麵對連續種植了15niandeyidachaxihongshi,nanwoshicunrenxuanzelezhongzhierchaxihongshihuoyichaxihongshijiayichatianjiaolaidikangzhongchazhangai。danshi,youyuduizhongchazhangaiderenshibuzu,zhongchawentirengnanyichedijiejue,yinci:
15nianxihongshidezhongzhi,nanwoshicunrenyirenshidaolezhongchadeweihai,zhidaolunzuoshijiejuezhongchadefangfa。danxihongshihetianjiaotongshuqieke,zhezhongyichagaierchadezhongzhifangfasuinenggaishanbufenzhongchazhangai,danbunengchedijiejue。erzaishixingyinianerchazhongzhidejichushang,zhuzhongturangdegailiangcaishijiejuezhongchazhangaidezuiyouxiaofangfa。
重茬障礙主要表現在土壤中,歸納起來有以下五點:
一yi是shi營ying養yang不bu足zu。多duo年nian連lian續xu種zhong植zhi同tong一yi作zuo物wu,由you於yu作zuo物wu都dou有you自zi己ji偏pian喜xi的de營ying養yang元yuan素su,對dui此ci元yuan素su連lian年nian消xiao耗hao後hou,如ru果guo不bu注zhu意yi補bu充chong該gai元yuan素su,就jiu容rong易yi造zao成cheng缺que素su症zheng。
二(er)是(shi)土(tu)壤(rang)結(jie)構(gou)及(ji)酸(suan)堿(jian)度(du)發(fa)生(sheng)變(bian)化(hua)。長(chang)期(qi)連(lian)作(zuo)土(tu)壤(rang)腐(fu)殖(zhi)質(zhi)降(jiang)低(di),團(tuan)粒(li)結(jie)構(gou)易(yi)遭(zao)破(po)壞(huai),土(tu)壤(rang)中(zhong)的(de)微(wei)生(sheng)物(wu)群(qun)體(ti)發(fa)生(sheng)改(gai)變(bian)可(ke)能(neng)導(dao)致(zhi)土(tu)壤(rang)酸(suan)堿(jian)度(du)變(bian)化(hua)。
三是病蟲害基數加大。特別是土傳病害及地下害蟲由於多年連作而隨之積累,容易引起某些病蟲害的突發性暴發。
四si是shi鹽yan類lei積ji累lei。由you於yu長chang期qi連lian作zuo及ji不bu恰qia當dang的de施shi肥fei,易yi造zao成cheng土tu壤rang養yang分fen流liu失shi或huo鹽yan分fen積ji累lei。尤you其qi是shi過guo度du施shi用yong化hua學xue肥fei料liao及ji以yi化hua肥fei代dai替ti有you機ji肥fei的de錯cuo誤wu施shi肥fei方fang法fa,造zao成cheng鹽yan分fen積ji累lei,嚴yan重zhong的de可ke形xing成cheng鹽yan堿jian地di。
五(wu)是(shi)自(zi)毒(du)作(zuo)用(yong)增(zeng)加(jia)。在(zai)正(zheng)常(chang)生(sheng)長(chang)條(tiao)件(jian)下(xia)作(zuo)物(wu)根(gen)係(xi)自(zi)身(shen)分(fen)泌(mi)有(you)毒(du)物(wu)質(zhi)同(tong)時(shi)土(tu)壤(rang)中(zhong)的(de)微(wei)生(sheng)物(wu)釋(shi)放(fang)出(chu)有(you)害(hai)物(wu)質(zhi),經(jing)多(duo)年(nian)連(lian)作(zuo)重(zhong)茬(cha),當(dang)土(tu)壤(rang)有(you)害(hai)物(wu)質(zhi)達(da)到(dao)某(mou)一(yi)臨(lin)界(jie)濃(nong)度(du)後(hou),就(jiu)會(hui)引(yin)起(qi)毒(du)害(hai)作(zuo)用(yong)。
解決重茬問題,也要從土壤做起、從根本做起。
一是重施有機肥且要充分腐熟。有機肥可以改良土壤;可以長期供足蔬菜所需養分;可以增進土壤肥力避免土壤疲勞;可ke以yi培pei養yang有you益yi微wei生sheng物wu,提ti高gao蔬shu菜cai抗kang病bing性xing能neng。同tong時shi結jie合he夏xia季ji高gao溫wen悶men棚peng,這zhe樣yang不bu僅jin促cu進jin有you機ji肥fei的de充chong分fen腐fu熟shu,而er且qie殺sha滅mie土tu壤rang和he有you機ji肥fei中zhong的de很hen多duo病bing原yuan菌jun,改gai良liang了le土tu壤rang。種zhong植zhi西xi紅hong柿shi和he甜tian椒jiao,一yi般ban每mei年nian施shi用yong雞ji糞fen等deng有you機ji肥fei的de量liang應ying為wei10-15立方米/畝。夏季高溫悶棚要選擇一段晴好天氣,采用幹濕結合的悶棚方式。把棚室各處密閉,不澆水幹悶棚7-10天,再澆水一次濕悶,這需要20-30天的時間才能充分腐熟有機肥,達到高溫悶棚的效果。
二是穴施或溝施生物菌肥,如落地生根抗死棵和激抗菌-968壯苗棵不死等,給作物根係創造一個有益菌群占優勢的良好土壤環境,減少病原菌對根係的侵染,降解土壤鹽害。
三san是shi注zhu意yi微wei量liang元yuan素su的de補bu充chong。連lian作zuo易yi造zao成cheng土tu壤rang中zhong微wei量liang元yuan素su的de偏pian耗hao,因yin此ci在zai施shi肥fei時shi,除chu應ying按an照zhao作zuo物wu需xu肥fei規gui律lv施shi用yong氮dan磷lin鉀jia複fu合he肥fei外wai,還hai要yao注zhu意yi補bu充chong微wei量liang元yuan素su,畢bi竟jing“最小養分律”告訴我們蔬菜產量不是隨著某種超量使用的營養元素提高,而是隨著相對而言含量低的“最小養分”變化,所以應首先把缺乏的微量元素補上。這樣施肥更明確,更有針對性,是避免重茬障礙,提高蔬菜產量的理想方法。
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