Nursery cultivation regimes, plant functional attributes, and field performance relationships in the Mediterranean oak Quercus ilex L.

Abstract

In this study we have addressed the effect of nitrogen fertilisation and shading used during nursery growth on the functional quality of Quercus ilex L. (holm oak) seedlings and their outplanting performance in an abandoned continental Mediterranean cropland. Three N fertilisation regimes: high and low fertilisation (154 and 34 mg N per plant, respectively) and no fertilisation, combined with two shade levels (full sun and 45% shade) were studied. Fertilisation increased the shoot size, shoot to root mass ratio (S/R), root N, and both shoot and root P concentration of the plants produced in the nursery. Fertilisation also enhanced the capacity of new root formation. Neither tissue K nor root mass was affected by N fertilisation. Shading increased S/R and root K concentration but reduced both shoot and root N concentration. Two years after planting, unfertilised seedlings had higher mortality and grew significantly less than those cultivated at both a low and a high fertilisation level. Shading during nursery growth had no influence on the outplanting performance of holm oak seedlings. Plants with a larger shoot and higher S/R had lower mortality and grew faster than those with a smaller shoot and lower S/R. Outplanting performance of holm oak seedlings was related with root N and P concentration and with RGC. No relationship was found with either shoot nutrient concentration or root mass. We conclude that high N fertilisation of holm oak seedlings in the nursery can improve their early field establishment in the afforestation Mediterranean abandoned croplands. #

Direct sowing of holm oak acorns: effects of acorn size and soil treatment

“…is one of the most representative species in the forest communities of the Mediterranean basin [35], especially on the Iberian Peninsula, where it forms part of the vegetation (existing as well as potential) in extensive areas [18,39]. The use of this evergreen sclerophilous tree in reforestation programs on abandoned agricultural lands promoted by the Common Agricultural Policy (CAP) has strongly increased in the last 12 years, in contrast to the Pinus species, which were widely used in the past [47]. Only in Andalusia (Spain), more * Corresponding author: francisco.bruno.ext@juntadeandalucia.es than 75 000 ha were reforested from 1993 to 1999, implying the introduction of millions of new seedlings.…”

“…ballota could be attributed to the low quality of seedlings used, as the cultivation regime in the nursery can strongly determine functional characteristics and response of the seedling in the field [47]. However, the high mortality rates of reforested seedlings in localities where there is even a vigorous natural regeneration suggest that not only the type of holm oak seedling commonly used in forestation but also the technique of introducing this species into the field should be reviewed.…”

CLONAL FORESTRY OF Piptocarpha angustifolia: SURVIVAL AND GROWTH VIGOR IN FIELD CONDITIONS

“…The aerial part height is a much applied characteristic to determine the quality of forest seedlings (GOMES et al, 2002), mainly related to the survivability in the field. Determining the optimum height for planting forest seedlings varies according to species and even to the same species in different environments (VILLAR-SALVADOR et al, 2004;JACOBS et al, 2005). On the other hand, when considering the production cost of forest seedlings, those with 20 ± 5 cm are produced in a shorter time, thereby reducing costs and the cycle (SIMÕES et al, 2012).…”

“…In general, research involving the quality of forest seedlings has focused on improving the shortterm survival and the growth in the field (CORTINA et al, 2013). One of the important factors influencing survival and vegetative vigor in the field has been the height of seedlings at planting (VILLAR-SALVADOR et al, 2004;JACOBS et al, 2005;REIS et al, 2008). The ideal time for expedition of the seedlings depends directly on the target species and nursery management practices , ranging from 15 to 30 cm for Eucalyptus spp.…”

“…(GOMES et al, 1996). However, some authors have identified a higher survival in the field for seedlings with larger aerial parts (VILLAR-SALVADOR et al, 2004;JACOBS et al, 2005).…”