Herbicide Rate, Glyphosate/Glufosinate Sequence and Corn/Soybean Rotation Effects on Weed Seed Banks

• Published in: Weed science Vol. 59; no. 3; pp. 398 - 403
• Main Authors: Simard, Marie-Josée, Rouane, Sébastien, Leroux, Gilles D
• Format: Journal Article
• Language: English
• Published: 810 East 10th Street, Lawrence, KS 66044-8897 Weed Science Society of America 01.07.2011; Cambridge University Press
• Subjects: Agricultural practices; Agronomy. Soil science and plant productions; Biological and medical sciences; Biotechnology; Cereal crops; Chemical control; Corn; Crop rotation; Crop yield; Cropping systems; Cropping systems. Cultivation. Soil tillage; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Cropping systems and patterns; Genetic engineering; Genetic engineering applications; Genetic technics; Genetics and breeding of economic plants; herbicide sequence; Herbicides; Methods. Procedures. Technologies; Parasitic plants. Weeds; Phytopathology. Animal pests. Plant and forest protection; Plant breeding: fundamental aspects and methodology; Plants; reduced rates; Research projects; Seed banks; Seed production; Seeds; Soybeans; Tillage; Transgenic animals and transgenic plants; Transgenic crops; Transgenic plants; Vegetables; Weed control; WEED MANAGEMENT; Weed seed banks; Weeds; reduced rates; soybean, Glycine max (L.) Merr; corn, Zea mays L; Transgenic crops; herbicide sequence; crop rotation; weed seed banks; glufosinate; Glyphosate; Biotechnology; Monocotyledones; Seeds; Organic phosphinate; C4-Type; Systemic; Cereal crop; Gramineae; Reduced rate protection; Dicotyledones; Weed science; Angiospermae; Transgenic plant; Seed bank; C3-Type; Organic compounds; Vegetals; Zea mays; Weed; Pesticides; Cropping system; Organic phosphonate; Glycine max; Herbicide; Restrictive practice; Grain legume; Application rates; Leguminosae; Aminoacid; Crop rotation; Spermatophyta; Genetic engineering; Genetically modified organism; Oil plant (vegetal); Chemical weed control
• ISSN: 0043-1745; 1550-2759
• DOI: 10.1614/WS-D-10-00162.1

The effect of herbicide rates on weed control and crop yield is the subject of countless and ongoing research projects. Weed seed banks receive very little attention in comparison. The seed bank resulting from 3 yr (2006 to 2008) of single herbicide rates in a cropping system where glyphosate/glufosinate and corn/soybean were rotated or not was evaluated in a field located in St-Augustin-de-Desmaures, Québec, Canada. Field plots under conventional tillage were seeded in corn every year, or corn and soybean (1 yr). These plots received the same herbicide every year or various glyphosate/glufosinate 3-yr sequences. Subplots were sprayed with a single POST application of the recommended rate of glyphosate (900 g ae ha−1) or glufosinate (500 g ai ha−1) or lower rates. Subplots received the same full (1.0×, recommended) or reduced (0.5×, 0.75×) rate every year. After crop harvest in 2008, soil cores were extracted and the weed seed bank was evaluated. Including soybean in the cropping system resulted in lower seed banks compared to those under continuous corn cropping. Including glufosinate in a glyphosate herbicide sequence increased weed seed banks due to the lower efficacy of the glufosinate rates tested at reducing the seed bank of annual grasses. Higher herbicide rates translated into lower seed banks, up to a certain rate. After 3 yr, the lowest seed bank (full glyphosate rates every year) still had 4,339 ± 836 seeds m−2 and was higher than the initial seed bank (2,826 ± 724 seeds m−2). Nomenclature: Glyphosate; glufosinate; corn, Zea mays L.; soybean, Glycine max (L.) Merr.