Impact of cereal rye cover crop on the fate of preemergence herbicides flumioxazin and pyroxasulfone and control of Amaranthus spp. in soybean

Abstract

Preemergence herbicides associated with cereal rye (Secale cereale L.) cover crop (cereal rye) can be an effective waterhemp [Amaranthus tuberculatus (Moq.) Sauer.] and Palmer amaranth (Amaranthus palmeri S. Watson) management strategy in soybean [Glycine max (L.) Merr.] production. Delaying cereal rye termination until soybean planting (planting green) optimizes biomass production and weed suppression but might further impact the fate of preemergence herbicides. Limited research is available on the fate of preemergence herbicides applied over living cereal rye in the planting green system. Field experiments were conducted in Illinois, Kansas, Pennsylvania, and Wisconsin to evaluate the fate of flumioxazin and pyroxasulfone and Amaranthus spp. residual control under different cover crop management practices in soybean in 2021 and 2022 (8 site-years). A flumioxazin + pyroxasulfone herbicide premix was applied preemergence at soybean planting under no-till without cereal rye, cereal rye early terminated before soybean planting, and cereal rye terminated at soybean planting. Flumioxazin and pyroxasulfone concentrations in the soil were quantified at 0, 7, and 21 d after treatment (DAT) and Amaranthus spp. density was determined at postemergence herbicide application. The presence of cereal rye biomass intercepted flumioxazin and pyroxasulfone at preemergence application and reduced concentration in the soil when compared to no-till, mainly at 0 DAT. Main differences in herbicide concentration were observed between no-till and cereal rye treatments rather than cereal rye termination times. Despite reducing herbicide concentration in the soil, early-season residual Amaranthus spp. control was not affected by the presence of the cereal rye biomass. The adoption of effective preemergence herbicides associated with a properly managed cereal rye cover crop is an effective option for integrated Amaranthus spp. management programs in soybean production systems.

Elucidating waterhemp (Amaranthus tuberculatus) suppression from cereal rye cover crop biomass

“…It is important to emphasize that this study focused on the physical influence of the cereal rye biomass on A. tuberculatus suppression and soil microenvironment (light, moisture, and temperature). The methodology adopted simulates the mulch effect of the cereal rye biomass following its termination and during decomposition, which is commonly observed when cereal rye is adopted ahead of soybean (Nunes et al 2023b). Because there was no cereal rye growth in the experimental area where the study was conducted, this study did not account for the effect of the cover crop on water (Reed and Karsten 2022) and nutrient (Finney et al 2016) dynamics during its growth and their potential impact on A. tuberculatus recruitment (Boyd and Van Acker 2003;Sweeney et al 2008).…”

“…Yadav et al (2023) reported that cereal rye associated with reduced soybean row spacing (38 vs. 76 cm) and effective A. tuberculatus control in the previous crop (corn) provided the best level of A. tuberculatus control during the soybean season. Nunes et al (2023b) observed that a cereal rye cover crop terminated at soybean planting (planting green) reduced early-season A. tuberculatus density similar to the use of a preemergence herbicide program. These studies provide evidence that cereal rye can be an effective tool for A. tuberculatus management.…”

“…These studies provide evidence that cereal rye can be an effective tool for A. tuberculatus management. Moreover, a similar trend across studies evaluating the use of cover crops for weed suppression is that delaying cover crop termination can increase biomass accumulation and improve weed suppression (Hodgskiss et al 2022;Nunes et al 2023b;Osipitan et al 2019). However, such studies focused on the applicability of this practice and did not investigate the underlying mechanism of A. tuberculatus suppression provided by the cereal rye cover crop.…”

Design, Synthesis, and Herbicidal Evaluation of Pyrrolidinone-Containing 2-Phenylpyridine Derivatives as Novel Protoporphyrinogen Oxidase Inhibitors

“…In addition, FLU has also been widely used in integrated weed management in no-till fields and orchards. 16,17 This constraint underscores the need for novel PPO inhibitors with enhanced selectivity and efficiency. 8,9,18 In 2003, Hamprecht et al employed a substructure splicing strategy to synthesize a biphenyl compound (Figure 1) with weak herbicidal activity.…”

“…However, because of its limitation in crop selectivity, FLU has only been used as a pre-emergence herbicide in crop fields such as cotton, peanut, and soybean. In addition, FLU has also been widely used in integrated weed management in no-till fields and orchards. , This constraint underscores the need for novel PPO inhibitors with enhanced selectivity and efficiency. ,, …”