Leaching and Carryover for Safrinha Corn of the Herbicides Imazapyr + Imazapic in Soil Under Different Water Conditions

Abstract

<jats:p>ABSTRACT Soil moisture can alter the transport and permanence of pre-emergent herbicides. The objective of this work was to evaluate the influence of water availability in the soil on the leaching of a commercial mixture of the herbicides imazapyr + imazapic, as well as the carryover effect of this herbicide in corn planted in succession to soybean. The experiment was carried out in leaching columns in a randomized block design with 4 replications. A 3x3x2 factorial scheme was used, with factor A being the irrigation (130%, 100% and 70% of field capacity (CC)), factor B the doses of the commercial mixture of the herbicides imazapyr + imazapic (0.00+ 0.00; 52.5 + 17.5 and 105 + 35 g ha-1) and factor C at soil depth (0-0.3 m and 0.3-0.6 m). Soybean sowing was performed at the top of the columns and immediately after herbicide mixture was applied. After 120 days the columns were opened, generating two sections, where corn (Zea mays) and the other watermelon (Citrullus lanatus) were sown as a bioindicator of herbicide residue. The fluorescence parameters of chlorophyll a at 15 and 30 days after germination (DAG) and shoot dry matter accumulation at 30 DAG were evaluated. There was greater retention of the herbicide imazapyr + imazapic at a depth of 0-0.3m at 70% CC condition and leaching at a depth of 0.3-0.6m at 130% CC condition, with a reduction in the mass accumulation of watermelon plants. The herbicide has a carryover potential for corn cultivation in soils maintained at 70% CC.</jats:p>

Imazapic interaction and mobility in soil cultivated with sugarcane in northeast Brazil

“…Imazapic has a high solubility in water, and when dissolved it has a high contamination capacity of surface and groundwater, both evaluated by the EPA (American Environmental Protection Agency) criteria and by the GUS method (Gonçalves et al, 2013). There are studies on the leaching and volatilization of Imazapic in tropical soils in Brazil (Inoue et al, 2014;Monquero et al, 2010;Souza et al, 2020). However, studies already carried out are still not enough due to great diversity of soils, climatic, geographical and geological diversity.…”

Agrotóxicos no Brasil: uma compreensão do cenário atual de utilização e das propriedades do solo que atuam na dinâmica e retenção destas moléculas

“…Assim, o solo é considerado o principal receptor de agrotóxicos, e seu destino no meio ambiente depende de interações físicas e químicas entre os agentes do solo e do químico aplicado. Essas interações resultam em uma maior ou menor disponibilidade de agrotóxicos para o seu papel agroquímico ou para causarem impactos ambientais (Souza et al, 2020).…”

Evaluation of imazapic and flumioxazin carryover risk for Carinata (Brassica carinata) establishment

“…(2) subsequent root growth and interception of the metabolite at deeper soil horizons (Souza et al 2020); and (3) the slow rate of the mechanism of action, which must first deplete amino acid seed reserves before symptoms of herbicide toxicity affect the plant (Webster and Masson 2001). This might explain why reductions in plant density due to imazapic, in contrast to flumioxazin, were not observed at 30 DAP but were evident at 57 DAP.…”