【摘要】 春玉米施氮具有玉米本茬效应和较大的后茬效应。玉米孕穗期施氮能实现较大的边际利润（施氮效益）。基苗肥＋穗肥的两次施氮法既有利于缓解玉米前期共生阶段生长弱势的矛盾，又能充分发挥玉米孕穗期施氮具有的高额利润报酬率，实现全年多熟高产高效。春玉米的施氮应根据施氮的后效应和穗肥高利润特点，在两茬施氮边际利润大于零的前提下，首先实现春玉米高产。其施氮量应视土壤肥力水平保持在３３３８７ｋｇ／ｈａ上下，基苗肥和穗肥比例５∶５左右，其中，穗肥用量控制在２２５ｋｇ／ｈａ以下，适施时间为叶龄余数５３７叶。更多还原

【Abstract】 The effects of nitrogen application (NA) on mutiple intercropping of spring maize were studied on upland during 1990～1993 The results indicate that it is effective for maize and more effective for the late stubble when nitrogen is applied in spring maize The most marginal profit of NA (efficieny of fertilizer nitrogen) can be obtained at ear bearing stage of maize Twice application ways of fertilization for base-seedling and heading can not only morderate the contradition of weak growth at early growth maize under symbiotic conditions, but also bring high remuneration profit rates into full play To achieve high yield and profit in mutiple cropping of whole year, the principle of NA in spring maize should be based on the characteristics of late effect of NA and high profit of fertilization for heading And the marginal profit of NA for two stubbles should be more than zero as a prerequisite The total amount of NA should be kept at about 333 87kg/ha depending on soil fertility The proportion of fertilization for base-seedling to heading in maize is about 5 to 5, no more than 225 00kg/ha for heading The optimum time of NA for ear fertilizer should be at 5 37th leaf from top更多还原