The Influence of Herbicide Underdosage on the Composition and Diversity of Weeds in Oilseed Rape (Brassica napus L. var. oleifera D.C.) Mediterranean Fields

Paola Deligios,Luigi Ledda,Gianluca Carboni,Roberta Farci,Stefania Solinas

doi:10.3390/su11061653

Paola Deligios, Luigi Ledda + Show 3 more

Open Access

https://doi.org/10.3390/su11061653

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Journal: Sustainability	Publication Date: Mar 19, 2019
Citations: 5	License type: CC BY 4.0

Affiliation: University of Sassari, Sardegna Agricoltura

Abstract

Weed flora is considered harmful for crop growth and yield, but it is fundamental for preserving biodiversity in agroecosystems. Two three-year trials were conducted in Italy (two different sites) to assess the effect of six herbicide treatments on the weed flora structure of an oilseed rape crop. We applied metazachlor during the pre-emergence stage at 25%, 50%, 75%, and 100% of the labelled dose (M25, M50, M75, M100); trifluralin (during the first growing season); post-emergence treatment (PE); and a weedy control (W). Species richness, and diversity indices were used to characterize weed flora composition and to evaluate the effect of herbicide treatments on the considered variables. Results highlighted that the weed community is characterized by a higher diversity in underdosed than in M100 treated plots. Raphanus raphanistrum and Sinapis arvensis were the most common species in M75 and M100 treatments in both sites, while more weed species were detected in underdosed treatments and in weedy plots. The highest Shannon index values were observed in the underdosed treatments. In general, only a slightly similar trend was observed between sites, weed abundance and diversity being positively affected both by low-input herbicide management and by environmental factors (e.g., pedoclimatic situation and previous crop).

Highlights

IntroductionBiodiversity is considered crucial for agricultural landscapes having a beneficial impact for cropping systems, especially if it does not limit the achievement of optimal yield [1,2]
Two three-year trials were conducted in Italy to assess the effect of six herbicide treatments on the weed flora structure of an oilseed rape crop
Biodiversity is considered crucial for agricultural landscapes having a beneficial impact for cropping systems, especially if it does not limit the achievement of optimal yield [1,2]

Summary

Introduction

Biodiversity is considered crucial for agricultural landscapes having a beneficial impact for cropping systems, especially if it does not limit the achievement of optimal yield [1,2]. Current crop production systems should be rescheduled to limit the dependence on external inputs and at the same time to foster an adequate enlargement of sustainability and biodiversity and crop yield [5,6]. Weed control management scheduling is addressed to limit dependence on herbicides by keeping the weed flora at a tolerable threshold of control instead of maintaining the crop totally free of weeds [13]. The investigation of the phytostructural effects due to herbicide underdosage is a key step in order to set up weed management systems characterized by a reduced reliance on chemical inputs [21]

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