爛種原因：種(zhong)子質(zhi)量(liang)差或(huo)(huo)(huo)貯藏不(bu)當、貯藏期過長(chang)；地勢低(di)洼，土(tu)壤(rang)黏重，質(zhi)地差，土(tu)壤(rang)含水量(liang)高，種(zhong)子出苗(miao)(miao)(miao)(miao)時(shi)間長(chang)；整地不(bu)實，影(ying)響(xiang)種(zhong)子對(dui)水分的吸收(shou)，苗(miao)(miao)(miao)(miao)弱；種(zhong)子沒有(you)精(jing)選(xuan)，大小不(bu)勻，播種(zhong)不(bu)細或(huo)(huo)(huo)深淺不(bu)一，造(zao)(zao)成出苗(miao)(miao)(miao)(miao)不(bu)齊或(huo)(huo)(huo)缺(que)苗(miao)(miao)(miao)(miao)斷(duan)壟(long)；多年連作(zuo)不(bu)倒茬，苗(miao)(miao)(miao)(miao)期病(bing)害嚴重，造(zao)(zao)成缺(que)苗(miao)(miao)(miao)(miao)斷(duan)壟(long)；施(shi)用未充(chong)分腐熟的有(you)機肥或(huo)(huo)(huo)施(shi)肥濃度過高，造(zao)(zao)成肥害，影(ying)響(xiang)出苗(miao)(miao)(miao)(miao)；低(di)溫(wen)待續時(shi)間長(chang)，造(zao)(zao)成發芽(ya)出苗(miao)(miao)(miao)(miao)遲緩而爛種(zhong)。

預防措施：(一)精細選(xuan)種(zhong)(zhong)。選(xuan)用新花(hua)生種(zhong)(zhong)子，對留種(zhong)(zhong)花(hua)生適期收獲并(bing)及時曬(shai)種(zhong)(zhong)，做到科(ke)學貯藏。播(bo)種(zhong)(zhong)前帶皮曬(shai)種(zhong)(zhong)，加快(kuai)花(hua)生新陳代謝，增強種(zhong)(zhong)子滲(shen)透力，提高種(zhong)(zhong)子吸水能力。播(bo)前1～3天剝殼，選(xuan)粒大無損傷、胚(pei)根未(wei)萌動的種(zhong)(zhong)子播(bo)種(zhong)(zhong)。(二)藥劑(ji)拌種(zhong)(zhong)。用種(zhong)(zhong)子重(zhong)量0.1%的50%的甲基硫菌(jun)靈或50%的多菌(jun)靈可(ke)濕(shi)性(xing)粉劑(ji)拌種(zhong)(zhong)，預防苗期病害。也可(ke)拌入種(zhong)(zhong)子重(zhong)量0.2%的50%的辛硫磷乳油(you)防治地下害蟲(chong)及鳥(niao)害和鼠(shu)害。(三)精細播(bo)種(zhong)(zhong)。播(bo)種(zhong)(zhong)深度4～6厘(li)米(mi)，要避免種(zhong)(zhong)子與肥料(liao)接觸。采用地膜(mo)覆蓋栽培，地溫可(ke)提高2～3℃，播(bo)后種(zhong)(zhong)子發(fa)(fa)芽、出(chu)苗快(kuai)，可(ke)減輕發(fa)(fa)病。