化肥汙染 蔬菜長期施用化肥的蔬菜,特別是氮肥過量所生產的“氮肥蔬菜”,其qi莖jing葉ye等deng可ke食shi部bu分fen,均jun被bei硝xiao酸suan鹽yan嚴yan重zhong汙wu染ran,會hui使shi蔬shu菜cai中zhong的de硝xiao酸suan鹽yan含han量liang成cheng倍bei增zeng加jia,硝xiao酸suan鹽yan在zai人ren體ti中zhong容rong易yi被bei還hai原yuan為wei亞ya硝xiao酸suan鹽yan,亞ya硝xiao酸suan鹽yan是shi一yi種zhong劇ju毒du物wu質zhi,它ta能neng引yin起qi人ren體ti細xi胞bao缺que氧yang。長chang期qi食shi用yong這zhe種zhong蔬shu菜cai,會hui造zao成cheng兒er童tong智zhi力li下xia降jiang,並bing能neng誘you發fa癌ai症zheng,危wei害hai極ji大da。因yin此ci,在zai一yi些xie發fa達da國guo家jia現xian已yi明ming文wen規gui定ding,氮dan肥fei蔬shu菜cai禁jin止zhi上shang市shi,以yi切qie實shi保bao證zheng消xiao費fei者zhe的de利li益yi。
蔬菜難以保存 全quan靠kao化hua肥fei生sheng產chan出chu來lai的de鮮xian嫩nen蔬shu菜cai,看kan起qi來lai莖jing嫩nen葉ye肥fei,不bu知zhi情qing者zhe以yi為wei質zhi量liang上shang乘cheng,其qi實shi這zhe種zhong蔬shu菜cai硝xiao酸suan鹽yan含han量liang超chao標biao,在zai堆dui放fang儲chu存cun過guo程cheng中zhong也ye容rong易yi發fa黴mei變bian質zhi,使shi有you毒du物wu質zhi的de含han量liang增zeng加jia。據ju測ce定ding,在zai冬dong春chun貯zhu藏zang過guo程cheng中zhong,施shi用yong過guo氮dan肥fei的de白bai菜cai比bi施shi農nong家jia肥fei的de白bai菜cai腐fu爛lan損sun壞huai率lv高gao20%以上,硝酸鹽含量也成倍增加。
土壤結構遭到破壞 蔬菜土壤長期施用硫酸銨、硫(liu)酸(suan)鉀(jia)以(yi)及(ji)含(han)氮(dan)的(de)化(hua)肥(fei),會(hui)破(po)壞(huai)土(tu)壤(rang)結(jie)構(gou),使(shi)土(tu)壤(rang)板(ban)結(jie),失(shi)去(qu)柔(rou)性(xing)和(he)彈(dan)性(xing),降(jiang)低(di)通(tong)水(shui)透(tou)氣(qi)性(xing)能(neng)。長(chang)期(qi)施(shi)用(yong)化(hua)肥(fei),土(tu)壤(rang)膠(jiao)體(ti)上(shang)的(de)鈣(gai)離(li)子(zi)不(bu)斷(duan)被(bei)交(jiao)換(huan)出(chu)來(lai),在(zai)雨(yu)水(shui)和(he)灌(guan)溉(gai)水(shui)的(de)淋(lin)洗(xi)下(xia),硫(liu)酸(suan)銨(an)、lvhuagaibeilinxidaoturangxiaceng,zaochenggengzuocengquegai,pohuaiturangjiegou,shiturangbiandebanjie,feilixiajiang,shucaichangshicha,jiangdichanliang。yinweilianghaodeturangjiegou,chuhanyoudaliangyoujizhiwai,yibandoufuhangaiyuansu,quegaideturangjiegouzaihao,yeshibugudingde,yizaodaopohuai,zhiyouhanyouyidinggaizhideturang,qigaizhishuiwenxingtuanlijiegou,caishizuilixiangdeturang,nengshengchanchugaochanzhiyoudeshucai。
造成土壤的酸化 危害硫酸銨、氯化銨、氯化鉀、過guo磷lin酸suan鈣gai等deng酸suan性xing化hua肥fei在zai連lian年nian大da量liang施shi用yong蔬shu菜cai地di後hou,會hui使shi土tu壤rang中zhong殘can留liu大da量liang的de酸suan類lei物wu質zhi,使shi中zhong性xing土tu壤rang變bian酸suan,酸suan性xing土tu壤rang更geng加jia酸suan化hua,既ji破po壞huai了le土tu壤rang微wei生sheng物wu區qu係xi,又you不bu利li於yu大da多duo數shu蔬shu菜cai的de正zheng常chang生sheng長chang。長chang期qi施shi用yong化hua肥fei,尤you其qi是shi連lian年nian多duo次ci施shi用yong硫liu酸suan銨an、硫酸鉀、氯lv化hua鉀jia等deng,隻zhi能neng增zeng加jia土tu壤rang中zhong的de硫liu酸suan根gen離li子zi和he氯lv離li子zi的de含han量liang,而er這zhe兩liang種zhong離li子zi對dui土tu壤rang來lai說shuo都dou是shi有you害hai的de離li子zi,不bu但dan有you害hai於yu蔬shu菜cai生sheng長chang,還hai會hui使shi土tu壤rang產chan生sheng次ci生sheng鹽yan漬zi化hua,破po壞huai土tu壤rang的de結jie構gou,影ying響xiang蔬shu菜cai對dui其qi他ta營ying養yang元yuan素su的de吸xi收shou。蔬shu菜cai地di長chang期qi過guo量liang施shi用yong化hua肥fei,不bu僅jin會hui對dui蔬shu菜cai造zao成cheng危wei害hai,還hai會hui妨fang礙ai蔬shu菜cai對dui其qi他ta營ying養yang元yuan素su的de吸xi收shou,引yin起qi缺que素su症zheng。例li如ru,過guo量liang施shi用yong含han氮dan化hua肥fei會hui引yin起qi蔬shu菜cai的de缺que鈣gai症zheng;硝態氮過多會引起缺鉬;鉀過多會降低鈣、鎂、硼的有效性;磷過多會降低鈣、鋅、硼的有效性等。
因此,蔬菜地應最大限度地施用有機肥或其他非化學氮肥,替代化學氮肥,在不影響蔬菜正常生長發育的前提下,盡量以圈肥、雞糞等有機肥和各種餅肥,如棉籽餅、菜籽餅、豆餅、生物菌肥等非化學類肥料,代替化學氮肥,以防止蔬菜汙染,減少化學肥料的殘留和對土壤造成的汙染和破壞作用。
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