Low-Input Herbicide Management: Effects on Rapeseed Production and Profitability

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

doi:10.3390/su10072258

Abstract

The oilseed rape conventional system can be moved to a more sustainable one by reducing herbicide application whilst ensuring at the same time effective weed control, maintaining oilseed rape yield, and quality and increasing profitability. Over three growing season periods, two field experiments at two different Southern Italy locations were carried out. In both sites, a conventional weed-control management system (recommended label dose), four alternative low-herbicide treatments, and an untreated control were compared. We monitored weeds and crop response to herbicide treatments, and calculated the net economic return, within site and year, for each treatment. In experiment 1, a half dose of herbicide did not show any significant difference in seed yield with respect to conventional treatment in two of three growing seasons. In experiment 2, compared with the conventional system, weedy control and the lowest applied herbicide dose treatment (25% of the recommended label dose) did not underline significant differences with regard to yield level. Net returns from the half dose of metazachlor herbicide were not significantly lower than net returns from conventional treatment in experiment 1 (on a three-year average 748 vs. 812 € ha−1, respectively). Our findings suggest that the herbicide dose might be cut by at least 50% in order not to jeopardize negative effects on production and economic performances.

Highlights

Oilseed rape cultivation (Brassica napus L. var. oleifera D.C.) offers various potential production purposes, as food and feed uses [1]
Oilseed rape plants grown under metazachlor treatments of 750 g a.i. and 500 g a.i. ha−1 remained unaffected with no visible stunting or chlorosis
Oilseed rape yield and net return were similar for both the treatments managed with the pre-emergence and the full labelled dose. These findings suggest that cropping system diversification by e.g., rotation with cereals or proposing low-herbicide managements might ensure the maintenance of good seed production as well as profitability and weed control, and promoting environmental and economic sustainability

Summary

Introduction

Oilseed rape cultivation (Brassica napus L. var. oleifera D.C.) offers various potential production purposes, as food and feed uses [1]. It is assumed that active herbicide ingredient hinders a specific weed target site [18], and on the other hand, it might cause stress to the crop species [19] In this regard, the main drawbacks related to the use of metazachlor are related to potential phytotoxicity effects during the first stages of the oilseed rape growing cycle [20,21]. Some recent microcosm studies [20,21] were carried out in order to better understand the metazachlor mode of action with regard to both physiological status and growth of a hydroponically oilseed rape cultivation in the short-term time frame. This paper analyses and assesses the consequences due to a decrease of herbicide rates towards both oilseed rape productivity and seed quality in order to reduce pesticide dependence and as a result foster environmental and economic sustainability

Methods

Results

Discussion

Conclusion