Coconut coir as a sustainable nursery growing media for seedling production of the ecologically diverse quercus species

Peat, a non-sustainable resource, is still predominately used in forest nurseries. Coconut 19 coir may provide an alternative, renewable, and reliable growing media but few studies have 20 evaluated this media type in forest nurseries. We assessed the influence of pure coir in combination 21 with various fertilization regimes on the growth and physiology of three ecologically diverse 22 Quercus species seedlings (Q. robur, Q. pubescens, Q. ilex) during nursery cultivation. Seedlings were 23 grown using peat and pure coir in combination with 3 fertilization treatments (standard, K enriched 24 , P enriched ). Data were collected for: 1) growth and physiological traits; 2) detailed above- and 25 below-ground morphological traits by destructive analysis; and, 3) NPK content in leaves, shoot 26 and roots, and in growing media following cultivation. 27 Peat and coir in combination with the various fertilization treatments affected above- and below-28 ground morphology and, to a lesser extent, physiological traits of Quercus seedlings. Large effects 29 of substrate occurred for most morphological variables, with peat more effective than coir in all 30 studied species. Fertilization also produced significant differences. The effect of K-enriched 31 fertilization on plant growth was clear across the three species and the two growing media. P-32 enriched fertilization in peat was the only combination that promoted a higher amount of this 33 element in the tissues at the end of cultivation. 34 Despite the relatively smaller size, seedlings produced in coir were in compatible with standard 35 Quercus forest stocktypes size, and showed a proportionally higher root system development and 36 fibrosity. Our results suggest that coir can be used as an alternative substrate to grow Quercus 37 species seedlings, and that fertilization can offset coir deficiencies in chemical properties. Because 38 several functional traits drive planting performance under varying environmental conditions 39 according to the Target Plant Concept, coir may thus serve as an acceptable material for seedling 40 cultivation in some cases.