Soil Application Research Articles

Short‐Term Benefits of Tillage and Agronomic Biofortification for Soybean–Wheat Cropping in Central India

ABSTRACTIn a changing climate, conservation tillage and agronomic biofortification are essential for enhancing crop yield, nutritional security, carbon stocks, and soil quality. Consequently, a field study was conducted in central India to assess the short‐term (4 years) effects of crop establishment techniques (CETs) and agronomic biofortification methods (ABMs) on soil health indicators, grain yield, and quality in the soybean–wheat cropping system. The experiment followed a split‐plot design with two CETs in the main plots (permanent broad bed furrow, PBBF, and conventional tillage, CT) and eight ABMs, each with three replications. The results indicated that PBBF and ABMs (seed inoculation with the microbial strains MDSR 14 + MDSR 34, and soil and foliar application of Zn+Fe) improved soil carbon stock (by 49.6% and 52.4%), available nitrogen, phosphorus, potassium, available Zn (by 30.0%), and Fe (by 21.9%) after the fourth year of the study. Similarly, PBBF and microbial inoculation increased soil enzyme activities (dehydrogenase, acid phosphatase, and β‐glucosidase), substrate‐induced respiration, and microbial biomass carbon content. As a result, a higher soybean equivalent yield (5.59% higher in PBBF and 14.2% higher with foliar spray of Zn+Fe) and seed quality attributes (crude protein yield, grain Zn, and Fe) were observed in PBBF and the foliar spray of Zn and Fe treatments compared to CT and control, respectively. Overall, adopting the short‐term PBBF system, microbial inoculation, and soil and foliar application of Zn and Fe improved rhizosphere biochemical properties, yield, and seed quality in the soybean–wheat system.

Immunomodulating melatonin-decorated silica nanoparticles suppress bacterial wilt (Ralstonia solanacearum) in tomato (Solanum lycopersicum L.) through fine-tuning of oxidative signaling and rhizosphere bacterial community

BackgroundTomato (Solanum lycopersicum L.) production is severely threatened by bacterial wilt, caused by the phytopathogenic bacterium Ralstonia solanacearum. Recently, nano-enabled strategies have shown tremendous potential in crop disease management.ObjectivesThis study investigates the efficacy of biogenic nanoformulations (BNFs), comprising biogenic silica nanoparticles (SiNPs) and melatonin (MT), in controlling bacterial wilt in tomato.MethodsSiNPs were synthesized using Zizania latifolia leaves extract. Further, MT containing BNFs were synthesized through the one-pot approach. Nanomaterials were characterized using standard characterization techniques. Greenhouse disease assays were conducted to assess the impact of SiNPs and BNFs on tomato plant immunity and resistance to bacterial wilt.ResultsThe SiNPs and BNFs exhibited a spherical morphology, with particle sizes ranging from 13.02 nm to 22.33 nm for the SiNPs and 17.63 nm to 21.79 nm for the BNFs, indicating a relatively uniform size distribution and consistent shape across both materials. Greenhouse experiments revealed that soil application of BNFs outperformed SiNPs, significantly enhancing plant immunity and reducing bacterial wilt incidence by 78.29% in tomato plants by maintaining oxidative stress homeostasis via increasing the activities of antioxidant enzymes such as superoxide dismutase (31.81%), peroxidase (32.9%), catalase (32.65%), and ascorbate peroxidase (47.37%) compared to untreated infected plants. Additionally, BNFs induced disease resistance by enhancing the production of salicylic acid and activating defense-related genes (e.g., SlPAL1, SlICS1, SlNPR1, SlEDS, SlPD4, and SlSARD1) involved in phytohormones signaling in infected tomato plants. High-throughput 16 S rRNA sequencing revealed that BNFs promoted growth of beneficial rhizosphere bacteria (Gemmatimonadaceae, Ramlibacter, Microscillaceae, Anaerolineaceae, Chloroplast and Phormidium) in both healthy and diseased plants, while suppressing R. solanacearum abundance in infected plants.ConclusionOverall, these findings suggest that BNFs offer a more promising and sustainable approach for managing bacterial wilt disease in tomato plants.Graphical

Efficacy of nano urea in replacing conventional nitrogen application and its effect on fruit quality in strawberry

In a study conducted on strawberry cv. Winter Dawn, the combined application of nano urea and Azotobacter was investigated for its impact on quality and biochemical attributes under protected cultivation. The findings revealed a noteworthy response of strawberry plants to foliar nano applications compared to conventional soil application of urea. Despite the lower nitrogen dosage associated with nanoparticle supplementation, strawberries with nanoparticles exhibited significant improvements in qualitative and biochemical parameters. These results underscore the potential of urea nanoparticles as a viable nitrogen source, advocating for alternative approaches to nitrogen fertilization. By fine-tuning the dosage ratio, this strategy shows promise in fostering a more environmentally friendly, sustainable and modern method for cultivating strawberries. The enhanced quality and biochemical attributes observed in strawberries treated with nano urea highlight the efficacy of this innovative approach in optimizing plant growth and productivity. Furthermore, the utilization of nano urea in combination with Azotobacter demonstrates synergistic effects, potentially enhancing nutrient uptake and utilization efficiency in plants. This holistic approach improves crop quality and reduces the environmental impact associated with traditional fertilization methods. In conclusion, the findings of this study support the adoption of urea nanoparticles as a valuable tool in strawberry cultivation, offering a pathway towards sustainable agricultural practices. Future research efforts should focus on optimizing application protocols and assessing long-term effects to fully exploit the potential of nano-based fertilizers for strawberry.

Effect of different concentrations of soil and foliar applied zinc, boron and iron fertilizers on seedling growth, chlorophyll content and productivity of chickpea seedlings under semi-arid environment

The effectiveness of zinc (Zn), boron (B), and iron (Fe) is reduced in semi-arid regions, which can lead to a deficiency of these nutrients and inhibit chickpea productivity. In this work, three field experiments were executed over two years where soil and foliar applications of Zn, B, and Fe were carried out, including controls (Zn0, B0, and F0), soil application at 4.125 kg/ha (Zn-1, B1, and F1) and 8.25 kg/ha (Zn-2, B2, and F2), and foliar spay at 0.3% at flowering initiating (Zn-3, B3, and F3) and one week after flowering initiation (Zn-4, B4, and F4, respectively). The results indicate that the deficiency of these nutrients inhibited chickpea growth and yield, leading to a reduction in the pigment contents. Nonetheless, soil and foliar application of Zn, B, and Fe significantly improved growth, chlorophyll contents, and yield, showing a dose-dependent effect. The best results were recorded for Zn-3, B2, and F2 treatments which significantly (P<0.05) increased shoot length (20.96-85.19%), root length (42.85-93.65%), shoot fresh (23-76%) and root fresh weight (45-90.32%), compared with the control treatment. Chlorophyll parameters, including chlorophyll a and b contents, showed similar trends. Zn-3, B2, and F2 treatments significantly increased biological and grain yields, which were associated with higher values of the number of pods per plant and the number of seeds per pod. In a nutshell, we suggest that Zn foliar application at 0.3% at flowering initiation and soil application of B and Fe at 25 kg/ha are beneficial for improving the growth, pigment content, and overall productivity of chickpea.

Exploring the bio-efficacy of biocontrol agents in mitigating <i>Meloidogyne incognita</i> menace in carrot cultivation

The nematicidal efficacy of liquid formulation of Pochonia chlamydosporia, Bacillus subtilis, Purpureocillium lilacinum, Trichoderma viride and vermiculite formulation of Rhizophagus intraradices were challenged against Meloidogyne incognita under glasshouse conditions. The in vivo experiment were piloted to test the potential of these biological agents by soil drenching of liquid formulation @ 1 ml/ pot or soil application of vermiculite formulation @ 1g/pot/dose. Their effect was compared with the granular application of Carbofuran @ 1g/pot/dose. All the liquid bioformulations investigated were capable of enhancing plant growth and lowering the pathogenicity and parasitic success of M. incognita in carrots. The soil drenching of P. chlamydosporia caused a significant reduction of galls in the root (51%), nematode population in the root (43.6%), egg mass in the root (65.3%) and infective juvenile population in soil (51.8%) over other treatments and Carbofuran.

Enhancing the productivity and nutritional quality of lentil (Lens culinaris L.) with combined foliar application of zinc and urea

There is need to enhance the nutritional quality of lentil for ameliorating nutrient deficiencies in people especially vegetarians. The study was carried out to investigate the effect of soil application of zinc (Zn) and foliar application of Zn and nitrogen [(N) through urea] on grain yield and enrichment of grain with Zn in lentil. The field experiments were conducted at two locations Ludhiana and Faridkot, India. The experiment was consisted of eleven treatments (control, soil application of 25 kg ha−1 ZnSO4 at sowing time, foliar spray of sole 0.5% ZnSO4 or 2% urea and combined foliar spray of 0.5% ZnSO4 + 2% urea at flowering, pod formation, and flowering + pod formation stages). The foliar application of 0.5% ZnSO4 + 2% urea spray at flowering + pod formation stages significantly improved the grain yield, Zn and iron (Fe) concentration at maturity in stover and grain (whole as well as split) of lentil and protein content in stover and grain. The combined application of ZnSO4 (0.5%) + urea (2%) at flowering + pod formation stages can be done to improve not only the grain yield (on an average 29.5%) but also the Zn (49.7%) and Fe (17.4%) concentration in lentil grain, which, can help in ameliorating malnutrition in human population.

Biocontrol potential of Bacillus subtilis CRB7 for the management of root-knot nematode in tomato under protected cultivation

In the present study, biocontrol potential of Bacillus subtilis CRB7 was evaluated to counter root-knot nematode infestation in tomato grown under protected cultivation. Under pot conditions, gall formation on roots was reduced when B. subtilis CRB7 applied at 1.25, 2.5 and 5 g plant−1. Nursery drench with B. subtilis CRB7 at 5, 10 and 15 g m−2 significantly reduced gall formation on roots (37.0 to 85.8%). Further, application of B. subtilis CRB7 as nursery drench at 15 g m−2, soil drench at 0.5% at 30 day’s interval and soil application of enriched vermicompost (5 kg 2 tonnes−1 of vermicompost ha−1) significantly reduced gall formation on roots (58.3% and 54.2%) and enhanced yield (29.8% and 15.4%) in two consecutive protected field experiments, respectively. Given its potent efficacy, B. subtilis CRB7 emerges as a promising component for the management of root-knot nematode in tomato grown under protected cultivation.

Soil application of FeCl3 and Fe2(SO4)3 reduced grain cadmium concentration in Polish wheat (Triticum polonicum L.)

BackgroundWheat is one of major sources of human cadmium (Cd) intake. Reducing the grain Cd concentrations in wheat is urgently required to ensure food security and human health. In this study, we performed a field experiment at Wenjiang experimental field of Sichuan Agricultural University (Chengdu, China) to reveal the effects of FeCl3 and Fe2(SO4)3 on reducing grain Cd concentrations in dwarf Polish wheat (Triticum polonicum L., 2n = 4x = 28, AABB).ResultsSoil application of FeCl3 and Fe2(SO4)3 (0.04 M Fe3+/m2) significantly reduced grain Cd concentration in DPW at maturity by 19.04% and 33.33%, respectively. They did not reduce Cd uptake or root-to-shoot Cd translocation, but increased Cd distribution in lower leaves, lower internodes, and glumes. Meanwhile, application of FeCl3 and Fe2(SO4)3 up-regulated the expression of TpNRAMP5, TpNRAMP2 and TpYSL15 in roots, and TpYSL15 and TpZIP3 in shoots; they also downregulated the expression of TpZIP1 and TpZIP3 in roots, and TpIRT1 and TpNRAMP5 in shoots.ConclusionsThe reduction in grain Cd concentration caused by application of FeCl3 and Fe2(SO4)3 was resulted from changes in shoot Cd distribution via regulating the expression of some metal transporter genes. Overall, this study reports the physiological pathways of soil applied Fe fertilizer on grain Cd concentration in wheat, suggests a strategy for reducing grain Cd concentration by altering shoot Cd distribution.

Bio-fortification with selenium (Se) improves quality and nutrient profile in citrus fruit

Selenium (Se) is an essential nutrient for the human body. Humans can enhance Se absorption by consuming horticultural plants, particularly fruits. Therefore, there is need for Se biofortification in fruits to meet the human demand for Se. The objective of this study was to determine the optimal Se application rate, application stage and method, and to assess their impacts on improving both the quality and nutrient profile of a sweet orange cultivar 'Hongjiangcheng' (Citrus sinensis (L.) Osbeck). 'Hongjiangcheng’ is a notable variety of mandarin orange, acclaimed for its large size, thin and smooth skin, orange-red flesh, tender and juicy texture, balanced sweetness and acidityand distinctive flavor. A field experiment was conducted at the Qiaotou Town Test Base in Chengmai County, Hainan Province, China. Biofortification of Se was done through foliar and soil application methods. Treatments were: Control (C) with no application of Se, foliar application of 25 (SeF1), 50 (SeF2), 100 (SeF3) and 200 (SeF4) mg/L and soil application of 100 mg/L (SeS1) as well as a combination of 100 mg/L Se in soil along with 50 mg/L Se on leaves (SeS1F2). At start of the experiment, 189 healthy, four-year-old citrus trees of similar size and normal growth were selected. The trees were divided into three groups of 63 each. Each group received the aforementioned treatments at the young fruit, expanding fruit and premature fruit stages. The Se was applied once during each stage before 9:00 am on sunny days. Treatments were arranged in a randomized complete block design with 9 biological replicates (7 treatments × 9 replicates = 63 citrus trees/ application stage). Foliar application of Se at rate of 200 mg/L (SeF4) enhanced total Se content in leaves by 105, 34 and 69 % at young fruit, expanding fruit and premature fruit stages compared to control (p≤0.05). Respective increments in fruits were 264, 22 and 21 %. The total Se content in leaves were 32 and 40 % higher in the SeF4 (foliar) compared to SeS1 and SeS1F2 (soil) treatments across all development stages (p≤0.05), respectively. The respective increments in fruits total Se content were 16 and 52 %. Only at the young fruit stage, the organic Se content in fruits was significantly higher in the SeF4 compared to soil application treatments (p≤0.05). Single fruit weight was enhanced by 16.61, 13.69 and 4.36 g by foliar than soil application at young fruit, expanding fruit and premature fruit stages, respectively. It was significantly higher (155.53 vs. 113.13 g) after application of SeF4 treatment at young fruit stage relative to all other treatments (p≤0.05). The application of SeF4 at the young fruit stage resulted in an increased seed rate (97 %), total soluble solids (28 %) and solid-to-acid ratio (75 %), while titratable acid decreased by 26 % compared to the control. Interestingly, Se application had non-significant effects on the fruit shape index, peel rate and residue rate across all stages (p>0.05). Additionally, a positive correlation was observed between fruit Se content and several quality indices like total soluble solids, solid acid ratio, fruit shape index and fruit weight at young fruit stage (p≤0.05). It is concluded that foliar application of Se at 200 mg/L (SeF4) during young fruit stage improved citrus Se content, its fruit weight and quality indices establishing these fruits as a valuable source of Se-rich food for human consumption.

The potential of seaweed biochar and fly ash amendments in enhancing vermi-degradation and the fertilizer value of cow manure, wastepaper-based vermicompost

This study evaluated the potential of amending cow manure (CM) based vermicompost with fly ash (FA) and seaweed biochar (Bio) on vermidegradation, nutrient release and early crop growth. All treatments, except CM + fly ash, resulted in a C/N ratio below 20, indicating a mature compost. The CM + Biochar treatment had the highest Olsen-P of 274.75 mg/kg whilst the CM + Fly ash treatment had the lowest concentration of 239.13 mg/kg. Only Zn showed a consistent increasing trend of 51.5 %, 45.6 %, 53.6 %, and 47.8 % for the CM + fly ash, CM + FA + Bio, CM + Bio, and CM treatments, respectively. For crop germination, the CM + fly ash compost needs to be substituted at 25 % in cocopeat, whilst 50 % substitution is suitable for seedling development. Future studies need to evaluate the potential of removing salts from seaweed-biochar, and the field soil application of seaweed and fly ash amended vermicomposts.

Sugarcane Response to Two Different Application Methods of Nano-Iron and Nano-Zinc

AbstractThere are many publications over the past 20 years comparing nano-nutrients with their traditional forms. Differently, this study examined the effect of applying nano-Fe and nano-Zn—in two different ways (foliar and soil application)—on sugarcane development, yield, and mineral status using a greenhouse experiment at the National Research Centre. The study results of first yield (plant cane crop) showed that nano-Fe caused an increase in plant height, number of leaves, fresh weight (FW) of leaves, FW of stalk, and total FW by 5.3%, 20.3%, 38.0%, 27.4%, and 33.3%, respectively, compared to nano-Zn. Despite the majority of growth metrics showed to be improved by using either of the two nano-sources, both nano-Fe and nano-Zn have been demonstrated to negatively impact nutrient ratios. The foliar application method was found to be superior, and the second application of nano-Zn to soil effectively halted the growth of all treated replicates. The data of the first ratoon (second yield) showed that FW of leaves, FW of stalk, total FW, and dried weight (DW) of stalk followed one trend line (nano-Fe–soil > control-foliar (sprayed distilled water) > nano-Zn-foliar > nano-Fe-foliar > control-soil (distilled water added to soil)). In conclusion it can be noticed that using nanoparticles as a fertilizer could be a weapon with double-edges, since this may induce unexpected harmful effects. It is recommended to conduct additional research to comprehend the mechanisms underlying why a nano-source that benefits plants may harm them after the second addition.

Effect of zinc management on yield, nutrient content, and acquisition of zero-tilled wheat (Triticum aestivum)

A field experiment was conducted during the winter (rabi) season 2018–19 and 2019–20 at Khalsa College, Amritsar, Punjab to find out the effect of soil and foliar application of ZnSO4 .7H2 O on zero till wheat. The experi- ment was conducted in a randomized complete block design with three replications. Treatments were control (noZn), soil application of 12.5, 25, 37.5, 50 kg/ha zinc sulfate heptahydrate (ZnSO4 .7H2 O), and foliar application of 0.5% Zn as one spray at heading initiation (5% ear emergence), one spray at 100% heading (complete ear emergence) and two sprays at heading initiation and 100% heading with a recommended dose of fertilizer. Results showed that the soil application of 50 kg Zn/ha with two foliar sprays of 0.5% zinc sulfate heptahydrate at heading initiation and 100% heading produced the highest yield attributes and grain yield of wheat. Application of 50 kg Zn/ ha with two foliar sprays of 0.5 % Zn at heading initiation and 100% heading registered ~25% higher grain yield over control. Grain Zn content (41.77ppm) percent increase was 33.9 with 50 kg Zn/ha with two foliar sprays of 0.5 % zinc at heading initiation and 100% heading over control (31.20 ppm).Likewise, application of 50 kg Zn/ha with two foliar sprays of 0.5 % Zn at heading initiation and 100% heading recorded the highest net returns among the Zn treatments. Overall, soil application of 50 kg Zn/ha with two foliar sprays of 0.5 % zinc at heading initiation and 100% heading improved the yield, uptake, and profitability of zero-tilled wheat in zinc-deficient soils.

Ecotoxicity of alkaline residue from the pulp and paper industry to soil faunal organisms

The increased production and expanding demand for cellulosic products have required companies to provide solutions for the proper disposal of generated residues without compromising soil quality. In this context, the current research aimed at evaluating the ecotoxicological impacts of dregs application in subtropical soils. The experiments were carried out with the earthworm Eisenia andrei, the springtail Folsomia candida, and the potworm Enchytraeus crypticus in two subtropical soils (Neosol and Cambisol) collected in the southern region of Brazil. The considerable differences in texture and organic matter content motivated the choosing of these soils. The reproductive rate of all organisms was influenced, with varying EC50 values depending on the soil type. However, more pronounced effects were observed for Neosol. The springtail F. candida proved to be the most sensitive to contamination (EC50 = 5.8 g kg−1 for Neosol and 48.5 g kg−1 for Cambisol), followed by the earthworm E. andrei (EC50 = 62.4 g kg−1 for Neosol and 129.5 g kg−1 for Cambisol) and the potworm E. crypticus (EC50 = 67.2 g kg−1 for Neosol and 230.4 g kg−1 for Cambisol). As a result, while dregs can be used to correct soil acidity, they have been shown to have negative effects on important organisms responsible for functions critical to maintaining ecosystem quality.

Improving Sunflower Yield through Liming and Phosphorus Fertilizer Application in the South-Central Coastal Region of Bangladesh

Along with salinity, low soil pH is the major constraint for growing winter crops in the south central coastal region of Bangladesh. Extensive research has been done to manage soil salinity, where managing low soil pH for crop production is scarce. The aim of the experiment was to improve sunflower (Helianthus annuus L. cv. Hybrid Unisun) yield through liming and phosphorus fertilizer application in the acidic saline soil of Amtali upazila of Barguna district, Bangladesh. During the winter season of 2024 a field experiment was carried out comprising two rates of lime 0 and 2 t ha-1 and four levels of phosphorus (P) having 0, 12, 24 and 36 kg P ha-1 using RCBD design. Lime application at 2 t ha-1 rate significantly increased stem girth, head diameter, number of seeds per head, 1000-seed weight, and seed, stover and root yields of sunflower. The application of P up to the highest level (36 kg P ha-1) significantly increased the growth and yield of sunflower. Lime application increased the soil pH by 0.72 unit compared to non-liming plot. The application of lime (2 t ha-1) along with 36 kg P ha-1 recorded the highest sunflower seed yield of 3.21 t ha-1 in the soil of Amtali upazila of Barguna district, Bangladesh. The benefit cost ratio (BCR) of different rates of P application without liming ranged from 5.28-10.09 but it decreased drastically while P was applied with lime having the BCR between 0.15-1.82. J Bangladesh Agril Univ 22(3):352-359, 2024

Sustainable management of blister and grey blight diseases of tea using antagonistic and plant growth promoting microbes in Western Ghats of India

The blister and grey blights are the devastating leaf diseases in tea. The severity of blister and grey blight diseases in tea ranged from 22% to 68% and 11.41%–57.02%, respectively in a survey conducted in Southern India during 2022–2023. The morphological and molecular identifications of pathogens revealed that Exobasidium vexans and Neopestalotiopsis clavispora were responsible for causing blister and grey blights on tea in southern India. The conventional management strategy with foliar spray of synthetic fungicides result in fungicidal residue in tea causes environmental pollution and health hazards to human. To overcome this the current study aims to manage the blister and grey blight diseases of tea through the microbial biocontrol agents. The bacterial biocontrol agents viz., Bacillus subtilis (BBV57), Bacillus amyloliquefaciens (TNAU), Pseudomonas fluorescens (Pf1) and the fungal antagonist, Trichoderma asperellum (TV 1) were evaluated for their efficacy against the both blight diseases. All the bio agents have significantly reduced the basidiospore germination and the mycelial growth of E. vexans and N. clavispora, respectively. Among the bio agents, B. amyloliquefaciens registered 88.36% reduction in the germination of E. vexans basidiospore and 85.56% of mycelial growth reduction of N. clavispora in vitro (P < 0.05). Under field conditions the combined soil and foliar application of bacterial antagonists viz., B. subtilis, B. amyloliquefaciens and P. fluorescens each with 1 ˟ 1011 CFU/ml @ 5% concentration at 7 days interval significantly reduced the blister blight incidence with 53.53% & 51.53% reduction over control and 51.53% & 43.65% of reduction over initial during first and second year, respectively. The combined application also reduced the grey blight incidence with 53.53% & 52.00% reduction over control and 56.81% & 47.65% of reduction over initial during first and second year, respectively. This treatments with bioagents were almost comparable with synthetic treatments, such as copper oxy chloride (0.25%) and hexaconazole (0.25%) with 64.63% and 64.76% reduction of blister and grey blight reduction in first year; 59.74%, 51.11% reduction in second year over control (P < 0.05), respectively. Thus, the application of B. subtilis, B. amyloliquefaciens and P. fluorescens can be recommended for the sustainable management of tea blister and grey blight diseases in tea gardens.

How Pharmaceutical Residues Occur, Behave, and Affect the Soil Environment.

Many pharmaceuticals (PhMs), compounds for the treatment or prevention of diseases in humans and animals, have been identified as pollutants of emerging concern (PECs) due to their wide environmental distribution and potential adverse impact on nontarget organisms and populations. They are often found at significant levels in soils due to the continuous release of effluent and sludge from wastewater treatment plants (WWTPs), the release of which occurs much faster than the removal of PhMs. Although they are generally present at low environmental concentrations, conventional wastewater treatment cannot successfully remove PhMs from influent streams or biosolids. In addition, the soil application of animal manure can result in the pollution of soil, surface water, and groundwater with PhMs through surface runoff and leaching. In arid and semiarid regions, irrigation with reclaimed wastewater and the soil application of biosolids are usual agricultural practices, resulting in the distribution of a wide number of PhMs in agricultural soils. The ability to accurately study the fate of PhMs in soils is critical for careful risk evaluation associated with wastewater reuse or biosolid return to the environment. The behavior and fate of PhMs in soils are determined by a number of processes, including adsorption/desorption (accumulation) to soil colloids, biotic (biodegradation) and abiotic (chemical and photochemical degradation) degradation, and transfer (movement) through the soil profile. The sorption/desorption of PhMs in soils is the main determinant of the amount of organic chemicals taken up by plant roots. The magnitude of this process depends on several factors, such as crop type, the physicochemical properties of the compound, environmental properties, and soil-plant characteristics. PhMs are assumed to be readily bioavailable in soil solutions for uptake by plants, and such solutions act as carriers to transport PhMs into plants. Determining microbial responses under exposure conditions can assist in elucidating the impact of PhMs on soil microbial activity and community size. For all of the above reasons, soil remediation is critical when soil pollutants threaten the environment.

Co-application of silicon and biochar affected anatomical and biochemical properties of corn leaf (Zea mays L.) under soil nickel toxicity

Soil pollution with heavy metals is a threat to crop production. Practically, application of silicon (Si) with biochar can be a cost-effective approach to immobilize metals in contaminated soils. Investigation of the anatomical and biochemical changes of corn leaf is important for describing the mechanisms of Si and biochar soil application in alleviating the negative effects of nickel (Ni) toxicity. A factorial pot experiment was conducted to investigate the effect of Si (0, 250 and 500 mg Si kg-1 soil) in combination with rice husk biochar (RHB) or sheep manure biochar (SMB) prepared at two pyrolysis temperatures (300 and 500 °C) on anatomical and biochemical properties of corn leaves in a Ni-polluted soil. The length, width, area and weight of third-leaf, and metaxylem and protoxylem of midrib improved by application of Si250 with RHB more than SMB. At Si250, RHB300 and RHB500 improved the stomatal area by 31.7 and 27.7% compared to control (without biochar), respectively. The leaf membrane stability index was increased by increasing Si application level and reached 69% in RHB300. In contrast to total chlorophyll, the highest carotenoid content, catalase and peroxidase was obtained by control (without Si and biochar) followed by SMB. At Si250, the highest relative water content (RWC) was observed in RHB300 by 34.8% increase. Also, RHB300 had the highest total dry matter, with increases of 82.2, 120.0 and 83.1% at Si0, Si250 and Si500, respectively. By increasing the Si level and biochar application, the shoot Ni decreased between 42.1 to 133.3%. Combined application of Si250 with RHB300 resulted in the highest dry matter through improving the leaf dimensions, metaxylem and protoxylem areas of midrib, membrane stability index, total chlorophyll, and RWC, while Ni uptake was reduced.

Evaluating the Effects of Rice Husk Derived Nanosilica on Growth, Photosynthesis, and Antioxidant Activity in Hybrid Maize

Drought stress was exacerbated by changing climatic conditions and impact the plant water relations from the cellular to whole plant level, thereby reducing the crop productivity and causing economic losses in agriculture. The present study was aimed to explore the potentials of nanosilica synthesized from rice husk in improving growth and drought stress tolerance in maize. Synthesized nanosilica from rice husk has spherical morphology, amorphous structure, siloxane bonding and higher purity (99.1%). Soil application of varied levels of synthesized nanosilica (0, 5, 10, 15, 20, 30 and 40mgkg-1) was tested with hybrid maize plants grown under irrigated and drought stress (100 and 50% field capacity, respectively). The results of the study revealed that, drought stress has adverse effect on plant growth, biomass production and physiological parameters. However soil application of nanosilica has significantly improved growth, physiological and biochemical attributes of both irrigated and drought stressed plants. Nanosilica application at 20mgkg-1 for irrigated and 30mgkg-1 for drought stressed hybrid maize plants has recorded higher plant height, biomass, chlorophyll a, chlorophyll b, superoxide dismutase, peroxidase, phenols, soluble proteins and considerably decreased the proline, electrolyte leakage and melondialdehyde content in hybrid maize. In contrary, higher doses of nanosilica (>30mgkg-1) caused a slight reduction in plant growth and antioxidant activity under both the water regimes. Hence, we conclude that, soil application of 20 and 30mgkg-1 nanosilica synthesized from rice husk had a positive effect on plant growth and development besides aided in mitigating drought stress.

Optimizing the radiation synthesis and swelling of agar-based acrylate superabsorbent hydrogel for irrigation water conservation

This study reports the synthesis of novel agar/poly methacrylic acid/poly acrylic acid (AG/PMAc/PAc) superabsorbent hydrogels via gamma radiation and their subsequent urea modification to enhance swelling and water retention for agricultural applications. The superabsorbent hydrogels were prepared by irradiating aqueous mixtures of varying agar concentrations with methacrylic acid/acrylic acid (MAc/Ac) monomers, followed by urea treatment at different cycles and concentrations. The morphological characteristics and chemical structures were confirmed by SEM and FTIR, respectively. The maximum swelling occurred at 6 % agar and 1 % urea modification. Remarkably, the 1 % urea-modified hydrogel displayed a 41.1 % swelling increase and 236.4 % enhancement after the second modification cycle compared to unmodified samples. Water retention studies showed the modified hydrogel retained 53.2 % moisture after 14 days versus the complete drying of unmodified hydrogels. Soil application studies demonstrated the modified hydrogel increased moisture content by 177.3 % after 20 days, promoting better growth with 30 % more leaves and 38.9 % higher stem length in Vicia faba plants versus controls. This novel radiation-synthesized, urea-modified hydrogel with exceptional swelling and moisture retention capabilities shows promising potential for sustainable agricultural irrigation and crop productivity enhancement under water-deficit conditions.

Agricultural Pest Management: The Role of Microorganisms in Biopesticides and Soil Bioremediation.

Pesticide use in crops is a severe problem in some countries. Each country has its legislation for use, but they differ in the degree of tolerance for these broadly toxic products. Several synthetic pesticides can cause air, soil, and water pollution, contaminating the human food chain and other living beings. In addition, some of them can accumulate in the environment for an indeterminate amount of time. The agriculture sector must guarantee healthy food with sustainable production using environmentally friendly methods. In this context, biological biopesticides from microbes and plants are a growing green solution for this segment. Several pests attack crops worldwide, including weeds, insects, nematodes, and microorganisms such as fungi, bacteria, and viruses, causing diseases and economic losses. The use of bioproducts from microorganisms, such as microbial biopesticides (MBPs) or microorganisms alone, is a practice and is growing due to the intense research in the world. Mainly, bacteria, fungi, and baculoviruses have been used as sources of biomolecules and secondary metabolites for biopesticide use. Different methods, such as direct soil application, spraying techniques with microorganisms, endotherapy, and seed treatment, are used. Adjuvants like surfactants, protective agents, and carriers improve the system in different formulations. In addition, microorganisms are a tool for the bioremediation of pesticides in the environment. This review summarizes these topics, focusing on the biopesticides of microbial origin.