华北平原滴灌灌溉频率对萝卜生长的影响

研究了华北平原秋萝卜滴灌条件下 ,不同滴灌频率处理对萝卜叶面积系数、叶绿素含量、萝卜周径膨大、萝卜干重积累、根长密度、根干重密度等萝卜生长参数的影响并比较了各处理间萝卜产量的差异 ,发现在华北平原下半年降雨较多的情况下种植秋萝卜 ;1滴灌频率无论是 1 d1次还是 8d1次 ,对萝卜生长发育都没有明显影响 ;2滴灌条件下萝卜的平均重量和产量大大高于地面灌溉     

Effects of drip irrigation frequency on soil wetting pattern and potato growth in North China Plain

The effect of irrigation frequency on soil water distribution, potato root distribution, potato tuber yield and water use efficiency was studied in 2001 and 2002 field experiments. Treatments consisted of six different drip irrigation frequencies: N1 (once every day), N2 (once every 2 days), N3 (once every 3 days), N4 (once every 4 days), N6 (once every 6 days) and N8 (once every 8 days), with total drip irrigation water equal for the different frequencies. The results indicated that drip irrigation frequency did affect soil water distribution, depending on potato growing stage, soil depth and distance from the emitter. Under treatment N1, soil matric potential (ψ_m) Variations at depths of 70 and 90 cm showed a larger wetted soil range than was initially expected. Potato root growth was also affected by drip irrigation frequency to some extent: the higher the frequency, the higher was the root length density (RLD) in 0–60 cm soil layer and the lower was the root length density (RWD) in 0–10 cm soil layer. On the other hand, potato roots were not limited in wetted soil volume even when the crop was irrigated at the highest frequency. High frequency irrigation enhanced potato tuber growth and water use efficiency (WUE). Reducing irrigation frequency from N1 to N8 resulted in significant yield reductions by 33.4 and 29.1% in 2001 and 2002, respectively. For total ET, little difference was found among the different irrigation frequency treatments.     

不同灌水量与灌水频率对加工番茄根系生长和产量的影响

为了了解不同灌水量和灌水频率对加工番茄根系生长和产量的影响,试验设置3个灌水定额和2个灌水频率.试验结果表明,加工番茄根系主要分布在(10,40］ cm土层(约占比63.20%~85.67%),随着土壤深度的增加,根系生长和干物质量逐渐减小;常规频率(F2)和低水(W3)有促使根系向深层土壤发育的趋势,高频灌溉(F1)和高水(W1)会促进根系在相对浅层的土壤范围内分布;相比常规频率,高频处理下土壤含水量波动较小,且保持在稳定的范围内.同时发现,土壤含水量、叶面积指数、干物质量和产量随着灌水定额和灌水频率的增大,均呈现出增加趋势;相同灌水频率下,高水和适水处理下加工番茄产量差异不具有统计学意义(P>0.05),但显著高于低水处理下加工番茄产量(P<0.05).综合考虑根系生长、产量和节约水资源,适用于西北地区加工番茄种植的较优灌溉制度为:75%ET₀的灌水定额,灌水频率苗期一周 1 次,开花坐果期至拉秧期一周3次.     

Potato evapotranspiration and yield under different drip irrigation regimes

A field experiment comparing different irrigation frequencies and soil matric potential thresholds on potato evapotranspiration (ET), yield (Y) and water-use efficiency (WUE) was carried out in a loam soil. The experiment included five treatments for soil matric potential: F1 (-15 kPa), F2 (-25 kPa), F3 (-35 kPa), F4 (-45 kPa) and F5 (-55 kPa) and six treatments for irrigation frequency: N1 (once every day), N2 (once every 2 days), N3 (once every 3 days), N4 (once every 4 days), N6 (once every 6 days) and N8 (once every 8 days). Results indicate that both soil matric potential and drip irrigation frequency influenced potato ET, Y and WUE. Potato ET increased as irrigation frequency and soil matric potential increased. Comparing soil water potential, the highest ET was 63.4 mm (32.1%) more than the lowest value. Based on irrigation frequency treatments, the highest ET was 36.7 mm (19.2%) more than the lowest value. Potato Y and WUE were also found to increase as irrigation frequency increased. Potato Y increased with an increase in soil water potential then started to decrease. The highest Y and WUE values were achieved with a soil matric potential threshold of -25 kPa and an irrigation frequency of once a day.Communicated by J. Ayars     

干旱区玉米滴灌需水规律的田间试验研究

在内蒙古干旱区的一种砂土及砂质壤土上 ,对玉米滴灌需水规律进行了田间试验研究。试验设置高灌水定额 ( 3 0～ 40 mm)、中灌水定额 ( 2 0～ 3 0 mm)和低灌水定额 ( 1 5～ 2 5 mm ) 3个处理 ,灌水周期相同 ,在需水高峰期为 3 d,其它时间为 4～ 7d。试验结果表明 ,中灌水定额处理的株高、叶面积和产量均明显高于低灌水定额处理 ,而高灌水定额与低灌水定额处理之间差异很小。因此对所研究土壤来说 ,建议采用灌水定额 2 0～3 0 mm,灌水周期 3～ 5 d的灌溉制度。这种情况下 ,玉米生育期需水量为 466mm (生育期有效降雨 1 0 1 .1mm)。对滴灌玉米作物系数的计算方法进行比较后发现 ,双作物系数法可以较好地描述灌水或降雨后地表蒸发对作物腾发的影响 ;在作物生育中期 ,分段单值平均法、双作物系数法的计算结果与实测值吻合良好。     

实用型滴灌灌溉计划制定方法

介绍了适合日光温室、塑料大棚等设施栽培和小块农田经济作物栽培滴灌灌溉计划制定的2种方法。方法一：将真空表负压计埋在滴头正下方20cm深度处监测土壤水势，每次的灌水量相同，或者将作物整个生育期分为2～3个生长阶段，每个生长阶段内每次的灌水量相同．只要土壤水势超出预定的范围，就进行灌溉。对于大部分作物，只要每次的灌水量在5mm左右，土壤水势保持在25～35kPa的范围内，就能获得比较理想的产量。方法二：在冠层顶部放置一个20cm标准蒸发皿，灌溉频率一定．将一个灌水周期内蒸发皿的蒸发量乘以比例系数作为下一个灌水周期的灌水量。对于大部分日光温室和塑料大棚栽培的作物来说，只要将这个比例系数定为1，灌水周期定为每天1次、每2天1次或每3天1次，就能获得比较理想的产量。     

不同灌水量和灌水频率对田间黄瓜耗水特性及产量的影响

【目的】确定大田黄瓜最适宜的灌溉频率和灌水量。【方法】试验于2018年在华北水利水电大学农业高效用水试验场进行,以20cm标准蒸发皿的累积蒸发量(E20)作为灌水依据,灌溉处理分为2个灌溉间隔(I1:3d;I2:6d)和3种水面蒸发系数(K1:0.5;K2:0.7;K3:0.9),共6个处理,对黄瓜耗水特性、产量构成和水分利用效率进行了分析。【结果】黄瓜整个生育期耗水量在380~570mm之间波动,黄瓜的产量在18.2~46.1t/hm2之间波动。从不同灌水频率组合来看,I2K3处理的产量最高,其中,K3处理的早期产量最高,而I1与I2处理的水分利用效率无明显差异。果实数与灌水量之间、耗水量与产量之间均呈正线性相关关系。【结论】建议对于田间黄瓜栽培,灌溉间隔设置为6d,蒸发皿系数选择0.9为宜。     

灌水频率对绿洲菊芋耗水特征及水分利用效率的影响

灌水频率对作物耗水特征和水分利用效率有重要影响,但对以收获地下块茎为主要目的的经济作物研究并不多见。以菊芋为材料,分别在苗期(S)、枝繁叶茂期(L)、现蕾期(B)和开花期(F)施加不同灌水组合,包括苗期600 m3/hm2(S600,下同)处理J1、S600+L600为J2、S600+B600为J3、S600+L300+B900为J4、S600+L900+B300为J5、S600+L600+B300+F900为J6及全生育期不灌水的对照CK,研究菊芋农田水分利用状况。结果表明,枝繁叶茂期和苗期是菊芋水分消耗和需求最大的时期,其次为现蕾期。不同灌水频率下菊芋苗期耗水量、耗水强度及耗水模数差异不大(p0.05),但与不灌水相比差异显著(p0.05)。枝繁叶茂期和现蕾期缺水导致菊芋耗水量和耗水强度显著下降,而开花期灌水菊芋耗水量、耗水强度及耗水模数显著增大。菊芋全生育期耗水量随灌水频率和灌水量增大而增大,但灌水频率和总灌水量一定时,不同生育期灌水量分配对菊芋耗水量无显著影响。不同灌水频率下菊芋全生育期耗水量比不灌水显著增加55.3%~205.6%,灌水频率越高耗水量越大。菊芋水分利用效率随灌水频率和灌水量增大而降低,但相同灌水频率和灌水量下菊芋生育期内灌水量不同时水分利用效率差异不大。总体而言,以收获地下块茎为主要目的的经济作物在耗水规律和水分利用特征方面明显不同于以收获籽粒为目的的粮食作物,应保证营养生长期和并进生长阶段的水分供应以满足蒸腾需水和光合同化对水分的需求,而生殖生长期则应适当减少灌水量以抑制作物奢侈蒸腾,提高水分利用效率。     

Numerical evaluation of subsurface trickle irrigation with brackish water

In this study, an assessment for a proposed irrigation system in the El-Salam Canal cultivated land, Egypt, was conducted. A numerical model (HYDRUS-2D/3D) was applied to investigate the effect of irrigation amount, frequency, and emitter depth on the wetted soil volume, soil salinity levels, and deep percolation under subsurface trickle irrigation (SDI) of tomato growing with brackish irrigation water in three different soil types. The simulations indicated that lower irrigation frequency increased the wetted soil volume without significant increase in water percolates below the plant roots. Deep percolation decreased as the amount of irrigation water and emitter depth decreased. With the same amount of irrigation water, the volume of leached soil was larger at lower irrigation frequency. The salinity of irrigation water under SDI with shallow emitter depth did not show any significant effect on increasing the soil salinity above tomato crop salt tolerance. Based on the results, it appears that the use of SDI with brackish irrigation water is an effective method for growing tomato crop in El-Salam Canal cultivated land especially with shallow emitter depth.     

微纳米气泡水滴灌对设施甜瓜产量、品质及灌溉水利用效率的影响

[目的]提出适合设施甜瓜栽培的微纳米气泡水(Micro-nano Bubble Water,MNBW)滴灌模式.[方法]以设施甜瓜为供试对象,采用地下滴灌系统进行MNBW灌溉,研究了MNBW和传统地下水(Conventional Groundwater,CGW)4种水源、2种施肥水平(100％和80％滴灌施肥水平)、3...     

Effect of irrigation and harvesting dates on the yield of spring-sown sugar-beet

Results are given from a 2-year trial (1979–80) on sugar-beet sown in the spring in the Sele River Plain (Southern Italy).Four watering regimes were compared in factorial combination with two harvesting dates: in addition to no irrigation, three different irrigation schedules were applied during the growing season, based on the net accumulated pan “A” evaporation, the crop coefficient and an irrigation cycle coefficient.In the 1st year, highest yields of roots and sucrose were obtained with the largest water depths (555 and 655 mm for the two irrigation dates) applying short irrigation cycles; in the 2nd year, with intermediate water depths (300 and 350 mm) and intermediate irrigation cycles. Irrigation increased mean weight and size of roots and decreased sucrose percentage. A 1-month delay in harvest increased mean weight, sizes and yield of roots and decreased the sucrose percent although the final sucrose yield was not affected.     

Frequency and amount of irrigation for maize in western Nigeria

This study was designed to investigate the frequency and amount of irrigation needed for maize in westerń Nigeria. The investigation indicated that about 330 mm of water either from irrigation or from well distributed rainfall is sufficient to produce a good crop of maize utilizing an irrigation frequency of 7 days. For good maize yields, soil moisture in the root zone should be maintained at a high level throughout the growing period. This avoids moisture stress and permits easy nutrient uptake by the plant, resulting in higher yields. Crop water use efficiency increased as the soil moisture level increased. A moisture level of approximately 70% of field capacity was sufficient to produce a good yield.     

Simulation of water dynamics and irrigation scheduling for winter wheat and maize in seasonal frost areas

Continuous cropping of winter wheat and summer maize is the main cropping pattern in North China Plain lying in a seasonal frost area. Irrigation scheduling of one crop will influence soil water regime and irrigation scheduling of the subsequent crop. Therefore, irrigation scheduling of winter wheat and maize should be studied as a whole. Considering the meteorological and crop characteristics of the area lying in a seasonal frost area, a cropping year is divided into crop growing period and frost period. Model of simultaneous moisture and heat transfer (SMHT) for the frost period and model of soil water transfer (SWT) for the crop growing period were developed, and used jointly for the simulation of soil water dynamics and irrigation scheduling for a whole cropping year. The model was calibrated and validated with field experiment of winter wheat and maize in Beijing, China. Then the model was applied to the simulation of water dynamics and irrigation scheduling with different precipitation and irrigation treatments. From the simulation results, precipitation can meet the crop water requirement of maize to a great extent, and irrigation at the seeding stage may be necessary. Precipitation and irrigation had no significant influence on evaporation and transpiration of maize. On the other hand, irrigation scheduling of winter wheat mainly depends on irrigation standard. Irrigation at the seeding stage and before soil freezing is usually necessary. For high irrigation standard, four times of irrigation are required after greening. While for medium irrigation, only once (rainy year) or twice (medium and dry years) of irrigation is required after greening. Transpiration of winter wheat is very close for high and medium irrigation, but it decreases significantly for low irrigation and will result in a reduction of crop yield. Irrigation with proper time and amount is necessary for winter wheat. Considering irrigation quota and crop transpiration comprehensively, medium irrigation is recommended for the irrigation of winter wheat in the studying area, which can reduce the irrigation quota of over 150 mm with little water stress for crop growth.     

The influence of method and frequency of irrigation on soil aeration and some biochemical responses of apple trees

Summary The effect of various irrigation regimes on soil aeration was tested in a two-year experiment with 15 year-old apple trees growing in soil containing 67% clay. Irrigation was applied by sprinklers at four intervals ranging from 3 to 18 days and by trickle irrigation every 7 days. Each treatment received a total of 800–850 mm water from May until September. Irrigation by sprinkling at 7 day intervals appeared to be optimal for fruit growth. Less frequent irrigations resulted in smaller fruits; sprinkling at 3–4 day intervals, as well as trickle irrigation reduced the fruit growth rate in July. Leaves from plots irrigated once every 3–4 days had a low chlorophyll content and accumulated relatively large amounts of ethanol, particularly when grafted on the Khashabi rootstock, which is highly susceptible to damage caused by inadequate soil aeration. With increasing intervals between irrigations, the resistance of the leaf surface to the diffusion of water vapour measured prior to irrigation increased, and water loss relative to that from an evaporation pan decreased. Sprinkling at intervals of 14 days resulted in maximal, and at 3–4 days in minimal, air contents of the soil when calculated as averages for the total period of irrigation. The decrease in soil air content with very frequent irrigations was particularly marked in the upper soil layer; this same layer also had a relatively low air content near the emitters in trickle irrigation. After each irrigation, relatively large amounts of ethylene accumulated in the soil atmosphere, indicating inadequate soil aeration, particularly with sprinkling intervals of 3–4 days and at a depth of 30 cm. However, the influence of the irrigation treatments on the oxygen and carbon dioxide contents of the soil atmosphere was small and not consistent.     

灌水模式对油葵耗水量产量及经济效益的影响

通过5种灌水处理模式和对照旱地油葵田间试验，探讨了灌水模式对油葵耗水量、产量、水分利用效率以及经济收入的影响。结果表明，油葵出盘前和灌浆后耗水量比其他时段多50％以上。在油葵不同生育阶段耗水量随着灌水量增加而增加；灌水定额120mm，灌两次水的灌水模式的产量最高，为2268kg／hm^2，而水分利用效率最大值出现在灌水定额66mm的灌水模式，灌水量增加反而使水分利用效率下降。经济分析结果表明，纯收入最高值出现在灌水模式93mm灌二水的处理，为2871元／hm^2，灌水定额增加或减少均导致经济收入下降。统计分析结果表明，干旱年份（全生育期有效降水量123mm）灌二水时，为了兼顾产量、水分利用效率以及经济收入，油葵最佳总灌水量以208-218mm为宜。全生育期有效降水量超过350mm的丰水年份不应该再灌水。     

不同沟灌方式下夏玉米棵间蒸发试验

采用常规沟灌和交替隔沟灌技术,研究了不同水分处理(水分控制下限为田间持水率的80%、70%、60%)夏玉米的棵间蒸发。结果表明:常规沟灌的灌后蒸发和全生育期棵间蒸发量均大于交替隔沟灌,灌水后短期内由于表层土壤含水率较高,土壤蒸发较大;在满足作物蒸腾耗水的基础上,交替隔沟灌减小了灌溉湿润面积而减小无效蒸发耗水;不同沟灌方式下土壤蒸发与表层土壤含水率呈明显的脉冲波动变化,而深层土壤含水率波动较弱;表层土壤含水率和叶面积指数对棵间蒸发影响明显,二者与相对土面蒸发强度均有良好的指数函数关系。水分下限控制合适,交替隔沟灌棵间蒸发与蒸腾耗水明显降低,是夏玉米适宜的灌水方式。     

The effects of different irrigation regimes on cucumber (Cucumbis sativus L.) yield and yield characteristics under open field conditions

A study was conducted to determine the effects of different drip irrigation regimes on yield and yield components of cucumber (Cucumbis sativus L.) and to determine a threshold value for crop water stress index (CWSI) based on irrigation programming. Four different irrigation treatments as 50 (T-50), 75 (T-75), 100 (T-100) and 125% (T-125) of irrigation water applied/cumulative pan evaporation (IW/CPE) ratio with 3-day-period were studied.Seasonal crop evapotranspiration (ET_c) values were 633, 740, 815 and 903 mm in the 1st year and were 679, 777, 875 and 990 mm in the 2nd year for T-50, T-75, T-100 and T-125, respectively. Seasonal irrigation water amounts were 542, 677, 813 and 949 mm in 2002 and 576, 725, 875 and 1025 mm in 2003, respectively. Maximum marketable fruit yield was from T-100 treatment with 76.65 t ha⁻¹ in 2002 and 68.13 t ha⁻¹ in 2003. Fruit yield was reduced significantly, as irrigation rate was decreased. The water use efficiency (WUE) ranged from 7.37 to 9.40 kg m⁻³ and 6.32 to 7.79 kg m⁻³ in 2002 and 2003, respectively, while irrigation water use efficiencies (IWUE) were between 7.02 and 9.93 kg m⁻³ in 2002 and between 6.11 and 8.82 kg m⁻³ in 2003.When the irrigation rate was decreased, crop transpiration rate decreased as well resulting in increased crop canopy temperatures and CWSI values and resulted in reduced yield. The results indicated that a seasonal mean CWSI value of 0.20 would result in decreased yield. Therefore, a CWSI = 0.20 could be taken as a threshold value to start irrigation for cucumber grown in open field under semi-arid conditions.Results of this study demonstrate that 1.00 IW/CPE water applications by a drip system in a 3-day irrigation frequency would be optimal for growth in semiarid regions.     

Rice growth, yield and water productivity responses to irrigation scheduling prior to the delayed application of continuous flooding in south-east Australia

The majority of rice grown in south-east Australia is continuously flooded for much of its growing season, but reduced irrigation water availability brought about by a combination of drought and environmental flow legislation has presented a need to maintain (or even increase) rice production with less irrigation water. Delaying the application of continuous flooding until prior to panicle initiation can increase input water productivity by reducing non-beneficial evaporation losses from free water and the soil. A field experiment was conducted over two growing seasons, 2008/9 and 2009/10, comparing a conventional dry seeded treatment (the control - continuous flooding from the 3 leaf stage) with delayed continuous flooding (10-20 days prior to panicle initiation) with several irrigation scheduling treatments prior to flooding commencement. In the first year, the delayed water treatments were irrigated at intervals of 40, 80 and 160 mm of cumulative reference evapotranspiration (ETo) prior to delayed continuous flooding, thereby imposing differing degrees of crop water stress. In year 2, the 80 and 160 mm treatments were modified by use of a crop factor (Kc) when the plants were small and the 40 mm treatment was replaced with a continuously flooded treatment throughout the crop duration.Decreases in net water input (irrigation + rain − surface drainage) and increases in input water productivity were achieved by reducing the flush irrigation frequency during the pre-flood period. Savings of 150 and 230 mm (10 and 15%) were achieved in Year 1 from the 80 and 160 mm cumulative ETo irrigation frequency treatments, respectively, in comparison to the control. In the second year, net water input savings of 230 and 330 mm (15 and 22%) were achieved with the 80/Kc and 160/Kc mm treatments, respectively. Input water productivity of the 160 mm treatment was 0.06 kg/m³ (8%) higher than the control in Year 1, while in Year 2 a 0.15 kg/m³ (17%) increase in input water productivity above the control was achieved by the 160/Kc mm treatment. Delaying the application of continuous flooding in the second year greatly extended the period of crop growth suggesting the need for earlier sowing (by 7-10 days) to ensure pollen microspore still occurs at the best time to minimise yield loss due to cold damage. Nitrogen fertiliser management is an important issue when delaying continuous flooding, and nitrogen losses appeared to increase with the frequency of irrigation prior to continuous flooding. This was likely due to increased denitrification from alternate wetting and drying of the soil. Further research is required to determine the most appropriate nitrogen management strategies, and to also better define the optimal pre-flood irrigation frequency.     

Application efficiency of micro-sprinkler irrigation of almond trees

Micro-sprinklers are becoming a preferred irrigation method for water application in orchards. However, there is relatively little data available to support a particular irrigation scheduling method. The objective of this study is to quantify the components of the water balance of an almond tree under micro-sprinkler irrigation. For that purpose, an experimental plot around an almond tree with an area of 2.0 m X 2.0 m without vegetation, representing about one quarter of the wetted area of the micro-sprinkler was instrumented with neutron access tubes, tensiometers and catch cans. Twenty-five access tubes with catch cans were distributed in a square grid of 0.5 m × 0.5 m, to a depth of 0.9 m. Eight pairs of tensiometers were installed at depths of 0.825 and 0.975 m within the experimental plot. During a 7-day period in August, 1995 the plot was sprinkler-irrigated on three days, and water application rates and uniformity coefficients were calculated for each irrigation event. Neutron probe readings at 15 cm depth increments and tensiometer readings were taken 4 to 6 times daily. Results showed large evaporation losses during and immediately after the irrigations. Evaporation losses of the wetted area was estimated to be between 2 and 4 mm/irrigation event. Consequently, application efficiencies were only 73–79%, the wetting of the root zone was limited to the 0–30 cm depth interval only, the soil profile was depleted of soil water, and daily crop coefficient values at days between irrigation events were between 0.6 and 0.8. The study recommends irrigation in the evening and night hours, thereby largely eliminating the evaporation losses that occur during daytime irrigation hours.     

地中仪地膜棉灌溉试验特征分析

利用不同地下水埋深的地中仪进行地膜棉的灌溉试验，分析了地膜棉不同生育期时蒸发、入渗的变化特征：受地膜棉的蒸腾作用，灌溉入渗量随其日耗水量增加而显著减少；棉花根系吸水影响深度与其日耗水强度成指数关系，其根系吸水最大影响深度为2．76m；棉花根系利用地下水量随埋深增加而减小，棉田最佳的灌水湿润深度应小于1．0m，当灌水湿润深度超过1．5m时，其根系不能更多利用地下水，即可认为是深层入渗。