Effect of planting density and environmental conditions on the qualitative structure of seedlings of selected black poplar clones (section Aigeiros Duby)

Rasadniĉka proizvodnja predstavlja poĉetnu fazu u celokupnom prosecu proizvodnje topole koja znaĉajno utiĉe na uspeh podizanja zasada i njihov kasniji razvoj. Jedan od osnovih zadataka rasadniĉke proizvodnje jeste izbor najpogodnije tehnologije pri proizvodnji sadnica odreĊenih klonova topola, kojom je moguće proizvesti maksimalan broj sadnica unapred odreĊenog kvaliteta za potrebe pošumljavanja. U radu je analiziran uticaj gustine sadnje reznica na proizvodnju sadnica tipa 1/1 i 1/2 kod pet klonova iz sekcije Aigeiros i to tri klona ameriĉke crne topole: B-229, 665 i S1-5 (Populus deltoides Bartr. ex Marsh) i dva klona evroameriĉke topole: I-214 i M-1 (Populus x euramericana (Dode) Guinier). Istraţivanja su obavljena u rasadniku „Ljutovo― u Novom Beĉeju u periodu 2012-2014. godine na dve forme zemljišta tipa fluvisol: peskovito-ilovasta i peskovita forma. Ogledi su osnovani reznicama koje su saĊene u tri razmaka sadnje: 0,70 m x (0,20, 0,30 i 0,40 m), u 4 ponavljanja sa sluĉajnim blok rasporedom tretmana. Preţivljavanje sadnica tipa 1/1 i 1/2 ostvareno je u zadovoljavajućem procentu kod istraţivanih klonova crnih topola. Dobijeni rezultati su pokazali da se klonovi razlikuju u postignutim srednjim visinama i srednjim preĉnicima oţiljenica (sadnica tipa 1/1) i sadnica tipa 1/2, pri ĉemu su primenjene gustine sadnje znaĉajno uticale na ove vrednosti, što je potvrĊeno LSD testom na nivou znaĉajnosti od 0,05. MeĊutim, razlike u vrednostima srednjih visina i preĉnika istraţivanih klonova oţiljenica u 2012. i 2013. godine jesu posledica razlika klimatskih faktora, pre svega koliĉine i rasporeda padavina i temperatura vazduha, što je potvrĊeno visokim uĉešćem oĉekivanih varijansi. Već kod sadnica tipa 1/2 zabeleţen je veći uticaj faktora gustina sadnje i ogled (forma zemljišta) u odnosu na uticaj klimatskih prilika u obe godine posmatranja. Istraţivani klonovi crnih topola su pokazali sliĉnost u obliku visinske strukture sadnica tipa 1/1 i 1/2, kao i razliĉitu pomerenost sumarnih krivih u koordinatnom sistemu u zavisnosti od gustine sadnje. Razlike u poloţaju visinskih krivih ukazuju na razlike u rastu sadnica istraţivanih klonova u zavisnosti od godine, forme zemljišta i gustine sadnje, što je uticalo na razliĉitu zastupljenost sadnica u odreĊenim visinskim kategorijama...Nursery production of seedlings represents a starting phase in the process of poplar production, the one that significantly affects the outcome of planting and further development of plantations. One of the main goals of nursery production is to select the most appropriate technology for the production of seedlings of certain poplar clones that would yield the maximum number of seedlings of predetermined quality suitable for afforestation. This research paper presents the analysis of the impact of different planting densities on the production of five 1/1 and 1/2 clones of the section Aigeiros, namely three clones of eastern cottonwood: B-229, 665 and S1-5 (Populus deltoides Bartr. ex Marsh) and two clones of Euroamerican poplar: I-214 and M-1 (Populus x euramericana (Dode) Guinier). The research was carried out in the "Ljutovo" nursery in Novi Becej in 2012–2014, on two kinds of soil: sandy-loamy and sandy forms of fluvisol. Cuttings were planted at three different distances: 0.70m x (0.20m, 0.30m and 0.40m), in 4 replicates in a randomized design. The perceived survival rate of 1/1 and 1/2 type seedlings of the researched black poplar clones was marked as satisfactory. The results showed the differences between clones in mean heights and diametres of rooted cuttings (seedlings of 1/1 type) and seedlings of 1/2 type. Both heights and diametres of seedlings were considerably affected by planting densities, which was confirmed by means of the LSD test at the significance level of 0.05. However, the differences in the mean values of the cuttings’ heights and diametres in 2012 and 2013 could also be attributed to the impact of different weather conditions, primarily the amount and distribution of precipitation and the air temperature, which was confirmed by high participation of the expected variances. With the type 1/2 seedlings, a higher impact of the planting density and the soil form factors was perceived, as compared to the impact of weather conditions in both years. The researched black poplar clones showed similarities in the height structure of 1/1 and 1/2 seedlings, and differences in the shifts of the summarizing curves in the coordinate system depending on the planting density..