The floristic composition of the weed community under conditions of higher maize densities

Abstract

The floristic composition and structure of the maize weed community was analyzed under conditions of higher crop densities and two-year climatic conditions. The studies were carried out on degraded chernozem at Zemun Polje in 1996 and 2004. The effect of maize density on the floristic composition, fresh and dry weight of weeds was observed over years. There were seven variants of the crop density: Gr 40,816, G2-50,124, G3-59,523 G4-69,686, G5-79,365, G6-89,286 and G7-98,522. Herbicides were applied. Weed sampling was done by the one square meter area method during the summer period. The number of plants per species was determined in each trial variant and also fresh weight of each species was measured per area unit and on the basis of it, the total fresh and dry weight of all weed species was calculated. At the end of the growing period, the hybrid yields were recorded and the means are presented in this paper. A total of 18 weed species were detected in maize weed community at Zemun Polje under conditions of the herbicide application. In 1996, the species Convolvulus arvensis (7.6 plants m~2), Sorghum halepense (5.1 plants m~2) and Solarium nigrum (4.6 plants m"2) prevailed, while in 2004, Solanum nigrum (44.6 plants m"2) was the most distributed species. The higher maize crop density was, the lower number of weed plants per species and total weed weight were over both years. The analysis of weed fresh weight in the density x year interaction showed the statistically significant differences. Obtained results point out to the fact that the choice of the appropriate growing density for each hybrid leads to higher yields and it significantly affects weediness of the given crop, which is another contribution of this measure to weed control.

Analiziran je floristički sastav i građa korovske zajednice kukuruza u uslovima povećane gustine kukuruza u klimatskim uslovima dve godine. Ispitivanja su obavljena na zemljištu tipa degradirani černozem u Zemun Polju u 1996. i 2004. godini. Praćen je uticaj gustine kukuruza na floristički sastav, svežu i suvu masu korova u zavisnosti od godine. Gustina useva je bila zastupljena sa sedam varijanti Gi-40.816; G2-50.124 G3-59.523; G4-69.686; G5-79.365; G6-89.286 i G7-98.522. Ispitivanja su izvedena u uslovima primene herbicida. Uzimanje uzoraka korova vršeno je metodom probnih kvadrata u letnjem periodu. Na svakoj varijanti ogleda određivan je broj jedinki i merena je sveža masa svake vrste po jedinici površine, na osnovu čega je izračunata ukupna sveža i suva masa svih vrsta korova. Na kraju vegetacije meren je prinos hibrida, a u radu su prikazane prosečne vrednosti. U korovskoj zajednici kukuruza Zemun Polja u uslovima primene herbicida registrovano je 18 vrsta korova. Najzastupljenije vrste u 1996. godini su bile Convolvulus arvensis (7,6), Sorghum halepense (5,1) i Solarium nigrum (4,6) jedinki m~2, a u 2004. Solarium nigrum (44,6) jedinki m"2. Sa povećanjem gustine useva kukuruza smanjuje se broj jedinki i ukupna suva masa korova u obe godine. Analizom sveže mase korova u interakciji gustina x godina dobijene su statistički značajne razlike. Dobijeni rezultati ukazuju da izborom odgovarajuće gustine gajenja za svaki hibrid pored povoljnih uslova na prinos, može značajno da se utiče i na stanje zakorovljenosti datog useva, što ide u prilog primeni ove mere u kontroli korova.