Ascophyllum Nodosum-Based biostimulant mitigates lactofen herbicide phytotoxicity in soybean crops

Abstract

Biostimulants may be a management strategy to mitigate injuries caused by herbicides in soybean crops due to their antioxidant properties. This hypothesis was evaluated in field experiments conducted over two crop seasons through based on assessments of plant growth and yield of soybean crops. Increasing rates (0.00, 0.33, 0.66, and 0.99 L cp. ha− 1) of a commercial biostimulant were applied at 0, 3, 6 and 9 days after application (DAA) of the herbicide lactofen (protox or PPO enzyme inhibitor); a control treatment was implemented without application of these products. The biostimulant Megafol® composed of urea, potassium acetate, vinasse, and extract from the algae Ascophyllum nodosum, was tested. The application of lactofen reduced plant growth (average reduction of 15.6 cm in the first harvest and 6.8 cm in the second harvest), resulting in losses in grain yield (average reduction of 559.7 kg ha− 1 in the second harvest) and the profitability (average reduction of US$2,780.0 ha− 1 in the second harvest) of using the biostimulant. However, this biostimulant mitigated damage to the crop, resulting in a lower impact on grain yield and profitability. Therefore, biostimulants should be applied at 3 DAA at a of 0.33 L ha− 1 (higher productivity observed: 3,946.9 kg ha− 1) or at 6 DAA at a rate of 0.66 L ha− 1 (greater profitability observed: US$4,835.4 ha− 1) to mitigate lactofen phytotoxicity. Thus, extreme and irreversible damage to soybean plants during their development caused by exposure to this herbicide is avoided.