水稻赤枯病是常見的生理性病害,多在水稻分蘖期發生,造成秧苗出葉慢、根係生長不良等,引起僵苗。近幾年該病在淮安市發生麵積較大,嚴重影響水稻生產。現將其發生原因與防治對策介紹如下。
水(shui)稻(dao)發(fa)生(sheng)赤(chi)枯(ku)病(bing),葉(ye)片(pian)上(shang)出(chu)現(xian)大(da)小(xiao)不(bu)等(deng)的(de)赤(chi)褐(he)色(se)斑(ban)點(dian),嚴(yan)重(zhong)時(shi)聚(ju)合(he)成(cheng)斑(ban)塊(kuai)或(huo)條(tiao)狀(zhuang),斑(ban)點(dian)先(xian)從(cong)下(xia)部(bu)老(lao)葉(ye)尖(jian)端(duan)產(chan)生(sheng),然(ran)後(hou)向(xiang)下(xia)逐(zhu)漸(jian)變(bian)成(cheng)赤(chi)褐(he)色(se),最(zui)後(hou)全(quan)葉(ye)枯(ku)死(si),嚴(yan)重(zhong)的(de)全(quan)株(zhu)隻(zhi)有(you)少(shao)數(shu)新(xin)葉(ye)保(bao)持(chi)綠(lv)色(se),遠(yuan)看(kan)全(quan)田(tian)似(si)火(huo)燒(shao)狀(zhuang)。
水稻赤枯病發生的內因是稻株體內鉀含量不足,營養比例失調,秧苗素質差,外因有以下幾種。(1)土壤缺鉀。土壤本身有效鉀含量低,不能滿足水稻的生長需要。該類型多發生在沙土田、漏水田、hongrangshuitianhehuangrangshuitian。changzaishuidaozaichahouliangzhoukaishifabing,chuqidaozhuyeselvelv,yepianxiaerruan,jibuyepianziyejianyanyeyuanxiangxiazhujianbianhuangsehuohuanghese,houchuxiandianxingzhengzhuang,daogenduanerxi,chenghuanghesehuoanhese,genbiaopicengshuijinzhuangtouming,genmaoshaoqieyituoluo。(2)根係中毒。土壤中含有大量還原性化學物質,如二價鐵、硫化氫等,毒害稻根。多發生在深泥田、長期深灌和施用大量未腐熟有機肥的田塊。(3)diwen。yinchangqidiwenyinyuyingxiangshuidaofagenjixifeinenglierfabing。zaidiwentiaojianxia,zhizhushangbunenyebianchengdanhuangse,yepianshangchuxianhesezhenjianzhuangbingban,laoyechuchenghuanglvsehuodanhese,suihouchuxiandianxingzhengzhuang,daogenruanmian、彈性差、白根少而細。此外,秧苗栽插過深、偏施氮肥、稻田長期積水等,都會引發水稻赤枯病。
防治水稻赤枯病,應采取綜合措施,以預防為主,並根據不同誘因采取相應的補救措施。(1)jinggengxizuo。qianchashouhuohoujishigengfanshaifa,tigaoturangshuhuachengdu。tuzhichadeyaozhonghaolvfei,zengshiyoujifeihuotuzafei,cujinturangtuanlijiegouxingcheng,fahuiturangqianzaifeili。(2)合理施肥。多施腐熟有機肥,增施磷鉀肥。使用綠肥和秸稈還田的田塊,應在插秧前10天耕翻,每畝施50公斤石灰,促進綠肥和秸稈腐爛。(3)jiaqiangtianguan。duiquejiaturangbushijiafei,shidangshisuxiaodanfei。youjizhiguoduodefajiaotiankuai,yinglijipaishui。diwenyinyuqijianjishipaishui,huanguanwendujiaogaodeheshui。yijingfashengchikubingdetiankuai,yinglijipaigantianshuishaitian,gaishanturangtongtouxing,bingpenshi0.2%磷酸二氫鉀溶液。
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