因配製苗床營養土過程中施化肥過多、fenfeiweifushuhuomiaochuangwenduguogaoerzhi。guayachutuqianfashengshaomiao,guayachengsuanbanzhuang,shangxiaoxiada,wuzhugenhuowugenmao,zhugenbiaomianchengxiuhuangse。guayachutuhoufashengshaomiao,ziyechengqueshuizhuang,xiaoqienonglv,youweinianhuoxinshengzhenyehuangbai,chenghuangxinmiao。fangzhimiaochuangshaomiaoshouxianyaokongzhimiaochuangshaoshihuaxuefeiliao,bushiweifushufenfei,zuihaoyong“康地蕾得”拌土,一般每平方苗床拌0.5-1.5千克。其次,在燒苗的苗床要勤澆水,嚴重時還要換土和遮蔭。
2、瓜苗生長點受阻
主要原因有:(1)肥fei害hai或huo藥yao害hai。剛gang出chu土tu的de瓜gua苗miao,生sheng長chang點dian較jiao幼you嫩nen,此ci時shi,如ru果guo葉ye麵mian噴pen藥yao或huo噴pen肥fei的de濃nong度du偏pian高gao或huo噴pen灑sa量liang過guo大da,極ji容rong易yi使shi生sheng長chang點dian造zao成cheng藥yao害hai而er停ting止zhi生sheng長chang。(2)低溫障礙和高溫障礙。幼苗遇到不良天氣時,造成苗床溫度過低,易受到凍害,生長點往往會被凍死而缺失;幼you苗miao遇yu到dao晴qing朗lang天tian氣qi時shi,午wu後hou太tai陽yang直zhi射she苗miao床chuang,使shi畦qi內nei溫wen度du過guo高gao,尤you其qi在zai苗miao床chuang濕shi度du較jiao小xiao的de情qing況kuang下xia,生sheng長chang點dian易yi灼zhuo燒shao,甚shen至zhi幼you嫩nen的de葉ye片pian易yi失shi水shui,幹gan裂lie,嚴yan重zhong時shi死si亡wang。特te別bie是shi靠kao近jin棚peng膜mo的de葉ye片pian,症zheng狀zhuang更geng為wei嚴yan重zhong,俗su稱cheng烤kao苗miao。防fang止zhi低di溫wen障zhang礙ai首shou先xian要yao提ti高gao苗miao床chuang土tu溫wen和he棚peng室shi溫wen度du;防止烤苗的措施主要是苗床要及時澆水保濕,在晴天的中午要及時通風,降低棚室和苗床溫度,白天保持25℃左右,夜間15-18℃,同tong時shi也ye要yao注zhu意yi避bi免mian幼you嫩nen的de小xiao苗miao突tu然ran見jian到dao強qiang烈lie的de光guang照zhao。造zao成cheng瓜gua苗miao生sheng長chang點dian受shou阻zu是shi屬shu生sheng理li性xing病bing害hai。除chu人ren工gong措cuo施shi防fang治zhi外wai,還hai應ying結jie合he化hua學xue藥yao劑ji防fang治zhi,發fa現xian症zheng狀zhuang初chu期qi,應ying及ji時shi噴pen灑sa“凱普克”300倍液,這樣能調節整棵瓜苗生理新陳代謝,有利於促進瓜苗細胞分裂和根係發育,提高了瓜苗生理活性,促進生長點正常發育。
3、徒長苗
也稱“高腳苗”,biaoxianxiapeizhouxichang,yebingchang,yepianxiao,yesedan,miaochangshixiruo。zhuyaoyuanyinshiyumiaoshimiaochuangbugantongfenghuotongfengbujishi,youqishizaiyoumiaotuxinqianbuzhuyitongfengjiangwen,miaochuanggaowengaoshisuozhi。yinci,zaimiaochuangguanliguochengzhong,tongfengjiangwen、降濕一定要及時。
4、苗床瓜苗易倒折
這主要是苗床猝倒病危害。主要原因苗床土溫低、濕度大,光照不足,陰雨、陰(yin)雪(xue),通(tong)風(feng)不(bu)良(liang)等(deng)不(bu)利(li)於(yu)瓜(gua)苗(miao)的(de)生(sheng)長(chang),而(er)利(li)於(yu)猝(cu)倒(dao)病(bing)菌(jun)的(de)生(sheng)長(chang)與(yu)繁(fan)殖(zhi)造(zao)成(cheng)的(de)。因(yin)此(ci),不(bu)能(neng)用(yong)冷(leng)水(shui)澆(jiao)潑(po)苗(miao)床(chuang),注(zhu)意(yi)提(ti)高(gao)土(tu)壤(rang)溫(wen)度(du),通(tong)風(feng)降(jiang)濕(shi),增(zeng)強(qiang)幼(you)苗(miao)的(de)抗(kang)病(bing)能(neng)力(li)是(shi)預(yu)防(fang)猝(cu)倒(dao)病(bing)發(fa)生(sheng)的(de)有(you)力(li)措(cuo)施(shi)。
還要結合化學藥劑防治,一旦有猝倒病發生,要立即用藥劑“百泰”1200倍液進行防治,阻止病害蔓延。
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