Cedrela odorata L. PRODUCTION IN A RAW SAWDUST SUBSTRATE IN TECHNICIAN SYSTEM AT TECPAN DE GALEANA, GUERRERO, MEXICO

Nursery high quality plants production by using expensive commercial substrates (peat moss, perlite, vermiculite) decreases profits; this is the main reason to search alternative production substrates. Pine sawdust is a sub product of forestry industry cheap and available in forest areas. In recent years it has been used as a substrateproviding good results. In this study it was evaluated the effect of different sawdust mixtures on Cedrela odorata L. plant growth in a technician system in forest nursery under shade cloth covered. A completely randomized experimental design was used with eleven substrate components combinations (sawdust + peat moss-perlite-vermiculite mixtures) ranging from 0% to 100% each. After three and a half months morphological variables were measured so as some quality indexes in seedlings. The largest diameter was obtained by the mixture of 70% sawdust + 30% peat moss mix-vermiculite-perlite. The highest in height by using the mixture 80% sawdust + 20% peat moss - vermiculite – perlite mixture. The highest leaves dry weight corresponded to 90 % sawdust + 10% peat moss-vermiculite-perlite mixture. However the highest root weight and total dry weight values occurred in 60% sawdust + 40% peat moss – perlite - vermiculite mixture. As for the height-diameter ratio (slenderness index), the best value is obtained a mixture of 80% sawdust + 20% peat moss, perlite, vermiculite. According to Dickson Quality Index (DQI), used to predict the plant field surviving, the highest value was obtained for the 60% sawdust + 40% peat moss-perlite-vermiculite mixture.