Controlling annual weeds in cereals by deploying crop rotation at the landscape scale: Avena sterilis as an example.
Weed control through crop rotation has mainly been studied in a nonspatial context. However, weed seeds are often spread beyond the crop field by a variety of vectors. For weed control to be successful, weed management should thus be evaluated at the landscape level. In this paper we assess how seed dispersal affects the interactions between crop rotation and landscape heterogeneity schemes with regard to weed control. A spatially explicit landscape model was developed to study both short- and long-term weed population dynamics under different management scenarios. We allowed for both two- and three-crop species rotations and three levels of between-field weed seed dispersal. All rotation scenarios and seed dispersal fractions were analyzed for both completely homogeneous landscapes and heterogeneous landscapes in which more than one crop was present. The potential of implementing new weed control methods was also analyzed. The model results suggest that, like crop rotation at the field level, crop rotation implemented at the landscape level has great potential to control weeds, whereby both the number of crop species and the cropping sequence within the crop rotation have significant effects on both the short- and long-term weed population densities. In the absence of seed dispersal, weed populations became extinct when the fraction of each crop in the landscape was randomized. In general, weed seed densities increased in landscapes with increasing similarity in crop proportions, but in these landscapes the level of seed dispersal affected which three-crop species rotation sequence was most efficient at controlling the weed densities. We show that ignoring seed dispersal between fields might lead to the selection of suboptimal tactics and that homogeneous crop field patches that follow a specific crop rotation sequence might be the most sustainable method of weed control. Effective weed control through crop rotation thus requires coordination between farmers with regard to cropping sequences, crop allocation across the landscape, and/ or the fraction of each crop across the landscape.
Departamento de Protección de Cultivos, Instituto de Agricultura Sostenible (CSIC), Av. Menendez Pidal s/n, Campus Alameda del Obispo, Apartado 4084, Córdoba 14080, Spain.
Lucía
L
González-Díaz
Femke
F
van den Berg
Frank
F
van den Bosch
José Luis
JL
González-Andújar
D000383:Agriculture / Q000379:methods*; D003198:Computer Simulation; D003710:Demography; D002523:Edible Grain / Q000502:physiology*; D008954:Models, Biological; D010572:Pest Control, Biological / Q000379:methods*; D057685:Plant Weeds / Q000502:physiology*; D006109:Poaceae / Q000502:physiology*