1.植株本身的原因。由於植株短期內大量花芽分化，各花序之間
、植株與花序之間、同tong一yi花hua序xu各ge朵duo花hua之zhi間jian存cun在zai著zhe爭zheng奪duo養yang分fen的de情qing況kuang，養yang分fen供gong應ying比bi較jiao好hao的de部bu位wei的de花hua較jiao少shao落luo花hua落luo莢jia。一yi般ban植zhi株zhu中zhong部bu營ying養yang好hao，落luo莢jia少shao。此ci外wai

，肥fei水shui調tiao節jie不bu當dang
，莖jing葉ye徒tu長chang
，營ying養yang生sheng長chang過guo旺wang或huo缺que肥fei少shao水shui，同tong化hua作zuo用yong弱ruo也ye易yi引yin起qi落luo花hua落luo莢jia。枝zhi葉ye生sheng長chang繁fan茂mao，密mi度du過guo大da，互hu相xiang遮zhe蔭yin或huo光guang照zhao不bu足zu也ye會hui引yin起qi落luo花hua落luo莢jia。

2.不良氣候條件的影響。春芸豆早期花芽分化時因溫  dudi，huawangwangfayubuliang，zaochengluohua。kaihuaqiyudiwenhuogaowenganhanhuogaowenduoyuyehuizaochengluohualuojia。yibanqingkuangxia，qianqiluohuazhuyaoshidiwenyingxianghuayafayu
，yingxiangshoufenshoujing（在低於15℃的溫度條件下不能正常授粉受精）。此ci外wai
，開kai花hua前qian期qi落luo花hua的de另ling一yi個ge原yuan因yin是shi植zhi株zhu存cun在zai著zhe營ying養yang生sheng長chang和he生sheng殖zhi生sheng長chang爭zheng奪duo養yang分fen的de矛mao盾dun。中zhong期qi落luo花hua的de原yuan因yin主zhu要yao是shi因yin為wei植zhi株zhu立li體ti結jie果guo造zao成cheng生sheng殖zhi生sheng長chang爭zheng奪duo養yang分fen的de矛mao盾dun。因yin此ci
，此ci期qi應ying大da肥fei大da水shui促cu進jin花hua果guo的de發fa育yu。後hou期qi落luo花hua的de原yuan因yin主zhu要yao是shi高gao溫wen多duo濕shi或huo高gao溫wen幹gan燥zao，影ying響xiang授shou粉fen及ji花hua粉fen的de萌meng發fa
，造zao成cheng落luo花hua落luo莢jia。

二、預防和控製措施 ①選擇適宜品種。應選用適應性強、坐莢率高的豐產優質的芸豆品種。②加(jia)強(qiang)肥(fei)水(shui)管(guan)理(li)。應(ying)在(zai)播(bo)種(zhong)前(qian)施(shi)足(zu)底(di)肥(fei)，合(he)理(li)密(mi)植(zhi)，使(shi)植(zhi)株(zhu)間(jian)有(you)良(liang)好(hao)的(de)通(tong)風(feng)透(tou)光(guang)條(tiao)件(jian)。苗(miao)期(qi)和(he)開(kai)花(hua)期(qi)以(yi)中(zhong)耕(geng)保(bao)墒(shang)為(wei)主(zhu)，促(cu)使(shi)植(zhi)株(zhu)根(gen)係(xi)健(jian)壯(zhuang)生(sheng)長(chang)發(fa)育(yu)。進(jin)入(ru)結(jie)莢(jia)盛(sheng)期(qi)應(ying)加(jia)強(qiang)肥(fei)水(shui)管(guan)理(li)，增(zeng)施(shi)磷(lin)鉀(jia)肥(fei)。③施用生長調節劑。花期噴施5~25×10-6的萘乙酸或30×10-6的番茄靈，可有效地防止落花落莢。