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Development of strategies to ensure grazing systems are sustainably produced in harsh environments, while not fertilizing them conventionally, is challenging. Figuring out the extent to which dose of inoculation and period of watering can positively influence the establishment of an effective symbiosis between U. brizantha cv. Marandu and Azospirillum brasilense is the point of this research. The treatment consisted of mixing 1 kg seeds with the inoculant of the strains Ab-V5 and Ab-V6 at 5, 10, 20, and 40 mL kg−1, 2 × 108 CFU mL−1. The plants grew in pots watered 2, 4, 8, and 16 days after sowing over thirty-days, twice. The bioagent at 5–10 mL kg−1 enabled the plants watered up to 4 days after sowing to peak the production of dry mass of shoots (28.50 g) and roots (12.55 g). The efficiency of the symbiosis goes down quickly with increasing dose and delay of watering. Hence, if the dose of inoculant is higher than 10 mL kg−1, it cannot successfully act in plants watered at least 8 days after sowing anymore. In conclusion, A. brasilense can assist in U. brizantha cv. Marandu growth and healthy development unless a lack of water in the substrate and an overdose collectively deter its potential.

Drought, heat, and salinity, as well as pests, are stressing agents, which have impressively declined the productivity and quality of sugarcane crop in harsh environments. Our study aimed to examine the effect of various chemical ripeners as alternatives to enhancing the reactiveness of the enzymatic antioxidant system of sugarcane crop. The field experiment consisted of spraying the ingredients, ethephon, ethyl-trinexapac, glyphosate, carboxylic compounds (MTD) and methyl-sulfumeturon on the Brazilian commercial varieties, SP80-1842 and SP80-3280, before flowering stage. The enzymatic assay comprised the monitoring of the rate of degradation of free radical by ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) in the extract from leaves of 11-month-old plants. Spraying glyphosate at 0.15 L ha−1 with MTD at 1.00 L ha−1 provided the highest activity of CAT, 0.65 µmol H2O2 min−1 mg−1 protein, in variety SP80-1842 Spraying glyphosate at 0.15 L ha−1 with ethephon at 0.33 L ha−1 caused the highest activity of APX, 1.70 nmol ascorbate min−1 mg−1 protein, in variety SP80-3280. The conclusion is, therefore, that mixtures of glyphosate with the insecticide/acaricide, MTD, and with the synthetic ethylene-releasing product, ethephon could help sugarcane crop grow adequately under uncontrollable or unpredictable agroecosystems like marginal lands.

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