Biochar Addition to the Loam Soil of Soybean Fields Can Reduce Trifluralin Usage in Velvetleaf Control

Biochar, made by the pyrolysis of various organic materials such as plants, can amend soil physicochemical properties and improve the efficiency of pre-planted incorporated (PPI) herbicides. The excessive consumption of PPI herbicides results in environmental predicaments; improving the PPI herbicides’ efficacy by changing the soil’s biological properties might solve this problem. Trifluralin, a PPI, is recommended against annual broadleaf weeds such as velvetleaf in soybean fields. In the present study, the treatments included normal soil (NS) (sand 30% + silt 35% + clay 35%) and manipulated soil (MS) (sand 27% + silt 32% + clay 32% + biochar 9%). Two blocks of NS received the recommended dose (RD) (1.7 L/ha) (NS + RD) and a reduced dose (1.2 L/ha) (NS + ReD) of trifluralin. Meanwhile, the block of MS was exposed to the reduced dose (MS + ReD) of trifluralin. Two days after the herbicide treatments, the seeds of Abutilon theophrasti were sown. Then, seven days after sowing, the growth of the weeds was monitored and the weed control percentage was calculated using the arcsine model based on observed data. The results showed that the NS + RD was the most effective treatment in velvetleaf control (100%), followed by MS + ReD (93.5%) with no significant difference. The NS + ReD treatment resulted in 81% weed control showing significant differences with the NS + RD and MS + ReD. Thus, it seems that biochar acts as a neutral buffer and decreases the necessity of PPI herbicide application in soybean fields. Biochar application can potentially reduce soil contamination, weed resistance, environmental pollution, and the adverse effects of PPI herbicides on the soil microbial population

Sulfur Application Amends Detoxification Processes in Eggplant in Response to Excessive Doses of Thiacloprid

Sulfur is considered an essential macronutrient during plant growth and is found to play critical roles in xenobiotic detoxifying processes in plants. In the present study, the effects of exogenous sulfur treatment as additional fertilization on detoxifying enzyme activities and plant health indicators were investigated in eggplant (Solanum melongena) seedlings exposed to excessive doses of thiacloprid. Eggplant seedlings (cultivar Hansel F1) were irrigated with ammonium sulfate (140 mg L−1) 14 days after sowing in combination with the spraying of a 4-fold recommended dose of thiacloprid. In another treatment, seedlings received ammonium sulfate (70 mg L−1) as a minimum sulfur need in their growth in combination with a mentioned dose of thiacloprid. After 14 days of treatment, leaves were collected to determine their physiological parameters. Based on results, plant health indicators including malondialdehyde, hydrogen peroxide, and electrolyte leakage index were significantly lower in treatments that received additional amounts of sulfur than other ones. Moreover, the activities of glutathione S-transferase, glutathione reductase, glutathione peroxidase, thioredoxin reductase, and cytochrome P450 monooxygenase were higher in them. Our findings suggest that sulfur can decrease membrane permeability and increase cell viability as well as magnify their detoxification capacity which consequently leads to the reduction of oxidative damage in plants. It can be concluded that the sulfur supply in eggplant farms where thiacloprid is intensively used against sap feeder insects should be considered because it can lead to reducing potential risk to the environment by decreasing pesticide damage to host plants as non-target organisms

Micronutrient Fertilization Amplified the Antioxidant Capacity in Tomato Plants with Improved Growth and Yield

Micronutrients play a critical role in plant growth and development, and their deficiency can have adverse effects on plant performance. These elements can also influence plant physiological processes as they are incorporated into the molecular structure of enzymes as cofactors. In this study, the impact of a micronutrient solution containing manganese (125 ppm), iron (200 ppm), zinc (60 ppm), and copper (20 ppm) was investigated on the growth parameters, yield, and antioxidant enzyme activity of tomato (Solanum lycopersicum) plants. Greenhouse tomatoes (cultivar Jet Star F1) were irrigated with the above-mentioned concentrations of elements in a completely randomized design, with five independent biological replicates. The micronutrient treatment increased the specific activities of superoxide dismutase, ascorbate peroxidase, glutathione reductase, guaiacol peroxidase, catalase, and phenylalanine ammonia-lyase, as well as the phenol and salicylic acid contents in tomato leaves. However, the malondialdehyde level and electrolyte leakage index were unaffected. Analysis of the plant growth parameters revealed that the micronutrients increased the stem diameter, root length, number of leaves, stem height, and fruit’s fresh weight in the treated plants. Overall, our results indicated that micronutrients positively affected the growth and development of tomato plants without adverse effects on the health indices. Moreover, the application of micronutrients can magnify the antioxidant capacity of tomato plants through increasing enzyme activity, as well as the phenol and salicylic acid levels. These changes would benefit those plants under abiotic/biotic stress conditions, where elevated levels of antioxidant activities are crucial

A Novel Biopesticide Formulation for Organic Management of Aphis gossypii in Cucumber Greenhouses

Intensive chemical pesticide usage in crop protection for pest control causes major pollution of the environment. Replacing chemical pesticides with biopesticide is an essential agro-ecological principle that should be considered in agro-ecosystems. In this study, a novel biopesticide formulation based on plant extract was prepared, and then aphid mortality in cucumber greenhouses was evaluated in comparison to common chemical insecticide. Our eco-friendly insecticide consists of methanolic extract of Rosmarinus officinalis (4.38 g in 1 L water) and succinic acid (0.5 g in 1 L water) in combination with Triton® X-100 (10 mL in 1 L water), canola seeds oil (10 mL in 1 L water), and potassium nitrate (5 g in 1 L water). Additionally, the common insecticide against Aphis gossypii in cucumber greenhouses is dichlorvos (Dichlorvos® 48% EC) which was applied at the recommended dose (0.6 g a.i./L). Twenty-four hours after sprayings, aphids that survived through each treatment were recorded, and mortality percentages were calculated. Results showed that in biopesticide treatment, mortality (65.6 ± 2.8%) has no significant difference compared to dichlorvos (71.1 ± 2.9%) (p = 0.0629). Finally, plant performance including numbers of leaves (p = 0.0951), flowers (p = 0.0842), fruits (p = 0.0730), and branches (p = 0.0698) were not influenced by the biopesticide application. Our results propose that the mentioned biopesticide can be used in cucumber greenhouses for aphid control with no adverse effect on plant growth and development, leading to zero-pollution tactics in crop protection, which is necessary for sustainable agriculture

Enhancing shelf life of bell peppers through preharvest fertigation with calcium and potassium thiosulfate: A focus on antioxidant and cell wall degradation enzymes

In this study, the effectiveness of preharvest fertigation using calcium thiosulfate (CaTS) and potassium thiosulfate (KTS) to enhance the shelf life of bell peppers was investigated. The nutrient solution was enriched with KTS (either 0.26 or 0.53 mM of a commercial formulation) or CaTS (0.66 mM of a commercial formulation), and compared to a commercial source-based nutrient solution as a control. Fruit quality attributes and the activity of key enzymes involved in oxidative stress defense, enzymatic browning, cell wall degradation, and membrane lipid degradation were investigated for 30 days of storage. Results showed that CaTS and KTS treatments preserved protein (a secondary energy reserve) and proline content, and enhanced the fruit's PSII activity throughout storage. Despite increased phenylalanine ammonia-lyase activity, CaTS and KTS fertigation did not affect polyphenol oxidase activity. CaTS and KTS fertigation increased the activity of five (out of seven) antioxidant enzymes and impaired the activity of one (out of two) cell wall hydrolytic enzyme. CaTS was the most effective treatment, followed by KTS (0.53 mM), in causing these promotive effects. In conclusion, preharvest application of CaTS (0.66 mM) and KTS (0.53 mM) prolonged the postharvest life and delayed senescence of bell pepper fruits by preserving fruit weight, firmness, and photosynthetic performance, as well as enhancing the antioxidant defense system