Evaluation of selected growth parameters of Paulownia cotevisa plantation in the Danubian Lowland | Michal Pástor, Jaroslav Jankovič, Martin Belko, Juraj Modranský | Agricultural Journals

Ectomycorrhiza-hydrogel additive enhanced growth of Norway spruce seedlings in a nutrient-poor peat substrate | Ivan Repáč, Zuzana Parobeková, Martin Belko | Agricultural Journals

Bareroot European beech (Fagus sylvatica L.) seedlings are frequently used in reforestation programs in Central Europe. However, beech outplanting is often unsuccessful due to drought stress. In this study, the effects of a simulated water deficit and of a hydrogel and ectomycorrhizal fungi (EMF) application were estimated on the development of 1 + 1 beech seedlings. The roots of 1-year-old bareroot seedlings were treated with the additives at the time of transplanting to pots in spring and then exposed to the whole growing season under different watering regimes: (i) full watering (FW; volumetric water content 70%), (ii) reduced watering (RW; 40%), (iii) periodic watering (PW; substrate rewetted to 70% after drying), and (iv) no watering (NW). Almost all FW seedlings survived the whole growing season, whereas all NW seedlings died after 17 weeks of desiccation. The survival and growth of FW and NW seedlings were significantly higher and lower, respectively, than those under both PW and RW treatments. The additives significantly increased survival in RW seedlings only but had no effect on growth. A promoting effect of FW on the chlorophyll a fluorescence parameters was found. The number and EMF colonization of the short roots were significantly lower in FW seedlings compared to the other watering treatments. The additives did not affect these parameters. The occurrence of neither treatment-specific EMF root morphotype nor fungi applied in the inoculum and traced by molecular analysis indicated the formation of ectomycorrhizas with native EMF in all treatments. The seedlings in the water-deficient treatments exhibited higher foliar nutrient concentrations than FW seedlings. The additives increased the concentration of nutrients in PW and phosphorus in NW seedlings. The results suggest the significant effect of the water supply, but a weaker effect of the additives tested on beech seedling development under experimental conditions.

The beginning of the systematic

Forest plantations, including those of Norway spruce, are increasingly threatened by drought in Central Europe. One of the measures understating this threat might be the use of drought-mitigative additives at planting. The effects of induced water limitation and the application of hydrogel Agrisorb and commercial ectomycorrhizal fungi (EMF) inoculum Ectovit on the development of 2 + 1 spruce seedlings were estimated in this study. The root systems of 2 + 0 seedlings were treated with the additives, along with their spring transplantation into peat-filled pots. The seedlings were then exposed throughout the entire growing season either to full watering (FW)—volumetric soil water content 70%, reduced watering (RW)—water content 40%, periodic watering (PW)—substrate rehydrated to 70% after drying to the wilting point (21%), or remained non-watered (NW). Survival, growth and chlorophyll fluorescence of the seedlings decreased proportionally to the increased drought intensity, while the highest root-to-shoot ratio and EMF colonization of roots occurred under PW and RW, respectively. NW seedlings died after 9 weeks of desiccation, whereas the EMF inoculum prolonged the survival time by one week. Ectomycorrhizas were formed predominantly with native EMF in all the treatments; nevertheless, compared with the uninoculated control, the formation of a treatment-specific EMF root morphotype and increased EMF colonization under PW and RW were observed on the inoculated seedlings. Both the EMF inoculum and the hydrogel increased survival under PW by approximately 15% but did not significantly affect growth, regardless of the watering regime. These results are limited to the experimental conditions and suggest a more dominant effects of the watering regimes compared with the additives tested.

Ongoing coniferous monocultures decline in Beskydy Mts. Slovakia, emerged into establishment of Demonstration object of reconstruction of spruce forests (DORS) Husárik, focused on various technological processes of regeneration of economically important tree species. For Norway spruce (Picea abies [L.] Karst.) assessment of less frequently used artificial regeneration technologies, including planting of containerized transplants (CRT) or direct seeding procedures (direct seeding DS, seeding into vegetation cell VCS) and commonly used planting of bareroot transplants (BRT) was carried out. Seven years after experimental plot establishment, the lowest survival rate was recorded for DS treatment with 42% survived seedlings, the highest for CRT treatment with 79% survived transplants. For germinated seedlings, average seeding spot occupation rate recorded for DS (72%) was significantly lower than for VCS (98%) one year after seeding and remained significantly lower also over further consecutive years. Average survival recorded for planted transplants over monitored period did not differ markedly and gradually decreased to 76% for BRT and 79% for CRT. Reflecting different ontogenetic stage of individuals assigned to selected treatment average height 134.6 cm for DS, 134.1 cm for VCS and 182.0 cm for CRT, 215.0 cm for BRT was recorded seven years after establishment. The results suggest that for spruce, less frequently used artificial regeneration technologies (VCS, CRT), that markedly curtail time period required for target tree species installation on planting sites, with survival and growth rate of plants recorded in this study, could provide reasonable alternative to commonly used planting of BRT.