EFFECTS OF DRIP IRRIGATION AND BIOORGANIC FERTILIZER APPLICATION ON PLANT GROWTH AND SOIL IMPROVEMENT

Greenhouse soil salinization has received extensive attention, due to its serious impact on agricultural environment and crop production. A study regarding the effect of drip irrigation and bioorganic fertilizer application on the greenhouse soil and tomato crop was carried out from May to October in south China. The experiment included three irrigation quotas of 15, 18 and 21 mm, and three bioorganic fertilizer application amounts of 2800, 3600 and 4400 kg/ha. A conventional treatment (abbreviated as CK), applied with inorganic fertilizer (180 kg/ha N, 90 kg/ha P2O5, 54 kg/ha K2O) and drip irrigation (18 mm), was adopted for comparison. The tomato yield, the fruit quality indicators, as well as the soil physicochemical properties were observed. Results showed that, irrigation quota of 18 mm combined with bioorganicfertilizer application amount of 4400 kg/ha resulted in the highest tomato yield (132,6 t/ha) among the treatments, and increased it by 24.6% compared to yield of CK. Both irrigation and fertilization had extremely significant (p<0.01) effect on the tomato yield and the contents of soluble solid, total acid and vitamin C in tomato fruit. The salt decrease rate in plough layer was significantly (p<0.05) affected by irrigation or/and fertilization. The treatment, combined with 21 mm irrigation quota and 3600 kg/ha fertilizer application amount, had a significantly (p<0.05) higher salt decrease rate (22.4%), relative to the other treatments. With regards to soil properties, irrigation had significant (p<0.05) effect on the soil indicators including soil bulk density, total porosity, organic matter and field capacity, and fertilization had significant (p<0.01) effect on organic matter content and field capacity. Overall, the treatments reduced the soil bulk density by 2,9-12.8%, and increased the soil total porosity, organic matter content and field capacity by 2.9-10.3%, 0.4-18.9% and 3.3-17.3%, respectively, relative to CK.