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1.
A field experiment was conducted with a bunched variety of peanut (Arachis hypogaea L.) cv. JL-24 during the summer seasons (March–June) of 1992 and 1993 in the humid tropical canal command area at the University Experimental Farm, Memari (23°1 N, 88°5 E and 21.34 m a.s.l) in West Bengal of eastern India. The soil at the site is of sandy loam (Typic Fluvaquent) texture and the area has a shallow water table. Weekly and seasonal field water balance components of actual evapotranspiration (ETa) including the capillary contribution into root zone were determined. Peanut yield and water productivity were determined for three ratios of irrigation water and cumulative pan evaporation (CPE) of 0.9, 0.7 and 0.5. Mean crop coefficients were determined for each 7-day period of growth and were related to leaf area index and growing degree-days. Average seasonal values of ETa of peanut were 434, 391 and 356 mm for the three treatments, respectively, for 115 days of growth. The total pod yield and WP were significantly higher in 0.9 IW:CPE treatment in the 1992 season. On an average, 0.9 IW:CPE treatment had 7 and 11% higher yields in 1992 and 1993, respectively, over treatments 0.7 and 0.5 IW:CPE. The maximum average Kc of 1.19 occurred about 9 weeks after sowing relative to grass reference ET (ETo). 相似文献
2.
Houshang Ghamarnia Mohsen Golamian Saloome Sepehri Issa Arji Samera Norozpour 《Irrigation Science》2013,31(3):285-299
Lysimetric experiments were conducted to determine the contribution made by groundwater to the overall water requirements of safflower (Carthamus tinctorius L.). The plants were grown in 24 columns, each having a diameter of 0.40 m and packed with silty clay soil. The four replicate randomized complete block factorial experiments were carried out using different treatment combinations. Six treatments were applied during each experiment by maintaining groundwater, with an EC of 1 dS m?1, at three different water table levels (0.6, 0.8 and 1.10 m) with and without supplementary irrigation. The uptake of groundwater as a part of crop evapotranspiration was measured by taking daily readings of the water levels found in Mariotte tubes. The supplementary irrigation requirement for each treatment was applied by adding water (EC of 1 dS m?1). The average percentage contribution from groundwater for the treatments (with and without supplementary irrigation under water table levels of 0.6, 0.8 and 1.10 m) were found to be 65, 59, 38% and 72, 70, 47% of the average annual safflower water requirement (6,466 m3 ha?1). The increase in groundwater depths under supplementary irrigation treatments from 0.6 to 0.80 and 1.10 m caused seed and oil yield reductions of (7, 23.10%) and (48.23, 65.40%), respectively. 相似文献
3.
《灌溉排水学报》2019,(9)
【目的】了解土壤环境、肥力变化,为改善土壤质量、提高作物产量提供一定的依据。【方法】以紫花苜蓿为试验材料,设置了4种不同的耕作方式,分别为平作不覆膜(TW)、平作覆膜(TM)、垄作不覆膜(RW)、垄作覆膜(RM),分析了4种耕作方式下土壤酶活性、含水率的变化情况及其对紫花苜蓿生长状况和产量的影响。【结果】与TW耕作方式相比,TM、RW、RM耕作方式均能显著提高土壤表层脲酶及碱性磷酸酶活性,并且对0～20 cm土壤酶活性影响最为明显。4种耕作方式对土壤表层0～10 cm范围内的含水率影响显著,与9月相比,7月4种耕作方式下的土壤含水率变化情况更大。4种耕作方式中垄作覆膜处理条件下紫花苜蓿平均株高最高,产量最大(7.42 kg/m2)。【结论】4种耕作方式中,RM耕作方式下,土壤酶活性平均值最高,土壤肥力状况最好,而在深度为0～60 cm范围内,0～20 cm深度处土壤酶活性变化最为明显;与耕作方式相比,季节性因素对土壤含水率的影响更大;RM处理条件下紫花苜蓿生长的更好。 相似文献
4.
地下水埋深对冬麦田土壤水分及产量的影响 总被引：14，自引：1，他引：14
通过6种地下水位控制处理和对照(自然地下水位)冬小麦试验,探讨了不同地下水埋深对冬麦田土壤水分季节变化规律和垂直变化规律、地下水-土壤水界面水分转化量变化过程以及对冬麦田田间土壤水分平衡的影响。结果表明,地下水埋深对冬麦田0～60cm土壤水分动态有着明显的影响。地下水埋深越浅,麦田表层和主要根层土壤储水量季节变化越强烈,地下水对土壤水分的补给量越大,冬小麦全生育期耗水量也随着增加;土壤排水量大小与灌溉量和降雨量大小有关。地下水位埋深越深,灌溉和降水后的土壤开始排水日期越滞后;无论地下水埋深深浅,冬麦田累计地下水补给量变化规律可分为4个阶段,即稳定增长期、缓慢增长期、快速增长期和趋于稳定期;地下水埋深1.5m时冬小麦产量最高,地下水位太深或太浅产量均下降。水分利用率最高值出现在地下水埋深1.0m的处理。地下水位在1.0m以下时,水分利用效率随地下水深度加深和灌水量增加而减少。 相似文献
5.
【目的】提高华北地区紫花苜蓿水分利用效率,兼顾产量与品质。【方法】于2018年4―9月,在河北涿州中国农业大学教学实验场,以紫花苜蓿品种WL363HQ为试验材料,开展紫花苜蓿田间灌溉试验。试验设置3个灌水处理:W1处理,灌水下限45%FC(田间持水率),灌水上限90%FC;W2处理,灌水下限60%FC,灌水上限90%FC;W3处理,根据当地生产经验定额灌溉为39 mm,研究了不同灌水下限对紫花苜蓿生长、产量和品质的影响。【结果】建植第5年的紫花苜蓿,全生长季需水量511.9 mm。苜蓿细根根系主要分布在0~40 cm土层,0~20 cm土层根系密度最高。灌水对第1、第2茬及全年产量没有显著影响(P>0.05),对第3茬产量有显著影响(P<0.05)。第1、第2、第3茬内采用W1处理苜蓿水分利用效率最高。不同灌水处理对苜蓿粗蛋白量没有显著影响(P>0.05),减少灌水量能增加苜蓿相对饲喂价值。【结论】建议华北地区紫花苜蓿第1、第2、第3茬采用45%FC灌水下限,第4茬采用60%FC灌水下限。 相似文献
6.
Summary Many irrigated lands in semi-arid regions of the world are underlain with saline high water tables. Water management is critical to maintain crop productivity under these conditions. A multi-seasonal, transient state model was used to simulate cotton and alfalfa production under various irrigation management regimes. The variables included in-season water application of 1.0 or 0.6 potential evapotranspiration (PET), and 18 or 33 cm pre-irrigation amounts for cotton. The water table was initially at a 1.5m depth and a 9 dS/m salinity. A impermeable lower boundary at 2.5 m depth was imposed. Irrigation water salinity was 0.4 dS/m. Climatic conditions typical to the San Joaquin Valley of California were used for PET and precipitation values. The simulations were for no-lateral flow and also lateral flow whereby the water table was raised to its initial level prior to each irrigation event. Uniform application of 1.0 PET provided for relative cotton lint yields and alfalfa yields of 95% or more for at least 4 years. In-season irrigation of cotton with 0.6 PET had higher yields when associated with a 33 cm rather than an 18 cm pre-irrigation. Lateral flow provided for higher cotton lint yields production than the no-lateral flow case for each pre-irrigation treatment. The beneficial effects of lateral flow diminished with time because of the additional salt which accumulated and became detrimental to crop production. Substantial alfalfa yield reductions occurred after the first year when irrigation was set at 0.6 PET regardless of other conditions. Evaporation losses from the soil during the cotton fallow season were higher when the soil water content entering the fallow season were higher.Research was supported by the University of California Salinity/ Drainage Task Force 相似文献
7.
Studies were conducted during 4 months of each growing season in 1994 and 1995 to measure water use of young apple trees (Malus domestica Borkh. cv ‘Fuji’) growing under different soil moisture regimes in temperate climate conditions and to evaluate monthly crop coefficients of such conditions. To do so, double pot lysimeters under a transparent rain shield were designed and installed. The three soil moisture regimes in three replicates each were: (A) drip-irrigation at −50 kPa of soil matric potential (IR50); (B) drip-irrigation at −80 kPa of soil matric potential (IR80); and (C) constant shallow water table at 0.45 m below the soil surface (WT45). In each treatment, soil surface was maintained with or without turf grasses. Monthly water use was not different in drip-irrigated treatments (IR50 and IR80), but greatest in the WT45 treatment. Monthly crop coefficients increased linearly in time for drip-irrigated apple trees (r2 values of 0.76*** for IR50 and of 0.77*** for IR80), while those obtained in the WT45 treatment fluctuated. Leaf water potential (LWP) of drip-irrigated trees was similar until 63 days after treatment (DAT), but the values for IR80 trees began to decline thereafter. The LWP of WT45 trees decreased from 48 DAT. Temporal variations in leaf water content (LWC) was similar to that of LWP, except for two abrupt decreases in IR80 trees. The LWC of WT45 trees began to decrease from 59 DAT, and this occurred 2 weeks after the reduction in LWP. Average shoot length of IR50 trees was greater than that of IR80 and WT45 trees. The results of this study provided water use and crop coefficients for apple trees in relation to soil moisture regimes under temperate climate. 相似文献
8.
Rob M. Stevens Gordon Harvey Scott Norton William Frahn 《Agricultural Water Management》2011,101(1):62-70
Wetting plant foliage with saline irrigation increases the uptake of toxic ions Na+ and Cl−. Over three consecutive seasons, Colombard vines grafted on Ramsey rootstock were irrigated with saline water (EC 3.5 dS/m) by over-canopy sprinklers during any one of the first three of the four annual growth stages: bud burst to full bloom (treatment BB-FB), full bloom to veraison (treatment FB-V), and veraison to harvest (treatment V-H). At other times, vines received non-saline water (EC 0.5 dS/m) as did the control. Seasonal average soil salinities remained relatively constant over the trial. In contrast, the concentrations of Na+ and Cl− in one-year old wood and grape juice more than doubled. In treatments FB-V and V-H the average yield over the three seasons was reduced by up to 15%. Results were compared with those obtained in an earlier study which was undertaken in the same vineyard with the same treatments applied via dripper. With drippers, the maximum reduction in the average yield over three seasons was 2%. Saline sprinkling caused rises in Na+ and Cl− concentrations of fruit, leaf lamina and one-year-old wood that were at least 7-fold, 5-fold and 2-fold greater, respectively, than the rises caused by application of the same treatments with drip. Progressive seasonal rises in the concentrations of Na+ and Cl− in these tissues were due in part to carryover of salt added in previous seasons; with saline sprinkling the magnitude of these carryovers was 4-fold greater than those with saline drip irrigation. With saline water, vignerons can reduce losses by using irrigation systems which do not wet the foliage. 相似文献
9.
为明确不同改良措施对膜下滴灌棉田土壤脱盐效果及棉花生理特征的影响,在野外大田设置了3种类型的改良措施试验:膜间间作的生物改良方式(苜蓿+棉花、孜然+棉花、碱蓬+棉花);土壤中施加不同剂量石膏的化学改良方式(分别施加0.75,1.50,2.25 kg/m2);生物和化学并用的综合改良方式(苜蓿+石膏、孜然+石膏、碱蓬+石膏)以及1组对照(共10个处理),以期为新疆盐碱地改良提供参考.结果表明:与对照相比,3种改良措施均有一定的脱(抑)盐和增产效果,其中苜蓿处理的脱盐效果最好,整个土层和膜间的脱盐率分别达到了56.0%和20.9%;碱蓬+石膏处理的增产效果最好,增产率达到了22.4%;化学改良和综合改良使得Na+和Cl-在生育期末的膜间土层出现聚集,而生物改良则使其在宽行出现了聚集;不同的改良措施均提高了棉花的蒸腾速率、气孔导度和光合速率,且日平均值从大到小表现为综合改良、化学改良、生物改良、对照;各种处理均在一定程度上提高了水分利用效率和灌溉水利用效率,从小到大依次为生物改良,化学改良,综合改良.因改良措施不同,对应的效果差异较大.若追求单一脱盐效果,可选用膜间种植苜蓿的生物改良方式.但是,碱蓬+石膏的综合改良处理不仅具有较好的增产效果,且水分利用效率也较高,在新疆盐碱地的改良中具有较好的前景. 相似文献
10.
喷灌条件下灌水量对建植初期紫花苜蓿产量与品质的影响 总被引：2，自引：0，他引：2
通过圆形喷灌机条件下的大田试验,研究了华北地区紫花苜蓿需水规律以及灌水量对苜蓿产量与品质的影响。结果表明:建植1年刈割4次的苜蓿,年需水量为663.39mm,平均日需水强度为3.6mm/d,需水量最大时期为第二、三茬。灌水量对全年产量影响不显著,其中85%ETc处理下年产量最高。在第一、四茬中,灌水量对产量影响不显著,85%ETc处理下获得最高产量;第二、三茬中,随灌水量增加产量逐渐增加,适当减少灌水(85%ETc)不会使产量明显减少,而灌水量减少至70%ETc时产量下降明显。同时,结果表明随着灌水量增加灌溉水分利用效率(IWUE)逐渐降低,且灌水量对各茬苜蓿品质均无显著性影响。综合考虑产量、品质与节水效果,建议采用85%ETc作为最优灌水量。 相似文献
11.
《Agricultural Water Management》2002,54(3):173-188
Two tillage and two water table control treatments under continuous maize cropping were evaluated over a 3-year period (1992–1994) for their effects on evapotranspiration, surface runoff (SR), tile drainage (TD) and soil water content in the root-zone on a clay loam soil in southern Ontario. The tillage treatments included soil saver (SS, reduced tillage) and moldboard plow (MP, conventional tillage). The water table control treatments included controlled drainage-subirrigation (CDS) and regular tile drainage (DR). There was no significant difference (P<0.05) in evapotranspiration estimates between the SS and MP tillage treatments. The SS tillage increased SR compared with MP tillage during the non-cropping periods in 1993 and 1994, but not in 1992. Relative to MP, the SS tillage increased soil profile water content during the cropping period but decreased soil profile water content during the non-cropping period in 1992. The CDS treatment produced significantly higher (P<0.05) evapotranspiration and soil water content than the drainage treatment during the dry 1993 and 1994 years, but not during the wet 1992 year. The CDS treatment also had significantly lower (P<0.05) TD and higher SR than the drainage treatment. For all the treatments, over 65% of SR and TD occurred in the 5 month non-cropping period from November to March. Of the total annual water input (precipitation and/or subirrigation) to the field site, 8% was partitioned to SR, 30% was partitioned to TD, 55% was removed by crop and soil evapotranspiration and 7% was accounted for by changes in soil profile water content. 相似文献
12.
泾惠渠灌区畦长对夏玉米耗水特性和产量影响 总被引：1，自引：0，他引：1
泾惠渠灌区中畦田规格参差不齐,灌区由于畦田过长而造成的灌溉水量浪费屡见不鲜,不仅没有形成高产而且极大的造成了水资源的浪费。通过大田与小区试验相结合,以当地农民习惯的灌溉方式为对照,设置3个灌溉畦长处理(80、120、240 m),每个处理设置3次重复,改水为80%。研究了灌溉畦长对夏玉米在生育期内的耗水特性和产量的影响,土壤水分分布与产量及其构成因素的关系等问题,选择出兼顾节水高产可行的最优畦长。研究结果表明:在生育期灌水后,80和120 m处理畦长内畦首、畦中和畦尾的土壤相对含水率较为均匀无显著差异,240 m处理畦长畦首、畦中和畦尾的土壤相对含水率产生显著性差异;80和120 m处理夏玉米在畦首、畦中和畦尾灌水均匀度较为平均且无显著差异,240 m畦长处理差异较为显著,且80 m畦长处理产量分布最为平均、平均水分利用效率最高产量为1.021 839万kg/hm2,水分利用效率为25.12 kg/(hm2·mm)。综合夏玉米产量及其分布、水分利用效率等因素,在泾惠渠灌区80 m的灌溉畦长是兼顾节水高产的最适宜畦长,该结论以期为泾惠渠灌区大田作物高产节水提供一定理论依据。 相似文献
13.
T. A. Howell K. R. Davis R. L. McCormick H. Yamada V. T. Walhood D. W. Meek 《Irrigation Science》1984,5(3):195-214
Summary A field experiment was conducted on the west side of the San Joaquin Valley in California to determine water use, crop growth, yield and water use efficiency of Acala (SJ-2) cotton (Gossypium hirsutum L.) grown in 0.5 m spaced rows on a Panoche clay loam soil (Typic Torriorthents). Evapotranspiration was determined by water balance techniques utilizing neutron soil moisture measurements. All neutron measurements were made within a 3 m soil profile in 0.20 m increments. The measured evapotranspiration was compared to climatic estimates of potential evapotranspiration, and to calculations using a one-dimensional soil water balance model that separately computed soil water evaporation and plant transpiration. Crop growth was determined by weekly destructive plant sampling. Leaf area was determined along with dry matter components of leaves, stems, fruiting parts (flowers and squares) and bolls. Final yield was determined by machine harvesting (brush stripper) 720 m2 from each plot. Lint yields and fiber quality were determined by sample ginning and fiber analysis at the U.S. Cotton Research Station at Shafter, California. Three irrigation regimes were established that resulted in an evapotranspiration range from a high deficit condition to full irrigation at the calculated atmospheric demand.The measured evapotranspiration of narrow row cotton under a full irrigation regime was 778 mm, 594 mm under a limited irrigation regime and 441 mm under a regime with no post-plant irrigation. The evapotranspiration from these irrigation treatments was accurately simulated by a water balance model. that used inputs of potential evapotranspiration, leaf area index, soil water holding capacity and root development.The average lint yield from narrow row cotton with a full irrigation regime was 1583 kg/ha, the average lint yield from a limited irrigation regime was 1423 kg/ha and the average lint yield from a treatment with no postplant irrigation (fully recharged soil profile at planting) was 601 kg/ha. The full irrigation regime resulted in a dry matter production of approximately 16 t/ha while the limited irrigated regime produce 11 t/ha and the no-postplant irrigation regime produced 7 t/ha of dry matter. The fiber quality results indicated significant (0.05 level) differences only in 50% span length and micronaire, with the 2.5% span length, uniformity index, elongation and strength indicating no difference.Cotton lint yield was found to be directly related to total evapotranspiration although the relationship was slightly non-linear while dry matter yield was found to be linearly related to evapotranspiration. Both lint and dry matter yield were found to have a linear relationship to estimated transpiration from the water balance model calculations.Contribution from the Unived States Department of Agriculture, Agricultural Research Service, Western Region and the University of California 相似文献
14.
Effects of applied water and sprinkler irrigation uniformity on alfalfa growth and hay yield 总被引：1，自引：0，他引：1
This study was conducted to investigate the effects of applied water and sprinkler irrigation uniformity on alfalfa (Medicago sativa L.) growth and hay yield in a semi-arid region. Field experiments were carried out in 2006 in Varamin, Iran, on three plots of 25 m × 30 m. Each plot was subdivided into 25 subplots of 5 m × 6 m. Different irrigation depths and sprinkler water uniformities were obtained by various scenarios of sprinkler nozzle pressure. In each plot, applied water was measured at 250 points (125 points above and 125 points below canopy) and the soil water content of 40 cm deep below soil surface was monitored at 25 points, each in the center of a subplot, throughout the irrigation season. The results showed that sprinkler water and soil water content uniformity varied between 66-78 and 88-91%, respectively. The findings revealed that soil water content uniformity was around 20% higher than sprinkler water uniformity. The irrigation uniformity below the canopy was estimated to be 2.5% greater than above the canopy, and canopy-intercepted water could account for 11-15% of the total seasonal applied water. Evaluation showed that alfalfa leaf area index relies more heavily on farm water application uniformity than hay yield and crop height. The experimental results illustrated that water distribution in sprinkler irrigation systems has a direct effect on alfalfa growth, hay yield and water productivity such that the applied water reduction and the increased sprinkler water uniformity led to an increased alfalfa water productivity of 2.41 kg m−3. 相似文献
15.
José O. Payero Norman L. Klocke Joel P. Schneekloth Don R. Davison 《Irrigation Science》2006,24(4):257-265
Many farmers in West Central Nebraska have limited irrigation water supplies, and need to produce crops with less water. This study evaluated the impact of four water management strategies on grain yield of surface-irrigated corn (Zea mays L.) at North Platte, Nebraska. Treatments included: (1) no irrigation (DRYLAND), (2) one irrigation prior to tassel formation (EARLY), (3) one irrigation during the silk stage (LATE), and (4) irrigation following farmer’s practices (FARMER). The study included three wet years (1992, 1993, and 1996) and 2 years with average annual rainfall for the area (1994 and 1995). Significant yield differences among treatments, and a yield response to irrigation, were only observed during the 2 years with average rainfall. During all years, the FARMER treatment was over-irrigated and resulted in considerable water losses by runoff and deep percolation. Grain yield response to irrigation during the three wet years was insignificant among the treatments, but significant during the dry years. The results of this study suggest that inducing stress is not a good strategy for increasing crop water productivity (yield per unit ETd) for corn and point out the need to minimize irrigation water losses and improve irrigation scheduling. 相似文献
16.
A field study was conducted in the semiarid region of northern Sudan to investigate the effects of variable irrigation on
the growth, yield, and water use efficiency (WUE) of alfalfa (Medicago sativa L.). Treatments were 65 mm of water applied every 7 days, 80 mm of water applied every 10 days, or 104 mm of water applied
every 13 days. The heavy, infrequent irrigation reduced stem height, stem density, leaf area index (LAI), total biomass production,
and the WUE of alfalfa plants. Maximum yields for six harvests were 15.3, 12.9, and 11.2 ton ha–1 and the WUE values were 0.12, 0.10, and 0.08 ton ha–1 cm–1 for the frequent, less-frequent, and infrequent irrigation regimes, respectively. In all the treatments, alfalfa dry matter
yield was positively correlated with stem height and LAI. The relationship between dry matter yield and total water use was
a linear function (R
2=0.99), regardless of the irrigation treatment. Alfalfa growth, yield, and WUE remained high during the relatively cool months
and declined during the hot period under the three water regimes. It was concluded that alfalfa grown under semiarid conditions
should be watered lightly and frequently to attain high yields and high WUE.
Received: 19 February 1996 相似文献
17.
《Agricultural Water Management》2002,56(2):131-141
Eight-year-old Murcott orange trees grown in greenhouse lysimeters filled with sandy soil were subjected to irrigation with saline water to investigate the influence of salinity on daily evapotranspiration (ET). The study was conducted in Japan from 1 August to 15 September 2000. The study duration was divided into three periods of about 2 weeks each. In period I, all lysimeters planted with a tree were irrigated with 60 mm of non-saline water at the water content of 70% of field capacity (FC). Salinity treatments for period II started on 14 August. The treatments during period II were as follows: Lysimeter 1 (L1) had 32 mm non-saline water with an electrical conductivity (ECI) of 1.0 dS/m applied. At the same time Lysimeter 2 (L2) had 32 mm of saline water with an ECI of 8.6 dS/m applied when the water content decreased to 70% of FC. Lysimeter 3 (L3) had 16 mm saline water (ECI=8.6 dS/m) applied at 85% of FC. The irrigation amounts during period II were equal to those corresponding to 1.2 times of water required to reach FC. Treatments in period III were the same as in period I.Daily ET was similar for all weighing lysimeters during period I. The average relative ET for L2 and L3 with respect to L1 (L2/L1 and L3/L1) were similar during this period, with a mean value of 0.99. During period II, ET from L1 was consistently higher than that from L2 and L3. In addition, L3 with a higher irrigation frequency because of irrigation at higher soil water content resulted in higher ET than L2. The average relative ET of period II was 0.71 and 0.88 for both L2 and L3. During the last half of period III, reductions occurred in the ET differences between the saline treatments (L2 and L3) and non-saline control (L1).Evaporation rates from soil did not exceed 0.7 mm per day. Transpiration rates from L1, L2 and L3 during period II varied between 6.3 and 3.1 mm per day, 4.5 and 2.2 mm per day, and 5.8 and 3.0 mm per day, respectively. The results reflected a tangible difference of water extraction by roots from individual soil layers. Maximum water uptake by these trees was observed at layer of 30–60 cm. Nevertheless, no clear differences in water extraction pattern between trees were observed.Approximately, 95% of drainage occurred during the first 2 days following irrigation. The electrical conductivity of soil water (ECS) and the electrical conductivity of drainage water (ECD) for the saline water treatments (L2 and L3), compared to the control (L1) were significantly different during period II. ECS values were 2–5 times higher in saline treatments compared to the control treatment. After irrigating trees with saline water, ECS increased from 5 to 14 and 16 dS/m in L2 and L3, respectively. Similarly, in both saline treatments, ECD values were greatly increased after irrigation. During period III, ECD values increased from 5 to 8 dS/m in L2, and from 3 to 11 dS/m in L3. By contrast, ECS declined from 14 to 5 dS/m in L2, and from 16 to 3 dS/m in L3 over the same period. 相似文献
18.
《Agricultural Water Management》2001,46(3):231-239
A field lysimeter study was conducted to investigate the effect of initial soil salinity and salinity level of brackish subirrigation water on tuber weight and tuber size of three potato (Solanum tuberosum L.) cultivars (Kennebec, Norland and Russet Burbank) under simulated arid conditions. Both saline and non-saline initial soil conditions were simulated in a total of 36 lysimeters. Eighteen lysimeters were flushed with fresh water (0.2 dS/m), while the remaining 18 lysimeters were flushed with brackish water (2 dS/m). For each soil condition, two subirrigation water concentrations, 1 and 9 dS/m, were used in nine lysimeters each. For each subirrigation water treatment, three potato cultivars were grown. In all lysimeters, water table was maintained at 0.4 m from the soil surface. Arid conditions were simulated by covering the lysimeter top with plastic mulch, allowing the potato shoots to grow through a cut in the mulch. The average root zone salinities (ECw) were found to be 1.2 and 1.5 dS/m in non-saline lysimeters subirrigated with 1 and 9 dS/m waters, respectively. The corresponding salinities were 3.2 and 3.7 dS/m in the saline lysimeters. Across cultivars, there was no significant effect of either initial soil salinity or subirrigation water salinity on total tuber weight. However, the weight of Grade A tubers was higher in non-saline soil than in saline soil. Kennebec and Russet Burbank Grade A tuber weights were not affected by the initial soil salinity. On the contrary, a significant reduction in Grade A and total tuber weight under initially saline soil was evident for the Norland cultivar. 相似文献
19.
《Agricultural Water Management》1997,32(3):285-291
The response of wheat (Triticum aestiuum L.) to varying depths of irrigation, quantity of water applied and to the drainage conditions was studied in 2 m × 2 m × 2 m size lysimeters filled in with a sandy loam soil. Saline water with an electrical conductivity of 8.6 dS m−1 was used for irrigation. The treatments included four irrigations of 5 cm depth, four irrigations of 7 cm, and three irrigations of 9 cm, scheduled on the basis of cumulative pan evaporation, while the drainage conditions were represented by the drained and undrained lysimeters. Another treatment, using good quality water for irrigation, represented the potential yield of the crop. The growth parameters, as well as the yield, showed an improvement with larger irrigation depth increments in the drained lysimeters. But, in contrast, in the undrained lysimeters, the yield was reduced with larger irrigation depth increments, mainly due to a sharp rise in water table depth during the irrigation cycles. The rise and fall in water table showed a high sensitivity and were also highly disproportionate to the irrigation and evapotranspiration events. The yield tended to be higher with a smaller depth of water applied more frequently in the undrained lysimeters. But, in view of the limitations of conventional surface irrigation to apply water in smaller depth increments, an improved drainage is imperative for cropping in shallow saline water table conditions. 相似文献
20.
《Agricultural Water Management》2002,54(3):189-203
This study was designed to evaluate the yield response of low-energy precision application (LEPA) and trickle-irrigated cotton grown on a clay-textured soil under the arid Southeast Anatolia Project (GAP) area conditions during the 1999 growing season at Koruklu in Turkey. The effects of four different irrigation levels (100, 75, 50, and 25% of cumulative Class-A pan evaporation on a 6-day basis) for LEPA, and two irrigation intervals (3-day and 6-day) and three different levels (100, 67, and 33% of cumulative Class-A pan evaporation on a 3-day and 6-day basis) for the trickle system on yield were investigated. Water was applied to alternate furrows through the double-ended Fangmeier drag-socks in the LEPA system. Trickle irrigation laterals were laid out on the soil surface at a spacing of 1.40 m. A total of 814 mm of water was applied to the full-irrigation treatments (100%) for both irrigation systems. Seasonal water use ranged from 383 to 854 mm in LEPA treatments; and 456 to 868 mm in trickle treatments. Highest average cotton yield of 5850 kg/ha was obtained from the full-irrigation treatment (100%) in trickle-irrigated plots with 6-day intervals. The highest yield in LEPA plots was obtained in LEPA-100% treatment with an average value of 4750 kg/ha. Seed cotton yields varied from 2660 to 5040 kg/ha and 2310 to 5850 kg/ha in trickle irrigation plots with 3-day and 6-day intervals, respectively, and from 2590 to 4750 kg/ha in LEPA plots. Irrigation levels both in LEPA and trickle-irrigated plots significantly increased yield. However, there was no significant yield difference between 100 and 67% irrigation levels in trickle-irrigated plots. Maximum irrigation water use efficiency (IWUE) and water use efficiency (WUE) were found as 0.813 and 0.741 kg/m3 in trickle-irrigated treatment of 67% with 6-day interval. Both IWUE and WUE values varied with irrigation quantity and frequency. The research results revealed that both the trickle and LEPA irrigation systems could be used successfully for irrigating cotton crop under the arid climatic conditions of the GAP area in Turkey. 相似文献