Estimation of key potentially toxic elements in arid agricultural soils using Vis-NIR spectroscopy with variable selection and PLSR algorithms

Potentially toxic elements (PTEs) pose a significant threat to soil and the environment. Therefore, the fast quantification of PTEs is crucial for better management of contaminated sites. Versatile technique such as Visible near-infrared spectroscopy (Vis–NIRS) (350–2,500 nm) has attracted tremendous attention for assessing PTEs and has achieved promising results combined with successful multivariate analysis. This research investigated the potential of Vis–NIRS combined with partial least squares regression (PLSR) and variable selection methods to assess key PTEs (Cd, Co, Cu, Cr, Pb, and Zn) in agricultural soils under arid conditions. The soil samples (80) were collected from a polluted area around Al-Moheet drainage, Minya Governorate–upper Egypt. The samples were scanned using an ASD FieldSpec-4 spectroradiometer. Simulated annealing (SA) and uninformative variable elimination (UVE) were used to select the effective wavelengths in predicting PTEs. PLSR was used to develop the spectral models using the full range (FR-PLS) and feature-selected spectra techniques SA (SA-PLS) and UVE (UVE-PLS). The results indicated that UVE-PLS models performed better than FR-PLS and SA-PLS models in predicting the key PTEs. The obtained coefficient of determination (R2) and the ratio of performance to deviation (RPD) were 0.74 and 2.48 (Cr), 0.72 and 2.03 (Pb), 0.62 and 1.86 (Cd), 0.59 and 1.78 (Cu), 0.52 and 1.68 (Co), and 0.46 and 1.41 (Zn), respectively. The results suggested that the UVE-PLS spectral model is promising for predicting Cr, Pb, and Cd, and can be improved for predicting Cu, Co, and Zn elements in agricultural soils

Geospatial evaluation and bio-remediation of heavy metal-contaminated soils in arid zones

Introduction: Soil pollution directly impacts food quality and the lives of both humans and animals. The concentration of heavy metals in Egypt’s drain-side soils is rising, which is detrimental to the quality of the soil and crops. The key to reducing the detrimental effects on the ecosystem is having accurate maps of the spatial distribution of heavy metals and the subsequent use of environmentally sustainable remediation approaches. The objective of this work is to assess soil contamination utilizing spatial mapping of heavy metals, determine contamination levels using Principal Component Analysis (PCA), and calculate both the contamination severity and the potential for bioremediation in the soils surrounding the main drain of Bahr El-Baqar. Furthermore, evaluating the capacity of microorganisms (bacteria, fungi, and “Actinomycetes) to degrade heavy elements in the soil.Methodology: 146 soil sample locations were randomly selected near the Bahr El-Baqar drain to examine the degree of soil pollution Ordinary Kriging (OK), method was used to map and analyze the spatial distribution of soil contamination by seven heavy metals (Cr, Fe, Zn, Cd, Pb, As, and Ni). Modified contamination degree (mCd) and PCA were used to assess the research area’s soil pollution levels. The process involved isolating, identifying, and classifying the microorganisms present in the soil of the study area. The study findings showed that variography suggested the Stable model effectively matched pH, SOM, and Cd values. Furthermore, the exponential model proved suitable for predicting Fe, Pb and Ni, while the spherical model was appropriate for Ni, Cr, and Zn.Results: The study revealed three levels of contamination, with an extremely high degree (EHDC) affecting approximately 97.49% of the area. The EHDC exhibited average concentrations of heavy metals: 79.23 ± 17.81 for Cr, 20,014.08 ± 4545.91 for Fe, 201.31 ± 112.97 for Zn, 1.33 ± 1.37 for Cd, 40.96 ± 26.36 for Pb, 211.47 ± 13.96 for As, and 46.15 ± 9.72 for Ni. Isolation and identification of microorganisms showed a significant influence on the breakdown of both organic and inorganic pollutants in the environment. The study demonstrated exceptionally high removal efficiency for As and Cr, with a removal efficiency reached 100%, achieved by Rhizopus oryzae, Pseudomonas aeruginosa, and Bacillus thuringiensis.Conclusion: This study has designated management zones for soil contamination by mapping soil pollutants, geo-identified them, and found potential microorganisms that could significantly reduce soil pollution levels

Phosphorus acquisition processes in the field: study of faba bean cultivated on calcareous soils in Algeria

International audienceLittle is known about the occurrence of phosphorus (P) acquisition processes in the field, especially for faba bean (Vicia faba L.) in calcareous soils. We sampled soil, rhizosphere and plant materials in 12 calcareous field sites in Algeria and performed physicochemical analysis during two growing seasons. Both proton exudation and root exploration increased in P-deficient soils as compared to P-sufficient soils. Inhibition of nitrogen (N) fixation and rhizosphere alkalization were observed in N-rich soils. We also found that calcium (Ca) concentrations in both shoots and roots significantly increased with P-deficiency. The same trend, although less significant, was observed with respect to Ca uptake. These field observations suggested that acidifying roots acquired P from dissolving Ca-P minerals. The concomitant increase of the ratio Ca/P uptake should further enhance their dissolution. Other rhizosphere processes such as the mineralization of organic P should control P acquisition as alkalization occurred in the root zone in response to the inhibition of N fixation. In conclusion, P-acquisition processes in the field were consistent with previous findings made at the laboratory. In addition, the variety of faba bean cultivated by local farmers appeared relatively well adapted to field conditions thanks to the deployment of rhizosphere processes

Influence of Nitrogen Fertilizer Rate on Yield, Grain Quality and Nitrogen Use Efficiency of Durum Wheat (Triticum durum Desf) under Algerian Semiarid Conditions

Nitrogen fertilizer application is conditioned closely by the amount of rainfall and its distribution. The current study aims at studying the effect of nitrogen (N) application rate on grain yield (GY), grain protein content (GPC), and nitrogen use efficiency (NUE) of durum wheat under Algerian semiarid conditions. Field trials were conducted during two contrasting and successive growing seasons (a dry year = 2016–2017 and a wet year = 2017–2018) on a local variety named Bousselam. A randomized complete block design (RCBD) was used with four replicates. Seven gradual treatments of fertilizer rate were studied: T1 = 0 unity of nitrogen (UN), T2 = 100 UN, T3 = 110 UN, T4 = 120 UN, T5 = 130 UN, T6 = 140 UN, and T7 = 150 UN. Results showed a significant difference between the dry and wet years. Only the GPC was higher in the dry year compared to the wet year having a difference of 2.94%. However, all other studied parameters were higher in the wet year, which resulted in a yield difference of 4.38 t ha−1. In addition, a significant effect of N rate on GY, thousand grain weight (TGW), and GPC was observed. A considerable difference between 120 UN and 150 UN was not noted in both years of study. Furthermore, the agronomic efficiency (AE) increased significantly with rainfall amount achieving a difference of 16.2 kg·kgN−1 between years. Finally, the results showed that using a high N amount led to a decrease in AE. Based on GY, apparent recovery efficiency (ARE), agronomic efficiency (AE), and marginal rate return (MRR) recorded in both years, the nitrogen application rate of 120 UN is recommended to be applied to wheat crops in Algerian semiarid conditions

Past and Future Changes of Land Use/Land Cover and the Potential Impact on Ecosystem Services Value of Damietta Governorate, Egypt

This investigation aims to assess the changes of Land Use/Land Cover (LULC) and its impact on ecosystem services value in Damietta Governorate, Egypt. To fulfill this aim, Landsat data of TM5 in 2001, ETM in 2011 and OLI in 2021 were used. The Maximum Likelihood Classifier was employed to track the changes in LULC of the study area. Cellular automata (CA) and Markov model adopted from IDRISI software were used for accurate prediction of the LULC in 2031. The VALIDATE model in TerrSet was used to compare the predicted 2031 LULC with actual 2021 LULC to assess the accuracy of the model. The Millennium Ecosystem Assessment was utilized to assess the value per unit area of land types. The results indicated that there was a noticeable change in different land cover classes during the duration 2001–2021. Results showed that there are decreases in the cultivated area and the bare area, meanwhile the urban area was increased. The cultivated area was remarkably decreased recording 548.2 km2 (62.15%) at 2001, 548.2 km2 (55.79%) at 2011 and 468.96 km2 (53.16%) at 2021 of the total study area. However, the percentage of urban area increased; reporting 65.69 km2 (7.45%), 124.57 km2 (14.12%), and 176.67 km2 (20.03%) at 2001, 2011, and 2021, respectively. LULC analyses in 2031 showed an increase in the urban area by 2.8% and a decrease in the cultivated area by 7.2%. The kappa index values are greater than 0.80, which shows a strong agreement between simulated and predicted LULC maps. The comprehensive index of Damietta Governorate ranges from 100 to 400. The ES that experienced positive ESV changes during the study period gives strength indicator for achieving the sustainable development of Damietta Governorate. To prevent further ecosystem degradation and to ensure the best possible delivery of ES, it is necessary to reduce the current drivers of LULC changes within the buildup in agricultural land. The study helps the local authorities to better understand the land use system and to develop an improved land use management strategies that manage the urban expansion and guarantee the ecological conservation

Phytochemical characterization of forest leaves extracts and application to control apple postharvest diseases

Abstract The study investigated the antifungal and phytochemical properties of three forest plants (Eucalyptus globulus, Pistacia lentiscus, and Juniperus phoenicea) against apple diseases caused by Colletotrichum gloeosporioides and Alternaria alternata. The determination of the total polyphenol and flavonoid contents in the three aqueous extracts of studied plants showed that E. globulus exhibited the highest contents than those of P. lentiscus and J. phoenicea. Furthermore, the three studied extracts showed very appreciable antioxidant activity with decreasing order: E. globulus, P. lentiscus, and J. phoenicea. The phytochemical analysis showed different common phenolic acids in the three studied plants namely: quinic acid, gallic acid, chlorogenic acid, and caffeoylquinic acid as well as other flavonoids mainly quercetin and catechin. The results of the current study demonstrated that the fungistatic activity of E. globulus EO (4 and 2 µl/ml) seemed to be the most effective under laboratory conditions with an inhibition zone diameter above 16 mm. However, the poisoned food technique indicated that the aqueous extract (80%) and the essential oil (4 µl/ml) of E. globulus exhibited the highest mycelial growth (> 67%) and spore germination (> 99%) inhibition. Preventive treatments with essential oils (4 µl/ml) and aqueous extracts (80%) applied to apple fruits inoculated with A. alternata and C. gloeosporioides resulted in the lowest lesion diameter ( 85.45%) and protective potentials (> 84.92%). The results suggest that E. globulus has a brilliant future in the management of anthracnose and Alternaria rot of apple and provide a basis for further studies on its effects under field conditions

Contribution of Eco-Friendly Agricultural Practices in Improving and Stabilizing Wheat Crop Yield: A Review

Wheat is considered to be a strategic crop for achieving food security. Wherefore, one of the current objectives of today’s agriculture is to ensure a consistent and sustainable yield of this particular crop while mitigating its environmental footprint. However, along with the genetic potential of varieties, agricultural practices play a key role in ensuring a high and stable yield of wheat. Under changing climatic conditions, new eco-friendly practices were adopted in the wheat farming system in recent decades. In this review, a large number of peer-reviewed articles have been screened during the last 15 years to evaluate the potential of some environmentally friendly agricultural practices such as tillage system, biological crop protection, crop rotation, intercropping systems, and the integration of resistant varieties in achieving a high and stable wheat yield. The present investigation unveiled that embracing eco-friendly agricultural methods in the wheat farming system holds the potential to engender high and sustainable wheat yields, contingent upon a normative strategy that comprehensively addresses multiple factors. These include the intrinsic attributes of the grown wheat cultivars, plant nutritional parameters, soil agrochemical characteristics, and specific climatic conditions. Further in-depth investigations under field conditions are necessary to help in the discernment of appropriate environmentally agricultural techniques that can efficaciously optimize the yield potential of the different cultivated varieties

The Use of Mycoendophyte-Based Bioformulations to Control Apple Diseases: Toward an Organic Apple Production System in the Aurès (Algeria)

The present study aims to investigate the effectiveness of bioformulations based on endophytic fungi to control apple scab and Valsa canker disease in two orchards in the Aurès region (Algeria). In both orchards, the results showed that the treatment of senescent apple leaves by invert emulsions containing Trichoderma longibrachiatum and Chaetomium globosum harmed the ascogenesis of winter forms of Venturia inaequalis by reducing the number of ascospore-ejecting asci, the number of morphologically mature asci, and a considerable increase in the immature asci number. This antifungal activity was more essential in soil-incorporated leaves, showing the importance of the combination of treatments with cultural practices to efficiently control the apple scab disease. Furthermore, the disease incidence decreased by 52.63% and 50.68% in R’haouat and Bouhmama orchards, respectively. Moreover, the treatment of Valsa ceratosperma cankers with a biogel containing the endophytic yeast Metschnikowia sp. led to wound healing varying from 43.52% and 87.97% after 120 days but remained more considerable than conventional treatment with Folicur (tebuconazol). The current results open real opportunities concerning the implementation of eco-friendly and potent apple protection systems

Multi-Sensor Remote Sensing to Estimate Biophysical Variables of Green-Onion Crop (<i>Allium cepa</i> L.) under Different Sources of Magnesium in Ismailia, Egypt

Foliar feeding has been confirmed to be the fastest way of dealing with nutrient deficiencies and increasing the yield and quality of crop products. The synthesis of chlorophyll and photosynthesis are directly related to magnesium (Mg), which operates in the improvement of plant tissues and enhances the appearance of plants. This study aimed to analyze the correlation between two biophysical variables, including the leaf area index (LAI), the fraction of absorbed photosynthetically active radiation (FAPAR), and seven spectral vegetation indices. The spectral indices under investigation were Atmospherically Resistant Vegetation Index (ARVI), Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI), Disease–Water Stress Index (DSWI), Modified Chlorophyll Absorption Ratio Index (MCARI), the Red-Edge Inflection Point Index (REIP), and Pigment-Specific Simple Ratio (PSSRa). These indices were derived from Sentinel-2 data to investigate the impact of applying foliar applications of Mg from various sources in the production of green-onion crops. The biophysical variables were derived using field measurements and Sentinel-2 data under the effects of different sources of Mg foliar sprays. The correlation coefficient between field-measured LAI and remotely sensed, calculated LAI was 0.72 in two seasons. Concerning FAPAR, it was found that the correlation between remotely sensed calculated FAPAR and field-measured FAPAR was 0.66 in the first season and 0.89 in the second season. The magnesium oxide nanoparticle (nMgO) treatments resulted in significantly higher yields than the different treatments of foliar applications. The LAI and FAPAR variables showed a positive correlation with yield in the first season (October) and in the second season (March). Yield in treatment by nMgO varied significantly from that in the other treatments, ranging from 69-ton ha−1 in the first season to 74.9-ton ha−1 in the second season. Linear regression between LAI and PSSRa showed the highest correlation coefficient (0.90) compared with other vegetation indices in the first season. In the same season, the highest correlation coefficient (0.94) was found between FAPAR and PSSRa. In the second season, the highest accuracy to the estimate LAI was found in the correlation between MCARI and PSSRa, with correlation coefficients of 0.9 and 0.91, respectively. In the second season, the highest accuracy to the estimate FAPAR was found with the correlation between PSSRa, ARVI, and NDVI, with correlation coefficients 0.97 and 0.96, respectively. The highest correlation coefficients between vegetation indices and yield were found with ARVI and NDVI in the first season, and only with NDVI in the second season

Improving Water Use Efficiency, Yield, and Fruit Quality of Crimson Seedless Grapevines under Drought Stress

Drought stress is a group of abiotic stresses that affects plant growth and yield production. A field experiment over two successive seasons (2021–2022 and 2022–2023) in sand soil was conducted to investigate the integration effect of deficit irrigation, soil amendment “hundzsoil”, and the spraying of proline on the water use efficiency (WUE), yield, and fruit quality of 8-year-old Crimson seedless table grapes. Four application rates of soil amendment (0, 2, 4, and 6 kg hundzsoil /vine) were added during the dormancy period, and four irrigation levels at 125, 100, 75, and 60% of the field capacity were applied just before flowering until harvest. Proline at two levels (0 and 500 ppm) was applied as a foliar spray. Parameters such as bud fertility, weight of 100 berries, juice volume, and cluster number were positively affected by irrigation at 75% FC along with applying hundzsoil at 2 and 4 kg/vine under proline spray in both seasons. Irrigation at the 125% FC level with a 6 kg hundzsoil application under proline spray resulted in the highest yield, berries number, cluster length, cluster weight, and total anthocyanin in both seasons. The TSS/acidity ratio was significantly and positively affected by deficit irrigation (60% FC level) under hundzsoil at a rate of 4 kg alongside proline spray. Reducing irrigation to 60% FC without hundzsoil and proline spray negatively affected numerous growth parameters and the yield. However, irrigation at 60% FC alongside 6 kg of hundzsoil and proline showed the highest IWUE in both seasons. Proline spray was a key factor in conserving water used for irrigation. This study recommends using deficit irrigation alongside hundzsoil application under proline spray as an adequate strategy for water use efficiency and improving the yield and fruit quality of Crimson seedless grapevines cultivated in sand soil