什么是水培蔬菜
水培指植物(wu)大(da)部分根系直接生長在營養液(ye)液(ye)層中(zhong)的無土栽培方式(Water Culture, Solution Culture)。主要有:營養液(ye)模技術(NFT,Nutrient Film Technique),植物被(bei)種植與1-2cm厚的不停(ting)地(di)循環流(liu)動的淺(qian)層營養液(ye)層上;深液(ye)流(liu)技術(shu)(DFT, Deep Flow Technique),營養液層深度最少4-5cm,最深(shen)8-10cm,有時甚至(zhi)更深,營(ying)養液按設定頻率循環流動;浮板水培技術(FCH,Floating Capillary Hydroponics),在較深(5-6cm)的營養液液層中放(fang)置一塊上鋪無紡布的泡沫塑料,根系(xi)生長(chang)在濕潤的無紡布上。
水培蔬菜的特點
1、根(gen)系以乳(ru)白色毛細根(gen)為主,用以吸收水(shui)分和營養;
2、根系適(shi)應水生環(huan)境(jing),外圍有(you)部分(fen)氣(qi)生根,用以吸收氧氣(qi);
3、生長周期短,上市早。
水培蔬菜生產管理
以管道式水培(pei)蔬菜生產設備為(wei)例。生產管理主(zhu)要(yao)是對營養(yang)液(ye)(ye)(ye)供(gong)(gong)(gong)(gong)液(ye)(ye)(ye)時(shi)間(jian)(jian)(jian)和供(gong)(gong)(gong)(gong)液(ye)(ye)(ye)次數(shu)的調節(jie)。營養(yang)液(ye)(ye)(ye)的供(gong)(gong)(gong)(gong)液(ye)(ye)(ye)時(shi)間(jian)(jian)(jian)和供(gong)(gong)(gong)(gong)液(ye)(ye)(ye)次數(shu)主(zhu)要(yao)依據栽培(pei)形式、蔬菜生長(chang)狀態(tai)、環境條件而定(ding)。在栽培(pei)過程中(zhong)應適時(shi)供(gong)(gong)(gong)(gong)液(ye)(ye)(ye),保(bao)證充(chong)足的養(yang)分供(gong)(gong)(gong)(gong)應。供(gong)(gong)(gong)(gong)液(ye)(ye)(ye)時(shi)間(jian)(jian)(jian)一(yi)般選擇在白天,夜間(jian)(jian)(jian)不供(gong)(gong)(gong)(gong)液(ye)(ye)(ye)或少供(gong)(gong)(gong)(gong)液(ye)(ye)(ye)。晴天供(gong)(gong)(gong)(gong)液(ye)(ye)(ye)次數(shu)多些(xie),陰雨天少供(gong)(gong)(gong)(gong)液(ye)(ye)(ye);氣溫(wen)高光照強時(shi)多些(xie),反之(zhi)少些(xie)。通常情況下(xia),每天供(gong)(gong)(gong)(gong)液(ye)(ye)(ye)2-4次,每(mei)次把握在30分鐘即可。這一點(dian)可以用(yong)時(shi)間(jian)控制器進行(xing)適時(shi)調節。
營(ying)養(yang)(yang)液使用一段時間后應適(shi)時更(geng)換。因為營(ying)養(yang)(yang)液在使用過(guo)程(cheng)中(zhong)會逐漸積累過(guo)多的(de)有(you)礙(ai)于植物生(sheng)長的(de)物質,營(ying)養(yang)(yang)不均衡(heng),病菌大量繁殖,致(zhi)使根系(xi)生(sheng)長受(shou)阻(zu),甚至導(dao)致(zhi)植株(zhu)死亡。一般(ban)對生(sheng)長周期(qi)較短(duan)的(de)蔬菜來說(shuo),每(mei)茬更(geng)換一次營(ying)養(yang)(yang)液。果菜類,每(mei)1-2個(ge)月更換一次營(ying)養(yang)液。
水培蔬菜到底安全嗎
1、水培營養液是根據蔬菜自然生長狀態下對養分的需求規律,利用一些化學肥料進行精確配制而成的,它與土壤里的有效養分的組成沒有任何本質的區別,土壤中大多數的養分也必須經過微生物的轉化或其他化學轉化的過程形成離子的形態才能被蔬菜吸收的。
觀點:水(shui)(shui)培蔬菜到(dao)底安不安全(quan)?水(shui)(shui)培蔬菜前景又如何(he)?
2、人工配制的營(ying)養(yang)液(ye)更符合蔬(shu)(shu)菜生(sheng)長(chang)(chang)的養(yang)分(fen)需(xu)求,能(neng)(neng)更精確、更合理(li)、更有(you)效地為蔬(shu)(shu)菜的生(sheng)長(chang)(chang)提供養(yang)分(fen)。不管是(shi)土壤(rang)種植(zhi)的還是(shi)水培的,蔬(shu)(shu)菜都(dou)是(shi)吸(xi)收(shou)同樣的化(hua)學離(li)子作為養(yang)分(fen),即使是(shi)有(you)機肥(fei)也是(shi)要轉化(hua)成離(li)子形態才(cai)能(neng)(neng)被蔬(shu)(shu)菜吸(xi)收(shou)的。
3、水培(pei)蔬(shu)菜(cai)(cai)沒有農(nong)藥污(wu)染(ran)和土(tu)壤(rang)中重金屬污(wu)染(ran)的(de)問題,可以說,水培(pei)更(geng)加容易實現蔬(shu)菜(cai)(cai)生產的(de)無公(gong)害化,產品更(geng)加安全。
觀點:水培蔬(shu)菜(cai)到(dao)底安不安全?水培蔬(shu)菜(cai)前景又(you)如何(he)?
4、有些不明科學道理(li)者對水培蔬(shu)菜食用(yong)安(an)全性的(de)擔(dan)心(xin)來(lai)源于對蔬(shu)菜中硝(xiao)酸鹽(yan)和亞(ya)硝(xiao)酸鹽(yan)含量(liang)過高的(de)擔(dan)心(xin)。實際上,蔬(shu)菜中對人體有害的(de)是亞(ya)硝(xiao)酸鹽(yan)而不是硝(xiao)酸鹽(yan)。
5、蔬菜中(zhong)的(de)(de)(de)(de)硝(xiao)(xiao)(xiao)酸(suan)(suan)鹽(yan)(yan)和亞(ya)硝(xiao)(xiao)(xiao)酸(suan)(suan)鹽(yan)(yan)含量受很(hen)多(duo)因素的(de)(de)(de)(de)影響(xiang),在(zai)(zai)自然界中(zhong),硝(xiao)(xiao)(xiao)酸(suan)(suan)鹽(yan)(yan)必須在(zai)(zai)還原的(de)(de)(de)(de)條件(jian)下才能通(tong)過微生物作(zuo)用形成亞(ya)硝(xiao)(xiao)(xiao)酸(suan)(suan)鹽(yan)(yan),由(you)于水培的(de)(de)(de)(de)營(ying)養液(ye)是(shi)不(bu)斷循環流動(dong)的(de)(de)(de)(de),因此,營(ying)養液(ye)中(zhong)的(de)(de)(de)(de)溶解氧含量始終處(chu)于一個較高的(de)(de)(de)(de)水平,也就是(shi)說營(ying)養液(ye)中(zhong)的(de)(de)(de)(de)氧化還原電位較高,根本不(bu)存在(zai)(zai)把硝(xiao)(xiao)(xiao)酸(suan)(suan)鹽(yan)(yan)還原為(wei)亞(ya)硝(xiao)(xiao)(xiao)酸(suan)(suan)鹽(yan)(yan)的(de)(de)(de)(de)途徑(jing),最終的(de)(de)(de)(de)結果(guo)就是(shi)水培蔬菜的(de)(de)(de)(de)亞(ya)硝(xiao)(xiao)(xiao)酸(suan)(suan)鹽(yan)(yan)含量極低。