Modeling Changes in Dormancy in Weed Soil Seed Banks: Implications for the Prediction of Weed Emergence.

BATLLA, DIEGO, KRUK, BETINA C. Y BENECH-ARNOLD ROBERTO LUIS

Handbook of Seed Physiology: applications to agriculture.

Food Product Press

Lugar: Nueva York, USA; Año: 2004; p. 245 - 272

The seedling stage is a common target of many weed mechanical control and post-emergence herbicide methods because of its high vulnerability (Fenner, 1987). The success of control methods targeted at weed seedlings depends upon reaching the highest number of individuals at this developmental stage. However, it is practically impossible to determine which proportion of a certain weed population is being reached by a control method. Indeed, the number of emerged seedlings can be counted, but we do not really know which fraction of the population they represent. Construction of weed seed germination models that predict which proportion of the seed bank germinate at a certain time would be useful tools for determining the most suitable time for seedling control and, consequently, should result in a higher efficacy of controls methods (Benech-Arnold and Sánchez, 1995). Although many models that successfully predict seed germination have been developed, one of the most important limitations for the formulation of such models in many common weed species is the existence of dormancy. Probably, the lack of detailed research intending to understand and quantify how environmental factors regulate dormancy status in field situations had prevented the elaboration of an adequate theoretical framework for the construction of predictive models addressing dormancy changes in weed seeds bank populations. In the first section of this chapter we discuss the different environmental factors affecting dormancy in weed seed banks, and present a general framework for classifying and understanding the effects of these factors on weed seed dormancy changes under field situations. The aim of this classification is merely to facilitate the conceptualization of the whole system. The second section will discuss some attempts to model weed seed dormancy in relation to the effect of those environmental factors.