Journal of Agriculture & Life Sciences

Effects of Chemical Form and Nitrogen Concentration of Fertilizer and Water Culture Medium pH on Growth and Root System Development of Alfalfa (Medicago sativa L.)
Daisuke Hirose

Abstract
Effects of differences in nitrogen concentration and water culture medium pH on growth and root system development of alfalfa grown in plots fertilized with ammonium nitrogen or nitrate nitrogen were investigated. Differences in dry weight, total root length, and mean lateral root length were observed between ammonium and nitrate plots at nitrogen concentrations of 20 and 30 ppm and pH 6.5. However, no difference was observed when the pH was shifted in the acid or alkaline direction. Differences in the number of roots between ammonium and nitrate plots were only observed at a nitrogen concentration of 20 ppm and pH 6.5. Moreover, no significant difference was observed when the pH was shifted in the acid or alkaline direction. These results indicated that the high growth-promoting effect of ammonium nitrogen and nitrate nitrogen on growth and root system development observed at nitrogen concentrations of 20 and 30 ppm and pH 6.5 are lost when the medium pH is shifted in either the acid or alkaline direction.

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