Winter Cereal Cover Crop Mulches and Inter‐Row Cultivation Effects on Cotton Development and Grass Weed Suppression

Abstract

A field experiment was conducted under Mediterranean conditions to study the effects of two barley (Hordeum vulgare L.), six triticale (X Triticosecale Wittmack) cultivars and three rye (Secale cereale L.) populations, used as cover crop mulches on the development of barnyardgrass [Echinochloa crus‐galli (L.)], bristly foxtail [Setaria verticillata (L.) P. Beauv.], large crabgrass [Digitaria sanguinalis (L.) P. Scop.], and cotton (Gossypium hirsutum L.). Cotton was grown with cereal mulches alone or in treatment combinations that included inter‐row cultivation, herbicide (quizalofop) application, or both. Three weeks after cotton planting, barnyardgrass, bristly foxtail, and large crabgrass emergence in mulched treatments was 28 to 69%, 33 to 57%, and 35 to 83% lower, respectively, than emergence in mulch‐free treatments. On the contrary, cotton emergence was not significantly affected by any of the cover crop mulches. Shoot number and fresh weight of the three weeds were in most cases decreased in cereal‐mulched treatments and were less in inter‐row cultivated treatments compared to those in uncultivated treatments. Cotton lint yields in cereal mulched‐inter‐row‐cultivated treatments were 28 to 84% greater than that in the corresponding mulch‐free treatments. However, cotton produced more lint yield when the three grasses had been controlled by quizalofop. The results of this study indicated that some winter cereals have the ability to suppress germination of annual grass weeds and in combination with inter‐row cultivation could increase cotton yield. However, herbicide usage is essential to maximize cotton yield and consequently to satisfy cotton producers.