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Compost is commonly utilized to improve properties of infertile sandy soils, despite its high biodegradability which may increase greenhouse gases emissions. It is possible to combine compost with biochar, which degrades at a slower rate, forming a “co-composted biochar” product. This mixture could enhance plant growth parameters beyond those attained for using each component, individually. To investigate this assumption, zucchini was selected as a test plant to be grown, under greenhouse conditions, on a sandy soil that received biochar, compost or co-composted biochar (from rice straw or sugarcane bagasse (SB)) for a duration of 15 days. This timeframe was deemed sufficient to achieve a relatively stable degradation rate for compost. Application of organic materials increased both fresh and dry weights of zucchini plants, particularly when co-composted biochar of SB was used. Specifically, plant fresh weights increased by 1.24–1.71 folds when using this additive versus the control group. Additionally, availability of nitrogen, phosphorus, and potassium in soil and their uptake by plants significantly increased owing to application of all additives, with superiority for the co-composted biochar of SB. Enhancements in plant fresh weights were strongly correlated with increasing availability and uptake of phosphorus by plants. In conclusion, organic amendments have a substantial positive impact on enhancing the nutritional status and growth of zucchini, even during the early vegetative growth stage (within the first 15 days after planting). The greatest improvements were observed when co-composted biochar of SB was used and this confirm the main hypothesis of the study.

Background: Humic acid affects plant growth. Its source and structure may play a central role to its functionality. The relationship between humic acid and plant bioactivity is still unclear. This study investigated the biostimulation effects of two natural humic acids derived from soil (SHA) and lignite (LHA) on Lepidium sativum in comparison to a synthetic humic acid model (HALP) with known structure. Results: All humic acids positively affected cress seed germination and root elongation. Greater root hairs density and dry matter, compared to control, were observed using concentration of 5 mg L−1 for HALP, 50 mg L−1 for LHA, and 100 mg L−1 for SHA. The germination index was the largest (698% more effective than control) with 50 mg L−1 of SHA, while it was 528% for LHA, and 493% for HALP at 5 mg L−1. SHA contained the lowest aromatic and phenolic C content, the largest pK2 value of 9.0 (7.7 for LHA and 7.6 for HALP), the least ratio between the aromaticity index and lignin ratio (ARM/LigR) of 0.15 (0.66 for LHA and 129.92 for HALP), and at pH 6.3 the lowest amount of free radicals with a value of 0.567 × 1017 spin g−1 (1.670 × 1017 and 1.780 × 1017 spin g−1 for LHA and HALP, respectively), with the greatest g value of 2.0039 (2.0035 for LHA and 2.0037 for HALP). Conclusions: The overall chemical structure of humic acids exerted a biostimulation of cress plantlets. The level of the intrinsic stable free radicals identified by EPR in the humic acids resulted well correlated to the ARM/LigR ratio calculated by NMR. Our results suggested that HA biostimulation effect is related to its applied concentration, which is limited by its free radical content. The modulation of the humic supramolecular structure by ROS and organic acids in root exudates can determine the release of bioactive humic molecules. When the content of the intrinsic humic free radicals is high, possible molecular coupling of the bioactive humic molecules may hinder their biostimulation activity. In such cases, a low humic acid concentration appears to be required to achieve the optimum biostimulation effects. [ABSTRACT FROM AUTHOR]

This study focused on assessing surface water quality in the northwest part of the Egyptian Nile Delta (El-Menoufia Governorate) and evaluated water suitability for irrigation purposes using the Irrigation Water Quality Index (IWQI), Permeability Index (PI), Wilcox, United State Salinity (USSL) diagram, and Piper trilinear diagrams categories, taking into consideration various water quality parameters. The results showed that, based on the IWQI, most of the water samples (61.8%) in the investigated area fell under the no restriction water (NR) category. Furthermore, the Wilcox diagram demonstrated that most of the investigated water samples (93.6%) are categorized as doubtful water; this shows that those samples have a higher sodium content material. According to the USSL diagram, most of the water samples (70.9%) fell into the high salinity (C) and moderate sodium (S) content (C3S2) class. According to the PI index, 8.2% of the tested water samples fell into class II (suitable for irrigation) and 91.8% fell into class III (unsuitable for irrigation). Based on the Piper trilinear, the water type is Na-Cl-HCO3. According to these results, most of the water samples require more water regulations, are categorized as doubtful water that causes plants' augmentation sensitivity if used for irrigation, and fell into the high salinity (EC) and sodium absorption ratio (SAR) magnitude, which might have negative outcomes on soil and plant health if used for irrigation, have extensive obstacles, and are improper for irrigation. Therefore, proper management practices and treatments may be vital to mitigate the adverse effects of salinity and SAR on soil and plant health in this study area. Therefore, addressing water deficiency and quality in Egypt's northwest Nile delta is crucial for suitable irrigation purposes. [ABSTRACT FROM AUTHOR]

Estimating soil erodible fraction based on basic soil properties in arid lands is a valuable research topic in the field of soil science and land management. The Proximal Sensing (PS) technique offers a non-destructive and efficient method to assess wind erosion potential in arid regions. By using Partial Least Squares Regression (PLSR) and Support Vector Machine (SVM) models and combining soil texture and chemical properties, determined through Visible-Near Infrared (vis-NIR) spectroscopy in 96 soil samples, this study aims to predict soil erodibility, soil organic matter (SOM), and calcium carbonate equivalent (CaCO3) in arid lands located in Elkobaneyya Valley, Aswan Governorate, Egypt. Results showed that the soil erodibility fraction (EF-Factor) had the highest values and possessed a strong relationship between slope and SOM of 0.01% in determining soil erodibility. The PLSR model performed better than SVM for estimating SOM, CaCO3, and EF-Factor. Furthermore, the results showed that the spectral responses of CaCO3 were observed in separate places in the wavelengths of 570, 649, 802, 1161, 1421, 1854, and 2362 nm, and the wavelengths with SOM parameter were 496, 658, 779, 1089, 1417, 1871, and 2423 nm. The EF-factor shows the highest significant correlation with spectral reflectance values at 526, 688, 744, 1418, 1442, 2292, and 2374 nm. The accuracy and performance of the PLSR model in estimating the EF-Factor using spectral reflectance data and the distribution of data points for both the calibration and validation data-sets indicate a good accuracy of the PLSR model, with RMSE values of 0.0921 and 0.0836 Mg h MJ−1 mm−1, coefficient of determination (R2) values of 0.931 and 0.76, and RPD values of 2.168 and 2.147, respectively. [ABSTRACT FROM AUTHOR]

[Objectives] The paper aimed to study the effects of pyrolysis temperature and feedstocks on the chemical properties and functional groups of biochar, and provide scientific basis for optimizing the chemical properties of biochar. [Methods]Wheat straw biochar(WB350, WB 450 and WB 550), rice straw biochar(RB350, RB 450 and RB 550)and corn straw biochar(CB350, CB 450 and CB 550)were obtained by pyrolysis of wheat, rice and corn straw at three temperatures(350, 450 and 550 ℃). The pH value, ash content, cation exchange capacity(CEC), total carbon(TC)and total nitrogen content(TN)of these biochar were analyzed. The chemical structure of biochar was analyzed by infrared spectroscopy and 13C nuclear magnetic resonance spectroscopy. [Results]When the temperature increased from 350 ℃ to 550 ℃, the pH value and C/N value of wheat, rice and corn straw biochar increased significantly, and the total nitrogen content decreased significantly; the ash content of rice and corn straw biochar increased significantly, while the CEC decreased significantly. From the perspective of different feedstocks, when the temperature was 350 and 550 ℃, the ash content of rice, corn and wheat bochar decreased in turn. At the same temperature, the CEC of corn straw biochar was significantly higher than those of wheat and rice straw biochar. At the same temperature, the total carbon content of wheat, corn and rice straw biochar decreased in turn; the total nitrogen content of corn, rice and wheat straw biochar decreased in turn; the C/N value of wheat, rice and corn straw biochar decreased in turn. With the increase of temperature, the content of aromatic functional groups increased and the content of aliphatic functional groups decreased. At 550 ℃, the absorption vibration of —CH2 and SiO2 of rice straw biochar was stronger than those of corn and wheat biochar; and the aromaticity index of rice, wheat and corn straw biochar decreased in turn; when the temperature was 350 ℃, the alkyl index of rice, corn and wheat straw biochar decreased in turn. [Conclusions]Among the biochar prepared at different temperatures and feedstocks, the biochar at a pyrolysis temperature of 550 ℃ had a high pH value, so it was recommended to use biochar pyroysis at 550 ℃ to improve acidic soil; the CEC of corn straw biochar was high, which was conducive to improving the level of soil fertility; rice straw biochar contained high ash content and more aliphatic functional groups at 350 ℃, while it had high aromaticity at 550 ℃. We speculate that it is a good material to enhance soil fertility and realize soil carbon sequestration and emission reduction at the same time. [ABSTRACT FROM AUTHOR]