前言在油菜栽培上施用氮肥已为—般人所重视,但磷、钾肥的作用则未予以足够的注意,而不少试验证明氮、磷、钾的营养作用是相互联系的,如William F.等用玉米试验证明供氮水平提高就使其对磷的吸收有更大的需要,用南瓜试验证明:缺钾 Preface The nitrogenous fertilizer application in rapeseed cultivation has been paid much attention by the people. However, the effects of phosphorus and potassium fertilizer have not been paid sufficient attention. However, many experiments have proved that the nutrition functions of nitrogen, phosphorus and potassium are interrelated. Such as corn proved to increase the level of nitrogen to make it more necessary for the absorption of phosphorus, pumpkin test proved: potassium deficiency