Herbicide Uptake and Regrowth Ability of Tall Fescue and Orchardgrass in S-Metolachlor-Contaminated Leachates from Sand Pot Experiment

Euro Pannacci,Maria Luce Bartucca,Francesco Tei,Daniele Del Buono,Primo Proietti,Luigi Nasini

doi:10.3390/agriculture10100487

Abstract

The ability of tall fescue (Festuca arundinacea L.) and orchardgrass (Dactylis glomerata L.), to remediate leachates polluted with S-metolachlor (SMR) has been assessed in static hydroponic cultures. Different SMR concentrations (0.25, 1.00, and 2.00 mg L−1) were applied in the growth media to test the capacity of the two grasses to tolerate and uptake this herbicide, and to regrowth after mowing. S-metolachlor did not severely affect the dry weight aerial biomass of D. glomerata and F. arundinacea, which were reduced by 5% and 10%, respectively, when compared to the untreated control, regardless of the SMR concentrations in the leachate. The regrowth ability of aerial biomass after mowing was reduced at the different SMR concentrations, according to a dose–response model. The SMR concentrations, which reduced the regrowth ability of F. arundinacea and D. glomerata of 10% and 30%, were found to be EC10 (Effective Concentration) of 0.21 and 0.38 mg L−1 and EC30 of 0.45 and 0.74 mg L−1, respectively. These values could be assumed as the SMR concentrations that were well tolerated by both the species, without compromising their aerial biomass regrowth. Finally, tall fescue was found to be more effective and faster than orchardgrass in decreasing the SMR in the leachate and, therefore, this species should be preferred to be used in the vegetative buffer strips (VBS).

Highlights

Due to the continuous evolution of weed resistance to herbicides, growers are forced to introduce a range of different tactics to control weeds
Festuca arundinacea L. and Dactylis glomerata L. are very diffused cool season perennial grass species native to Europe. These perennial grasses offer some major advantages for phytoremediation strategies: (i) greater biomass production and extensive fibrous root systems; (ii) regrowth ability after mowing that allows an increase in the uptake and detoxification of herbicides and a more effective remedial action; (iii) long-lived species that increase their persistence in the buffer strips [20]
Glasshouse trial was carried out maintaining the air temperature between 15 ◦ C and 30 ◦ C and using F. arundinacea and D. glomerata in the static hydroponic cultures according to the methodology already described by Del Buono et al [19]

Summary

Introduction

Due to the continuous evolution of weed resistance to herbicides, growers are forced to introduce a range of different tactics to control weeds. This environment-friendly technology takes advantage of the capacity of some plants to tolerate high amounts of contaminants dispersed in polluted soils and/or water, and to pick up and degrade them, remediating the contaminated matrices [13] These species could be used in the vegetative buffer strips (VBS), which have been proposed in recent years as a means to reduce surface water contamination caused by agricultural non-point pollution [14,15,16]. (ii) regrowth ability after mowing that allows an increase in the uptake and detoxification of herbicides and a more effective remedial action; (iii) long-lived species that increase their persistence in the buffer strips [20] They have been successfully used for the phytoremediation of polluted soils and ground waters [19,21], data on the ability of these grass species to remediate water polluted with S-metolachlor are not available. D. glomerata (orchardgrass) in the remediation of soil polluted with SMR by measuring the effects of SMR on the plants aerial and root biomass, on their regrowth after mowing, and the residual amounts of the herbicide in time, in the plant growth mediums

Plant Material and Growth Conditions

Statistical

Effects

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