滴灌条件下枣树耗水规律的研究

试验通过研究枣树的茎流来预测其耗水量,为合理灌溉提供科学依据。利用植物茎流计在滴灌条件下测定枣树的茎流变化,结果表明2010年5月15日的最大值出现在中午12∶00,达到1834．28 g · h－1,6月26日的最大茎流速率在13∶00,达到4861．89 g·h－1,7月20日最大值出现在15∶00,达到6385．88 g·h－1,8月10日最大茎流出现在16∶00,达到5816．86 g · h－1;最小茎流都是出现在凌晨4∶00～8∶00。5月份的日平均累计流量比较小,枣树在这个月的日平均耗水量反而最小,到了7、8月份,随着温度的升高和雨季的结束,枣树耗水量明显增加,8月的日平均耗水累计量最高;通过相关分析,地表最高温度和最高气温对枣树的茎流量影响较大。研究得出：土壤含水量是影响茎流的变化主要因素,其它环境因子对茎流的影响也很重要。     

柴达木盆地沙棘茎流速率与环境因子的关系

采用热扩散flow-32包裹式茎流计,于2014年6—9月对柴达木盆地的沙棘茎流速率进行连续观测,并应用Vantage Pro 2小型气象站对林地的太阳辐射、大气温度、相对湿度主要气象因子进行同步采集,对不同天气条件下沙棘茎流速率的变化规律以及茎流速率与主要气象因子的相关关系进行研究。结果表明:典型晴天下沙棘茎流日变化呈双峰型,典型阴天下沙棘茎流呈单峰型,晴天的平均茎流速率是阴天的2.87倍;生长季各月的平均茎流速率为:8月7月9月6月;6—9月沙棘茎流速率与温度、太阳辐射呈极显著正相关(P0.01),与湿度呈极显著负相关(P0.01),各气象因子相关系数绝对值为:太阳辐射(0.811)大气温度(0.594)湿度(-0.571),太阳辐射是主导环境要素;用SPSS软件针对上述3种环境因子进行多元线性逐步回归,得回归模型Fs=19.268-0.221Ta-0.055RH+0.036Rs(R2=0.82),能够对柴达木盆地的沙棘蒸腾耗水量进行预测。     

夏玉米茎流速率变化规律及其影响因子研究

采用FLOW32-1K包裹式茎流计测量茎流速率,分析2018年夏玉米(郑单958)蒸腾量(本研究采用茎流)与气象因子,包括净辐射、温度、饱和水汽压差(VPD)、风速的相关性,并以Pearson相关性系数进行评价。结果显示:试验期间土壤含水率保持在田间持水率的70%～80%,得出在玉米不受水分胁迫条件下,茎流速率与净辐射、温度、VPD、风速均呈线性相关,相关系数分别为0.754、0.622、0.674、0.443,表明太阳辐射与茎流速率关系最密切,与风速关系最小。在夏玉米生长吐丝期、灌浆期和成熟期,晴天时茎流速率日变化为单峰曲线,早上5∶00茎流开始启动,随后茎流速率逐渐上升,在11∶00茎流速率达到峰值74.5 g·h~(-1),随后又降低,一般在21∶00降低为0.0。雨天时由于大气辐射不稳定,表现为多峰曲线,且茎流速率波动较大(0～37.7 g·h~(-1))。经计算夏玉米在灌浆生长期叶面积指数稳定在4.4,这时基础作物系数K_(cb)为1.0,9月10日后显著下降,至收获时(10月1日)降低至0.55。     

不同生育期幼龄枣树茎流特征及其与环境因子的关系

采用包裹式茎流计对位于新疆阿克苏地区温宿县新疆林科院佳木试验站内的幼龄枣树茎流速率进行连续测定,并同步监测样地内太阳辐射、温度、空气湿度以及风速4个环境因子,研究不同生育期枣树茎流特征及其与环境变化的关系。结果表明:1夜间均存在茎流活动,茎流速率变化曲线除果实膨大期为双峰外,其余生育期内均为单峰;2日累积量变化过程曲线均为"S"形,日均耗水量和总耗水量的趋势均为先增大后减小,且差异性明显,萌芽展叶期最低,果实膨大期最大,日均耗水量分别为2.78 L和8.31 L,总耗水量分别为83.39 L和249.30L;3茎流速率曲线与太阳辐射和温度曲线波形变化趋势基本一致,与空气湿度曲线波形变化趋势相反,茎流速率与环境因子进行偏相关分析,影响枣树茎流速率的主要因子有所差异,但太阳辐射偏相关系数最高,按生育期顺次分别为0.767、0.762、0.873、0.838、0.603和0.825,利用多元线性回归对不同生育期枣树茎流速率与环境因子进行逐步回归,经过回归系数和相关系数检验,各多元线性回归方程均达到了显著水平。     

半干旱区玉米茎流规律及其对气象因子的响应

采用包裹式茎流计和小型自记式气象站对甘肃省会宁县太平镇主要农作物玉米的茎流速率及其周围的气象因子进行同步观测。分析结果表明:1)玉米的日茎流速率变化趋势基本一致,都呈"几"字型变化。晴朗天气下,茎流启动时间为6:00,于14:00~15:30达到峰值,持续较短时间后迅速降低,至晚上22:00达到较低值且在夜间保持了一定的茎流活动。而多云和阴雨天气玉米茎流速率则呈不规则曲线。2)玉米茎流速率与气象因子变化趋势相吻合。相关性分析结果表明,影响玉米茎流的主要因子依次是:光合有效辐射、空气温度、空气湿度、风速。玉米茎流速率与气象单因子分析及逐步回归方程表明,对半干旱区玉米茎流起关键作用的气象因子是光合有效辐射与空气湿度。     

塔里木沙漠公路防护林乔木状沙拐枣耗水特性

利用植物茎流计,测定了塔里木沙漠公路塔中段乔木状沙拐枣茎干液流变化及耗水特性.结果表明3株乔木状沙拐枣在一个生长季内的日平均耗水量为4 183.4 g;在现行的灌溉管理条件下,4～10月3株基径为3.6,3.1,1.9 cm的乔木状沙拐枣日平均耗水量分别为6 203.5,4 829.1,1 517.5 g;7月份是耗水量最大的季节.乔木状沙拐枣液流日变化呈单峰曲线型,并随环境因子的变化有所波动;液流高峰值出现在12:00～15:00,最小值出现在0:00～3:00,夜间仍保持较高的液流速率.乔木状沙拐枣液流速率与基径呈正相关关系,在6月底,3株基径为3.6,3.1,2.1 cm的乔木状沙拐枣日耗水量分别为9 521.2,5 803.1 g/d和1 818.8 g/d.不同天气条件下沙拐枣日平均率日耗水量的排列顺序为:小雨＜阴天＜浮尘＜沙尘暴＜多云＜晴天.干旱的环境条件和较为充足的水分供应是耗水量大的一个重要原因.     

不同灌水量下幼龄枣树茎流变化规律

探讨了不同灌水量(W1,32 L;W2,48 L;W3,64 L以及W4,80 L)对4年生幼龄枣树茎流速率变化规律的影响以及茎流速率与环境因子之间的关系,通过美国Dynamax公司生产的Flow~(-3)2包裹式茎流计进行茎流速率的测定,并在样地内安装HOBO小气候仪同步获取太阳辐射、温度、空气湿度以及风速等气象数据。结果表明:不同灌水量下,枣树茎流速率日变化趋势均为单峰形曲线,除W4外,枣树茎流速率平均值随着灌水量的增加而逐渐增大,W1、W2和W3处理的茎流速率的平均峰值分别为516.63、819.04 g·h~(-1)和974.86 g·h~(-1);枣树茎流日累积量变化过程曲线均呈现较为明显的"S"形,除W4外,随着灌水量的增加,枣树茎流日累积量增加,W1、W2、W3和W4茎流日累积量分别为4.98、7.02、9.10 L和8.63 L;不同灌水量下茎流速率与太阳辐射、温度以及风速呈正相关,且茎流速率与太阳辐射和温度相关性达到显著水平,其中与太阳辐射的相关性最高,W1、W2、W3和W4处理下相关系数分别为:0.939、0.944、0.959和0.939;而与空气湿度呈现出较明显的负相关,相关系数分别为-0.579、-0.815、-0.822和-0.730。     

不同程度干旱胁迫及复水对春玉米(丹玉39)茎流动态的影响

利用大型移动防雨棚开展了玉米干旱胁迫及复水试验,通过分析玉米植株茎流速率变化规律,揭示了不同程度干旱胁迫及复水对玉米植株茎流速率的影响及其对环境因子的响应规律。结果表明:1不同发育期干旱胁迫及对照试验的玉米植株茎流速率在晴天均呈单峰曲线,在阴天或多云天呈现不规则的上下波动状态;干旱胁迫导致玉米茎流速率显著下降并且峰值提前;复水后的茎流速率与对照间的差异缩小,但仍低于对照且峰值提前;2比较拔节—吐丝期茎流速率平均值为:对照重度干旱胁迫中度干旱胁迫,吐丝—乳熟期和乳熟—成熟期均为:对照中度干旱胁迫重度干旱胁迫。3茎流速率与净辐射、气温呈现显著正相关,与相对湿度呈现显著负相关;重度干旱胁迫后,土壤水分的亏缺影响了玉米植株茎流速率,减弱了相对湿度对其茎流速率的影响。     

干旱绿洲区微喷灌枣园蒸散量时空尺度转换研究

为探究干旱绿洲区不同时空尺度单棵枣树蒸散量向枣园尺度蒸散量的转换关系,通过涡度系统、茎流计和微型蒸渗仪对枣园蒸散量、枣树蒸腾量和土壤蒸发量进行了监测.通过对茎流系统与涡度系统测量的不同时间、空间尺度的枣园蒸散量进行分析,分析从点(枣树)尺度蒸散量向面(枣园)尺度蒸散量的转换关系得出:(1)全生育期蒸腾量为403.2 m...     

西葫芦根腐和茎基腐病新病原-露湿拟漆斑菌Paramyrothecium roridum

 2013年12月,甘肃省白银市水川镇日光温室中的西葫芦发生了严重的根腐和茎基腐,部分棚室病株率达50%,从病根和病茎上分离得到拟漆斑菌属真菌3株,病株分出率27.3%。采用胚根和茎基部接种法测定了菌株FG-62对西葫芦的致病性:茎基部接种后27 d,植株开始出现凋萎;接种后40 d,两种接种法的西葫芦苗均呈现严重根腐和茎基腐症状,茎基部接种的西葫芦凋萎株率达30%;从病根和病茎上均可再分离出原接种菌。菌株FG-62在PDA平板上25℃培养14 d,产生大量墨绿色至黑色分生孢子座,分生孢子无色至淡榄黑色,单胞,杆状或腰鼓状,两端钝圆,大小为(7.04~9.15)μm ×(1.97~2.46)μm,聚集的分生孢子呈黑色。BLASTn分析结果显示,菌株FG-62(GenBank 登录号 MK252098)的rDNA-ITS序列与露湿拟漆斑菌Paramyrothecium roridum分离物E-469 (GenBank 登录号KY582183.1)和CBS 357.89(源自模式材料,GenBank 登录号NR_145077.1)的序列相似性分别达99.65%和96.83%。依据病原菌形态学和rDNA-ITS序列,将其鉴定为露湿拟漆斑菌P. roridum (Basionym:Myrothecium roridum)。这是露湿拟漆斑菌引起西葫芦根腐和茎基腐的首次报道。     

Mulching mode and planting density affect canopy interception loss of rainfall and water use efficiency of dryland maize on the Loess Plateau of China

High and efficient use of limited rainwater resources is of crucial importance for the crop production in arid and semi-arid areas. To investigate the effects of different soil and crop management practices(i.e., mulching mode treatments: flat cultivation with non-mulching, flat cultivation with straw mulching, plastic-covered ridge with bare furrow and plastic-covered ridge with straw-covered furrow; and planting density treatments: low planting density of 45,000 plants/hm~2, medium planting density of 67,500 plants/hm~2 and high planting density of 90,000 plants/hm~2) on rainfall partitioning by dryland maize canopy, especially the resulted net rainfall input beneath the maize canopy, we measured the gross rainfall, throughfall and stemflow at different growth stages of dryland maize in 2015 and 2016 on the Loess Plateau of China. The canopy interception loss was estimated by the water balance method. Soil water storage, leaf area index, grain yield(as well as it components) and water use efficiency of dryland maize were measured or calculated. Results showed that the cumulative throughfall, cumulative stemflow and cumulative canopy interception loss during the whole growing season accounted for 42.3%–77.5%, 15.1%–36.3% and 7.4%–21.4% of the total gross rainfall under different treatments, respectively. Soil mulching could promote the growth and development of dryland maize and enhance the capability of stemflow production and canopy interception loss, thereby increasing the relative stemflow and relative canopy interception loss and reducing the relative throughfall. The relative stemflow and relative canopy interception loss generally increased with increasing planting density, while the relative throughfall decreased with increasing planting density. During the two experimental years, mulching mode had no significant influence on net rainfall due to the compensation between throughfall and stemflow, whereas planting density significantly affected net rainfall. The highest grain yield and water use efficiency of dryland maize were obtained under the combination of medium planting density of 67,500 plants/hm~2 and mulching mode of plastic-covered ridge with straw-covered furrow. Soil mulching can reduce soil evaporation and retain more soil water for dryland maize without reducing the net rainfall input beneath the maize canopy, which may alleviate the contradiction between high soil water consumption and insufficient rainfall input of the soil. In conclusion, the application of medium planting density(67,500 plants/hm~2) under plastic-covered ridge with bare furrow is recommended for increasing dryland maize production on the Loess Plateau of China.     

Effects of the growing-maize canopy and irrigation characteristics on the ability to funnel sprinkler water

Stemflow is vital for supplying water, fertilizer, and other crop essentials during sprinkler irrigation. Exploring the spatial and temporal variations of crop stemflow and its influencing factors will be essential to preventing soil water and nutrient ion's migration to deeper layers, developing, and optimizing effective sprinkler irrigation schedules. Based on the two-year experimental data, we analyzed the variation patterns (stemflow amount, depth, rate, and funneling ratio) of maize stemflow during the growing season, and clarified its vertical distribution pattern. Meanwhile, effects of sprinkler irrigation and maize morphological parameters on stemflow were investigated. The results showed that stemflow increased gradually as maize plant grew. Specifically, stemflow was small at the pre-jointing stage and reached the maximum at the late filling stage. The upper canopy generated more stemflow than the lower canopy until the flare opening stage. After the tasseling stage, the middle canopy generated more stemflow than the other positions. Variation in canopy closure at different positions was the main factor contributing to the above difference. As sprinkler intensity increased, stemflow also increased. However, the effect of droplet size on stemflow was inconsistent. Specifically, when sprinkler intensity was less than or equal to 10 mm/h, stemflow was generated with increasing droplet size. In contrast, if sprinkler intensity was greater than or equal to 20 mm/h, stemflow tended to decreased with increasing droplet size. Compared with other morphological parameters, canopy closure significantly affected the generation of stemflow. Funneling ratio was not significantly affected by plant morphology. Based on the results of different sprinkler intensities, we developed stemflow depth versus canopy closure and stemflow rate versus canopy closure power function regression models with a high predictive accuracy. The research findings will contribute to the understanding of the processes of stemflow involving the hydro-geochemical cycle of agro-ecosystems and the implementation of cropland management practices.     

Characteristics of Caragana korshinskii and Hippophae rhamnoides stemflow and their significance in soil moisture enhancement in Loess Plateau, China

Stemflow of xerophytic shrubs represents a significant component of water replenishment to the soil-root system and influences water utilization of plant roots at the stand scale,especially in water-scarce semi-arid ecosystems.The stemflow of two semi-arid shrubs(Caragana korshinskii and Hippophae rhamnoides)and its effect on soil moisture enhancement were evaluated during the growing season of 2011 in the semi-arid loess region of China.The results indicated that stemflow averaged 12.3%and 8.4%of the bulk precipitation for C.korshinskii and H.rhamnoides,respectively.Individual stemflow increased in a linear function with increasing rainfall depth.The relationship between funneling ratios and rainfall suggested that there existed a rainfall depth threshold of 11 mm for both C.korshinskii and H.rhamnoides.Averaged funneling ratios were 156.6±57.1 and49.5±30.8 for C.korshinskii and H.rhamnoides,respectively,indicating that the canopy architecture of the two shrubs was an effective funnel to channel stemflow to the root area,and C.korshinskii showed a greater potential to use stemflow water in the semi-arid conditions.For individual rainfall events,the wetting front depths were approximately 2 times deeper in the rooting zone around the stems than in the bare area outside canopy for both C.korshinskii and H.rhamnoides.Correspondingly,soil water content was also significantly higher in the root area around the shrub stem than in the area outside the shrub canopy.This confirms that shrub stemflow conserved in the deep soil layers may be an available moisture source for plant growth under semi-arid conditions.     

大果沙棘的光合特性研究

本文采用LI-6200光合分析仪,对于祁连山区东段栽培的植物种大果沙棘光合速率进行了日变化和季节变化测试,结果分析表明:大果沙棘光合速率日变化呈典型的单峰曲线,峰值出现在一日之中的9:00时为12.00μmol.m-2.s-1,大果沙棘光合速率在季节变化中最高值在8月份为6.6084μmol.m-2.s-1。经对光合速率及同步测得的多项影响因子的光量子密度、大气温度、大气CO2浓度、气孔阻力等进行相关分析,大果沙棘的Pn与QNTM、TAIR、EAIR、VPD、RS各因子呈极显著正相关关系;与CO2、COND、CINT三项因子呈极显著负相关关系。并得出大果沙棘Pn与QNTM、TAIR、VPD、CINT影响因子之间的回归方程及水分利用效率(WUE)。     

古尔班通古特沙漠梭梭和白梭梭树干茎流特征

通过对古尔班通古特沙漠2个主要建群种梭梭(Haloxylon ammodendron)和白梭梭(Haloxylon persicum)树干茎流的野外实验观测,分析植株冠层和降雨特征对树干茎流形成的影响,并明确了树干茎流量在降雨再分配中的比例。结果表明：当降雨量≥2.4 mm时,梭梭和白梭梭开始有树干茎流产生。梭梭、白梭梭的树干茎流量随树冠体积的增大而增加,但是,当梭梭树冠体积大于4 m³,白梭梭树冠体积大于1.5 m³时,树干茎流量随树冠体积的增加不再增大,甚至有下降趋势。梭梭和白梭梭的树干茎流量和降雨量之间存在显著正相关,累计树干茎流量分别占降雨总量的9.1%和6.4%。梭梭和白梭梭的集流率均随降雨量增加而增大,能够有效地将树干茎流汇聚到树干基部, 梭梭表现出更强的汇集树干茎流的潜力。     

JICA项目地基GPS大气可降水量资料精度检验

利用中日JICA项目2011—2012年位于青藏高原及其东部山区6个GPS探测的逐时大气可降水量(GPSPWV)以及探空观测计算得到的每日2个时次(0:00 UTC和12:00 UTC)的大气可降水量资料(RS-PWV),验证GPS-PWV资料的准确度,分析了其误差的分布特征,并初步探讨了地面气温对误差的影响。结果表明:(1)受海拔高度的影响,GPS-PWV普遍比RS-PWV偏高;受水汽含量的影响,12:00 UTC的偏差普遍大于0:00 UTC,但两者之间逐日变化具有很好的一致性,其相关关系通过了0.001的显著性检验。(2)各站GPS-PWV和RS-PWV的平均均方根误差(RMSE)在0.23~0.33 cm,平均相对误差(MRE)在9.13%~29.01%,RMSE(MRE)随着站点海拔高度降低而增大(减小)。(3)各站PWV存在明显的季节差异,其PWV偏差同样具有明显的年变化特征:在7—9月最大,在12月至次年3月较低。(4)各站PWV偏差频率分布在0:00 UTC的峰值中心位于0 cm,偏差主要集中在-0.1~0.1 cm,而12:00 UTC的峰值中心相对右移,峰值要比0:00 UTC低,偏差值分布较分散。(5)在一定温度范围内,随着地面温度升高,PWV偏差有所增加。     

灌水量对全膜垄作沟灌玉米产量及水分利用效率的影响

针对河西灌区水资源紧缺的问题,探索玉米合理的灌溉量,以期指导区域玉米合理灌溉。通过在石羊河流域设置不同的灌水量梯度,研究不同灌水量对全膜垄作沟灌玉米产量及水分利用效率,以及土壤含水率、产量要素的影响。结果表明:全膜垄作沟灌玉米灌水量从4 500 m~3·hm~(-2)增加到4 725 m~3·hm~(-2)、4 950 m~3·hm~(-2)时,产量并没有随着灌水量的增加而增加,灌水量增加到5 175 m~3·hm~(-2)时,在水分利用效率没有降低的情况下,产量相对于4 500、4 725 m~3·hm~(-2)和4 950 m~3·hm~(-2)处理明显增加11.46%、8.39%和8.54%,其中果穗长度、穗粒数和百粒重平均增加4.88%、3.27%和4.31%是其产量增加的主要原因。对于土壤含水率,玉米需水盛期的7月16日至8月3日,5 175 m~3·hm~(-2)处理显著高于其他三个处理,而灌浆期各处理间则差异不显著。与播前期相比,收获期土壤含水率降低层主要集中在20~80 cm土层,土层贮水量平均降低6.72 mm,且各处理0~110 cm土层贮水量差异并不明显。因此,本研究表明5 175 m~3·hm~(-2)为石羊河流域全膜垄作沟灌条件下的适宜灌溉量,但灌浆中后期的最后一次灌水应考虑适当降低灌水量。     

塔克拉玛干沙漠腹地植物固沙灌溉制度初步研究

通过对塔克拉玛干沙漠腹地三种灌溉方式土壤水分和植物灌溉后水分周期动态的连续测定 ,对该地区植物固沙的灌溉制度进行了初步的研究。结果表明 ,在塔克拉玛干沙漠腹地造林 ,滴灌、沟灌和畦灌地每年灌溉水量分别为 3 4 6 - 41 6 m3 /亩、894- 1 0 73 m3 /亩和 1 5 5 8-1 870 m3 /亩 ,每次灌溉后的间隔期 ,7— 8月份 5— 7天 ,其它月份 7— 1 0天灌溉一次较为合理 ,这样年植物整个生育期灌溉 2 5— 3 0水时 ,植物的生长不会受到水分的严重协迫     

中间锦鸡儿冠层降雨再分配特征

以荒漠草原人工中间锦鸡儿(Caragana intermedia)灌丛为对象,研究降雨量及降雨强度对两类形态灌丛(健康组和退化组)穿透雨、树干茎流和冠层截留的影响。结果表明:①试验期间共观测到有效降雨33次,以中小降雨事件为主,总降雨量为251mm,次平均降雨量和平均降雨强度分别为7.6mm和1.14mm·h^-1,其中降雨量<2mm,降雨强度<1mm·h^-1的降雨事件出现次数最多。②健康组和退化组中间锦鸡儿平均穿透雨率、树干茎流率和冠层截留率分别为66.7%、8.5%、24.8%和75.4%、8.7%、16.0%,两类形态灌丛之间穿透雨和截留存在显著差异(P<0.05)。③两类形态灌丛的穿透雨量、树干茎流量、截留量与降雨量成线性函数、对数函数和幂函数关系,且其穿透雨率、树干茎流率和截留率与降雨量、降雨强度之间成对数函数和幂函数关系。灌丛形态退化显著改变了冠层降雨再分配格局,冠层截留显著降低,穿透雨显著增加,潜在提高了降水对土壤水分的直接补充,一定程度上有利于人工中间锦鸡儿稳定性的维持。     

不同种源沙柳(Salix psammophila)苗木蒸腾耗水特性的研究

于2004年生长季节利用BP3400精密天平等仪器,在人工模拟干旱的条件下,对5个种源沙柳苗木的连日耗水量和耗水速率日变化规律进行观测。结果表明:5个种源沙柳的连日耗水量呈现一致的波动递减趋势;耗水速率日变化均呈明显的"单峰型"曲线,峰值出现在12:00-14:00,随干旱胁迫的加剧,民勤和榆林种源提前到10:00-14:00。白天平均耗水速率和最大耗水速率均是适宜水分>中度干旱>严重干旱。民勤种源在整个干旱胁迫过程中总耗水量最小为1876.9g,其次是达拉特种源(1972.8g)和盐池种源(2001.8g),耗水量最大是乌审旗(2200.6g)和榆林种源(2112.9g)。沙柳各种源最大耗水速率与白天平均耗水速率的比值非常接近,平均为1.56,根据这一比例关系,在对沙柳的最大耗水速率进行测定后,可以推算出其白天的平均耗水速率,并进一步推算白天(或整天)的耗水量。