chanliangzengjia,xujialiangtigao。suizheyumichanliangshuipingdetigao,zaiguanjianshengyuqiyaoqiuturangyouxiaojiadegongyingxiangyingzengjia。xuduoyumichangqidingweishiyandejieguozhengming,dangchanliangzengjia10%~20%時,吸鉀量也出現了相應增加。適當提高玉米組織的含鉀量才能保持穩定的高產。北方春播玉米區盡管土壤速效鉀含量處於較高水平(如 70~130毫克/公斤),施用鉀肥仍有增產效果。特別是一些速效鉀含量中等、緩(huan)效(xiao)鉀(jia)的(de)容(rong)量(liang)也(ye)不(bu)大(da)的(de)土(tu)壤(rang),就(jiu)要(yao)考(kao)慮(lv)高(gao)產(chan)田(tian)增(zeng)施(shi)鉀(jia)肥(fei)。因(yin)此(ci)在(zai)以(yi)產(chan)量(liang)目(mu)標(biao)作(zuo)為(wei)推(tui)薦(jian)施(shi)鉀(jia)的(de)主(zhu)要(yao)依(yi)據(ju)時(shi),既(ji)要(yao)注(zhu)意(yi)對(dui)有(you)效(xiao)鉀(jia)含(han)量(liang)較(jiao)低(di)的(de)土(tu)壤(rang)增(zeng)施(shi)鉀(jia)肥(fei)是(shi)保(bao)證(zheng)高(gao)產(chan)的(de)必(bi)要(yao)措(cuo)施(shi),還(hai)要(yao)注(zhu)意(yi)一(yi)些(xie)土(tu)壤(rang)有(you)效(xiao)鉀(jia)水(shui)平(ping)即(ji)使(shi)中(zhong)等(deng)時(shi),增(zeng)施(shi)適(shi)量(liang)鉀(jia)肥(fei)也(ye)有(you)良(liang)好(hao)的(de)效(xiao)果(guo)。
種(zhong)植(zhi)密(mi)度(du)增(zeng)加(jia),需(xu)鉀(jia)量(liang)提(ti)高(gao)。當(dang)前(qian)雜(za)交(jiao)玉(yu)米(mi)高(gao)產(chan)栽(zai)培(pei)中(zhong)常(chang)常(chang)通(tong)過(guo)增(zeng)加(jia)密(mi)度(du)而(er)使(shi)產(chan)量(liang)得(de)到(dao)大(da)幅(fu)度(du)提(ti)高(gao),與(yu)此(ci)同(tong)時(shi)高(gao)密(mi)度(du)植(zhi)株(zhu)對(dui)農(nong)田(tian)的(de)吸(xi)鉀(jia)量(liang)也(ye)明(ming)顯(xian)提(ti)高(gao)。所(suo)以(yi)在(zai)密(mi)度(du)增(zeng)加(jia)時(shi),如(ru)不(bu)相(xiang)應(ying)增(zeng)施(shi)鉀(jia)肥(fei)或(huo)提(ti)高(gao)土(tu)壤(rang)鉀(jia)的(de)有(you)效(xiao)性(xing),則(ze)作(zuo)物(wu)因(yin)吸(xi)鉀(jia)難(nan)以(yi)保(bao)證(zheng),產(chan)量(liang)可(ke)能(neng)下(xia)降(jiang)或(huo)達(da)不(bu)到(dao)理(li)想(xiang)水(shui)平(ping)。但(dan)是(shi)增(zeng)施(shi)鉀(jia)肥(fei)5~6公斤/畝(mu)後(hou),產(chan)量(liang)不(bu)降(jiang)反(fan)而(er)有(you)所(suo)提(ti)高(gao)。尤(you)其(qi)在(zai)有(you)效(xiao)鉀(jia)含(han)量(liang)不(bu)高(gao)並(bing)有(you)灌(guan)溉(gai)條(tiao)件(jian)的(de)玉(yu)米(mi)地(di)塊(kuai)。所(suo)以(yi)在(zai)對(dui)玉(yu)米(mi)推(tui)薦(jian)施(shi)肥(fei)時(shi),為(wei)了(le)適(shi)應(ying)較(jiao)高(gao)的(de)密(mi)度(du)和(he)產(chan)量(liang)水(shui)平(ping),施(shi)鉀(jia)量(liang)要(yao)比(bi)常(chang)規(gui)量(liang)適(shi)當(dang)提(ti)高(gao)。
氮(dan)鉀(jia)平(ping)衡(heng),需(xu)鉀(jia)量(liang)提(ti)高(gao)。密(mi)植(zhi)高(gao)產(chan)玉(yu)米(mi)栽(zai)培(pei)中(zhong),協(xie)調(tiao)鉀(jia)肥(fei)和(he)氮(dan)肥(fei)的(de)平(ping)衡(heng)供(gong)應(ying)很(hen)關(guan)鍵(jian)。通(tong)常(chang)情(qing)況(kuang)下(xia),為(wei)了(le)實(shi)現(xian)高(gao)產(chan)目(mu)標(biao)而(er)偏(pian)多(duo)施(shi)氮(dan),由(you)此(ci)加(jia)重(zhong)了(le)植(zhi)株(zhu)病(bing)蟲(chong)害(hai)如(ru)莖(jing)腐(fu)、根腐、青枯病等的感染率。如果不相應增加鉀肥供應,會形成氮鉀失調的症狀。缺鉀首先減弱了玉米莖、葉ye的de抗kang折zhe強qiang度du和he表biao皮pi厚hou度du,既ji加jia重zhong了le倒dao伏fu的de可ke能neng性xing,又you提ti高gao了le玉yu米mi對dui蟲chong害hai和he病bing害hai的de敏min感gan性xing。眾zhong所suo周zhou知zhi,在zai營ying養yang元yuan素su中zhong氮dan和he鉀jia對dui玉yu米mi抗kang病bing性xing的de影ying響xiang都dou大da,但dan二er者zhe的de作zuo用yong方fang向xiang不bu同tong,氮dan偏pian多duo往wang往wang會hui增zeng加jia玉yu米mi對dui病bing害hai的de敏min感gan性xing,而er鉀jia的de作zuo用yong則ze相xiang反fan,可ke以yi增zeng加jia作zuo物wu的de抗kang病bing性xing。
那麼,怎樣診斷田間缺鉀呢?缺鉀應怎樣補鉀呢?
dangchunyumijinrubajiejieduan,congxiaolabakoudaodalabakoudeshengyushiqishitakuaisushengchangshiqi,duidanlinjiayaosudexuqiudouyousuozengchang。tongchangzaishijishengchanzhongxiguanyuzhizhuishidanfeierbuzhuyizhuishijiafei,danshizaichunyumigaochanmizhizaipeizhong,daodixubuxuyaozhuifei,zhiyaowenyiwentianjianshengchangdeyumi,guanchazhizhushengchangzhuangkuang,jiukenengdedaohuida。najiushijingchangzaishangwujiushidiandeshihoupaodaoyumidikan,youqiguafengdetianqigengyaokan,ruguokandaochunyumideyepianzaishangwujiudanianle,natajiushigaosuni“我缺鉀了”。因(yin)為(wei)對(dui)於(yu)一(yi)般(ban)不(bu)急(ji)需(xu)灌(guan)溉(gai)的(de)農(nong)田(tian),正(zheng)常(chang)健(jian)壯(zhuang)的(de)玉(yu)米(mi)植(zhi)株(zhu),上(shang)午(wu)不(bu)會(hui)出(chu)現(xian)葉(ye)片(pian)打(da)蔫(nian)現(xian)象(xiang)的(de),到(dao)中(zhong)午(wu)後(hou)出(chu)現(xian)打(da)蔫(nian)現(xian)象(xiang)才(cai)是(shi)正(zheng)常(chang)的(de)。因(yin)為(wei)鉀(jia)可(ke)以(yi)影(ying)響(xiang)葉(ye)片(pian)氣(qi)孔(kong)的(de)關(guan)閉(bi)和(he)增(zeng)加(jia)植(zhi)株(zhu)保(bao)水(shui)功(gong)能(neng)。缺(que)鉀(jia)時(shi)氣(qi)孔(kong)阻(zu)力(li)大(da),不(bu)能(neng)正(zheng)常(chang)關(guan)閉(bi),導(dao)致(zhi)玉(yu)米(mi)體(ti)內(nei)水(shui)分(fen)損(sun)失(shi)嚴(yan)重(zhong)而(er)出(chu)現(xian)打(da)蔫(nian)現(xian)象(xiang)。這(zhe)時(shi)必(bi)須(xu)追(zhui)施(shi)鉀(jia)肥(fei)加(jia)以(yi)補(bu)救(jiu)。最(zui)可(ke)行(xing)的(de)措(cuo)施(shi)就(jiu)是(shi)追(zhui)施(shi)氯(lv)化(hua)鉀(jia)5~8公斤,溝施或穴施後,複土即可。
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