Suzbijanje korova u pitomoj nani (Mentha x piperita L.) primenom prirodnih i sintetičkih malčeva

Mogućnosti suzbijanja korova malčiranjem ispitivane su u zasadu pitome nane gajene na proizvodnim površinama Instituta za proučavanje lekovitog bilja “Dr. Josif Pančić” u Pančevu (44°52'20.0"N, 20°42'04.7"E, 81 m n.v.), Južni Banat. U našim agroekološkim uslovima pitoma nana se gaji kao jednogodišnja vrsta i obično daje dve žetve. Obzirom da ne postoji lista dozvoljenih herbicida u lekovitom bilju, glavni izazov u njenom gajenju predstavlja suzbijanje korova. U preliminarna istraživanja uključeno je 14 malčeva (5 sintetičkih i 9 prirodih). Po dva malča iz svake grupe (sintetički: PE sivo-crna i agrotekstilna crna folija; prirodni: piljevina bagrema i iglice crnog bora) koja su se u preliminarnim ogledima pokazala kao najpogodnija za suzbijanje korova u pitomoj nani, uključena su u detaljna ispitivanja u narednim dvogodišnjim ogledima. Eksperimentalni zasadi su zasnivani sadnjom stolona (1.500 kg ha-1) u jesen, na međurednom razmaku od 0,7 m. Sintetički malčevi su postavljani duž redova (širina 0,7 m, na svakih 10 cm reda otvori Ø 10 cm), a prirodni u međuredu (sloj 5-10 cm, širine 0,5 m). Efekasnost malčeva u suzbijanju korova procenjena je na osnovu poređenja sa zakorovljenom kontrolom, a njihov efekat na prinos sa nezakorovljenom kontrolom. Detaljno je analiziran i efekat malčeva na kvalitet prinosa a u te svrhe je utvrđen udeo lista sa cvetom i stabla, sadržaj i hemijski kvalitet etarskog ulja, relativni sadržaj hlorofila u listu i prinos stolona. Utvrđen je i uticaj malčeva na temperatutu i pH reakciju površinskog sloja zemljišta. Potpuno suzbijanje korova i najveći prinos ostvareni su pri primeni folija dok je efikasnost prirodnih malčeva bila znatno niža (u zavisnosti od ocene, od 28,9 - 81,8%). Prinosi ostvareni u 2017. su bili niži (usled nepovoljnih meteoroloških prilika) od prinosa u 2016., kada je ukupan prinos (u obe žetve) na agrotekstilnoj crnoj foliji bio 5,6 t ha-1, a na sivo-crnoj foliji 4,7 t ha-1. Ipak, kada se uzme u obzir većina ispitivanih parametara (udeo lista sa cvetom i stabla, sadržaj etarskog ulja i prinos stolona) najpovoljniji efekt u zasadu pitome nane ispoljila je sivo-crna folija. Weed control by mulching in the peppermint plantation was conducted on the experimental fields of the Institute for Medicinal Plant Research "Dr Josif Pančić", in the South Banat, Serbia (44°52'20.0"N, 20°42'04.7"E, 81 m above sea level). In our agro-ecological conditions, peppermint is grown as an annual species with two harvests. In its cultivation the main problem is a weed control, as no or limited use of herbicides is advised in medicinal plants. Preliminary research included 14 mulches (5 synthetic and 9 organic). Two mulches from each group (synthetic: PE silver-black and agrotextile black foil; organic: acacia sawdust and black pine needles), which proved to be the most suitable for weed control in peppermint, were included in further two-year experiment. Experimental plantings were established in autumn, with stolons (1500 kg ha-1) at a row spacing of 0.7 m. Synthetic mulches were placed along the rows (width 0.7 m, openings Ø 10 cm at every 10 cm of the row), while organic mulches were spread between the rows (layer 5-10 cm, width 0.5 m). The efficacy of mulch on weed suppression was compared with control with weeds, while the efficacy on yield was compared with non-weed control. The quality of yield was examined in detail and the ratio of leaves with flowers to stem, the content and chemical conposition of essential oil, the relative content of chlorophyll in the leaf, as well as the yield of stolons were determined with regard to it. The influence of mulch on the soil temperature and soil reaction (pH) in the surface layer was also determined. Total weed suppression was obtained with the use of synthetic mulches, where the highest yield of absolutely dry biomass of the aboveground part of peppermint were recorded both experimental years, while the efficacy of organic mulches ranged from 28,9 to 81,8%. Yields achieved in 2017 were lower (due to climatic conditions) compared to that in 2016; the yield in the treatment with agrotextile black mulch was 5.6 t ha-1, while the one achieved with the silver-black mulch was 4.7 t ha-1. Under the silver-black mulch, the peppermint plants generally achieved better ratio of leaves with flowers to stem, higher content of essential oil and higher yield of stolons, compared to those under the organic mulches.