Characterizing population growth rate of Convolvulus arvensis in wheat-sunflower no-tillage systems

• Published in: Crop science 2005-09, Vol.45 (5), p.2106-2112
• Main Authors: Jurado-Exposito, M, Lopez-Granados, F, Gonzalez-Andujar, J.L, Garcia-Torres, L
• Format: Article
• Language: English
• Subjects: Agricultural practices; Biological and medical sciences; Cereal crops; Convolvulus arvensis; Crop rotation; Diseases and pests; field crops; Fundamental and applied biological sciences. Psychology; Generalities, botany, ecology, damages, economic importance; grain crops; Growing season; Growth rate; Helianthus annuus; Herbicides; minimum tillage; no-tillage; Parasitic plants. Weeds; Phytopathology. Animal pests. Plant and forest protection; Plant growth; Population growth; spatial variation; temporal variation; Tillage; Triticum aestivum; Weed control; Weeds; Wheat
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2004.0502

Convolvulus arvensis L. is an important perennial weed that infests wheat (Triticum aestivum L.) and sunflower (Helianthus annuus L.) in Spain. Many fields of this rotation have been converted to no-tillage or reduced tillage, so perennial weeds such as C. arvensis have become more troublesome since they cannot be reduced in abundance by repeated tillage or cultivation. The population growth rate (PGR) is important in forecasting future population trends, and it can be used to develop weed control strategies in which applications of herbicides are spatially targeted to minimize possible damage. The objectives of this study were to assess and map PGR of C. arvensis in a wheat-sunflower no tillage rotation and to determine the temporal stability of the distribution function of C. arvensis. PGR was calculated over the course of four growing seasons (1999-2002) in a wheat-sunflower crop rotation in no-tillage systems. Spatial variability of PGR was analyzed by geostatistics. Temporal stability of the distribution function of C. arvensis PGR over time was established by a generalization of the two-sample Cramer-von Mises test for a difference between two univariate probability distributions. Year and crop influenced PGR, being larger in the sunflower phase (PGR = 0.52) than in the wheat phase (PGR = 0.16) of a sunflower-wheat rotation system because the density of C. arvensis was greater when growing in competition with wheat than with sunflower. The PGR showed a moderate degree of aggregation in patches in both rotations, although the temporal stability of the PGR distribution function was not observed. Overall, PGR became stable over the four growing seasons. Knowledge of growth rate spatial dynamics could improve C. arvensis management if it were complemented with spatially herbicide targeted applications.