《 農民日(ri)報(bao) 》（ 2014年11月19日(ri)   06 版）

    隨著氣溫(wen)降(jiang)低，大棚也(ye)都(dou)已(yi)穿(chuan)上了“棉襖”。盡管(guan)菜(cai)農(nong)朋(peng)(peng)友(you)都(dou)知(zhi)道冬季大棚蔬菜(cai)的管(guan)理(li)是以溫(wen)度管(guan)理(li)為主線(xian)，卻有一些菜(cai)農(nong)朋(peng)(peng)友(you)常常顧(gu)此失彼，在細節上出現漏洞。特(te)別是一些新(xin)手，更容易出現紕漏。

    為(wei)提醒菜(cai)農(nong)(nong)，特別是(shi)那(nei)些剛開始(shi)種(zhong)棚(peng)的菜(cai)農(nong)(nong)，能(neng)夠(gou)及時查(cha)漏補(bu)缺，為(wei)低溫(wen)時期(qi)棚(peng)菜(cai)的生長創(chuang)造適宜的條件(jian)，筆者梳理了生產中常被忽視(shi)的一些細節(jie)，在此匯總(zong)如下，希望(wang)能(neng)對當前(qian)天氣(qi)下棚(peng)室(shi)蔬菜(cai)的健康生長有所(suo)幫助。

    放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)要(yao)分(fen)次(ci)(ci)(ci)放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)，放(fang)(fang)小(xiao)風(feng)(feng)(feng)(feng)(feng)(feng)現在(zai)晚上棚(peng)(peng)(peng)(peng)(peng)內(nei)(nei)(nei)溫(wen)度(du)(du)低、濕度(du)(du)大(da)，由此造(zao)成大(da)量的(de)霧氣在(zai)蔬菜(cai)的(de)葉片(pian)及果(guo)實表(biao)面凝結(jie)，出(chu)現結(jie)露(lu)現象。而菜(cai)農由于(yu)(yu)農活較忙，往往一(yi)(yi)(yi)次(ci)(ci)(ci)性(xing)將(jiang)(jiang)風(feng)(feng)(feng)(feng)(feng)(feng)口(kou)開到(dao)最大(da)。一(yi)(yi)(yi)次(ci)(ci)(ci)放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)過(guo)大(da)，冷空氣進(jin)(jin)入(ru)棚(peng)(peng)(peng)(peng)(peng)中，導致蔬菜(cai)葉片(pian)及果(guo)實溫(wen)度(du)(du)、濕度(du)(du)劇(ju)(ju)烈變化(hua)，就會(hui)造(zao)成果(guo)實表(biao)面起皴(cun)，嚴(yan)重的(de)會(hui)產(chan)生(sheng)大(da)量裂果(guo)，使蔬菜(cai)果(guo)實失去商品性(xing)，效益降(jiang)低。針對(dui)這種情況(kuang)，菜(cai)農應該(gai)循序(xu)漸(jian)進(jin)(jin)地放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)。在(zai)晴天剛拉開大(da)棚(peng)(peng)(peng)(peng)(peng)時，棚(peng)(peng)(peng)(peng)(peng)內(nei)(nei)(nei)空氣中的(de)二(er)氧(yang)化(hua)碳濃(nong)度(du)(du)最高，為(wei)保證(zheng)棚(peng)(peng)(peng)(peng)(peng)內(nei)(nei)(nei)蔬菜(cai)對(dui)二(er)氧(yang)化(hua)碳的(de)需求，不(bu)使二(er)氧(yang)化(hua)碳因放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)造(zao)成浪費，這時菜(cai)農不(bu)要(yao)急于(yu)(yu)放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)，而應在(zai)拉棚(peng)(peng)(peng)(peng)(peng)后(hou)1小(xiao)時再(zai)放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)。放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)時先開小(xiao)口(kou)，這時的(de)主要(yao)目的(de)是將(jiang)(jiang)棚(peng)(peng)(peng)(peng)(peng)內(nei)(nei)(nei)的(de)濕氣緩慢排出(chu)，防止果(guo)面的(de)露(lu)水急劇(ju)(ju)干燥(zao)，導致裂果(guo)。隨著棚(peng)(peng)(peng)(peng)(peng)內(nei)(nei)(nei)溫(wen)度(du)(du)的(de)升高，再(zai)逐漸(jian)將(jiang)(jiang)放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)口(kou)加大(da)，以利(li)于(yu)(yu)棚(peng)(peng)(peng)(peng)(peng)外二(er)氧(yang)化(hua)碳進(jin)(jin)入(ru)棚(peng)(peng)(peng)(peng)(peng)內(nei)(nei)(nei)，促進(jin)(jin)蔬菜(cai)的(de)光(guang)合(he)作用。到(dao)下午關(guan)風(feng)(feng)(feng)(feng)(feng)(feng)時也(ye)不(bu)要(yao)一(yi)(yi)(yi)次(ci)(ci)(ci)性(xing)將(jiang)(jiang)放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)口(kou)關(guan)閉(bi)，因為(wei)風(feng)(feng)(feng)(feng)(feng)(feng)口(kou)關(guan)閉(bi)后(hou)棚(peng)(peng)(peng)(peng)(peng)內(nei)(nei)(nei)的(de)溫(wen)度(du)(du)又會(hui)有(you)一(yi)(yi)(yi)個上升的(de)過(guo)程，這樣容易導致放(fang)(fang)棚(peng)(peng)(peng)(peng)(peng)后(hou)夜(ye)溫(wen)過(guo)高，加大(da)植株對(dui)葉片(pian)制造(zao)有(you)機(ji)物(wu)質的(de)呼吸消耗(hao)，菜(cai)農可以逐漸(jian)將(jiang)(jiang)風(feng)(feng)(feng)(feng)(feng)(feng)口(kou)關(guan)小(xiao)。先將(jiang)(jiang)風(feng)(feng)(feng)(feng)(feng)(feng)口(kou)關(guan)閉(bi)一(yi)(yi)(yi)半，半小(xiao)時到(dao)一(yi)(yi)(yi)個小(xiao)時后(hou)再(zai)完全(quan)關(guan)閉(bi)放(fang)(fang)風(feng)(feng)(feng)(feng)(feng)(feng)口(kou)；或者先將(jiang)(jiang)風(feng)(feng)(feng)(feng)(feng)(feng)口(kou)關(guan)閉(bi)，然后(hou)再(zai)將(jiang)(jiang)風(feng)(feng)(feng)(feng)(feng)(feng)口(kou)打開通風(feng)(feng)(feng)(feng)(feng)(feng)降(jiang)溫(wen)10~15分(fen)鐘(zhong)，如此兩次(ci)(ci)(ci)，當(dang)棚(peng)(peng)(peng)(peng)(peng)內(nei)(nei)(nei)溫(wen)度(du)(du)穩定在(zai)15℃左右(you)時即可將(jiang)(jiang)風(feng)(feng)(feng)(feng)(feng)(feng)口(kou)完全(quan)關(guan)閉(bi)。

    必須要增光(guang)(guang)(guang)進入冬季(ji)以(yi)后，大(da)風天(tian)氣漸多，致使(shi)棚(peng)(peng)(peng)膜(mo)上塵(chen)(chen)(chen)(chen)土增多。據研(yan)究，在(zai)覆(fu)新膜(mo)后5天(tian)，棚(peng)(peng)(peng)膜(mo)上落的(de)(de)(de)塵(chen)(chen)(chen)(chen)土可使(shi)薄(bo)膜(mo)透光(guang)(guang)(guang)率(lv)下降10%；在(zai)12天(tian)時(shi)(shi)，棚(peng)(peng)(peng)膜(mo)透光(guang)(guang)(guang)率(lv)下降幅度(du)可達20%。冬天(tian)我(wo)國北(bei)方(fang)的(de)(de)(de)光(guang)(guang)(guang)照(zhao)強(qiang)度(du)在(zai)4萬(wan)勒克(ke)(ke)斯(si)左(zuo)右(you)，如果(guo)塵(chen)(chen)(chen)(chen)土遮去20%，則進入棚(peng)(peng)(peng)中的(de)(de)(de)光(guang)(guang)(guang)照(zhao)強(qiang)度(du)通(tong)常(chang)只有3萬(wan)勒克(ke)(ke)斯(si)左(zuo)右(you)，陰天(tian)時(shi)(shi)數(shu)值更(geng)低(di)。而多數(shu)蔬菜所需飽和(he)光(guang)(guang)(guang)照(zhao)強(qiang)度(du)在(zai)4萬(wan)勒克(ke)(ke)斯(si)左(zuo)右(you)。光(guang)(guang)(guang)照(zhao)不(bu)足就(jiu)(jiu)成為影響蔬菜產量(liang)提高的(de)(de)(de)重要原(yuan)因，而除(chu)掉棚(peng)(peng)(peng)膜(mo)上的(de)(de)(de)塵(chen)(chen)(chen)(chen)土就(jiu)(jiu)顯得(de)尤為重要。因此，菜農(nong)可以(yi)通(tong)過(guo)設置除(chu)塵(chen)(chen)(chen)(chen)布條將(jiang)(jiang)棚(peng)(peng)(peng)膜(mo)上的(de)(de)(de)大(da)部分(fen)塵(chen)(chen)(chen)(chen)土除(chu)去，但由于布條南北(bei)兩端的(de)(de)(de)擺幅最(zui)小，除(chu)塵(chen)(chen)(chen)(chen)效果(guo)最(zui)差，菜農(nong)可使(shi)用(yong)(yong)抹(mo)布將(jiang)(jiang)前(qian)臉處及棚(peng)(peng)(peng)膜(mo)最(zui)北(bei)邊的(de)(de)(de)塵(chen)(chen)(chen)(chen)土抹(mo)去。多數(shu)菜農(nong)都知道在(zai)棚(peng)(peng)(peng)內設置反(fan)(fan)光(guang)(guang)(guang)幕可充(chong)分(fen)利用(yong)(yong)照(zhao)在(zai)棚(peng)(peng)(peng)墻上的(de)(de)(de)反(fan)(fan)光(guang)(guang)(guang)，以(yi)利于蔬菜的(de)(de)(de)生長(chang)。但是有的(de)(de)(de)大(da)棚(peng)(peng)(peng)里(li)反(fan)(fan)光(guang)(guang)(guang)幕掛(gua)得(de)太(tai)低(di)，蔬菜植(zhi)(zhi)株容易將(jiang)(jiang)光(guang)(guang)(guang)擋住，導(dao)致反(fan)(fan)光(guang)(guang)(guang)幕的(de)(de)(de)使(shi)用(yong)(yong)效果(guo)差。在(zai)張掛(gua)時(shi)(shi)，將(jiang)(jiang)寬1.0~1.2米(mi)的(de)(de)(de)反(fan)(fan)光(guang)(guang)(guang)幕掛(gua)在(zai)后墻1.7米(mi)高的(de)(de)(de)地方(fang)，這樣可以(yi)防止(zhi)蔬菜植(zhi)(zhi)株遮擋太(tai)陽(yang)射到反(fan)(fan)光(guang)(guang)(guang)膜(mo)上的(de)(de)(de)光(guang)(guang)(guang)，同(tong)時(shi)(shi)反(fan)(fan)射的(de)(de)(de)陽(yang)光(guang)(guang)(guang)又可照(zhao)到蔬菜上。菜農(nong)且不(bu)可將(jiang)(jiang)整個(ge)棚(peng)(peng)(peng)后墻懸掛(gua)反(fan)(fan)光(guang)(guang)(guang)幕，以(yi)防降低(di)后墻的(de)(de)(de)儲熱量(liang)。

    棚(peng)內(nei)(nei)(nei)懸掛(gua)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)計高(gao)(gao)濕(shi)(shi)(shi)(shi)(shi)是(shi)冬(dong)棚(peng)蔬菜生產中(zhong)的(de)(de)(de)一(yi)(yi)大(da)(da)弊端，因而(er)(er)控(kong)制(zhi)(zhi)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)是(shi)冬(dong)棚(peng)蔬菜管理的(de)(de)(de)重(zhong)點之(zhi)一(yi)(yi)。但如(ru)何進行控(kong)濕(shi)(shi)(shi)(shi)(shi)，將濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)控(kong)制(zhi)(zhi)在(zai)什么范圍內(nei)(nei)(nei)呢(ni)？現在(zai)，有(you)(you)不(bu)少菜農(nong)知(zhi)道(dao)，將棚(peng)內(nei)(nei)(nei)的(de)(de)(de)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)控(kong)制(zhi)(zhi)在(zai)70%~80%左(zuo)右是(shi)比較合適(shi)的(de)(de)(de)。但因為棚(peng)內(nei)(nei)(nei)沒有(you)(you)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)計，菜農(nong)不(bu)能準(zhun)確把握(wo)棚(peng)內(nei)(nei)(nei)的(de)(de)(de)空氣(qi)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)，而(er)(er)懸掛(gua)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)計就是(shi)一(yi)(yi)個很好(hao)(hao)的(de)(de)(de)解決方法，這(zhe)一(yi)(yi)點對(dui)于(yu)新種棚(peng)的(de)(de)(de)菜農(nong)來說尤為重(zhong)要，以便準(zhun)確了解棚(peng)內(nei)(nei)(nei)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)的(de)(de)(de)高(gao)(gao)低(di)，及時(shi)(shi)采(cai)取(qu)相應解決措施。例(li)如(ru)，冬(dong)季大(da)(da)棚(peng)危害(hai)(hai)最為嚴(yan)重(zhong)的(de)(de)(de)是(shi)灰霉(mei)病(bing)(bing)，而(er)(er)它在(zai)低(di)溫高(gao)(gao)濕(shi)(shi)(shi)(shi)(shi)下(xia)危害(hai)(hai)嚴(yan)重(zhong)，當(dang)棚(peng)內(nei)(nei)(nei)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)低(di)于(yu)95%時(shi)(shi)病(bing)(bing)原孢子就不(bu)能萌發，而(er)(er)霜霉(mei)病(bing)(bing)在(zai)18℃左(zuo)右時(shi)(shi)要求(qiu)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)高(gao)(gao)于(yu)83%才可(ke)(ke)大(da)(da)量發生。如(ru)果(guo)將棚(peng)內(nei)(nei)(nei)溫度(du)(du)(du)(du)(du)(du)控(kong)制(zhi)(zhi)在(zai)病(bing)(bing)菌發病(bing)(bing)所需的(de)(de)(de)適(shi)宜濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)之(zhi)下(xia)，就可(ke)(ke)很好(hao)(hao)地(di)控(kong)制(zhi)(zhi)病(bing)(bing)害(hai)(hai)的(de)(de)(de)發生。當(dang)棚(peng)內(nei)(nei)(nei)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)過大(da)(da)時(shi)(shi)，菜農(nong)除可(ke)(ke)通(tong)過放風(feng)降濕(shi)(shi)(shi)(shi)(shi)外(wai)，還可(ke)(ke)向地(di)面撒(sa)施草(cao)木灰也可(ke)(ke)起到良好(hao)(hao)的(de)(de)(de)吸濕(shi)(shi)(shi)(shi)(shi)作用，也可(ke)(ke)有(you)(you)效降低(di)棚(peng)內(nei)(nei)(nei)空氣(qi)濕(shi)(shi)(shi)(shi)(shi)度(du)(du)(du)(du)(du)(du)。      劉聰