调亏灌溉和灌溉方式对香梨树吸收根系重分布的影响

于2009—2010年开展了田间试验,研究了调亏灌溉对成龄库尔勒香梨树吸收根系重分布的影响。灌溉方式为地表滴灌与漫灌,滴灌试验包括轻度与重度水分胁迫处理(在新梢及果实生长缓慢期分别按蒸发量的60%与40%灌溉,在其他生育期按蒸发量的80%灌溉),对照处理为充分灌溉,在整个生育期按蒸发量的80%灌溉。每年4—8月份,漫灌每月灌溉1次,灌水定额为300 mm。所有处理在2009年之前均为漫灌。研究结果表明,成龄库尔勒香梨树的吸收根系主要分布于地表以下20~60 cm。梨树需要2 a时间调整吸收根系的分布以适应灌溉方式由漫灌转为滴灌。土壤水分胁迫减小了梨树吸收根系的根长,抑制了梨树的营养生长,其后恢复充分灌溉可促进根系的生长。梨树新梢及果实生长缓慢期的土壤水分胁迫对根系生长的抑制效果超过了对新梢生长的抑制;但吸收根系的生长与果实产量之间并无显著的相关性。     

滴灌带铺设模式对成龄枣树根系再分布及产量的影响

【目的】探明长期漫灌改滴灌后适宜的滴灌带铺设模式对成龄枣树根系再分布及产量的影响。【方法】以新疆长期漫灌红枣为研究对象,设置3个滴灌带铺设模式,分别为枣树二侧50 cm(T1)、35 cm(T2)和20 cm(T3)处铺设滴灌带,以漫灌为对照(CK),研究漫灌改滴灌对土壤水分分布、枣树根系再分布及产量的影响。【结果】漫灌改滴灌后,土壤湿润区显著收缩,水分集中在根系聚集区;随着滴灌带铺设距离的增大,土壤湿润区由窄深型演变为宽浅型,有利于红枣根系生长。长期漫灌条件下成龄枣树根系空间分布相对均匀,经过连续2 a的滴灌调控,T1、T2、T3处理0～60 cm土层平均根长密度分别比CK增加了32.7%、31.6%和21.4%;水平方向上,T1处理和T2处理距离树干0～75 cm根长密度较CK提高了20.1%和24.5%,T3处理0～50 cm根长密度较CK提高了25.8%,但50～100 cm下降了15.2%;漫灌改滴灌还可显著提高红枣产量和灌溉水分利用效率,滴灌第2年,T1处理和T2处理红枣产量分别达到了9 135 kg/hm~2和9 107 kg/hm~2,分别比CK提高了12.9%和12.5%。【结论】针对新疆长期漫灌红枣改滴灌初期,35 cm或50 cm的滴灌带铺设模式,有利于提高枣树根系的调控和果实产量。     

滴灌湿润比对成龄库尔勒香梨树根系分布的影响

在充分灌溉条件下采用3种滴灌湿润比(20%、40%、60%).以漫灌为对照.研究库尔勒成龄香梨吸水根(根直径≤1 mm)在0～70 cm土层内分布的变化,探讨滴灌湿润比对根系分布的影响.结果表明,漫灌成龄库尔勒香梨树吸水根水平方向上在距树体1～2 m内从树行由内向外呈递增趋势;垂直方向上根系随深度呈递增趋势.滴灌对成龄...     

间接地下滴灌灌溉深度对枣树根系和水分的影响

为探讨间接地下滴灌及导水装置埋深(灌溉深度)对南疆极端干旱区矮化密植红枣根系生长分布特征及产量、水分利用率的影响,试验设间接地下滴灌(ISDI)3个导水装置埋深水平,分别为20、27、35 cm,以地表滴灌(DI)为对照,共4个处理,经过2~4 a的田间试验后,采用环状壕沟分层挖掘法对以枣树树干为中心,半径为1 m的90°扇形区域内0~100 cm土层进行根系取样。结果表明,相对于DI,ISDI下各根系分布较均匀,生长方向基本向下延伸;ISDI显著增加了根径小于5 mm根系根长密度,细根(根径小于2 mm)是DI的3倍,但减少了根径大于5 mm根系根长密度,相对增加了20~40 cm土层根系根长占总根长的比率;垂直方向上随着灌溉深度的增加表层根系根长密度相对减少,深层相对增加;水平方向上各处理根系根长密度基本呈现随着与树干水平距离的增加而减小的趋势,但在0~20 cm土层减小的幅度较大,在20~40 cm土层其减小的幅度较小;随着灌溉技术由DI到ISDI及灌溉深度的增加,细根分布基本呈现出由"宽浅型"向"深根型"发展的趋势。相对DI,ISDI具有较好的节水增产效果,提高产量及灌溉水生产率最大达20%。建议幼龄期南疆密植枣树的导水装置埋深为27~35 cm。研究为极端干旱区枣树适宜灌溉技术的选择及其技术要素的制定提供依据。     

不同种植方式和亏缺灌溉对设施黄瓜生理特性及WUE的影响

【目的】揭示滴灌水分亏缺和种植方式对设施黄瓜叶片光合特性、物质积累与水分利用效率的调控效应,筛选适宜的亏缺灌溉栽培模式。【方法】以"津优316"黄瓜为试材,在定植密度相同时,设置了"等行距+70%灌溉量"(T1)、"宽窄行+70%灌溉量"(T2)、"等行距+常规灌溉量"(T3)、"宽窄行+常规灌溉量"(T4)4个处理,定植后第5天开始不同灌溉量处理,分析了定植后6周内黄瓜叶片生理特性、光合作用、水分利用率(WUE)、形态指标和物质积累、以及全生育期黄瓜总产量对滴灌水分亏缺和种植方式的响应规律。【结果】不同种植方式对黄瓜生理特征、光合作用、形态指标、物质积累、水分利用效率的影响均不显著。亏缺灌溉黄瓜植株受到不同程度水分胁迫,可溶性物质量和脱落酸量显著增加;由于气孔限制值(Ls)增加,净光合速率(Pn)降低了10.75%,蒸腾速率(Tr)降低了15.03%,物质积累减少了15.46%,总产量降低了12.60%,但水分利用效率提高了20.97%。不同处理中,T4处理产量最高,作物水分利用效率(WUEET)最低,与T4处理相比,T1处理的黄瓜植株受到一定程度的水分胁迫,Pn显著降低了13.68%,干物质积累显著降低了9.41%,黄瓜总产量降低了9.30%,但WUEET提高了23.96%;T2处理黄瓜叶片过氧化物酶(POD)活性、丙二醛(MDA)量、可溶性蛋白量、脱落酸(ABA)量显著增加,植株受到水分胁迫,Pn显著降低了10.52%,干物质积累显著降低了23.55%,总产量显著降低了12.37%,但WUEET显著提高了23.96%;T3处理黄瓜植株未受到水分胁迫,Pn、干物质积累、总产量、WUEET差异不显著。【结论】亏缺灌溉黄瓜虽然产量降低,但由于耗水量的大幅降低,水分利用效率显著提高。T1处理虽然总产量降低了9.30%,但提高黄瓜水分利用率23.96%,是适宜的滴灌水分亏缺模式。     

不同滴灌方式下咸水灌溉对棉花根系分布的影响

通过大田试验研究了不同滴灌方式利用咸水灌溉对棉花根系分布的影响。结果表明,2种滴灌方式下土壤中的水分和盐分在1 m土体内随土壤深度的增加和咸水浓度的增加而增加,且由于滴头的洗盐作用,地表滴灌和地下滴灌方式下土壤中的水盐分布深度均有所下移。正是由于水盐在土壤有这样的分布特征,2种滴灌方式下不同盐度咸水灌溉后,作物不仅可以感受到变化了的环境信息,而且自发地改变结构形态、空间构型,即增加根长、根干重、根半径以及根表面积,对盐胁迫做出适应性的根系形态变化。     

基质配方和灌溉方式对生菜根系和产量的影响

为筛选高产的生菜栽培基质配方及配套灌溉方式,根据滴灌和微喷灌水分在基质中的分布特点,研究了4种有机基质和2种灌溉方式下生菜产量和根长密度分布状况,分析了在滴灌和微喷灌条件下生菜根长密度剖面相对分布的异同,提出了生菜根长密度垂向分布模型及生菜产量和根长密度的关系模型。结果表明:滴灌处理在12 cm以下基质层含水率明显高于上层基质,微喷灌处理基质水分主要集中在15 cm以上基质层且水分分布较均匀。复配基质栽培生菜的根长密度比纯醋糟基质高27%,且在剖面的垂直分布随深度增加而递减;微喷灌下生菜根系集中于表层(0~6 cm),占71%以上,较滴灌有上移现象。复配基质栽培生菜产量比纯醋糟基质高10%。灌溉方式对生菜产量影响具有季节性,春季滴灌的生菜产量比微喷灌高22%以上,夏季滴灌的生菜产量比微喷灌低11%。选用复配基质进行栽培,春、夏季分别采用滴灌和微喷灌的方式最有利于生菜高产和根系的生长。     

膜下滴灌下土壤水盐动态对棉花根系时空分布特征的影响

为讨论在膜滴灌条件下水分和盐分的运移对棉花根系时空分布的影响,选择淡水和成水2个处理,在其3个不同生育期(蕾期、花铃期和吐絮期)采集距滴头不同距离和深度上的根系,并监测各剖面的水分、盐分及地上植株的农艺性状.对其根长密度与地上部分、水分和盐分的运移进行分析,研究表明根系对水分和盐分的胁迫表现明显,当土壤体积含水率在20...     

交替隔沟灌溉下玉米根长密度分布及水分利用

为了探明交替隔沟灌溉和常规沟灌条件下玉米根长密度的分布规律及水分利用效率(WUE),研究了2种沟灌方式下玉米根长密度的空间分布和水分利用情况。结果表明,玉米根长密度在根区水平向和垂向呈指数分布。交替隔沟灌溉促进了玉米根系的水平向伸展和下扎深度,常规沟灌在垄位的大密度根系分布集中在20～60cm。交替隔沟灌溉增大了根系下扎深度,有利于根系吸收深层土壤水分,在非充分供水条件下提高了作物的水分利用效率,交替隔沟灌溉水分利用效率较常规沟灌提高5%以上。     

立体种植农田不同生育期及土壤水分的根系分布特征

在立体种植农田中,作物根系分布是影响作物间水肥竞争及利用效率的首要因素。针对滴灌条件下番茄套种玉米立体种植农田设置高(T1)、中(T2)、低(T3)3个土壤水分处理,研究不同水分处理对立体种植农田不同位置土壤含水率、作物根系分布的影响,探讨立体种植农田根系在不同生育期生长发育特征。结果显示:立体种植农田番茄侧土壤含水率平均值显著低于玉米侧,膜内土壤含水率明显高于膜外土壤含水率,膜内不同位置土壤含水率无明显差异;随着生育期的推进作物间根系呈"不交叉—轻度交叉—完全交叉—轻度交叉"规律;随着土壤含水率的增加根系总量呈增长趋势,在0~30 cm的滴灌湿润区,作物根系分布最密集,约占总根系的60%~70%,且高水分处理根量显著大于低水分处理,根长密度、根表面积密度、根体积密度以及根重密度均呈现T1T2T3的趋势,而在非滴灌主要湿润区则正好相反;累积根系分布曲线分析显示随着土壤含水率增加根系向土壤下层生长,随着生育期推进根系向作物中间发展。立体种植农田作物在不同生育期根系分布变化明显,同时土壤水分对根系分布影响较大。     

The response of sap flow in apple roots to localised irrigation

The oft-touted reason for the efficiency of drip irrigation is that roots can preferentially take up water from localised zones of water availability. Here we provide definitive evidence of this phenomenon. The heat-pulse technique was used to monitor rates of sap flow in the stem and in two large surface roots of a 14 year old apple tree (Malus domestica Borkh. cv. Braeburn). The aim was to determine the ability of an apple tree to modify its pattern of root water uptake in response to local changes in soil water content. We monitored the water status of the soil close to the instrumented roots by using time domain reflectometry (TDR) to measure the soil's volumetric water content, θ, and by using ceramic-tipped tensiometers to measure the soil's matric pressure head, h. A variation in soil water content surrounding the two roots was achieved by supplying a single localised irrigation to just one root, while the other root remained unwatered. Sap flow in the wetted root increased straight away by 50% following this drip irrigation which wetted the soil over a zone of approximately 0.6 m in diameter and 0.25 m in depth. Sap flow in the wetted root remained elevated for a period of about 10 days, that is until most of the irrigation water had been consumed. A comparative study of localised and uniform irrigation was then made. Following irrigation over the full root zone no further change in sap flow in the previously wetted root was observed when referenced to the corresponding sap flow measured in the stem of the apple tree. However sap flow in the previously dry root responded to subsequent irrigations by increasing its flow rate by almost 50%. These results show that apple roots have the capacity to transfer water from local wet areas at much higher rates than normally occurs when the entire root zone is supplied with water. They are also able to shift rapidly their pattern of uptake and begin to extract water preferentially from those regions where it is more freely available. Such an ability supports the use of drip irrigation for the efficient use of scarce water resources. We conclude that the soil-to-root pathway represents a major resistance to water uptake by apple, even at the relatively high soil water pressure heads developed during parts of this experiment, during which the tree was not even under any stress.     

地面坡度对滴灌水分入渗过程的影响

通过土箱模拟滴灌实验,研究了不同地面坡度下滴灌水分运移规律。结果表明,地面各方向湿润半径、滴头下湿润深度和最大湿润深度均与时间呈显著的幂函数关系;随着地面坡度的增大,地面顺坡方向湿润锋推进加快,逆坡方向及滴头处横坡方向湿润锋推进减缓,横坡方向最大湿润宽度也随着坡度的增大而减小;在纵剖面上随着地面坡度的增大,滴头下入渗深度逐渐减小,而最大入渗深度则逐渐增加,最大入渗深度的位置也距滴头越远;地表和纵剖面湿润范围的变化表明,与水平地面相比,整个湿润体随着地面坡度的增大明显向下坡方向偏移,且坡度越大,偏移距离越大,湿润体形状由对称的半椭球形向下坡大而上坡小的梨形变化。     

滴灌条件下土壤基质势对豇豆产量和灌溉水利用效率的影响

研究了华北半湿润区滴灌条件下不同土壤基质势对露地栽培豇豆产量和灌溉水利用效率的影响。试验共有5个处理,分别控制滴头正下方0.2 m深度处土壤基质势下限高于-10、-20、-30、-40和-50 kPa。研究分析发现,土壤基质势对豇豆的产量没有明显的影响,并且随着土壤基质势控制的降低,豇豆整个生育期的灌水量明显降低,灌溉水利用效率显著升高。因此,在华北半湿润区,在保证豇豆安全度过苗期之后,可以通过控制滴头正下方0.2 m深度处土壤基质势下限高于-50 kPa来制定豇豆的滴灌灌溉计划。     

Influence of different water quantities and qualities on lemon trees and soil salt distribution at the Jordan Valley

The influences of water quantity and quality on young lemon trees (Eureka) were studied at the University of Jordan Research Station at the Jordan Valley for 5 years (1996–2000). Five water levels and three water qualities were imposed via trickle irrigation system on clay loam soil. The primary effect of excess salinity is that it renders less water available to plants although some is still present in the root zone. Lemon trees water requirements should be modified year by year since planting according to the percentage shaded area, and this will lead into substantial water saving. Both evaporation from class A pan and the percentage shaded area can be used to give a satisfactory estimate of the lemon trees water requirement at the different growth stages. The highest lemon fruit yield was at irrigation water depth equal to evaporation depth from class A pan when corrected for tree canopy percentage area. Increasing irrigation water salinity 3.7 times increased average crop root zone salinity by about 3.8–4.1 times.The high salt concentration at the soil surface is due to high evaporation rate from wetted areas and the nature of soil water distribution associated with drip irrigation system. Then, the salt concentration decreased until the second depth, thereafter, salt concentration followed the bulb shape of the wetted soil volume under trickle irrigation. Irrigation water salinity is very important factor that should be managed with limited (deficit) irrigation. But increasing amount of applied saline water could result in a negative effect on crop yield and environment such as increasing average crop root zone salinity, nutrient leaching, water logging, increasing the drainage water load of salinity which might pollute ground water and other water sources.     

盐碱地滴灌对新疆杨生长及土壤盐分分布影响

通过田间试验研究高垄覆膜滴灌模式下不同土壤基质势对盐碱地新疆杨生长以及土壤盐分分布的影响。试验设5个水平的土壤基质势处理：-5kPa（S1）,-10kPa（S2）,-15kPa（S3）,-20kPa（S4）,-25kPa（S5）,每个处理重复3次,按随机区组布置。试验结果表明,2009年生育末期,根系周围土体中的盐分比...     

多点源滴灌条件下土壤水分运移模拟试验研究

为了指导密植作物的滴灌系统合理设计,通过室内物理试验模拟了多点源滴灌条件下土壤水分运移过程,重点研究了不同滴头流量下交汇湿润体内的土壤水分时空动态分布规律．多点源滴灌条件下土壤水分运动遵循先点源入渗、再湿润锋交汇和最后形成湿润带的规律．灌水结束时,土壤水分分布呈现湿润体上部复杂、下部相对简单的特征．湿润体上部,在滴头下方存在土壤含水率相对较高的区域,2个滴头之间近地表处存在土壤含水率相对较低的区域;湿润体下部同一深度土层上的含水率有趋于一致的趋势．灌水结束后,由于土壤水分再分布,同一深度土层上含水率差异逐渐减小．灌水量相同条件下,灌水结束时,滴头流量小的入渗深度较大,湿润体内土壤平均含水率较低;灌水结束后,受土壤水分再分配的作用,不同滴头流量下入渗深度的差异较灌水结束时有所减小．     

小滴头流量下灌水频率对膜下土壤湿润区的影响

为了探明灌水频率对小滴头滴灌土壤湿润区的影响,在实验室对沙土和中壤土进行了膜下间歇滴灌试验,滴头流量分别为0．3、0．5、0．7L／h;灌水频率分别为1、2、3、4次灌完。在灌水量相同的情况下观测了土壤的湿润区运移过程和含水率分布。结果表明,小滴头流量下改变滴水频率对土壤湿润体的大小影响很小;随着灌水频率的增加,土壤湿...     

库尔勒香梨覆膜滴灌效应研究

在滴灌方式下,通过覆盖地膜的栽培方式研究了库尔勒香梨生长特性以及果实品质和产量。结果表明,地膜滴灌（MD）显著提高了香梨根际区土壤水分含量,0～60cm土层土壤含水率显著高于未覆盖滴灌（ND）和漫灌（CK）,该土层土壤含水率与叶片含水率之间的相关性显著高于60～100cm土层。土壤含水率的增加促进了叶片含水率和叶绿素含...     

Spatial root distribution of mature apple trees under drip irrigation system

The study was undertaken in order to quantify the effect of 12-year irrigation by drip emitters placed on one side of the tree trunk on the rooting pattern of Gloster apple trees (Malus domestica Borkh) grafted on M26 rootstock under the conditions of south-west Poland. The orchard was established in 1994 and since 1995 was drip irrigated under three treatments: V0 - without irrigation (control), V1 - intensive irrigation, and V2 - economical irrigation. In March 2007, after 12 years of irrigation, a profile trench observation method was used to map the number and the location of root distribution in clay loam (Luvisol) soil.The root system architecture was largely affected by irrigation. In case of the trees irrigated intensively (V1), the study showed asymmetry in the distribution of roots of diameter <1 mm and 1-3 mm. In V1, shallow root system, concentrated in the wetted zone developed on the irrigated side of the tree, where on the side of the tree trunk opposite the emitter trees developed significantly larger numbers of roots, which penetrated deeper soil layers. There were no statistically significant differences in the number of roots between both sides of the tree trunk under the treatment with economical irrigation (V2). Moreover, spatial roots distribution over the entire soil profile was found to be the most uniform compared to the other experimental treatments (V0 and V1). Finally, the study examined the relationship between root system and yield. Obtained results showed that in the 3-year period less frequent water application (V2) resulted in the highest yield.