Effects of Application of Nitrogen and Potassium Fertilizers on Available Nutrient,Water-soluble Salt in Soil and the Growth of Tomato

The effects of application of nitrogen and potassium fertilizers on available nutrients,water-soluble salt in soil and the growth of tomato were studied with an pot experimental method.The results showed that the contents of NO-3-N,available K,and water-soluble salt in soil were significantly increased as the increasing addition of N and K fertilizers.And there were significantly linear relationships between soil NO-3-N and rate of N fertilizer added,available K in soil and rate of K fertilizer added.Addition of N and K fertilizers at rate of 0.1 g/kg increased the contents of NO-3-N and available K in soil by 50.5 mg/kg and 79.5 mg/kg,respectively.The increase rate of water-soluble salt in soil by addition of N fertilizer was two times of that by K fertilizer.When the contents of water-soluble salt in soil were higher than 0.8 g/kg,it had negative effects on the flowering rate and growth of tomato;When it reached to 0.9 g/kg,it significantly inhibited the growth of tomato,and resulted in the relative accumulation of chlorophyll in tomato leaves.The contents of proline in leaves of tomato were also significantly increased as the accumulation of water-soluble salt in soil.Therefore,we need to pay attention to the hidden accumulation of water-soluble salts in soil under sunlight greenhouse.