Effects of different nitrogen fertilization patterns on the quality of the lettuce and soil environment

The effects on nourishment and safe quality of the lettuce and soil environment in the greenhouse with the different nitrogen fertilization patterns were studied, the results indicate that the base fertilizer should be put the important place in planting lettuce, the vegetable can be harvested safely after applying fertilizer two weeks. Early application of the nitrogen fertilizer is beneficial to the quality of the lettuce and also avoid the nitrate and nitrite accumulation, excessive top dressing in the anaphase is disadvantageous to quality of the vegetable, also threatens vegetable and soil safety, so the top dressing is not proper to apply in the anaphase of vegetable.