Research Journal of Biological Sciences
Year:
2012
Volume:
7
Issue:
5
Page No.
200 - 203
References
Mengel, K. and E.A. Kirkby, 1987. Principles of Plant Nutrition. 4th Edn., International Potash Institute, Berne, Switzerland.
Siavosh, S., R.J. Manuel and G.M. Elena, 2008. Impact of farming systems on the physical, chemical and biological soil features in the Andes of Colombia. Center for Research in Sustainable Agricultural Production Systems (CIPAV). Carrera 2 West #11-54 Cali, Colombia.