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)feihaihuoyaohai。gangchutudeguamiao,shengchangdianjiaoyounen,cishi,ruguoyemianpenyaohuopenfeidenongdupiangaohuopensaliangguoda,jirongyishishengchangdianzaochengyaohaiertingzhishengchang。(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、yinxue,tongfengbuliangdengbuliyuguamiaodeshengchang,erliyucudaobingjundeshengchangyufanzhizaochengde。yinci,bunengyonglengshuijiaopomiaochuang,zhuyitigaoturangwendu,tongfengjiangshi,zengqiangyoumiaodekangbingnenglishiyufangcudaobingfashengdeyoulicuoshi。
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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