1. Allen , R.G. , Pereira , L.S. , Raes , D. Smith , M. 1998 . Crop evapotranspiration: guidelines for computing crop water requirements . FAO Irrigation & Drainage Paper No. 56, FAO, Rome, Italy .
2. Humic Acid Addition Enhances B and Pb Phytoextraction by Vetiver Grass (Vetiveria zizanioides (L.) Nash)
3. Anonymous 2005 . Agriculture Statistics . Prime Ministry, Republic of Turkey, Turkish Statistical Institute, Ankara, Turkey .
4. Anonymous 2006 . Agriculture Statistics Prime Ministry, Republic of Turkey, Turkish Statistical Institute Ankara, Turkey
5. AOAC (Association of Official Analytical Chemists) 2005 . Official Methods of Analysis , 18th edn. AOAC-Int., Arlington, Virginia, USA .