions of Rhizosphere-Associated Microbiome

Some plant secondary metabolites, such as procyanidins, have been demonstrated to cause biological denitrification inhibition (BDI) of denitrifiers in soils concomitantly with a gain in plant biomass. The present work evaluated whether procyanidins had an impact on the diversity of nontarget microbial communities that are probably involved in soil fertility and ecosystem services. Lettuce plants were grown in two contrasting soils, namely Manziat (a loamy sand soil) and Serail (a sandy clay loam soil) with and without procyanidin amendment. Microbial diversity was assessed using Illumina sequencing of prokaryotic 16S rRNA gene and fungal ITS regions. We used a functional inference to evaluate the putative microbial functions present in both soils and reconstructed the microbial interaction network. The results showed a segregation of soil microbiomes present in Serail and Manziat that were dependent on specific soil edaphic variables. For example, Deltaproteobacteria was related to total nitrogen content in Manziat, while Leotiomycetes and Firmicutes were linked to Ca2+ in Serail. Procyanidin amendment did not affect the diversity and putative activity of microbial communities. In contrast, microbial interactions differed according to procyanidin amendment, with the results showing an enrichment of Entotheonellaeota and Mucoromycota in Serail soil and of Dependentiae and Rozellomycetes in Manziat soil.

Potato injury risk and weed control from reduced rates of PPO inhibitor herbicides

The ability to use the protoporphyrinogen oxidase (PPO) inhibitor herbicides fomesafen, flumioxazin, and sulfentrazone in potato is limited regionally or by soil texture largely because of crop injury noted in research in the 1990s. With that in mind, we evaluated if reducing the herbicide rates could maintain weed control while providing more consistent crop safety. Studies were conducted on a silt loam and a coarse-textured loamy sand soil. Soil texture played a greater than anticipated role in PPO inhibitor herbicide injury risk as it relates to high precipitation events. For example, in 2020 at the silt loam location, there were five precipitation events across the season that exceeded 2.5 cm, including one 6 days after treatment (DAT), and a seasonal total precipitation that was over 10 cm greater than the previous year. Despite excessive moisture and initial potato injury as high as 27% where flumioxazin was applied at the high rate with s-metolachlor, by 29 DAT injury was less than 10% in all treatments and marketable tuber yield was similar among treatments. In contrast, in 2020 at the loamy sand location there were four precipitation events across the season that exceeded 2.5 cm and potato injury was as much as 60%. In 2020 the high amount of injury from flumioxazin was hypothesized to be caused by precipitation prior to herbicide application and not after, suggesting a need for more research in this area. This work documents the fine line between yield reduction presumably caused by reduced weed control and yield reduction assumed to be related to herbicide injury. This delineation between adequate weed control and consistent crop safety may differ by soil texture and environmental conditions, supporting the notion that custom-tailored weed management may become more necessary as high precipitation events become more common in Upper Midwest USA agricultural systems.