Herbs

Herbs because of their much nutritional value in many countries have important role in family daily food basket. They also have different kinds of vitamins, minerals and cellulose materials that play very important role in human health (Peyvast, 2009). Greenhouse production industry and plants production in hydroponic systems has grown a lot in recent years. This production method can provides high-quality products in every year and free from pesticides and herbicide residual usage for farmers and growers (Mairapetyan, 1999; Dorais, et al. 2001). Root environment in hydroponics systems always has enough water, air and food. This system increases the absorption and roots metabolic activities that lead to high growth rate of plants (Mairapetyan. 1999; Dorais et al. 2001; Manukyan, et al. 2004). In order to provide appropriate levels of nutrient elements for plants accurate nutritional programs must be used (Iersel and Kang, 2002). Different concentrations of nutrient solution have been published on the basis of fertilizer recommendations and select on the basis of experience, plant species and cultivars, growth stage and plant breeding system (Schwarz, et al. 2002).

Effect of different concentrations of nutrient solution was examined on growth, yield and quality of basil and stated that the best growth and most yield of basil obtained with standard solution or half the concentration of standard solution (Suh, et al. 1999). Affect of different concentrations of nutrient solution on salvia plants expressing that nutrient solution concentration has a significant effect on plant root and shoot dry weight. (Kang and Iersel, 2004). Udagawa (1995) compare different concentrations of nutrient solution on dill a...

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... Iersel, (2004) and Udagawa (1995) in similar experiments stated that concentration of nutrient solution have significantly effect on root, shoot of dill and thyme dry weight. Such results don’t observe in our study on basil plants.

Conclusion

Herbs like cress and basil no need much concentration of nutrient solution and moderate amount of all elements is more benefit for them. Cress and basil response differently to ammonium concentration in nutrient solution. Ammonium has a positive effect on Cress while basil shows negative response to ammonium in this reason nutrient solution with low ammonium concentration was proposed for basil production in nutrient film technique. In other hand nutrient solution containing suitable concentration of ammonium proposed for cress production. However the suitable concentration of this ion must be tested in next experiments.