Effects of soil compaction on early response of Q. robur seedlings since germination.

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1 Effects of soil compaction on early response of Q. robur seedlings since germination. Cambi M., Mariotti., Maltoni., Fabiano, F., Tani., Marchi E. GESF - University of Florence Department of gricultural, Food and Forestry Systems raşov - 25 th and 29 th September, 2017

2 ackground Forest operations with heavy machinery determine changes in soil characteristics due to compaction Soil structure & hydrology Porosity ulk density eration Gas diffusion rate Water infiltration Hydraulic conductivity Soil iota & Respiration Plant growth Root system depth Roots length Height & Diameter iomass Shoot/Root ratio Physiology Seedlings establishment

3 ackground Seedlings in harsh environments (i.e. Mediterranean) need to: be able to overcome the dry season reach groundwater or to follow declining groundwater take advantage of transitory resources (competition) Thus, an early and quick development of a deep root-system is more effective to a successful establishment

4 im ssessment of the early response of pedunculate oak seedlings to simulated soil compaction since germination Shoot- and root-system morphological traits were analyzed for about 1.5 months in an open-air environment Three levels of compaction were compared Still few literature on the effects of compaction on early seedlings development 4

5 Materials and Methods ) Simulated compression in lab D and PO measured at the beginning (T0) and during cultivation: T1: 31 days after sowing T2: 42 days after sowing T3: 51 days after sowing ) Experimental design & Sowing H 40 cm 3 randomized blocks (20 containers x 3 treatments x 3 blocks) Pre-germinated acorns (size selected within acorns weight range; radicle max < 5 mm) Silty loamy soil (alluvial soil) 400 dan D 16 cm 1700 dan 4000 dan C0 C1 C2

6 Materials and Methods C) Repeated measurements of morphological traits -Height (repeated measurements) days -Morphological traits by destructive analysis (at T1, T2, T3) H RcD Leaves fresh and dry biomass Shoot system fresh and dry biomass Main root length Root system depth Root system width Root system fresh and dry biomass Shoot/root ratio: fresh and dry biomass; height/main root lenght (H/MRL)

7 Results Time T0 T1 T2 T3 verage bulk density (g/cm 3 ) C0 C1 C ± 0.04 a 0.44 ± 0.01 a 0.43 ± 0.01 a 0.43 ± 0.04 a fter the first month, soil parameters started to change towards recovery 1 ± 0.02 b 0.96 ± 0.03 b 0.89 ± 0.02 b C 0.93 ± 0.02 b Time T0 T1 T2 T ± 0.02 c 1.49 ± 0.01 c 1.43 ± 0.04 c 1.43 ± 0.03 c a) Soil parameters verage soil porosity (%) C0 C1 C2 79 ± 1.67 a 80 ± 1.30 a 82 ± 0.89 a 82 ± 1.22 a Differences among treatments were maintained throughout the experiment (lowercase letters: comparison among treatments within time; capital letters: among times within treatment) 60 ± 0.89 b 61 ± 1.0 b 62 ± 1.14 b 63 ± 0.71 b 40 ± 0.89 c 41 ± 0.89 c 43 ± 0.84 c 41 ± 0.55 c

8 Results b) Germination In C2: higher mortality and later emergence c) Height +64% +73% C0 C1 C2

9 Results d) Root-system growth significant differences among treatments resulted at each time, both for root system depth and main root length, ranking C0>C1>C2 C0 C1 C % cm +101 % +5.3 cm Root system depth at T3

10 e) iomass Results C0 C1 C2 - C2 < C1 and C0 (fresh and dry) in total, shoot- and root-system T1 - Seedlings in C2 had higher S/R and H/MRL +167% +76% T2 Total dry biomass +185% +136% T3 +185% +125 %

11 Conclusions Constraint effect of soil compaction on Q. robur seedlings development occurred since the first growth phases The early effects were clearer on root- than on shoot-system and biomass Compaction affected biomass and shoot-system early growth when D is 1.5 gr/cm 3 Soil compaction can affect emergence + early growth rate + depth of root-system Effects of soil compaction after forest operation on regeneration can be worse in Mediterranean environments Forest operation sustainability: to set up mitigation and recovering practices for minimizing the extension and severity of soil compaction

12 Thank you for your attention 12