The Effects of Seed Burial and Flooding Depths on Emergence and Seedling Growth of Watergrass (Echinochloa oryzoides) and Barnyardgrass (E. crus-galli)

پژوهشهای زراعی ایران

Article 9, Volume 10, Issue 4 - Serial Number 28, January 2013, Pages 699-708   

Document Type: Research Article

DOI: 10.22067/gsc.v10i4.20350

Authors

E Mohammadvand^* ; A Koocheki; M Nasiri mahalati; A Shahdi

Department of Agronomy and Plant Breeding, Faculty of Agricultural Sciences, University of Guilan, Rasht

Abstract

In order to determine the effects of seed burial and flooding depths on the emergence and seedling growth of watergrass (Echinochloa oryzoides) and barnyardgrass (E. crus-galli), this experiment was conducted in a covered free air condition, at the Rice Research Institute of Iran, Rasht in summer of 2009. The treatments included four seeding depths (0.1 (seeds were mixed with the top soil), 2, 4 and 6 cm), and four flooding depths (0.1 (saturated soil with no standing water), 3, 6, and 9 cm) arranged as a factorial arrangement in a randomized complete block design with three replications. After 28 days, number of emergent seedlings, weed seedlings height, root and shoot fresh weight, leaf and root area were measured, and emergence percentage and root/shoot ratio were calculated. Since no germination of seeds was observed at the 6 cm sowing depth, this treatment wasn’t presented in results. Measured or calculated variable per unit was significantly different between two species and between various levels of seed burial and flooding depths. These variables also influenced by the interactions of the mentioned factors with an exception of emergence percentage. Emergence percentage and growth characteristics except for plant height were higher in E. oryzoides than E. crus-galli when weed seeds were located in the depth of 0.1 centimeter. In seeds located in the depth of 2 centimeters, all variables were higher in E. oryzoides than E. crus-galli. In both species, the higher values for mentioned variables was observed in the saturated condition of soil, when weed seeds were located at the depth of 0.1 centimeter and reduced with increasing flooding and seed burial depth. Results indicated that flooding condition with adequate height caused major limiting effects on emergence, establishment and growth of two Echinochloa species, especially when the seeds were deeply buried; but at decreased height specially saturated soils, emergence and growth of E. oryzoides were significantly more than E. crus-galli.

Keywords

Burying depth; Growth characteristics; Inhibition; Water management