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50年代和60年代,在用多芽种的情况下,于播种前施氮磷钾肥,因为用种量大,经间苗后可留出均匀植株,所以肥料对幼苗的毒性未加以注意;70年代后用单芽种,定距离点播,施肥严重影响,特别是用溶性高的氮、钾、钠是引起株数减少的主要原因。在播种单粒种和定距离点播,于播前1—2周前施肥,土壤易被压实,再整地则减少土壤水份,因此要在播种随播种机将氮肥施于种沟两侧。据试验指出,播前几天用125公斤N/公顷撒施则推迟出苗,而且播后干旱,则保苗减少。好的保苗应为70000株/公顷。因此要限制撒肥机破坏土
In the 1950s and 1960s, with the use of multi-buds, NPK fertilizers were not applied prior to sowing due to the large amount of seed used and uniform plants after the shoots, so the toxicity of the fertilizer to seedlings was neglected. In the 1970s After using a single species, from a fixed distance, fertilization seriously affected, especially the high solubility of nitrogen, potassium, sodium is caused by the main reason to reduce the number of plants. In the sowing of single species and on-demand distance, 1-2 days before sowing before fertilization, soil is easy to compaction, then soil preparation to reduce soil moisture, so in the sowing planter nitrogen fertilizers will be applied to both sides of the ditch. According to the tests, spraying with 125 kg N / ha for a few days before sowing delayed the emergence of seedlings, and the drought after sowing reduced the number of seedlings. Good sapling should be 70,000 / ha. Therefore, to limit soil manure spreading machine