Agrochemicals, Volume 4, Issue 3 (September 2025) – 5 articles

Pinus taeda plantations have been facing declining productivity in South America, especially due to competition for natural resources such as light, water, and nutrients. Competition with spontaneous vegetation in the early years is one of the main constraints on growth and biomass allocation in trees. However, the best method and timing for weed control and its impact on the productivity of Pinus taeda plantations are unknown. This study aims to evaluate whether weed control increases the growth and above-ground biomass production of Pinus taeda plantations in southern Brazil. This study was conducted at two sites with five-year-old Pinus taeda plantations in southern Brazil, with each being submitted to different weed control methods. This study was conducted in randomized blocks, with nine treatments: (i) NC—no weed control, i.e., weeds always present; (ii) PC—physical weed control; (iii) CC–T—chemical weed control in the total area; (iv) CC–R—chemical weed control in rows (1.2 m wide); (v) C6m, (vi) C12m, (vii) C18m, and (viii) C24m—weed control up to 6, 12, 18, and 24 months after planting; and (ix) COC—company operational weed control. The following parameters were evaluated: the floristic composition and weed biomass, height, diameter, stem volume, needle biomass, branches, bark, and stemwood of Pinus taeda. Control of the weed competition, especially by physical means (PC), and chemical control over the entire area (CC–T) promoted significant gains in the growth and above–ground biomass production of Pinus taeda at five years of age, particularly at the Caçador site. The results reinforce the importance of using appropriate strategies for managing weed control to maximize productivity, especially before canopy closure. In addition, the strong correlation between growth variables and the total biomass and stemwood indicates the possibility of obtaining indirect estimates through dendrometric measurements. The results contribute to the improvement of silvicultural management in subtropical regions of southern Brazil. Full article

Chitosan is an eco-friendly polysaccharide, enhancing growth and managing disease infections in fruits and vegetables. This study examines the effects of preharvest application of chitosan and calcium (Ca) on yield and postharvest chitosan coating on tomato storage. There were nine preharvest treatments, viz., T0 = control, T1 = 50 ppm chitosan, T2 = 80 ppm chitosan, T3 = 0.50% Ca, T4 = 1.0% Ca, T5 = T1 and T3 (combined), T6 = T2 and T3 (combined), T7 = T1 and T4 (combined), and T8 = T2 and T4 (combined), and three postharvest treatments, viz., C0 = control, C1 = 0.10% chitosan, and C2 = 0.20% chitosan, to examine the yield parameters and major physical and biochemical qualities of tomatoes on different days after postharvest storage (DAPS). The results revealed that chitosan and Ca treatments had a significant influence on yield while showing an insignificant impact on the biochemical qualities of fresh-harvested tomatoes. Postharvest application of chitosan coatings effectively reduced weight loss and shrinkage (34–37%) compared to the control. At 20 DAPS, only the 0.20% solution met the marketable threshold of ≥5.0, while the control failed in 100% of the samples. As storage duration increased, titratable acid and vitamin C decreased, while lycopene and sugar content rose in tomatoes. This research indicates that foliar spraying with 80 ppm chitosan during fruit initiation significantly boosts tomato yield, and a 0.20% chitosan coating on postharvest tomatoes enhances longevity and preserves biochemical quality. Full article

Surfactants are widely utilized in agriculture as emulsifying, dispersing, anti-foaming, and wetting agents. In these adjuvant roles, the inherent biological activity of the surfactant is secondary to the active ingredients. Here, the hydrophilic non-ionic surface-active tri-block copolymer Pluronic^® F68 is investigated for direct biological activity in wheat. F68 binds to and inserts into lipid membranes, which may benefit crops under abiotic stress. F68’s interactions with Triticum aestivum (var Juniper) seedlings and a seed-borne Bacillus spp. endophyte are presented. At concentrations below 10 g/L, F68-primed wheat seeds exhibited unchanged emergence. Root-applied fluorescein-F68 (fF68) was internalized in root epidermal cells and concentrated in highly mobile endosomes. The potential benefit of F68 in droughted wheat was examined and contrasted with wheat treated with the osmolyte, glycine betaine (GB). Photosystem II activity of droughted plants dropped significantly below non-droughted controls, and no clear benefit of F68 (or GB) during drought or rehydration was observed. However, F68-treated wheat exhibited increased transpiration values (for watered plants only) and enhanced shoot dry mass (for watered and droughted plants), not observed for GB-treated or untreated plants. The release of seed-borne bacterial endophytes into the spermosphere of germinating seeds was not affected by F68 (for F68-primed seeds as well as F68 applied to roots), and the planktonic growth of a purified Bacillus spp. seed endophyte was not reduced by F68 applied below the critical micelle concentration. These studies demonstrated that F68 entered wheat root cells, concentrated in endosomes involved in transport, significantly promoted shoot growth, and showed no adverse effects to plant-associated bacteria. Full article

The conventional agricultural industry largely relies on pesticides to maintain healthy and viable crops. Application of fungicides, both pre- and post-harvest of crops, is the go-to method for avoiding and eliminating Botrytis cinerea, the fungal pathogen responsible for gray mold. However, conventional fungicides and their residues have purported negative environmental and health impacts. Natural products, such as essential oils, are viewed as a promising alternative to conventional fungicides. The current research is an in vitro study on the antifungal activity of a natural water-based fungicide (N.F.), which uses a blend of essential oils (ajowan, cassia, clove, eucalyptus, lemongrass, oregano) as the active ingredients against B. cinerea. Compared to conventional fungicides tested at the same concentration (50 μL/mL), those with active ingredients of myclobutanil or propiconazole; the N.F. demonstrated significant (F(3,16) = 54, p = <0.001) and complete fungal growth inhibition. While previous research has largely focused on the antifungal properties of single essential oils and/or isolated compounds from essential oils, this research focuses on the efficacy of using a blend of essential oils in a proprietary delivery system. This research is of importance to the fields of agronomy, ecology, and health sciences. Full article

This study aimed to evaluate the agronomic performance and environmental impact of controlled-release coated fertilizers (CRCFs) in upland maize systems. Specifically, we sought to determine the optimal nitrogen (N) application rate that maximizes nitrogen use efficiency (NUE) and minimizes nutrient runoff, while maintaining yield comparable to conventional fertilization practices. A two-year field experiment (2017–2018) was conducted to assess CRCF formulations composed of urea, MAP, and potassium sulfate encapsulated in LDPE/EVA coatings with talc, humic acid, and starch additives. Treatments included various nitrogen application rates (33–90 kg N ha⁻¹) using CRCF and a conventional NPK fertilizer (150 kg N ha⁻¹). Measurements included fresh ear yield, aboveground biomass, NUE, and concentrations of total N (TN), nitrate N (NO₃⁻–N), and total P (TP) in surface runoff. Statistical analyses were performed using linear and quadratic regression models to determine yield responses and agronomic optimal N rate. CRCF treatments produced yields comparable to or exceeding those of conventional fertilization while using less than half the recommended N input. The modeled agronomic optimum N rate was 88.4 kg N ha⁻¹, which closely matched the maximum observed yield. CRCF application significantly reduced TN, NO₃⁻–N, and TP runoff in 2017 and improved NUE up to 71.2%. Subsurface placement and sigmoidal nutrient release contributed to reduced nutrient losses. CRCFs can maintain maize yield while reducing N input by approximately 40%, aligning with climate-smart agriculture principles. This strategy enhances NUE, reduces environmental risks, and offers economic benefits by enabling single basal application. Further multi-site studies are recommended to validate these findings under diverse agroecological conditions. Full article