Effects of Combinations of Nitrogen Fertilizer and Temperature on the Early Growth of Alfalfa (Medicago sativa L.) under Short-day Conditions

Abstract

I investigated the effects of nitrogen fertilizer and temperature on the early growth of alfalfa under short-day conditions using ^<15>N. The dry weight, total nitrogen content, and ^<15>N content in the NH_4 plot were higher than those in the NO_3 plot both at 20/15 and 30/250℃. The relative specific activity (RSA) of ^<15>N in the roots at both temperatures was higher in the NH_4 plot than in the NO_3 plot. These results suggest that the variation in the growth may be attributable to the differences in the uptake of nitrogen fertilizer.