Use of preparations for strengthening plants in organic production of lettuce

U ekološkoj poljoprivredi postoje ograničenja i strogi nadzor glede upotrebe agrokemikalija, što uključuje pesticide te mineralna dušična gnojiva i ostala mineralna gnojiva s lako dostupnim hranivima. Svi preparati korišteni u ekološkoj proizvodnji trebaju biti prirodnog podrijetla, minimalno prerađeni i što manje škodljivi prema korisnim organizmima. Što se tiče gnojidbe, ona se provodi upotrebom organskih gnojiva s vlastitog gospodarstva u koja spadaju stajski gnoj, gnojnica i kompost ili se primjenjuju prirodni pripravci za jačanje otpornosti biljaka na bazi koprive, gaveza, preslice, hrena i drugih ljekovitih biljaka. Osim ovih tradicionalnih, koriste se i komercijalni pripravci koji smiju sadrţavati tvari odobrene Uredbom Komisije EZ (889/2008). Cilj istraživanja u ovom radu bio je ispitati učinak dvaju tradicionalnih preparata (ekstrakt koprive i ekstrakt gaveza) u usporedbi s komercijalnim preparatom ('EkoBooster 2'), čija je upotreba dozvoljena u ekološkom sustavu poljoprivredne proizvodnje. Promatran je njihov učinak na morfološke i gospodarske pokazatelje i osnovni kemijski sastav dviju sorti salate ('Trocadéro' i 'Quattro stagioni'). Sorta 'Quattro stagioni' pokazala se boljom u većini promatranih pokazatelja u odnosu na sortu 'Trocadéro'. Svi primijenjeni pripravci ostvarili su bolje rezultate u odnosu na netretirane biljke, iz čega se može zaključiti da je njihova primjena opravdana u ekološkom uzgoju lisnatog povrća kratke vegetacije, koje za odgovarajući rast treba lako pristupačna hraniva.In organic agriculture use of agrochemicals which includes pesticides, mineral and nitrogen fertilizers as well as mineral fertilizers with easily accessible nutrients are prohibited or strictly controlled. All preparations used in organic agriculture should be naturally formed, minimal processed and less toxic to useful organisms. Fertilization in this farming system is carried out using organic fertilizers which includes manure, liquid manure and compost. Natural preparations for strengthening plants based on nettle, comfrey, field horsetail, horseradish and other medicinal plants can be also applied. Apart traditional, commercial products with substances approved by Commission Regulation EC (889/2008) can also be used. Goal of this research was to examine the effect of two traditional preparations (extracts of nettles and comfrey) and one commercial preparation ('Ekobooster 2') allowed in organic system. The effect on morphological and agronomic parameters and basic chemical composition of two lettuce cultivars ('Trocadéro' i 'Quattro stagioni') was examined. Cultivar 'Quattro stagioni' proved to be better for most observed parameter in relation to 'Trocadéro'. 'Ekobooster 2', nettle and comfrey achieved better results than the control (untreated), so it can be concluded that their use is reasonable in organic cultivation of leafy vegetables with short growing season that for proper growth need easily accessible nutrients