Effects of pre- and post-emergence weed control on weed population and maize yield in different tillage systems

Abstract

The effect of chemical weed control with reduced herbicide rates (pre-em., pre-em. + post-em., post-em.) on weed population density and maize yield was compared in three tillage systems (mouldboard, chisel, disk harrowing) for lessive pseudogleyic soil in north-eastern Croatia (1997Croatia ( -1999. These main weeds were present in all tillage variants:and Calystegia sepium (L.) R.Br. The density of all weeds was significantly affected by tillage and it ranged from 204 plants on untreated plots with mouldboard to 372 and 421 plants per m 2 with chisel ploughing and disk harrowing, respectively. In comparison with standard tank-mixture of atrazine herbicide (metolachlor 50% & atrazine 20%) at the recommended rate, atrazine-free herbicide combinations (metolachlor + 50% prosulfuron & 30% primisulfuron-methyl; sulcotrione + bromoxynil; thifensulfuron-methyl + nicosulfuron) showed a similar total efficacy of weed control (95-96%). Band spraying with standard treatment at a half-recommended rate combined with mechanical weed control brought a satisfactory total weed reduction (83-87%). The weed control methods had no effects on maize yields that were significantly affected by year and tillage. Compared to the highest yield with mouldboard ploughing (10.2 t/ha), average percent yield depressions with chisel ploughing and disk harrowing were 10 and 22%, respectively.

Influence of weed infestation on morphological parameters of maize (Zea mays L.)

“…The significant unfavourable development of the years 1998/1999 and 1999/2000 was proved in the studied parameters, as well as in the dry mass yield. Gyenesne et al (2002) and Knežević et al (2003) presented statistically significant effect of the year on the ear yield. Significant differences among studied factors are given in the Table 7.…”

Calystegia sepium – an expansive weed of maize fields near Krakow

“…Knežević et al [8] as well as Burger et al [15] point to C. sepium as one of the species that will very soon gain regional importance as a weed of maize fields, next to Setaria viridis, Echinochloa crus-galli, Chenopodium album, and Ambrosia artemisiifolia.…”

“…Calystegia sepium poses a significant threat to maize crops throughout France and the Netherlands (widespread and regular populations of C. sepium), though less widespread and more sporadic populations of this species occur in southwestern Germany, and regional or rare populations in southern Poland [6,7]. Interestingly, C. sepium affects maize irrespective of the prevailing soil tillage system, whether it is chisel, disk harrowing, or moldboard plough [8].…”

Détermination des périodes de compétition des mauvaises herbes en culture d’oignon (<i>Allium cepa L.</i>) au Nord-Est du Bénin

“…Pour le maïs, cette période se situait entre 10 et 24 jours après le semis ou entre 8 et 45 jours après l'émergence (Schmid et al, 1983). Pour le soja, elle se situait entre 9 et 19 jours après l'émergence en fonction de la densité de semis (Knezevic et al, 2003). Pour le cotonnier, cette période se situait après la levée entre 2 et 4 semaines en culture irriguée et entre 6 à 8 semaines en culture pluviale (Schwerzel et Thomas, 1971).…”

“…Les travaux de recherche relatifs à la détermination des périodes de compétition des mauvaises herbes ont surtout porté sur le cotonnier au Togo, au Zimbabwé, en Colombie, en Tanzanie et en Inde (Schwerzel et Thomas, 1971 ;Gurnah, 1974 ;Faure et al, 1988 ;Cousinie et al, 1989 ;Shelke et Bhosle, 1990 ;Tonato et al, 1989 ;Tonato et al, 1990 ;Douti et Djagni, 1995). Parmi les céréales, le riz a bénéficié de la même attention (Boyoda, 1991 ;Arraudeau, 1998), de même que le maïs (Niéto et al, 1968 ;Schmid et al, 1983 ;Knezevic et al, 2003). D'autres cultures notamment l'igname ont été étudiées par Kasasian et Seeyave (1969), puis par Crowther, cité par Hamdoum et Tigani (1977).…”