Subsequent crops are often sensitive to acetolactate synthase (ALS)-inhibiting herbicide residues, particularly in alkaline soils. The main objective of this study was to compare the impact of different ALS-inhibiting residual herbicides on growth of oil-seed rape (Brassica napus L. subsp. napus) and sugar beet (Beta vulgaris L.) in alkaline soil. In this regard, three experiments were conducted in Prague, Czech Republic, during 2021-2023. In spring, six herbicides (amidosulfuron, chlorsulfuron, imazamox, propoxycarbazone, pyroxsulam, sulfosulfuron) were applied at three application rates (1N - full, 0.5N - half, and 0.05N - 5 % of full). One and four months after application, half of each plot was sown with oilseed rape, and the other half was sown with sugar beet. Herbicide phytotoxicity and aboveground biomass were assessed four weeks after crop emergence. Weather conditions during experimental years, herbicides used, herbicide application rates and the period between herbicide application and crop sowing affected herbicide phytotoxicity and aboveground biomass of both crops. The most damaging effects were recorded with the application of chlorsulfuron for oilseed rape (phytotoxicity was 96-98 % at one month after 1N application) and sulfosulfuron and chlorsulfuron for sugar beet (phytotoxicity was 97-100 % and 90-100 %, respectively). Pyroxsulam caused the least damage to both the crops (average phytotoxicity was 18 %). Herbicide phytotoxicity was 3-times higher, and crop biomass was almost half as much as at the first assessment compared to the second assessment. Sugar beet was more sensitive than oilseed rape to chlorsulfuron and sulfosulfuron, especially in dry conditions, where 0.05 N rates caused biomass reduction of 20-60 % in sugar beet. Most of the tested herbicides could have residual effect that likely damages crops in rotation, particularly if a dry period occurs after the application of herbicides and/or sowing of crops.
Soil salinity is represent a significant environmental stressor that profoundly impairs crop productivity by disrupting plant physiological functions. To mitigate this issue, the combined application of biochar and nanoparticles has emerged as a promising strategy to enhance plant salt tolerance. However, the long-term residual effects of this approach on cereal crops remain unclear. In a controlled pot experiment, rice straw biochar (BC) was applied in an earlier experiment at a rate of 20 t/ha, in conjunction with ZnO and Fe2O3 nanoparticles at concentrations of 10 mg L- 1 and 20 mg L- 1. Two rice genotypes, Jing Liang You-534 (salt-sensitive) and Xiang Liang You-900 (salt-tolerant), were utilized under 0% NaCl (S1) and 0.6% NaCl (S2) conditions. Results showed that, application of residual ZnOBC-20 significantly enhanced rice biomass, photosynthetic assimilation, relative chlorophyll content, SPAD index, enzyme activities, K+/Na+ ratio, hydrogen peroxide (H2O2) levels, and overall plant growth. Specifically, ZnOBC-20 increased the tolerance index by 142.8% and 146.1%, reduced H2O2 levels by 27.11% and 35.8%, and decreased malondialdehyde (MDA) levels by 33% and 57.9% in V1 and V2, respectively, compared to their respective controls. Residual of ZnOBC-20 mitigated oxidative damage caused by salinity-induced over-accumulation of reactive oxygen species (ROS) by enhancing the activities of antioxidant enzymes (SOD, POD, CAT, and APX) and increasing total soluble protein (TSP) content. Xiang Liang You-900 exhibited a less severe response to salinity compared to Jing Liang You-534. Additionally, residual of ZnOBC20 significantly enhanced the anatomical architecture of both root and leaf tissues and regulated the expression levels of salt-related genes. Residual of ZnOBC-20 also improved salt tolerance in rice plants by reducing sodium (Na+) accumulation and enhancing potassium (K+) retention, thereby increasing the K+/Na+ ratio under saline conditions. The overall results of this experiment demonstrate that, residual effects of ZnOBC-20 not only improved the growth and physiological traits of rice plants under salt stress but also provided insights into the mechanisms behind the innovative combination of biochar and nanoparticles residual impacts for enhancing plant salt tolerance.
Studying the impact of residual soil nanomaterials is a promising challenge for sustainable agricultural development to improve soil health and crop productivity. The objective of this study is to assess the long-term impacts of 50, 100, and 250 mg kg-1 soil of nanobiochar (nB) and nano-water treatment residues (nWTR) on the fertility, biological activity, and yield of maize (Zea mays L.) growing in heavy metal-contaminated soils. The results showed that when nB and nWTR were added in larger quantities, the concentrations of lead (Pb), nickel (Ni), cadmium (Cd), and cobalt (Co) extracted with DTPA decreased. With the addition of nB or nWTR, it also showed a significant increase in exchangeable cations, cation exchange capacity (CEC), soil fertility, soil organic matter (OM), microbial biomass carbon (MBC), and a decrease in soil salinity and sodicity. Catalase and dehydrogenase activities rose as nB addition increased, while they decreased when nWTR addition increased. In comparison to the control, the addition of nB and nWTR greatly boosted maize yield by 54.5-61.4% and 61.9-71.4%, respectively. These findings suggest that the researched nanomaterials' residual effect provides an eco-friendly farming method to enhance the qualities of damaged soils and boost maize production. Our research suggested that adding recycling waste in the form of nanoparticles could immobilize heavy metals, improve soil characteristics, and increase the soil's capacity for productivity.