1.生長減慢,植株較弱
genxixishoushuifenheyangfenxuyaonengliang,turangshuifenguoduoshigenxizhouweiqueyang,zhinengjinxingwuyanghuxi,nengliangzhuanhuanxiaolvjiangdi,bunengtigongzugoudenenglianggonggeigenxixishoushuifeidexuyao。yinci,yumishoulaoshigenxixishoudeshuifenhenshao,zaiqingtianzhongwuqianhou,yepianfashengweinian,guanghezuoyongjianruo,zhizaodeyoujiwuzhijianshao。lingyifangmian,genxixishoudeyingyangwuzhiyeyinnenglianggongyingbuzuerdadajianshao。zhejiushiyumideshengchangqueshaobiyaodewuzhijichu,biaoxianweishengchanghuanman,zhizhuruanruo。
2.葉片發黃,莖稈變紅
玉(yu)米(mi)的(de)氮(dan)素(su)營(ying)養(yang)主(zhu)要(yao)來(lai)源(yuan)於(yu)溶(rong)解(jie)在(zai)水(shui)中(zhong)的(de)硝(xiao)態(tai)氮(dan)和(he)銨(an)態(tai)氮(dan)及(ji)有(you)機(ji)質(zhi)中(zhong)的(de)有(you)機(ji)氮(dan)。當(dang)受(shou)澇(lao)時(shi),前(qian)者(zhe)一(yi)部(bu)分(fen)被(bei)流(liu)失(shi),另(ling)一(yi)部(bu)分(fen)會(hui)經(jing)反(fan)硝(xiao)化(hua)作(zuo)用(yong)而(er)還(hai)原(yuan)為(wei)氣(qi)態(tai)氮(dan)而(er)跑(pao)到(dao)大(da)氣(qi)中(zhong)去(qu)。另(ling)一(yi)方(fang)麵(mian),由(you)於(yu)缺(que)乏(fa)氧(yang)氣(qi),土(tu)壤(rang)中(zhong)好(hao)氣(qi)性(xing)微(wei)生(sheng)物(wu)無(wu)法(fa)分(fen)解(jie)有(you)機(ji)物(wu)質(zhi),所(suo)以(yi)有(you)機(ji)質(zhi)中(zhong)的(de)氮(dan)素(su)也(ye)就(jiu)不(bu)能(neng)轉(zhuan)化(hua)為(wei)根(gen)係(xi)可(ke)吸(xi)收(shou)的(de)速(su)效(xiao)氮(dan)。由(you)於(yu)這(zhe)兩(liang)方(fang)麵(mian)的(de)原(yuan)因(yin),受(shou)澇(lao)地(di)塊(kuai)土(tu)壤(rang)中(zhong)速(su)效(xiao)氮(dan)含(han)量(liang)很(hen)低(di),玉(yu)米(mi)由(you)於(yu)吸(xi)收(shou)不(bu)到(dao)足(zu)夠(gou)的(de)氮(dan)素(su),葉(ye)片(pian)變(bian)黃(huang)。為(wei)了(le)增(zeng)強(qiang)對(dui)這(zhe)種(zhong)不(bu)利(li)環(huan)境(jing)的(de)抵(di)抗(kang)能(neng)力(li),莖(jing)稈(gan)中(zhong)的(de)葉(ye)綠(lv)素(su)轉(zhuan)變(bian)成(cheng)花(hua)青(qing)素(su),呈(cheng)現(xian)紫(zi)紅(hong)色(se)。
3.根係發黑、腐爛
在(zai)受(shou)澇(lao)土(tu)壤(rang)中(zhong),由(you)於(yu)缺(que)乏(fa)氧(yang)氣(qi),嫌(xian)氣(qi)性(xing)微(wei)生(sheng)物(wu)活(huo)動(dong)加(jia)強(qiang),有(you)機(ji)質(zhi)發(fa)酵(jiao)分(fen)解(jie),大(da)量(liang)積(ji)累(lei)二(er)氧(yang)化(hua)碳(tan),會(hui)使(shi)根(gen)係(xi)細(xi)胞(bao)受(shou)害(hai)。同(tong)時(shi)土(tu)壤(rang)氧(yang)化(hua)還(hai)原(yuan)電(dian)勢(shi)下(xia)降(jiang),有(you)害(hai)的(de)還(hai)原(yuan)物(wu)質(zhi)硫(liu)化(hua)氫(qing)、氧化亞鐵等大量出現,都會使根係受害。受害比較輕的表現為部分根係變黑,重的全部變黑、黴爛,以至整個植株死亡。
澇害常與寡照同時發生,低溫、寡照與澇害相結合,對玉米危害比較重,並且常常誘發病害蔓延,使玉米減產。
農田積水,但天氣晴朗,太陽輻射強烈,溫度劇烈上升時,蒸騰加強,葉片很快發生萎蔫;土壤中嫌氣性微生物活動加劇,根係受害加重,所以高溫強光的澇害對玉米的危害比較嚴重。
不bu同tong品pin種zhong和he不bu同tong生sheng育yu階jie段duan抗kang澇lao能neng力li不bu同tong。苗miao期qi抗kang澇lao能neng力li弱ruo,廣guang東dong春chun種zhong玉yu米mi是shi春chun季ji播bo種zhong,苗miao期qi正zheng值zhi陰yin雨yu連lian綿mian季ji節jie和he夏xia種zhong玉yu米mi苗miao期qi常chang遭zao遇yu持chi續xu大da雨yu至zhi暴bao雨yu,故gu常chang常chang發fa生sheng澇lao害hai和he濕shi害hai。據ju研yan究jiu,七qi葉ye前qian土tu壤rang含han水shui量liang達da到dao田tian間jian持chi水shui量liang的de90%(相當於壤質土的土壤濕度23%)時shi,玉yu米mi開kai始shi受shou害hai。土tu壤rang水shui分fen處chu於yu飽bao和he狀zhuang態tai時shi,玉yu米mi根gen係xi受shou到dao嚴yan重zhong損sun傷shang,生sheng長chang停ting止zhi。土tu壤rang積ji水shui,根gen係xi腐fu爛lan,地di上shang部bu變bian紅hong,下xia部bu葉ye片pian枯ku死si,時shi間jian過guo長chang則ze全quan株zhu死si亡wang。拔ba節jie後hou抗kang澇lao能neng力li逐zhu漸jian增zeng強qiang。抽chou雄xiong前qian後hou抗kang澇lao能neng力li進jin一yi步bu增zeng強qiang,這zhe時shi近jin地di麵mian的de莖jing節jie上shang長chang出chu幾ji層ceng氣qi生sheng根gen,有you很hen好hao的de抗kang澇lao作zuo用yong。據ju有you關guan部bu門men試shi驗yan,抽chou雄xiong前qian淹yan水shui三san天tian,氣qi生sheng根gen很hen快kuai噴pen出chu,平ping均jun每mei株zhu氣qi生sheng根gen增zeng加jia27.5m,植株基本無受澇症狀。成熟期根係衰老,抗澇能力降低。
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