控制性分根区交替滴灌对苹果幼树形态特征与根系水分传导的影响

采用固定滴灌(根区一侧固定供水)、控制性分根区交替滴灌(根区两侧交替供水)和常规滴灌(紧贴幼树基部供水)3种灌水方式和3种灌水定额(固定滴灌和交替滴灌均为10、20和30 mm,常规滴灌为20、30和40 mm),对比研究了控制性分根区交替滴灌对苹果幼树形态特征与根系水分传导的影响.结果表明： 交替滴灌的根区两侧土壤出现反复干湿交替过程,常规滴灌的根区两侧土壤含水率差异不显著.在灌水定额相同时,灌水侧的土壤含水率在3种灌水方式间差异不显著.与常规滴灌和固定滴灌相比,交替滴灌显著增加了苹果幼树的根冠比、壮苗指数和根系水分传导,在30 mm灌水定额处理下,交替滴灌的根冠比分别增加31.6%和47.1%,壮苗指数增加34.2%和53.6%,根系水分传导增加9.0%和11.0%.3种灌水方式下,根干质量和叶面积均与根系水分传导呈显著线性正相关.控制性分根区交替滴灌增强了苹果幼树根系水分传导的补偿效应,促进了根系对水分的吸收利用,有利于干物质向各个器官均衡分配,显著提高了根冠比和壮苗指数.     

不同滴灌方式和NaCl处理对苹果幼树生长和水分传导的影响

为了探讨不同滴灌方式和土壤盐分对苹果(Malus pumila)幼树生长和水分传导(简称水分传导K)的影响。采用3种滴灌方式(交替滴灌(ADI, 根区两侧交替灌水)、固定滴灌(FDI, 根区固定一侧灌水)和常规滴灌(CDI, 根区两侧均灌水))和4个NaCl浓度梯度(0 (CK)、0.2% (S₁)、0.3% (S₂)、0.4% (S₃))。结果表明: 滴灌方式和NaCl浓度对苹果幼树生长和水分传导有显著影响。在相同的滴灌处理下, 随着NaCl浓度的增大, 苹果幼树的干物质、叶面积和净生长量及水分传导均显著地下降。根系水分传导(K_r)与总根干重间, 冠层水分传导(K_sh)与冠层干重间均呈显著的线性相关关系。在相同的NaCl处理下, 与CDI处理相比, ADI处理节水达50%, 平均根系干重、冠层干重、总干重、叶面积、净生长量和K_r仅分别下降了8.7%、19.24%、13.47%、11.87%、32.96%和10.72%; 这说明ADI处理对果树的生长和K_r具有明显的促进作用。在高盐分S₂和S₃处理下, ADI处理的叶水分传导(K_l+p)分别降低了33.56%和44.26%, 但ADI处理的K_r反而高出了CDI达1.13%和10.91%, 说明ADI处理增强了苹果幼树根源水力信号的传输效率和调控苹果幼树体内水分平衡的能力及抗盐分胁迫能力。ADI处理的生长状况和K_r均高于FDI。采用ADI处理进行灌溉不仅提高了节水调控能力, 而且也增强了抗盐分胁迫能力。     

根区不同灌溉方式对苹果幼苗水流阻力的影响

研究了滴灌条件下根区不同灌溉方式（交替滴灌ADI、固定滴灌FDI和常规滴灌CDI）和灌水量对苹果幼苗及各组成部分水流阻力、气孔导度和叶面积的影响.结果表明：根区灌溉方式和灌水量对苹果幼苗水流阻力（R）的影响显著; 在相同的根区灌溉方式下,苹果幼苗根系阻力（R_r）随着灌水量的减少而增大,冠层阻力（R_s）随着灌水量的减少而减小.在相同灌水量下,与常规滴灌相比,交替滴灌和固定滴灌均提高了苹果幼苗叶片和叶柄阻力（R_l+p）,降低了幼苗全株阻力（R_t）、R_r、R_s以及侧枝和主杆阻力（R_lb+mr）.在20 mm和30 mm灌水定额下,交替滴灌的R_l+p分别比常规滴灌高1.06%和0.63%.在平均节水达33%的前提下,交替滴灌和固定滴灌的平均R_l+p分别比常规滴灌高19.65%和24.34%,但交替滴灌和固定滴灌的平均R_lb+mr分别降低了4.83%和14.97%.交替滴灌和固定滴灌等局部根区不同灌溉方式通过有效减小苹果气孔导度和叶面积,提高了R_l+p,从而减少了叶片的蒸腾失水,提高了苹果幼苗的水分利用效率,通过降低R_r和R_lb+mr提高了苹果幼苗调控水分的能力和抗干旱能力.     

根系分区交替滴灌对苹果幼苗生理特性和水分利用效率的影响

以矮化红富士苹果幼苗为试验材料,采用交替滴灌(ADI)、固定滴灌(FDI)和常规滴灌(CDI)3种滴灌方式和3种灌水量对苹果幼苗的生理特性和水分利用效率进行了研究,以阐明根系分区交替灌溉下苹果幼苗生理特性和节水机理.结果表明:与CDI方式相比,当灌水定额由20 mm增大到30 mm时,ADI方式提高了苹果幼苗根干重、根系导水率、叶水势和净光合速率,降低了其蒸腾速率、棵间蒸发量和蒸散量,从而使得ADI方式下的叶片水分利用效率、总水分利用效率和灌溉水分利用效率较CDI方式大大提高;3种滴灌方式的根系导水率均存在显著的季节变化,并以8月份最大,12月份最小;与CDI方式相比, ADI和FDI方式在节水达33.3%时的平均根系导水率仅分别降低了5.81%和14.7%,但水分利用效率、灌溉水利用效率分别较CDI方式高出16.31%和14.48%、40.52%和27.65%.可见,局部根区灌溉方式能促进苹果幼苗生长和光合作用,并主要通过提高根系导水率的途径来提高水分利用效率.     

分根区干湿交替对玉米光合速率及蒸腾效率的影响

以玉米为材料研究了分根区干湿交替对叶片光合速度及蒸腾效率的影响,结果发现控制１／２根区交替供水和固定１／２根区供水在减少用水量的同时,叶片蒸腾速度明显下降,而光合速度不明显,蒸腾效率提高;控制１／２根区交替供水比固定１／２根区供水在光合维持高水平稳定时所要求的土壤含水量低,其蒸腾效率较高。干湿交替能够增加根冠比、根干重和根九。证明控制性分根交灌溉可提高玉米腾效率达到节水的目的。     

根区湿润方式对玉米根系生长发育的影响

将厚塑料紧密地固定在盆栽试验用桶壁和底的中央,玉米种子播种于厚塑料布的正上方,在均匀灌水、固定部分根区灌水和根系分区交替灌水3种方式下,分期测定两个1／2根区根系的长度、面积、干重以及单位面积的平均根长和比根长,研究不同根区根系的生长发育特征。结果表明,处理40d时,与其他根区相比,固定灌水非灌水区的比根长和单位面积平均根长明显增大,说明土壤水分减少使根系直径变小。根面积、长度以及干重的增长速率均表现为,处理0～5d内,与均匀灌水及其非灌水区相比,两种局部灌水的灌水区均显著增大;处理10～15d内,交替灌水的灌水区较其他根区明显增大,固定灌水的灌水区与均匀灌水相近。固定灌水时,灌水区根系的面积、长度、干重及其增长速率较之非灌水区显著增大;交替灌水时,两个根区的增长速率呈交替变化,其绝对数值随时间延长趋于相同。表明交替灌水不仅可刺激供水区根系的补偿生长,而且对恢复供水区也有补偿效应,并能够促使不同根区的根系均衡发展。     

灌水量对小桐子形态特征和水分利用的影响

小桐子是能源作物中最具发展潜力的原料树种,而土壤水分是影响小桐子苗木质量和水分利用效率的关键.设置4个灌水处理(W1:472.49 mm;W2:228.79 mm;W3:154.18 mm和W4:106.93 mm),研究灌水量对小桐子幼树生长、形态特征和水分利用的影响.结果表明:与W1相比,W2、W3和W4处理小桐子叶面积和基茎截面面积显著降低,胡伯尔值显著增加,提高了根系向叶片传输水分的效率,提高小桐子抗旱能力;W2处理根系和冠层干物质量显著降低,粗高比增加,但壮苗指数变化不显著,而W3和W4处理壮苗指数显著降低.表明灌水量228.79~472.49 mm有利于小桐子壮苗指数的提高.与W1相比,W3处理节约灌水量达67.4%,总干物质量和蒸散量分别显著降低17.4%和68.6%,因此,小桐子灌溉水利用效率和总水分利用效率显著增加153.2%和163.2%.本试验条件下,有利于小桐子水分利用效率提高的最佳灌水量为154.18 mm.     

不同膜下滴灌方式对设施黄瓜生理特性及水分利用效率的影响

为了探明黄瓜膜下分根交替滴灌的节水效果,为设施黄瓜节水灌溉提供理论依据和技术参数,以‘津优3号’黄瓜为试材,采用随机区组设计,以土壤田间持水量的65%为灌水下限,田间持水量的90%为灌水上限,研究了分根交替滴灌(APDI)、固定1/2根区滴灌(FPDI)和传统滴灌(CDI)3种灌溉模式对黄瓜生长、生理特性、产量与品质及水分利用效率的影响,结果表明:(1)随灌溉处理时间的延长,3种灌溉模式的单株叶面积和株高的差异越来越显著,而茎粗和叶片数差异不显著;(2)与传统滴灌相比,分根交替滴灌模式下黄瓜叶片净光合速率略有下降而蒸腾速率显著降低,水分利用效率显著提高;(3)分根交替滴灌处理下黄瓜可溶性蛋白、可溶性糖含量与传统滴灌相比差异不显著,Vc含量却显著增加;(4)分根交替滴灌模式下黄瓜产量比传统滴灌下降1.5%,而灌水量减少17%,水分利用效率提高18.6%,节水效果显著。综上所述,分根交替滴灌可以在保证设施黄瓜产量没有显著下降的前提下,改善品质和显著提高水分利用效率,可作为设施节水提质增效的一种灌溉模式,推广应用前景广阔。     

不同灌溉方式对玉米根毛生长发育的影响

在盆栽条件下,采用分根装置,在光学显微镜和电子显微镜下对均匀灌水、固定部分根区灌水和根系分区交替灌水3种方式下各1/2根区的根毛发育状况进行观察并采样照相,研究不同根区根毛的生长发育特征.结果表明：处理40 d时,固定部分根区灌水条件下,非灌水区的根毛有明显退化脱落现象,退化区所占比例为20.96%,明显大于其他根区;灌水区的根系发黄,有腐烂斑,且根分枝有退化现象,根毛密集区的密集程度不如非灌水区,但根毛退化区所占比例小（15.72%）,退化程度轻.均匀灌水根系的根毛发育状况与固定灌水的灌水区类似.交替灌水条件下,先灌水区和后灌水区根毛密集区的密集程度均较高,根毛退化脱落区分别占9.77%和10.38%,明显小于均匀灌水和固定灌水.说明采用交替灌水方式可促进根系根毛的生长发育,而持续湿润或干燥不利于根系根毛的生长发育.     

交替地下滴灌对春玉米产量和水分利用效率的影响

采用自动式遮雨棚水分精量控制试验研究了交替地下滴灌条件下不同灌溉定额对春玉米产量和水分利用效率的影响.结果表明:交替地下滴灌春玉米需水关键时期为拔节-抽雄期、抽雄-灌浆期,具体表现为耗水模系数与耗水强度大,且对水分敏感性高,在灌溉条件有限的情况下要优先满足春玉米这两个时期的水分需求.随着灌溉定额的增加,产量呈现增加趋势;灌溉定额小于2764.5 m³·hm^-2时产量随灌溉定额增加快速增加,大于2764.5 m³·hm^-2时产量随灌溉定额增加缓慢增加;当灌溉定额为3357.1 m³·hm^-2时产量最高,达12109.0 kg·hm^-2.与固定地下滴灌相比,在灌溉定额相同条件下,交替地下滴灌产量提高5.4%,水分利用效率提高1.4%,灌溉水利用效率提高5.6%.与固定地下滴灌相比,灌溉定额减少20%时,交替地下滴灌虽然产量下降1.8%,但水分利用效率提高11.0%,灌溉水利用效率提高22.7%.综合考虑产量、水分利用效率两个指标,确定试验区春玉米交替地下滴灌的适宜灌溉定额为1600.4～3357.1 m³·hm^-2.     

交替根区滴灌下不同施氮量对葡萄干物质积累、分配和产量的影响

本试验采用盆栽的方法,在避雨栽培条件下,研究不同的灌溉方式和供氮水平对葡萄干物质积累与分配、产量和水氮生产效率的影响,以探讨北方鲜食葡萄生产最佳的水氮耦合管理模式。灌溉方式包括常规灌溉100%灌溉量(CDI)、单侧固定根区灌溉50%灌溉量(FDI)和双侧根区交替灌溉50%灌溉量(ADI);土壤施氮浓度设置0.4(N₁)、0.8(N₂)、1.2 g·kg^-1(N₃) 3个水平。结果表明: 与CDI模式相比,ADI和FDI总修剪量降低了34.8%和11.2%;随着施氮量的增加,生长冗余增加;CDIN₃处理葡萄树体冗余生长最高。ADI干物质积累量最高,分别比CDI、FDI提高5.1%和12.8%;N₂和N₃处理的树体总干物质量显著高于N₁处理。与其他灌溉模式相比,ADI模式下叶果比显著降低,收获指数显著提高;施氮量对各项指标影响不显著。所有组合中,ADIN₂处理冗余生长量与当年生物量比值最低。葡萄产量表现为ADI分别比CDI和FDI平均提高6.0%和10.4%,同一灌溉模式下,产量随着施氮量的增加而增加,以ADIN₂、ADIN₃耦合处理葡萄产量最高。与其他灌溉模式相比,ADI模式显著提高了葡萄水分利用效率,以ADI与N₂、N₃水平的耦合处理水分利用效率较高;不同施氮水平下,氮素利用效率表现为ADI＞CDI＞FDI,并随施氮水平的增加而降低。综合分析认为,ADIN₂处理能够减少葡萄冗余生长,有利于干物质向果实积累,产量较高,水氮生产效率较高,是较适宜北方葡萄生产的水氮组合模式。     

石羊河流域干旱荒漠绿洲区不同滴灌模式下葡萄茎液流变化及其与环境因子的关系

研究了石羊河流域干旱荒漠绿洲区交替滴灌（ADI）、固定滴灌（FDI）和常规滴灌（CDI）模式下葡萄茎液流的变化规律及其与气象因子和土壤含水率的相关关系.结果表明：研究区葡萄茎液流表现出与太阳辐射同步的昼夜变化节律;新梢生长期和开花期CDI处理的茎液流量显著大于其它两个处理;影响瞬时茎液流的主要气象因子是太阳辐射和气温,日茎液流量与平均气温和风速具有线性相关关系;不同灌溉方式下葡萄茎液流与气象因素的相关程度依次为：CDI>ADI>FDI;葡萄日茎液流量与参考作物蒸发蒸腾量（ET₀）呈显著线性相关关系.与CDI相比,ADI节省50%水量,而茎液流总量仅降低6.56%,且其葡萄茎液流和水分传导具有明显的补偿效应.     

Effects of alternate partial root-zone irrigation on soil microorganism and maize growth

Partial root-zone irrigation creates a dynamic heterogeneous distribution of soil moisture that may affect the numbers and activities of soil microorganisms. In this study, three irrigation methods, i.e. conventional irrigation (CI), alternate partial root-zone irrigation (APRI, alternate watering on both sides of the pot) and fixed partial root-zone irrigation (FPRI, fixed watering on one side of the pot), and three watering levels, i.e. well-watered, mild and severe water deficit, were applied on pot-grown maize. Numbers of soil microorganisms, plant height, stalk diameter, leaf area and biomass accumulation were monitored over the treatment period. A quadratic parabola relationship between the number of soil microorganisms and soil water content was found, indicating the number of soil microorganisms reached a peak at the mild soil water deficit condition, possibly due to better soil aeration. The peak number of soil microorganism was obtained when soil water content was 66, 79 and 75% of field capacity for CI, FPRI and APRI, respectively. Soil microorganisms were evenly distributed in both sides of APRI and their total numbers were always higher than those under other two irrigation methods for the same soil water content. The count of soil microorganisms in the dry root zone of FPRI was reduced by a lack of water. Maximum biomass accumulation was obtained under well watered condition but severe water deficit led to a 50% reduction in the CI treatment. Such reduction was much smaller under APRI and therefore the highest water use efficiency was obtained. Our results suggest that APRI maintained the best aeration and moisture condition in the soil and enhanced the activities of soil microorganisms, which might also have benefited the plant growth.     

Benefits of alternate partial root-zone irrigation on growth, water and nitrogen use efficiencies modified by fertilization and soil water status in maize

Alternate partial root-zone irrigation (APRI) is a new water-saving technique and may improve crop water use efficiency without much yield reduction. We investigated if the benefits of APRI on biomass accumulation, water and nitrogen use efficiencies could be modified by different soil fertilization and watering levels in pot-grown maize (Zea mays L. cv. super-sweet No 28, a local variety). Three irrigation methods, i.e. conventional irrigation (CI), alternate partial root-zone irrigation (APRI, alternate watering on both sides of the pot) and fixed partial root-zone irrigation (FPRI, fixed watering on one side of the pot), two watering levels, i.e. water deficit (W₁, 45–55% of field capacity) and well-watered (W₂, 70–80% of field capacity), and two N fertilization levels, i.e. no fertilization and fertilization, were designed. Results showed that APRI and FPRI methods led to more reduction in transpiration than in photosynthesis, and thus increased leaf water use efficiency (leaf WUE, i.e. the ratio of leaf net photosynthetic rate to transpiration rate). Compared to the CI treatment, APRI and FPRI increased leaf WUE by 7.7% and 8.1% before the jointing stage and 3.6% and 4.2% during the jointing stage, respectively. Under the fertilization and well-watered conditions, APRI treatment saved irrigation water by 38.4% and reduced shoot and total dry masses by 5.9% and 6.7%, respectively if compared to the CI treatment. APRI also enhanced canopy WUE (defined as the amount of total biomass per unit water used) and nitrogen (N) apparent recovery fraction (Nr, defined as the ratio of the increased N uptake to N applied) by 24.3% and 16.4%, respectively, indicating that effect of APRI can be better materialized under appropriate fertilization and water supply. Responsible Editor: Rana E. Munns     

不同水氮条件下灌溉方式对玉米干物质量和氮钾利用的影响

由于作物需水随生育期的变化,分根区交替灌溉(AI)的节水效果也会随生育期而发生变化,探明不同生育期分根区交替灌溉对玉米生长和水分养分利用的影响,以期为分根区交替灌溉的实施和充分发挥其节水节肥效果奠定理论基础。通过盆栽试验,在2种灌水水平(正常灌水和轻度缺水)和2种有机无机氮比例(100%无机氮和70%无机氮+30%有机氮)下,以常规灌溉(CI)为对照,分别研究苗期—灌浆初期、苗期—拔节期以及拔节期—抽雄期进行AI对玉米干物质量、氮钾含量和吸收量以及土壤碱解氮和速效钾含量的影响。结果表明,在轻度缺水和有机无机氮肥配施下,与CI相比,拔节期—抽雄期分根区交替灌溉玉米地上部和总干物质量分别增加29.6%和27.4%,地上部和总N吸收量增加50.7%和50.4%。与单施无机氮肥相比,有机无机氮肥配施会在不同程度上增加地上部和总N吸收量,但是一般降低土壤碱解氮和速效钾含量,这说明在轻度缺水和有机无机N肥配施下,拔节期—抽雄期进行分根区交替灌溉提高玉米总干物质量和N吸收量。     

Effects of partial root-zone irrigation on hydraulic conductivity in the soil-root system of maize plants

Effects of partial root-zone irrigation (PRI) on the hydraulic conductivity in the soil-root system (L(sr)) in different root zones were investigated using a pot experiment. Maize plants were raised in split-root containers and irrigated on both halves of the container (conventional irrigation, CI), on one side only (fixed PRI, FPRI), or alternately on one of two sides (alternate PRI, APRI). Results show that crop water consumption was significantly correlated with L(sr) in both the whole and irrigated root zones for all three irrigation methods but not with L(sr) in the non-irrigated root zone of FPRI. The total L(sr) in the irrigated root zone of two PRIs was increased by 49.0-92.0% compared with that in a half root zone of CI, suggesting that PRI has a significant compensatory effect of root water uptake. For CI, the contribution of L(sr) in a half root zone to L(sr) in the whole root zone was ～50%. For FPRI, the L(sr) in the irrigated root zone was close to that of the whole root zone. As for APRI, the L(sr) in the irrigated root zone was greater than that of the non-irrigated root zone. In comparison, the L(sr) in the non-irrigated root zone of APRI was much higher than that in the dried zone of FPRI. The L(sr) in both the whole and irrigated root zones was linearly correlated with soil moisture in the irrigated root zone for all three irrigation methods. For the two PRI treatments, total water uptake by plants was largely determined by the soil water in the irrigated root zone. Nevertheless, the non-irrigated root zone under APRI also contributed to part of the total crop water uptake, but the continuously non-irrigated root zone under FPRI gradually ceased to contribute to crop water uptake, suggesting that it is the APRI that can make use of all the root system for water uptake, resulting in higher water use efficiency.