Field and pot experiments were carried out to study nitrate accumulation in leafy vegetables.N application rates at 0,90,180,270kg N/hm 2 were used in the field experiments with Chinese cabbage(\%Brassica Chinensis var. Oleifera Makino et Nenoto),green cabbage(\%Brassica Chinensis \%L.),spinach(\%Spinacia oleracea\% L.)and repe(\%Brassica campestris\% L.)as vegetables,and winter wheat(\%Triticusp aestvum\% L.)as a comparison crop.and they were planted on a vegetable field.The N rates of 0,0.20,0.40,0....