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”,qijingyedengkeshibufen,junbeixiaosuanyanyanzhongwuran,huishishucaizhongdexiaosuanyanhanliangchengbeizengjia,xiaosuanyanzairentizhongrongyibeihaiyuanweiyaxiaosuanyan,yaxiaosuanyanshiyizhongjuduwuzhi,tanengyinqirentixibaoqueyang。changqishiyongzhezhongshucai,huizaochengertongzhilixiajiang,bingnengyoufaaizheng,weihaijida。yinci,zaiyixiefadaguojiaxianyimingwenguiding,danfeishucaijinzhishangshi,yiqieshibaozhengxiaofeizhedeliyi。
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、氯(lv)化(hua)鈣(gai)被(bei)淋(lin)洗(xi)到(dao)土(tu)壤(rang)下(xia)層(ceng),造(zao)成(cheng)耕(geng)作(zuo)層(ceng)缺(que)鈣(gai),破(po)壞(huai)土(tu)壤(rang)結(jie)構(gou),使(shi)土(tu)壤(rang)變(bian)得(de)板(ban)結(jie),肥(fei)力(li)下(xia)降(jiang),蔬(shu)菜(cai)長(chang)勢(shi)差(cha),降(jiang)低(di)產(chan)量(liang)。因(yin)為(wei)良(liang)好(hao)的(de)土(tu)壤(rang)結(jie)構(gou),除(chu)含(han)有(you)大(da)量(liang)有(you)機(ji)質(zhi)外(wai),一(yi)般(ban)都(dou)富(fu)含(han)鈣(gai)元(yuan)素(su),缺(que)鈣(gai)的(de)土(tu)壤(rang)結(jie)構(gou)再(zai)好(hao),也(ye)是(shi)不(bu)固(gu)定(ding)的(de),易(yi)遭(zao)到(dao)破(po)壞(huai),隻(zhi)有(you)含(han)有(you)一(yi)定(ding)鈣(gai)質(zhi)的(de)土(tu)壤(rang),其(qi)鈣(gai)質(zhi)水(shui)穩(wen)性(xing)團(tuan)粒(li)結(jie)構(gou),才(cai)是(shi)最(zui)理(li)想(xiang)的(de)土(tu)壤(rang),能(neng)生(sheng)產(chan)出(chu)高(gao)產(chan)質(zhi)優(you)的(de)蔬(shu)菜(cai)。
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、lvhuajiadeng,zhinengzengjiaturangzhongdeliusuangenlizihelvlizidehanliang,erzheliangzhongliziduituranglaishuodoushiyouhaidelizi,budanyouhaiyushucaishengchang,haihuishiturangchanshengcishengyanzihua,pohuaiturangdejiegou,yingxiangshucaiduiqitayingyangyuansudexishou。shucaidichangqiguoliangshiyonghuafei,bujinhuiduishucaizaochengweihai,haihuifangaishucaiduiqitayingyangyuansudexishou,yinqiquesuzheng。liru,guoliangshiyonghandanhuafeihuiyinqishucaidequegaizheng;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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