Respose of corn growth and yield characteristics to different rounds of irrigation in the soil contains Apirus and Atlantis herbicide residues

Maize (Zea mays L.) is an annual plant from the Poaceae family, which ranks third among crops due to its special characteristics, including a wide range of adaptation in tropical and subtropical climates. In recent years, herbicides that inhibit the action of acetyl coenzyme A carboxylase and Acetolactate synthase have been widely used to control narrow leaves. One of the significant consequences of these herbicides being released into the environment is their persistence in the soil. This issue, along with the harmful effects on the activity of microorganisms and stability in the soil ecosystem, poses a serious threat to crop rotation, as their gradual leaching and runoff can lead to underground and surface water pollution.

This experiment aimed to investigate the residual effect of Acetolactate synthase inhibitor herbicides on some growth and yield characteristics of corn in different rounds of irrigation was conducted at Shadid Beheshti of Andimshek Agro-industrial Company in 2020-2021 and 2021-2022. The Acetolactate synthase inhibiting herbicides used in wheat were Atlantis herbicide (Mesosulfuron-methyl+ iodosulfuron-methyl-sodium, OD 1.2%, 1.5 L ha-1), Apirus herbicide (Sulfosulfuron, WG 75%, 26.6 g.ha-1), weedy check, and weed-free check as main-plot and different rounds of irrigation (one, two, three, and four rounds between wheat harvest to corn sowing) as sub plot were examined using a split-plot design with randomized complete block design with four replications. The investigated traits included plant length, number of leaves, ear length, ear diameter, number of rows per ear, number of seeds per row, 100 seeds weight, seed yield, biological yield, harvest index, and herbicide carryover in the soil.

The analysis of variance revealed that the application of herbicide and irrigation rounds significantly affected the assessed traits of corn. The highest values for plant length, number of leaves, ear length, ear diameter, number of rows per ear, number of seeds per row, 100 seeds weight, seed yield, and biological yield were observed in the weed-free check with four rounds of irrigation. The weedy check with one round of irrigation had the lowest values for these traits. Increasing the irrigation rounds reduced the negative effect of Acetolactate synthase inhibiting herbicides on corn plants, and Atlantis herbicide demonstrated a more destructive effect compared to Apirus herbicide. Examination of herbicide carryover in the soil indicated higher residues of Atlantis herbicide compared to Apirus herbicide, resulting in a more detrimental impact on corn plants.

Based on the results of this study, Apirus herbicide, with better weed control in corn fields and lower soil stability, had a less negative effect on corn plants compared to Atlantis herbicide. The findings from the two years of testing supported this conclusion. Additionally, it was observed that increasing soil moisture through more rounds of irrigation reduced herbicide carryover in the soil and consequently minimized their negative effects on corn plants. Therefore, based on the results of this experiment, it seems that in the rotation of wheat-corn, the use of Apirus herbicide in wheat cultivation to control weeds, as well as the implementation of a rounder irrigation method for corn, can lead to a better corn yield compared to the use of Atlantis herbicide.
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