INFIVE   05416
Unidad Ejecutora - UE
capítulos de libros
Perennial weeds in Argentinean crop systems: Biological and ecological characteristics and basis for a rational weed management
Agricultural Research Updates
Nova Science Publishers
Lugar: New York; Año: 2013; p. 43 - 62
In the last two decades, cropland changes from conventional tilled systems to zero tillage systems have been detected in Pampean agroecosystems. Dominant species are the primary weed due to the fact that they are adapted to the cropping system. Weed population shifts were observed when conventional tillage systems were changed to non-tillage. However, a great proportion of perennial species would be expected in non-till environments. In Argentinean crop systems only a few perennials have transcended in importance. In this context, Sorghum halepense has been one of the most important species in dispersion and aggressiveness. In addition, the low sensitivity of several populations to glyphosate contributes to their complex management. Populations from diverse ecological regions have differential mechanisms for adaptation according to the different environments where they have been growing. Even in non-till systems, Cynodon dactylon is another summer crops primary perennial weed and it is considered as highly plastic species in response to growth factors. Water and radiation have been major factors affecting the growth, conditioning the aggressiveness of the weed. Recently, the combining uses of zero tillage and round-up ready soybeans have promoted an increased shift in weed herbicide resistance. The detection of a glyphosate-resistant Lolium perenne population has increased interest in researchers of these biotypes. Several physiological traits influence their management in winter cereal crops. The plasticity of these weeds to adapt to zero tillage systems requires a design of integrated weed management program according to biological traits of the weeds. Several strategies of mapping and monitoring of weed populations, crop rotations, biocontrol and rotation of herbicides, among other, could be used to maintain the competitive ability of crops rather than eradication of weeds.