Effects of Nitrogen Application Rate on Tomato Growth and Nitrogen Use Efficiency

A field experiment was conducted to study the effects of nitrogen( N) application rate on tomato growth,yield,N uptake amount and N use efficiency. The results showed that the plant height of tomato increased with the increase of N application rate,when N application rate was 324 kg / ha,tomato showed overgrowth of leaves,but stem diameter of tomato had no significant difference under all treatment. Chlorophyll content of tomato leaves under the treatment with N was higher than that under the treatment without N,chlorophyll content was highest when N application rate was 162 kg / ha. Yield and N uptake amount of tomato increased with the increase of N application rate when N application rate was lower than 243 kg / ha,yet yield and N uptake amount of tomato decreased if N application rate further increased. With the increase of N application rate,partial factor productivity from applied N( PFPN) decreased,agronomic efficiency of applied N( AEN) and apparent recovery efficiency of applied N( REN) first increased and then decreased,reached the highest value when N application rate was 162 kg / ha. Therefore,through fully analyzing the effects of N application rate on tomato growth,yield,N uptake amount and N use efficiency,the reasonable N application rate should be controlled at 162—243 kg / ha.