冬dong小xiao麥mai苗miao期qi和he返fan青qing期qi發fa生sheng的de凍dong害hai對dui產chan量liang影ying響xiang極ji大da。這zhe兩liang個ge時shi期qi的de凍dong害hai近jin年nian來lai在zai辛xin集ji等deng地di的de小xiao麥mai生sheng產chan中zhong時shi常chang發fa生sheng,給gei農nong民min造zao成cheng較jiao大da經jing濟ji損sun失shi。小麥發生凍害的主要原因有以下幾點:
1.氣候原因。全球氣候變暖,小麥播種後至越冬前氣溫比過去偏高,導致部分小麥生長過快,抗寒性減弱,造成小麥凍害。
2.整地質量差。近幾年小麥整地播種方式一般是采用犁地、旋耕、播(bo)種(zhong)或(huo)者(zhe)直(zhi)接(jie)用(yong)旋(xuan)耕(geng)機(ji)旋(xuan)耕(geng)兩(liang)遍(bian),就(jiu)直(zhi)接(jie)播(bo)種(zhong)。這(zhe)種(zhong)整(zheng)地(di)方(fang)式(shi)造(zao)成(cheng)土(tu)壤(rang)過(guo)於(yu)疏(shu)鬆(song),土(tu)壤(rang)中(zhong)水(shui)分(fen)散(san)失(shi)嚴(yan)重(zhong),土(tu)壤(rang)熱(re)容(rong)量(liang)小(xiao),進(jin)入(ru)冬(dong)季(ji)後(hou),造(zao)成(cheng)小(xiao)麥(mai)地(di)上(shang)部(bu)葉(ye)片(pian)及(ji)根(gen)部(bu)凍(dong)害(hai),這(zhe)是(shi)造(zao)成(cheng)小(xiao)麥(mai)大(da)麵(mian)積(ji)凍(dong)害(hai)的(de)主(zhu)要(yao)原(yuan)因(yin)。
3.播(bo)期(qi)不(bu)當(dang)。近(jin)幾(ji)年(nian)農(nong)村(cun)勞(lao)動(dong)力(li)大(da)量(liang)外(wai)出(chu)務(wu)工(gong),秋(qiu)作(zuo)物(wu)收(shou)獲(huo)後(hou)農(nong)民(min)不(bu)分(fen)小(xiao)麥(mai)品(pin)種(zhong)的(de)特(te)性(xing),搶(qiang)時(shi)播(bo)種(zhong),把(ba)部(bu)分(fen)需(xu)要(yao)晚(wan)播(bo)品(pin)種(zhong)提(ti)前(qian)播(bo)種(zhong),造(zao)成(cheng)小(xiao)麥(mai)年(nian)前(qian)出(chu)現(xian)瘋(feng)長(chang)、旺長現象,抗寒性降低,造成大麵積凍害。
4.氮dan肥fei使shi用yong量liang過guo大da。氮dan肥fei是shi小xiao麥mai生sheng長chang必bi不bu可ke少shao的de肥fei料liao,但dan使shi用yong過guo多duo且qie一yi次ci性xing作zuo基ji肥fei施shi入ru易yi引yin起qi幼you苗miao旺wang長chang,葉ye片pian細xi嫩nen,分fen蘖nie節jie無wu法fa儲chu藏zang足zu夠gou的de糖tang分fen,越yue冬dong易yi受shou凍dong害hai。
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