Effect of different drip nitrogen fertilizer levels on tomato growth and water consumption

Afield experiment was conducted to study the effect of drip nitrogen fertigation on tomato growth, yield, evapotranspiration( ET) and water use efficiency (WUE) under polythene film mulched condition. Four different treatments of nitrogen fertilizer levels applied in the experiment were f1:17.5kg (.) ha(-1), f2:54. 8kg (.) ha(-1), f 3:105. 8kg (.) ha(-1) and f 4:202.4kg (.) ha(-1). The soil matric potential at 0.2 m depth under drip emitter was controlled immediately at-20 kPa for four treatments. Results indicated that tomato yields were almost same for all treatments. However, ET increased as fertilizer increased, reached a maximum value at f 2 level, and then decreased. The maximum ET was 307mm and the minimum was 277mm. The WUE had a contrary tendency with that for ET. Thus, nitrogen fertigation had no significant influences on tomato yield, maybe there were enough manure and ammonium di-hydrogen phosphate applied as base fertilizer