The present study was conducted during the two growing seasons 2002 and
2003 at EI-Nubaria Agric. Res. Station, Agric. Res. Center, Bihira Governorate, in
order to investigate the effect of two soil mixtures (clay + sand), two organic manures
(chicken + compost) and two biofertilizers (Azotobacter chroococcum + A. vinalendii)
on growth, yield, chemical composition and leaf mineral contents of Stevia rebaudiana
plant. Results showed that all growing media and biofertilizers enhanced the growth
and chemical composition (chlorophyll mg/g f.w., Carbohydrates %, Stevioside % and
leaf nutrients uptake). The medium containing clay + sand + chicken2 plus inoculation
with biofertilizer produced the tallest plants, increased the number of shoots and
leaves (number, area and fresh and dry weight). Also, the maximum content of total
chlorophyll, total carbohydrates, Stevioside, nitrogen, phosphorus and potassium
were highest from the plants cultivated in the same medium. In general, using chicken
manures gave results better than using compost manure. However, the medium of
clay + sand produced the shortest plants and other characters in both seasons. Based
on the obtained results, it is recommended to inoculate Stevia seedlings with the
biofertilizer and addition of organic manures to improve growth, yield and leaves
quality, as well as to reduce the amount of the mineral fertilizers.