Abstract: Solution culture was used to study the effect of different combination between ammonium and bicarbonate coexisted in the mediumon growth , nutritional element uptake by different kidney organs kidney beans. The
obtained results showed that : ①supplying nitrate nitrogen as main N source , the growth status was the best ; supplying ammonium nitrogen as main N source without bicarbonate in the nutrient solution , the roots of kidney beans were harmed during the early growth period , and the wilting phenomena of leaves took place. In nutrient solution having ammonium as main N source with addition of bicarbonate , the growth status became increasingly better with the increase of bicarbonate concentration. This showed bicarbonate and ammonium coexisting in a moderate proportion could be against the inhibition to beans growth. ②Under the same reatment , the sequence of uptake amounts of several nutrient elements by whole plants of beans were : N > K> P >Mg > Fe >Mn ; When the ammonium nitrogen as main N source in the nutrient solution , with increasing bicarbonate concentration in nutrient solution , the N , P , Ca , and Mg uptake amounts were also increased. ③Mainly supplying NO_3^--N in the solution favored for the accumulation of P , Fe , and Mn in the root parts , and mainly supplying NH₄⁺-N, with increasing bicarbonate concentration in the nutrient solution , the accumulation of N , P , Ca , Mn in the roots took place.

Key words: Hydroponics experiments, Bicarbonate, Ammonium stress, Ion antagonism, Kidney beans