Relación amonio / nitrato en la producción de hierbas aromáticas en hidroponía

the production of aromatic herbs could be a profitable alternative for greenhouse production. the objective of this research was to determine the effects of different nh4+ /no3- ratios on the growth and production of three aromatic herbs: chives (allium schoenoprasum), basil (ocimum basilicum l.) and dill (anethum graveolens l.). the experiment was conducted in the colegio de postgraduados at montecillo, estado de mexico, mexico, from january to may 2005, under greenhouse conditions. the herbs were cultivated in a hydroponic system with drip irrigation. a mixture of volcanic rock, locally called "tezontle" and coconut fiber (60:40) was used as substrate; the universal steiner's nutritive solution was modified to obtain four different nh4+/no3- ratios: 0/100, 20/80, 40/60 and 100/0. the studied parameters were: plant height, leaf area and total biomass. the 0/100-ratio significantly increased leaf area and total biomass production of chives. the greater height, leaf area and total biomass production of basil were observed with the 20/80 ratio. for dill, no significant differences were observed for the effects of the nh4+ /no3- ratios studied.