Effect of fertilization on distribution of nitrate in cucumber and soil in sunlight greenhouse

A field experiment was conducted in sunlight greenhouse to study the effect of fertilization on NO2--N and NO3--N contents of cucumber, NO3--N content in soil, and cucumber yield. The result shown that, application of N 400kg/hm2 and P2O5 250 kg/hm2, the NO3--N content in 0-20 and 20-40 cm soil layers related with the growth and developing stage of cucumber during the cucumber growth period under condition of Huangmian soil on Loess Plateau. The NO3--N content was relatively higher before fruiting stage, however, the NO3---N content became lower with the cucumber growing developing and increased after harvest in 0-20 and 20-40cm soil layers. After harvest the cucumber, the NO3--N accumulation and leaching in 40-160cm soil profile was highest by using chemical fertilizer, lower by using methane and lowest by using manure. Foliage dressing by urea and organic K during cucumber growth period could reduce the rates of fertilizer and manure and decreased the NO3--N content in 0-200cm soil layer. The cucumber yield was higher by using methane and foliage spray of urea and organic K than that application of NP fertilizers and without fertilizers.