Uticaj meteoroloških prilika na kritičan period suzbijanja korova i prinos kukuruza u Srbiji

Corn is one of the leading crops grown in Serbia (on over 1 000 000 ha), mostly in the territory of Vojvodina (about 60%), with the rest being grown in Central Serbia. Corn production is affected by a number of different factors during the vegetation season, both abiotic and biotic. Weather conditions during the season are a factor which can affect both the crop yield directly and the development of weeds that can be found in the corn field, and consequently determine the critical period for weed control (CPWC). Therefore, the aim of this paper is to study the impact of weather conditions during two vegetation seasons on the start of the critical period for weed control in conventional corn production. Field experiments were conducted during 2015 and 2016 in the area of Padina (South Banat region). The experiment was set up as a randomized block system, divided into two sections. Soil-applied herbicides (PRE-EM) based on S-metolachlor (1.5 L ha-1) + terbuthylazine (1.5 L ha-1) were applied in the first section, while the second section was left untreated. Seven treatments (seven weed control periods) were tested in each section, in three replicates. The size of the experimental plot was 10 m x 4.2 m. The obtained results have shown that the highest corn yield (12803 kg ha-1) was achieved in the treatment with PRE-EM herbicide application in 2016, when the precipitation was 526.4 mm, while in the same year the untreated plots yielded 9.5% less (11588 kg ha-1). In 2015, with the precipitation of 281.1 mm, corn yield in the PRE-EM treatments was 9045 kg ha-1, which was approximately 30% less, when compared to 2016. In 2015, which was a dry season, the corn yield in PRE-EM treated plots was 2.6% higher, when compared with the untreated plots. In 2015, the CPWC started in the four leaves growth stage (BBCH 14) in the PRE-EM treatments and in the two leaves growth stage (BBCH 12) in the untreated plots. In 2016, the CPWC in PRE-EM treatments started in the five leaves growth stage (BBCH 15), while in the untreated plots it began with the first leaf growth stage (BBCH 11). Therefore, soil-applied herbicides and better suited weather conditions enable a more flexible weed control, in terms of the start and length of the CPWC in corn fields in the region of South Banat.Kukuruz predstavlja jednu od vodećih kultura koja se gaji u Srbiji (na preko 1 000 000 ha), najvećim delom je zastupljen je na teritoriji Vojvodine (oko 60%), a ostatak je u Centralnoj Srbiji. U toku vegetacionog perioda usev kukuruza se nalazi pod velikim uticajem različitih faktora kako abiotičke tako i biotičke prirode. Jedan od faktora koji može imati direktni uticaj na prinos useva kao i na razvoj korovskih vrsta koje se mogu naći u usevu kukuruza, a samim tim na kritičan period suzbijanja korova (KPSK) jesu vremenski uslovi tokom vegetacione sezone. Stoga cilj u ovim istraživanjima je bio ispitivanje uticaja meteoroloških prilika tokom dve vegetacione sezone na početak kritičnog perioda u suzbijanju korova u konvencionalnoj proizvodnji useva kukuruza. Poljski eksperimenti su izvedeni tokom 2015. i 2016. godine na području Padine (Južni Banat). Eksperiment je postavljen po slučajnom blok sistemu pri čemu je eksperimentalno polje podeljeno u dva potpolja, gde su u prvom primenjeni zemljišni herbicidi (pre-em) na bazi S-metolahlora (1,44 kg a.s. ha-1) i terbutilazina (0,75 kg a.s. ha-1), a drugo potpolje je bilo bez primene herbicida. U svakom potpolju je ispitivano sedam tretmana (sedam vremena uklanjanja korova) u tri ponavljanja. Veličina eksperimantalne parcele je bila 10 m x 4,2 m. Dobijeni rezultati su pokazali da je najveći prinos kukuruza ostvaren u varijanti sa primenom pre-em herbicida (12803 kg ha-1) u 2016. godini kada je nivo padavina iznosio 526,4 mm, dok je u istoj godini bez pre-em herbicida prinos za 9,5% bio niži (11588 kg ha-1). U 2015. godini sa padavinama od 281,1 mm, takođe u varijanti sa pre-em primenom herbicida, ostvaren je prinos od 9045 kg ha-1 što je u poređenju sa 2016. godinom bilo za skoro 30% manje. U 2015. godini, kao sušnoj sezoni, prinos kukuruza sa pre-em herbicidinim tretmanom je bio za 2,6% veći u poređenju sa varijantom bez pre-em tretmana. KPSK u 2015. godini sa primenom pre-em herbicida počeo je u fazi četiri lista kukuruza (BBCH 14), a bez pre-em tretmana u fazi razvijena dva lista kukuruza (BBCH 12). U 2016. godini KPSK u tretmanu sa pre-em herbicidima je počeo u fazi pet razvijenih listova (BBCH 15), dok je bez pre-em herbicida počeo u fazi prvog lista kukuruza (BBCH 11). Dakle, zemljišna primena herbicida i povoljniji meteorološki uslovi daju mogućnost fleksibilnijeg suzbijanja korova po pitanju početka i dužine trajanja KPSK u usevu kukuruza na području Južnog Banata