【作者】 管大海；

【导师】 李召虎； 张明才；

【作者基本信息】 中国农业大学 ， 作物栽培学与耕作学， 2014， 博士

【摘要】 水资源是限制华北平原农业可持续发展的主要因素,提高水资源利用效率是该地区农业发展急需解决的问题。水分利用效率(WUE)与作物根系生长和分布关系密切。本研究通过根钻、根箱和原位扫描的方法,研究不同水分条件和耕作方式下冬小麦、夏玉米根系生长和分布,探讨了根系和水分利用、物质积累及产量的内在关系,并阐明了化控措施对根系生长和水分利用的调控机制。主要结果如下：1.研究了雨养条件下(W0)不同耕作方式对冬小麦根系生长和水分利用的影响。翻耕(PT)促进了冬小麦花期前根系发生和生长,提高了产量和WUE。与免耕(NT)相比,PT促进了花前根系生长和群体建成,提高了穗数和产量,其中2011-2012年和2012-2013年冬小麦产量分别提高10.6%和5.2%。耕作方式影响了各生育时期耗水量,但总耗水量没有显著差异,且PT的WUE最高,比NT下两小麦季的WUE分别高14.9%和7.3%。2.拔节一水(W1)结合NT处理提高了冬小麦产量和WUE。W1+NT处理下,冬小麦群体建成和根系分布较为合理,在灌浆期光合同化能力及光合同化物对产量的贡献率较高。和其他处理组合相比,W1+NT总耗水量较低,提高了WUE。3.烯效唑和矮壮素复配剂(HK-1)处理增加了冬前分蘖,抑制了冬后分蘖发生,促进了冬小麦前期根系生长和群体建成,提高了穗数和产量。HK-1增加了冬前分蘖期根条数、根粗、根重和根冠比,促进了整个生育期深层(20-50cm)根系生长,提高了WUE。4.PT促进了夏玉米根系建成和物质运输,提高了产量和WUE。在2011年和2012年夏玉米季,PT比NT产量分别高10.8%和9.9%。PT显著提高了整个生育期0-400cm土层根系根重,增加了花期和成熟期10-50cm土层的根长和表面积密度。同时,在2011和2012年,PT下根系伤流量及NH4+、NO3-、P、K、Ca、Mg、Fe、Zn等运输速率要显著高于旋耕(RT)和NT。5.乙烯利(Eth)拔节期处理显著减少了玉米吐丝后根系大小和营养运输能力,抑制了地上部生长,但显著增加了十二叶展(V12)前根冠比。Eth处理显著减少低密度下夏玉米的产量和WUE,但在高密度下对产量和WUE影响较小。更多还原

【Abstract】 Water storage is a limiting factor for a sustainable development of agriculture in North China Plain (NCP). Water use efficiency (WUE) is closely related to root growth and distribution. Studies were conducted to1) examine root growth and distribution of winter wheat and summer maize using soil core method, root box and in situ scanning under different tillage practices and irrigation treatments;2) investigate the relationship between root density, dry matter accumulation, water consumption and yield;3) illuminate the regulation mechanism of plant growth regulator on root growth and water use efficiency. The main results summarized as follow:(1) Field study was carried out to examine the effect of different practices on root growth, water use and yield of winter wheat under rain-fed condition (WO). Plowing tillage (PT) promoted root growth of winter wheat before flowering compared with no tillage (NT) and increased yield and WUE. Compared with NT, PT promoted root growth and plant population establishment before flowering stage, thus increased spikes and grain yield. Under PT, grain yield was increased by10.6%and5.2%, in2011-2012and2012-2013winter wheat growing season, respectively. Tillage practices affected water consumption at different growing stages, but there was no difference between tillage practices for the total water consumption (ET). The PT had the highest WUE and it increased byl4.9%and7.3%compared with NT, in the two winter wheat growing seasons, respectively.(2) Combined with NT, irrigated wheat once at jointing stage (W1) increased WUE and grain yield. The root had a relatively rational distribution under W1+NT compared with the other combinations and photosynthetic capacity and contribution of photosynthates to grain is greater. ET under NT+W1was lower than the other combination while WUE of NT+W1is higher.(3) Uniconazole and Cycocel (HK-1) increased tillering capacity and root growth of winter wheat before winter, constrained the tillers after winter and increased spikes and grain yield and WUE. The HK-1increased root number, root diameter, root weight and root/shoot ratio at tillering stage before winter. The HK-1increased WUE and root growth at deeper soil profile (20-50cm) during the whole growth period.(4) Plowing tillage promoted root growth and nutrition delivery rate during the whole growing period, and increased yield and WUE of summer maize. As compared with NT, yield was increased by10.8%and9.9%under PT, in2011and2012, respectively. The PT increased root weight in the0-40cm soil layer during the whole growth period. The root length density and root surface area density were significantly increased in10-50cm soil layer, but there was no difference among tillage practices below60cm. At the same time, the delivery rate of NH4+, NO3-, P, K, Ca, Mg, Fe, Zn etc. in root bleeding sap was higher than that under NT.(5) Ethephon (Eth) applied at jointing stage restrained root growth and nutrition delivery rate. Eth restrained shoot growth, but significantly increased root/shoot ratio before V12. The grain yield and WUE were lower at lower plant density under Eth treatment compared with control. However, there was no significant difference in yield and WUE at higher plant density compared with control.更多还原