Effects of nitrogen fertilizer rates on growth and photosynthesis of cucumber in cassava compound substrate

Experiments were conducted to study the effects of different amounts of nitrogen fertilizer rates( 0 g、1 g、4 g、15 g、25 and 50 g per bucket) on vegetative growth and photosynthesis on cucumber Lufeng cultivated in mixed substrate of cassava residue. The results showed: In the stage of vegetative growth,with the nitrogen fertilizer rates increase,the plant height,stem diameter and leaf area all tend to increase first and the decrease later; in the later stage of vegetative growth,the plants planted with the nitrogen fertilizer rates of 5 g and 15 g per bucket perform best; The Chl contents and net photosynthetic rate of cucumber leaves is increased as the nitrogen fertilizer rates increase. The total Chl contents is the highest with the nitrogen fertilizer rate of 15 g per bucket. The total net photosynthetic rate is the highest with the nitrogen fertilizer rate of 25 g per bucket.