Effect of Cover Crops on Yield and Weeds Control of Lettuce Icebergs (Lactuca sativa var. Ice berg)

Abstract

Background & Objective: Cover crops are one of the alternative methods to reduce chemical inputs to control weeds. The aim of this study was to investigate the ability of weed control by cover crops in monoculture and dual and triple intercropping as well as their effect on iceberg lettuce (Lactuca sativa var. Ice berg) yield. Methods & Materials: A field experiment in the form of randomized complete block design with three replications was conducted in 2017 in the research field of the Faculty of Agriculture, Mohaghegh Ardabili University. Experimental treatments include cultivation of barley cover crops (Hordum vulgare L.), sunnhemp (Cartalaria juncea) and buckwheat (Fagopyrum esculentum) as monoculture (100% of recommended seeds) and dual and triple intercropping (50 and 33.3% of the recommended seeds, respectively). Results: The results showed that the highest biomass of cover crops was obtained from barley monoculture treatments and it’s intercropping with sunnhemp (1323.25 and 1247.14 g.m-2, respectively). The lowest weeds biomass (115.75 g.m-2) was belonged to sunnhemp + buckwheat. The highest lettuce fresh yield (7207 g.m-2) was obtained from barley + buckwheat + sunnhemp. The results of this experiment showed that double and triple intercropping of barley, sunnhemp and buckwheat compared to monoculture and control treatment had more effective control over Chenopodium album, Circium arvense, Amaranthus retroflexus and Sinapis arvensis. Conclusion: From the results, it can be concluded that cover crops in double and triple intercropping based on the obtained weed biomass have a better ability to control weeds.

Keywords

• buckwheat
• cover crops
• residues
• sunnhemp
• weeds control