EFFECTS OF AMMONIUM AND NITRATE RATIOS ON PLANT GROWTH, NITRATE CONCENTRATION AND NUTRIENT UPTAKE IN FLOWERING CHINESE CABBAGE

In order to clarify the effect of different nitrogen forms on growth, nitrate concentration and nutrient uptake of flowering Chinese cabbage, hydroponic experiment was conducted under four ammonium and nitrate ratios (0 : 100, 25 : 75, 50 : 50, 75 : 25) with three cultivars. The results indicated that, compared to complete nitrate treatment (CK) in nutrient solution, plant biomass of flowering Chinese cabbage was promoted in low ammonium enhancement (25%) (T1) treatment, while it was decreased in medium (50%) (T2) and high (75%) (T3) ammonium enhancement treatments. With the increase of ammonium ratio, nitrate concentration in leaf and flower stalk of flowering Chinese cabbage for 3 cultivars reduced gradually. Compared to CK, the accumulations of plant total nitrogen, phosphorus and potassium were increased significantly in T1 treatment, while it was decreased significantly in T3 treatment. Plant biomass and nutrient uptake were enhanced and nitrate concentration in product organs was reduced by 25% ammonium enhancement in nutrient solution, so it was appropriate in hydroponics for flowering Chinese cabbage.