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1.
Dry matter,harvest index,grain yield and water use efficiency as affected by water supply in winter wheat 总被引:3,自引:0,他引:3
Food production and water use are closely linked processes and, as competition for water intensifies, water must be used more
efficiently in food production worldwide. A field experiment with wither wheat (Triticum Aestivum L.), involving six irrigation treatments (from rain-fed to 5 irrigation applications), was maintained in the North China
Plain (NCP) for 6 years. The results revealed that dry matter production, grain yield and water use efficiency (WUE) were
each curvilinearly related to evapotranspiration (ET). Maximum dry matter at maturity was achieved by irrigating to 94% and
maximum grain yield to 84% of seasonal full ET. A positive relationship was found between harvest index (HI) and dry matter
mobilization efficiency (DMME) during grain filling. Moderate water deficit during grain filling increased mobilization of
assimilate stored in vegetative tissues to grains, resulting in greater grain yield and WUE. Generally, high WUE corresponded
with low ET, being highest at about half potential ET. At this location in NCP, highest WUE and grain yield was obtained at
seasonal water consumption in the range 250–420 mm. For that, with average seasonal rainfall of 132 mm, irrigation requirements
was in the range of 120–300 mm and due to the deep root system of winter wheat and high water-holding capacity of the soil
profile, soil moisture depletion of 100–150 mm constituted the greater part of the ET under limited water supply. The results
reveal that WUE was maximized when around 35% ET was obtained from soil moisture depletion. For that, seasonal irrigation
was around 60–140 mm in an average season. 相似文献
2.
为提高旱区作物蒸发蒸腾量估算精度,以石羊河流域春玉米为研究对象,分析灌水量对FAO-56估算作物蒸发蒸腾量精度的影响,并对估算误差进行讨论,提出使用部分根区含水量平均值用于土壤水分胁迫系数计算.结果表明:FAO-56对不同灌水处理下作物蒸发蒸腾量的估算精度存在较大差异,可较精确地估算低灌水处理下作物蒸发蒸腾量;随着灌水量增大,其估算精度有所降低,对高灌水处理下作物蒸发蒸腾量的估算误差达-14.13%;根区上部土层含水量与土壤水分胁迫状况关系紧密,以缓变层及以上土层含水量平均值代替整个根区含水量平均值用于土壤水分胁迫系数计算,可有效改善高灌水处理下旱区作物蒸发蒸腾量计算精度,亦可较为精确地估算低灌水处理下作物蒸发蒸腾量. 相似文献
3.
Summary Field experiments were conducted to study the effects of irrigation and antitranspirants on evapotranspirations (ET), water use efficiency (WUE) and the soil moisture extraction patterns of a barley crop grown on a sandy loam soil during the 1977 – 78 and 1978 – 79 seasons. An increase in irrigation frequency increased ET and decreased WUE. The moisture use by barley decreased with soil depth irrespective of treatment. The unirrigated barley extracted relatively more, but absolutely less moisture than the irrigated barley from the deeper soil layers. The application of various antitranspirants had no significant effect either on seasonal ET or on the pattern of moisture extraction from the root zone soil. However, daily ET was reduced significantly after the application of stomata closing type chemicals (Phenyl mercuric acetate [PMA] or Atrazine) used in conjunction with reflecting type antitranspirant (Kaolin). The moisture conservation effects of these chemicals lasted about two weeks under clear weather conditions. Such rainless periods occurred during anthesis and grain development of barley in the 1977 – 1978 crop season, explaining the significant increase in WUE following the use of PMA or Atrazine with Kaolin which only occurred in this crop season. 相似文献
4.
Summary The feasibility of scheduling soybean [Glycine max (L.) Merr.] irrigation by using terminal leaflet angle data was evaluated by simultaneously measuring the angles to the horizontal of the uppermost terminal leaflet and soil moisture contents on plots with different soil moisture regimes during and following a drying cycle. Severe water stress was avoided. The percentage of leaflets with an angle greater than or equal to 45 degrees correlated significantly with both water content in the top 0.45 m of soil and the ET/Epan ratio. 相似文献
5.
不同水分条件对草坪草耗水及生长影响的研究 总被引:4,自引:0,他引:4
利用小型蒸渗仪,开展了不同土壤水分条件下,早熟禾、高羊茅、结缕草、野牛草4种草坪草的耗水规律及生长特性的试验研究。研究发现草坪草的耗水在时间上的变化为双驼峰型,第一个耗水高峰期出现在5月中旬到6月末,第二个耗水高峰期出现在7月中旬到9月中旬。各年中草坪草耗水随降雨的变化而变化。且S1处理的草坪生长量、根重均高于S2和S3处理,但S2和S3处理的草坪生长量、根系发育差异不大。草坪草累积耗水量和日平均耗水量均随控制土壤水分下限的降低而显著降低。在草坪灌溉管理中灌溉控制土壤水分下限可控制在40%~60%的田间持水量。 相似文献
6.
The increasing demand for irrigation water to secure food for growing populations with limited water supply suggests re-thinking
the use of non-conventional water resources. The latter includes saline drainage water, brackish groundwater and treated waste
water. The effects of using saline drainage water (electrical conductivity of 4.2–4.8 dS m−1) to irrigate field-grown tomato (Lycopersicon esculentum Mill cv Floradade) using drip and furrow irrigation systems were evaluated, together with the distribution of soil moisture
and salt. The saline water was either diluted to different salinity levels using fresh water (blended) or used cyclically
with fresh water. The results of two seasons of study (2001 and 2002) showed that increasing salinity resulted in decreased
leaf area index, plant dry weight, fruit total yield and individual fruit weight. In all cases, the growth parameters and
yield as well as the water use efficiency were greater for drip irrigated tomato plants than furrow-irrigated plants. However,
furrow irrigation produced higher individual fruit weight. The electrical conductivity of the soil solution (extracted 48 h
after irrigation) showed greater fluctuations when cyclic water management was used compared to those plots irrigated with
blended water. In both drip and furrow irrigation, measurements of soil moisture one day after irrigation, showed that soil
moisture was higher at the top 20 cm layer and at the location of the irrigation water source; soil moisture was at a minimum
in the root zone (20–40 cm layer), but showed a gradual increase at 40–60 and 60–90 cm and was stable at 90–120 cm depth.
Soil water content decreased gradually as the distance from the irrigation water source increased. In addition, a few days
after irrigation, the soil moisture content decreased, but the deficit was most pronounced in the surface layer. Soil salinity
at the irrigation source was lower at a depth of 15 cm (surface layer) than that at 30 and 60 cm, and was minimal in deeper
layers (i.e. 90 cm). Salinity increased as the distance from the irrigation source increased particularly in the surface layer.
The results indicated that the salinity followed the water front. We concluded that the careful and efficient management of
irrigation with saline water can leave the groundwater salinity levels unaffected and recommended the use of drip irrigation
as the fruit yield per unit of water used was on average one-third higher than when using furrow irrigation. 相似文献
7.
Evapotranspiration data assimilation with genetic algorithms and SWAP model for on-demand irrigation 总被引:3,自引:1,他引:2
Evapotranspiration (ET) is one of the indicators of water use efficiency. Periodic information of ET based on remote sensing
is useful for an on-demand irrigation (ODI) management. The main objective of this paper was to develop an ET data assimilation
scheme to optimize the parameters of an agro-hydrology model for ODI scheduling. The soil, water, atmosphere, and plant (SWAP)
simulation model has been utilized for this purpose. We computed remote sensing-based ET for a wheat field in the Sirsa Irrigation
Circle, Haryana, in India using 18 cloud-free moderate resolution imaging spectroradiometer images taken between December
2001 and April 2002. The surface energy balance algorithm for land (SEBAL) was used for this purpose. Because ET estimates
from SEBAL provide information on the surface soil moisture state, they were treated as observations to estimate unknown parameters
of the SWAP model via a stochastic data assimilation (genetic algorithm) approach. The SWAP parameters were optimized by minimizing
the residuals between SEBAL and SWAP model-based ET values. The optimized parameters were used as input to SWAP to estimate
soil water balance for ODI scheduling. The results showed that the selected parameters (i.e. sowing, harvesting, and irrigation
scheduling dates) were successfully estimated with the data assimilation methodology. The SWAP model produced reasonable states
of water balance by assimilating ET observations. The root mean square of error was 0.755 and 2.132 cm3/cm3 for 0–15 and 15–30 cm soil depths the same layers, respectively. With optimized parameters for ODI, SWAP predicted higher
yield and water use efficiency than traditional farmer’s irrigation criteria. The data assimilation methodology produced can
be considered as an operational tool at the field scale to schedule irrigation or predict irrigation requirements from remote
sensing-based ET. 相似文献
8.
Agricultural production has forced researchers to focus on increasing water use efficiency by improving either new drought-tolerant
plant varieties or water management for arid and semi-arid areas under water shortage conditions. A field study was conducted
to determine effects of seasonal deficit irrigation on plant root yield, quality and water use efficiency (WUE) of sugar beet
for a 2-year period in the semi-arid region. Irrigations were applied when approximately 50–55% of the usable soil moisture
was consumed in the effective rooting depth at the full irrigation (FI) treatment. In deficit irrigation treatments, irrigations
were applied at the rates of 75, 50 and 25% of full irrigation treatment on the same day. Irrigation water was applied by
a drip irrigation system. Increasing water deficits resulted in a relatively lower root and white sugar yields. The linear
relationship between evapotranspiration and root yield was obtained. Similarly, WUE was the highest in DI25 irrigation conditions
and the lowest in full irrigation conditions. According to the averaged values of 2 years, yield response factor (k
y
) was 0.93 for sugar beet. Sugar beet root quality parameters were influenced by drip irrigation levels in both years. The
results revealed that irrigation of sugar beet with drip irrigation method at 75% level (DI25) had significant benefits in
terms of saved irrigation water and large WUE, indicating a definitive advantage of deficit irrigation under limited water
supply conditions. In an economic viewpoint, 25% saving of irrigation water (DI25) caused 6.1% reduction in the net income. 相似文献
9.
Citrus irrigation scheduling is usually based on evapotranspiration (ET) multiplied by a crop coefficient that varies throughout the year. However, ET at 10°C and less has not been investigated. Citrus acclimate to temperatures below 10°C, which affects ET, and therefore may allow irrigation scheduling to be adjusted accordingly. Three separate growth chamber experiments were conducted in complete block design with two temperature treatments and 8-one tree replications with the objective of determining water use of ‘Hamlin’ orange exposed to cold temperatures. The treatments included: full cold-acclimating temperatures, alternating 10 days cold and 3 days warm temperatures, and alternating 10 days warm and 3 days cold temperatures. Although well-watered, trees exposed to temperatures ≤10°C demonstrated lower water use compared to trees held at temperatures that promoted growth. Reduction of water use of cold-treated plants than the controls was 66, 20–57, and 14–28% during full cold-acclimating temperatures, alternating 10 days cold and 3 days warm, and alternating 10 days warm and 3 days cold temperatures, respectively. Reduced water use of cold-treated plants was due to stomatal closure, increased root resistance, and decreased leaf area. Effective irrigation scheduling based on water requirements as they change during cold-acclimating temperatures should save water while providing adequate water for yield and quality. 相似文献
10.
Techniques for estimating seasonal water use from soil profile water depletion frequently do not account for flux below the root zone. A method using tensiometers for obtaining evapotranspiration losses from the root zone and water movement below it is discussed. Soil water flux below the root zone is approached by a sequence of pseudo steady state solutions of the flow equation. Upward soil water flux contributed 36 to 73% to the total water requirement of winter wheat (Triticum aestivum L.) whereas soil water depletion accounted for 11 to 19% only. Water use efficiency with one irrigation during an early stage of plant development is greater than with no or three irrigations. This is the result of both decrease of resistance due to soil moistening and better root development. Tensiometer readings were also interpreted to estimate root zones, water table depths and soil moisture contents. Methods described in this paper can be used in determining seasonal water use by growing crops, replacing or supplementing lysimeter or meteorology approaches to this problem. 相似文献
11.
The 2-year field experiments were carried out to research the effect of different irrigation methods, namely border irrigation,
sprinkler irrigation, and surface drip irrigation, on root development and profile water uptake in winter wheat. Results showed
that the main root distribution zone moved upward under sprinkler and surface drip irrigation when compared to the traditional
border irrigation. Profile root distribution pattern changed with irrigation methods. Soil profile water uptake was correlated
to the root system and soil water dynamics. Due to the appropriate soil water and higher root density in the surface soil
layer under sprinkler and surface drip irrigation, the main water uptake zone was concentrated in the upper layer. Because
of the water deficit in the surface layer under border irrigation, water uptake in 50–100 cm depth was stimulated, which caused
the main uptake zone downward. The amount and pattern of root water uptake varied with irrigation methods. This may provide
valuable information on the aspect of agricultural management. 相似文献
12.
Precision irrigation involves the accurate and precise application of water to meet the specific requirements of individual
plants or management units and minimize adverse environmental impact. Under precision irrigation applications, water and associated
solute movement will vary spatially within the root zone and excess water application will not necessarily result in deep
drainage and leaching of salt below the root zone. This paper estimates that 10% of the irrigated land area (producing as
much as 40% of the total annual revenue from irrigated land) could be adversely affected by root zone salinity resulting from
the adoption of precision irrigation within Australia. The cost of increases in root zone salinisation due to inappropriate
irrigation management in the Murray and Murrumbidgee irrigation areas was estimated at AUD 245 million (in 2000/01) or 13.5%
of the revenue from these cropping systems. A review of soil–water and solute movement under precision irrigation systems
highlights the gaps in current knowledge including the mismatch between the data required by complex, process-based soil–water
or solute simulation models and the data that is easily available from soil survey and routine soil analyses. Other major
knowledge gaps identified include: (a) effect of root distribution, surface evaporation and plant transpiration on soil wetted
patterns, (b) accuracy and adequacy of using simple mean values of root zone soil salinity levels to estimate the effect of
salt on the plant, (c) fate of solutes during a single irrigation and during multiple irrigation cycles, and (d) effect of
soil heterogeneity on the distribution of water and solutes in relation to placement of water. Opportunities for research
investment are identified across a broad range of areas including: (a) requirements for soil characterisation, (b) irrigation
management effects, (c) agronomic responses to variable water and salt distributions in the root zone, (d) potential to scale
or evaluate impacts at various scales, (e) requirements for simplified soil–water and solute modelling tools, and (f) the
need to build skills and capacity in soil–water and solute modelling. 相似文献
13.
H. M. du Plessis 《Irrigation Science》1985,6(1):51-61
Summary The extent to which evapotranspiration (ET) of Valencia citrus trees is affected by differing soil water depletions (SWD) and soil salinity regimes was determined during five seasons during which soil salinity levels varied. Three weighing lysimeters, each with a 14 year old tree, were used to measure daily ET and to schedule irrigation to maintain SWD at maxima of 15, 75 and 150 mm respectively. Tensiometers and salinity sensors were used to indicate the in situ soil matric and soil solution osmotic potentials. Total soil water potential was calculated from tensiometer and salinity sensor readings weighted for root density with depth. The total of these for the summer months was found to be linearly related (Fig. 5) to the mean ET/Ep (Ep=A-pan evaporation). The slope and threshold of ET reductions with decreasing soil water potential for the low frequency irrigation treatment (150 mm SWD) show good agreement with the slope and threshold of yield decrease that is calculated from soil salinity in the lysimeter using previously reported salinity-yield relationships. The reduced water uptake due to increasing soil salinity has important implications for soil salinity control, since the lower uptake should in theory increase the leaching fraction. This implies a degree of self adjustment to the leaching fraction when irrigating with increasingly saline waters if water applications are scheduled as for non-saline conditions. 相似文献
14.
The infiltration and redistribution of soil moisture under surface drip irrigation considering hysteresis were investigated in two soils (loamy sand and silt loam) of different texture. The effect of continuous versus intermittent application of 1, 2 and 4 l/h to the soils was evaluated in terms of wetting front advance patterns and deep percolation under the root zone. For this purpose, a cylindrical flow model incorporating hysteresis in the soil water retention characteristic curve, evaporation from the soil surface, and water extraction by roots was used. The results show that, compared with continuous irrigation, pulse irrigation slightly reduces the water losses under the root zone in both cases (with and without hysteresis). Also, at the total simulation time, in both types of irrigation, hysteresis reduces significantly the water losses under the root zone. Finally, the effect of hysteresis was found to be greater at higher discharge rate (4 l/h) and consequently at higher water content at the soil surface. 相似文献
15.
Field experiments were conducted for 2 years (1997 and 1998) on sandy loam soil in northwestern Botswana to study the effect
of five levels of pan evaporation replenishment (20, 40, 60, 80 and 100%) on marketable yield, yield components, irrigation
production efficiency and economic return of winter broccoli, carrot, rape and cabbage under a drip irrigation method. The
highest mean marketable yield (2 years) of broccoli (19.1 t/ha), carrot (58.9 and 32.9 t/ha), rape (61.8 t/ha) and cabbage
(97.2 t/ha) was recorded at 80% of pan evaporation replenishment. The irrigation production efficiency of broccoli (5.9 kg/m3), rape (14.6 kg/m3) and cabbage (23.6 kg/m3) was maximum at 80, 20 and 60% of pan evaporation replenishment respectively. Irrigation replenishment up to 80% of pan evaporation
loss did not influence the irrigation production efficiency for total and root yield of carrot. The results revealed that
a further increase in irrigation amount resulting from 100% of pan evaporation replenishment did not increase the marketable
yield of crops but reduced the irrigation production efficiency significantly. The seasonal water applied and marketable yield
of broccoli, carrot, rape and cabbage showed quadratic relationships (R
2 = 0.85–0.98), which can be used for allocating irrigation water within and between the crops. The net return increased with
the increase in pan evaporation replenishment. The results revealed that the rape crop is the most remunerative, followed
by cabbage, broccoli and carrot.
Received: 2 November 1998 相似文献
16.
Response of sweet orange cv ‘Lane late’ to deficit irrigation in two rootstocks. I: water relations,leaf gas exchange and vegetative growth 总被引:2,自引:1,他引:1
The influence of a deficit-irrigation (DI) strategy on soil–plant water relations and gas exchange activity was analysed during
a 3-year period in mature ‘Lane late’ (Citrus sinensis (L.) Osb.) citrus trees grafted on two different rootstocks, ‘Cleopatra’ mandarin (Citrus reshni Hort. ex Tanaka ) and ‘Carrizo’ citrange (C. sinensis L., Osbeck × Poncirus trifoliata L.). Two treatments were applied for each rootstock: a control treatment, irrigated at 100% ETc (crop evapotranspiration)
during the entire season, and a DI treatment, irrigated at 100% ETc, except during Phase I (cell division) and Phase III (ripening
and harvest) of fruit growth, when complete irrigation cut-off was applied. Under soil water deficit, the seasonal variations
of soil water content suggested that ‘Cleopatra’ mandarin had a better root efficiency for soil water extraction than ‘Carrizo’
citrange. Moreover, in all years, trees on ‘Cleopatra’ reached a lower water-stress level (midday xylem water potential values
(Ψmd) > −2 MPa), maintaining a better plant water status during the water-stress periods than trees on ‘Carrizo’ (Ψmd < −2 MPa). Similarly, net CO2 assimilation rate (A) was higher in trees on ‘Cleopatra’ during the water-stress periods. In addition, the better plant water status in trees
on ‘Cleopatra’ under DI conditions stimulated a greater vegetative growth compared to trees on ‘Carrizo’. From a physiological
point of view, ‘Cleopatra’ mandarin was more tolerant of severe water stress (applied in Phases I and III of fruit growth)
than ‘Carrizo’ citrange. 相似文献
17.
An artificial capillary barrier to improve root zone conditions for horticultural crops: physical effects on water content 总被引:1,自引:1,他引:0
Eviatar Ityel Naftali Lazarovitch Moshe Silberbush Alon Ben-Gal 《Irrigation Science》2011,29(2):171-180
Capillary barriers (CBs) occur at the interface of two soil layers having distinct differences in textural and hydraulic characteristics.
The objective of this study was to introduce an artificial CB, created by a layer of gravel below the root zone substrate,
in order to optimize conditions for the cultivation of horticultural crops. Potential root zone formats were analyzed with
and without the gravel CBs for variables including the following: depth of CB; barrier separating the root zone from the surrounding
soil; and root zone soil texture. Field and simulated results revealed that artificial CBs increased root zone water content
and changed water flow dynamics. Volumetric soil water content was increased by 20–70%, depending on the soil texture and
depth of the barrier. Sandy soil texture and shallower placement resulted in relatively higher water content. For sandy soil
without plants, a shallow (0.2 m depth) CB increased water content of the overlaying soil by 50% compared to the control.
The introduction of a gravel CB below the root zone of pepper plants (Capsicum Annum L.) lead to 34% higher matric head, 50% lower diurnal fluctuations in matric head and 40% increase in pepper fruit yield.
Increasing water content by way of artificial CBs appeared to improve the water use efficiency of pepper plants. Such an improvement
could lead to reduced water and fertilizer application rates and subsequent reduction in contamination below the root zone.
This is especially relevant for substrates of low water-holding capacity typically used in horticulture crop production. 相似文献
18.
Ali Osman Demir Abdurrahim Tanju Göksoy Hakan Büyükcangaz Zeki Metin Turan Eyüp Selim Köksal 《Irrigation Science》2006,24(4):279-289
The response of sunflower (Helianthus annuus L.) to 14 irrigation treatments in a sub-humid environment (Bursa, Turkey) was studied in the field for two seasons. A rainfed (non-irrigated) treatment as the control and 13 irrigation treatments with full and 12 different deficit irrigations were applied to the hybrid Sanbro (Novartis Seed Company) planted on clay soil, at three critical development stages: heading (H), flowering (F) and milk ripening (M). The yield increased with irrigation water amount, and the highest seed yield (3.95 t ha−1) and oil yield (1.78 t ha−1) were obtained from the HFM treatment (full irrigation at three stages); 82.9 and 85.4% increases, respectively, compared to the control. Evapotranspiration (ET) increased with increased amounts of irrigation water supplied. The highest seasonal ET (average of 652 mm) was estimated at the HFM treatment. Additionally, yield response factor (k
y) was separately calculated for each, two and total growth stages, and k
y was found to be 0.8382, 0.9159 (the highest value) and 0.7708 (the lowest value) for the total growing season, heading, and flowering-milk ripening combination stages, respectively. It is concluded that HFM irrigation is the best choice for maximum yield under the local conditions, but these irrigation schemes must be re-considered in areas where water resources are more limited. In the case of more restricted irrigation, the limitation of irrigation water at the flowering period should be avoided; as the highest water use efficiency (WUE) (7.80 kg ha−1 mm−1) and irrigation water use efficiency (IWUE) (10.19 kg ha−1 mm−1) were obtained from the F treatment. 相似文献
19.
为探明渗灌条件下渗灌管首末端压力与土壤水分运移之间的关系,设置了3个试验小区进行不同灌水流量和灌水持续时间的试验.通过连续定点观测茶树根区(纵向30 cm深,横向30 cm宽)土壤含水率的变化和渗灌管首末端灌水压力,研究了渗灌管不同首末端压力下土壤水分运移的变化规律.研究表明:灌水前土壤含水率不仅影响土壤入渗能力,而且决定着土壤水分运移方向;渗灌管首末端压力累积值与灌水持续时间呈线性关系,当茶树根区土壤含水率达到田间持水量时,累积曲线斜率发生突变,可以利用累积曲线斜率发生突变时的灌水持续时间作为控制充分灌水(100%田间持水量)的临界值,避免土壤水分无效渗漏.该研究为渗灌系统控制灌水持续时间及研发智能化渗灌灌溉系统提供了一种参考方法. 相似文献
20.
滴灌紫花苜蓿根层水分稳定同位素特征分析 总被引:1,自引:0,他引:1
为了明确滴灌紫花苜蓿根层水分运移,进一步阐明滴灌节水机理,采用液态水稳定氢氧同位素技术,分析了滴灌紫花苜蓿根层水分稳定氢氧同位素分布特征。结果表明,紫花苜蓿根层水分稳定氢氧同位素在下层富集,且随土壤剖面深度的增加同位素富集量有增加的趋势。滴灌条件下,紫花苜蓿根层发育有较多细根,可迅速而高效地利用灌溉水,灌溉后紫花苜蓿对灌溉水的利用不明确偏向于某一深度土层,根层内各土层土壤水均有利用。灌溉前土壤干旱时,滴灌紫花苜蓿以30 cm上下土层土壤水作为主要水分来源的概率较高。 相似文献