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1.
A 3-year study was carried out to assess the root biomass production, crop growth rate, yield attributes, canopy temperature
and water-yield relationships in Indian mustard grown under combinations of irrigation and nutrient application for revealing
the dynamic relationship of crop yield (Y) and seasonal evapotranspiration (ET). Three post-sowing irrigation treatments viz. no irrigation (I
1), one irrigation at flowering (I
2) and two irrigations one each at rosette and flowering stage (I
3), three nutrient treatments viz. no fertilizer or manure (F
1), 100% recommended NPK i.e., 60 kg N, 13.1 kg P and 16.6 kg K ha−1 (F
2) and 100% recommended NPK plus farmyard manure @ 10 Mg ha−1 (F
3) were tested in a split-plot design. Root biomass was significantly greater in I
3 than I
2 and I
1, and in F
3 than F
2 and F
1. The I
3 × F
3, I
2 × F
3 and I
3 × F
2 combinations maintained significantly greater crop growth rate, plant height, yield components, ET and crop yield and better
plant water status in terms of canopy temperature, canopy-air temperature difference (CATD) and relative leaf water content
(RLWC). Number of siliqua plant−1 and seeds siliqua−1 were the major contributors to the seed yield. Marginal analysis of water production function was used to establish Y–ET relationship. The elasticity of water production (E
wp) provides a means to assess relative changes in Y and ET, and gives an indication of improvement of Y due to nutrient application. The ET–Y relationships were linear with marginal water use efficiency (WUEm) of 3.09, 4.23 and 3.95 kg ha−1 mm−1 in F
1, F
2 and F
3, respectively, and the corresponding E
wp were 0.63, 0.71 and 0.61. This implies that the scope for improving yield and WUE with 100% NPK was little compared with
100% NPK + farmyard manure. The crop yield was highest in I
3 × F
3 combination, and the similar yield was obtained in I
2 × F
3 and I
3 × F
2 combinations. Application of organic manure along with 100% NPK fertilizers maintained greater crop growth rate, better water
relation in plants, yield attributes and saved one post-sowing irrigation. 相似文献
2.
Tieguanyin Oolong tea (Camellia sinensis (L.) O. Kuntze) is a name brand important commodity for Anxi county, Fujian province in China. Four-year-old tea plants at a tea plantation in Anxi were subjected to six different irrigation treatments (i.e. 5, 10, 15, 20, and 25 d irrigation intervals for T1 to T5 with a rate of 3.5 kg water per plant, plus a non-irrigated control). After 50 d of irrigation treatments, leaf water potential was −1.70, −2.34, −2.48, −2.89, −3.55, and −4.92 MPa for treatment T1, T2, T3, T4, T5, and control, respectively. Leaf biomass yield increased by 32.8%, 21.9%, and 21.3% for T1, T2, and T3, respectively, compared to control. The net photosynthesis (Pn), stomatal conductance (gs) and transpiration (E) decreased with irrigation interval increasing. Tea polyphenol (TP) and free amino acid (AA) decreased when the irrigation intervals were increased, but caffeine (CA) content apparently increased as the irrigation intervals were increased. To balance irrigation water demand and tea yield and quality, it is recommended that the irrigation interval should be set at 10 d with a rate of 3.5 kg water per plant for the optimal production in Anxi, Fujian province of China. 相似文献
3.
Improving irrigation water management is becoming important to produce a profitable crop in South Texas as the water supplies shrink. This study was conducted to investigate grain yield responses of corn (Zea mays) under irrigation management based on crop evapotranspiration (ETC) as well as a possibility to monitor plant water deficiencies using some of physiological and environmental factors. Three commercial corn cultivars were grown in a center-pivot-irrigated field with low energy precision application (LEPA) at Texas AgriLife Research Center in Uvalde, TX from 2002 to 2004. The field was treated with conventional and reduced tillage practices and irrigation regimes of 100%, 75%, and 50% ETC. Grain yield was increased as irrigation increased. There were significant differences between 100% and 50% ETC in volumetric water content (θ), leaf relative water content (RWC), and canopy temperature (TC). It is considered that irrigation management of corn at 75% ETC is feasible with 10% reduction of grain yield and with increased water use efficiency (WUE). The greatest WUE (1.6 g m−2 mm−1) achieved at 456 mm of water input while grain yield plateaued at less than 600 mm. The result demonstrates that ETC-based irrigation can be one of the efficient water delivery schemes. The results also demonstrate that grain yield reduction of corn is qualitatively describable using the variables of RWC and TC. Therefore, it appears that water status can be monitored with measurement of the variables, promising future development of real-time irrigation scheduling. 相似文献
4.
This study compares the effects of different irrigation regimes on seed yield and oil yield quality and water productivity of sprinkler and drip irrigated sunflower (Helianthus annus L.) on silty-clay-loam soils in 2006 and 2007 in the Mediterranean region of Turkey. In sprinkler irrigation a line-source system was used in order to create gradually varying irrigation levels. Irrigation regimes consisted of full irrigation (I1) and three deficit irrigation treatments (I2, I3 and I4), and rain-fed treatment (I5). In the drip system, irrigation regimes included full irrigation (FI-100), three deficit irrigation treatments (DI-25, DI-50, DI-75), partial root zone drying (PRD-50) and rain-fed treatment (RF). Irrigations were scheduled at weekly intervals both in sprinkler and drip irrigation, based on soil water depletion within a 0.90 m root zone in FI-100 and I1 plots. Irrigation treatments influenced significantly (P < 0.01) sunflower seed and oil yields, and oil quality both with sprinkler and drip systems. Seed yields decreased with increasing water stress levels under drip and sprinkler irrigation in both experimental years. Seed yield response to irrigation varied considerably due to differences in soil water contents and spring rainfall distribution in the experimental years. Although PRD-50 received about 36% less irrigation water as compared to FI-100, sunflower yield was reduced by an average of 15%. PRD-50 produced greater seed and oil yields than DI-50 in the drip irrigation system. Yield reduction was mainly due to less number of seeds per head and lower seed mass. Soil water deficits significantly reduced crop evapotranspiration (ET), which mainly depends on irrigation amounts. Significant linear relationships (R2 = 0.96) between ET and oil yield (Y) were obtained in each season. The seed yield response factors (kyseed) were 1.24 and 0.86 for the sprinkler and 1.19 and 1.06 for the drip system in 2006 and 2007, respectively. The oil yield response factor (kyoil) for sunflower was found to be 1.08 and 1.49 for both growing seasons for the sprinkler and 1.36 and 1.25 for the drip systems, respectively. Oil content decreased with decreasing irrigation amount. Consistently greater values of oil content were obtained from the full irrigation treatment plots. The saturated (palmitic and stearic acid) and unsaturated (oleic and linoleic acid) fatty acid contents were significantly affected by water stress. Water stress caused an increase in oleic acid with a decrease in linoleic acid contents. The palmitic and stearic acid concentrations decreased under drought conditions. Water productivity (WP) values were significantly affected by irrigation amounts and ranged from 0.40 to 0.71 kg m−3 in 2006, and from 0.69 to 0.91 kg m−3 in 2007. The PRD-50 treatment resulted in the greatest WP (1.0 kg m−3) and irrigation water productivity (IWP) (1.4 kg m−3) in both growing seasons. The results revealed that under water scarcity situation, PRD-50 in drip and I2 in sprinkler system provide acceptable irrigation strategies to increase sunflower yield and quality. 相似文献
5.
Precision irrigation in grapevines could be achieved using physiologically based irrigation scheduling methods. This paper describes an investigation on the effects of three midday stem water potential (midday ΨS) thresholds, imposed from post-setting, over water use, vegetative growth, grape quality and yield of grapevines cv. Cabernet Sauvignon. An experiment was carried out on a vineyard located at the Isla de Maipo, Metropolitana Region, Chile, throughout the 2002/03, 2003/04 and 2004/05 growing seasons. Irrigation treatments consisted in reaching the following midday ΨS thresholds: −0.8 to −0.95 MPa (T1); −1.0 to −1.2 MPa (T2) and −1.25 to −1.4 MPa (T3) from post-setting to harvest. Results showed significant differences in grape quality components among treatments and seasons studied. In average, T3 produced smallest berry diameter (6% reduction compared to T1), high skin to pulp ratio (13% increment compared to T1) and significant increments in soluble solids and anthocyanins. Improvements in grape quality attributes were attributed to mild grapevine water stress due to significant reductions in water application (46% for T2 and 89% for T3 less in average, both compared to T1). This study found significant correlations between midday ΨS and berry quality components, no detrimental effects on yield by treatments were found in this study. This research proposes a suitable physiological index and thresholds to manage RDI and irrigation scheduling on grapevines to achieve high quality grapes on mild water stress conditions. 相似文献
6.
During 2 years, a melon crop (Cucumis melo L. cv. Sancho) was grown under field conditions to investigate the effects of different nitrogen (N) and irrigation (I) levels on fruit yield, fruit quality, irrigation water use efficiency (IWUE) and nitrogen applied efficiency (NAE). The statistical design was a split-plot with four replications, where irrigation was the main factor of variation and N was the secondary factor. In 2005, irrigation treatments consisted of applying daily a moderate water stress equivalent to 75% of ETc (crop evapotranspiration), a 100% ETc control and an excess irrigation of 125% ETc (designated as I75, I100 and I125), while the N treatments were 30, 85, 112 and 139 kg N ha−1 (designated as N30, N85, N112 and N139). In 2006, both the irrigation and N treatments applied were: 60, 100 and 140% ETc (I60, I100 and I140) and 93, 243 and 393 kg N ha−1 (N93, N243 and N393). Moderate water stress did not reduce melon yield and high IWUE was obtained. Under severe deficit irrigation, the yield was reduced by 22% mainly due to decrease fruit weight. The relative yield (yield/maximum yield) was higher than 95% when the irrigation depth applied was in the range of 87-136% ETc. In 2006, the interaction between irrigation and N was significant for yield, fruit weight and IWUE. The best yield, 41.3 Mg ha−1, was obtained with 100% ETc at N93. The flesh firmness and the placenta and seeds weight increased when the irrigation level was reduced by 60% ETc. The highest NAE was obtained with quantities of water close to 100% ETc and increased as the N level was reduced. The highest IWUE was obtained with applications close to 90 kg N ha−1. The I243 and I393 treatments produced inferior fruits due to higher skin ratios and lower flesh ratios. These results suggest that it is possible to apply moderate deficit irrigation, around 90% ETc, and reduce nitrogen input to 90 kg ha−1 without lessening quality and yields. 相似文献
7.
The reported study aimed at developing an integrated management strategy for irrigation water and fertilizers in case of wheat crop in a sub-tropical sub-humid region. Field experiments were conducted on wheat crop (cultivar Sonalika) during the years 2002–2003, 2003–2004 and 2004–2005. Each experiment included four fertilizer treatments and three irrigation treatments during the wheat growth period. During the experiment, the irrigation treatments considered were I1 = 10% maximum allowable depletion (MAD) of available soil water (ASW); I2 = 40% MAD of ASW; I3 = 60% MAD of ASW. The fertilizer treatments considered in the experiments were F1 = control treatment with N:P2O5:K2O as 0:0:0 kg ha−1, F2 = fertilizer application of N:P2O5:K2O as 80:40:40 kg ha−1; F3 = fertilizer application of N:P2O5:K2O as 120:60:60 kg ha−1 and F4 = fertilizer application of N:P2O5:K2O as 160:80:80 kg ha−1. In this study CERES-wheat crop growth model of the DSSAT v4.0 was used to simulate the growth, development and yield of wheat crop using soil, daily weather and management inputs, to aid farmers and decision makers in developing strategies for effective management of inputs. The results of the investigation revealed that magnitudes of grain yield, straw yield and maximum LAI of wheat crop were higher in low volume high frequency irrigation (I1) than the high volume low frequency irrigation (I3). The grain yield, straw yield and maximum LAI increased with increase in fertilization rate for the wheat crop. The results also revealed that increase in level of fertilization increased water use efficiency (WUE) considerably. However, WUE of the I2 irrigation schedule was comparatively higher than the I1 and I3 irrigation schedules due to higher grain yield per unit use of water. Therefore, irrigation schedule with 40% maximum allowable depletion of available soil water (I2) could safely be maintained during the non-critical stages to save water without sacrificing the crop yield. Increase in level of fertilization increases the WUE but it will cause environmental problem beyond certain limit. The calibrated CERES-wheat model could predict the grain yield, straw yield and maximum LAI of wheat crop with considerable accuracy and therefore can be recommended for decision-making in similar regions. 相似文献
8.
Abdrabbo A. Abou Kheira 《Agricultural Water Management》2009,96(10):1409-1420
Precision irrigation management and scheduling, as well as developing site- and cultivar-specific crop coefficient (Kc), and yield response factor to water deficit (ky) are very important parameters for efficient use of limited water resources. This study investigated the effect of deficit irrigation, applied at different growth stages of peanut with sprinkler irrigation in sandy soil, on field peanut evapotranspiration (ETc), yield and yield components, and water use efficiencies (IWUE and WUE). Also, yield response factor to water deficit (ky), and site- and cultivar-specific Kc were developed. Four treatments were imposed to deficit irrigation during late vegetative and early flowering, late flowering and early pegging, pegging, and pod formation growth stages of peanut, and compared with full irrigation in the course of the season (control). A soil water balance equation was used to estimate crop evapotranspiration (ETc). The results revealed that maximum seasonal ETc was 488 mm recorded with full irrigation treatment. The maximum value of Kc (0.96) occurred at the fifth week after sowing, this value was less than the generic values listed in FAO-33 and -56 (1.03 and 1.15), respectively. Dry kernels yield among treatments differed by 41.4%. Deficit irrigation significantly affected yields, where kernels yield decreased by 28, 39, 36, and 41% in deficit-irrigated late vegetative and early flowering, late flowering and early pegging, pegging, and pod formation growth stages, respectively, compared with full irrigation treatment. Peanut yields increased linearly with seasonal ETc (R2 = 0.94) and ETc/ETp (R2 = 0.92) (ETp = ETc with no water stress). The yield response factor (ky), which indicates the relative reduction in yield to relative reduction in ETc, averaged 2.9, was higher than the 0.7 value reported by Doorenbos and Kassam [Doorenbos, J., Kassam, A.H., 1979. Yield response to water. FAO Irrigation and Drainage Paper 33, Rome, Italy, 193 pp.], the high ky value reflects the great sensitivity of peanut (cv. Giza 5) to water deficit. WUE values varied considerably with deficit irrigation treatments, averaging 6.1 and 4.5 kg ha−1 mm−1 (dry-mass basis) for pods and kernels, respectively. Differences in WUE between the driest and wettest treatment were 31.3 and 31.3% for pods and kernels, respectively. Deficit irrigation treatments, however, impacted IWUE much more than WUE. Differences in IWUE between the driest and wettest treatment were 33.9 and 33.9% for pods and kernels, respectively. The results revealed that better management of available soil water in the root zone in the course of the season, as well as daily and seasonal accurate estimation of ETc can be an effective way for best irrigation scheduling and water allocation, maximizing yield, and optimizing economic return. 相似文献
9.
A study was conducted to determine the water stress effect on yield and some physiological parameters including crop water
stress index for drip irrigated second crop watermelon. Irrigations were scheduled based on replenishment of 100, 75, 50,
25, and 0% soil water depletion from 90 cm soil depth with 3-day irrigation interval. Seasonal crop evapotranspiration (ET)
for I100, I75, I50, I25, and I0 were 660, 525, 396, 210, and 70 mm in 2003 and 677, 529, 405, 221, and 75 mm in 2004. Fruit yield was significantly lowered
by irrigation water stress. Average water-yield response factor for both of the years was 1.14. The highest yield was obtained
from full irrigated treatment as 34.5 and 38.2 t ha−1 in 2003 and 2004, respectively. Lower ET rates and irrigation amounts in water stress treatments resulted in reductions in
all measured parameters, except water-soluble dry matter concentrations (SDM). Canopy dry weights, leaf relative water content,
and total leaf chlorophyll content were significantly lowered by water stress. Yield and seasonal ET were linearly correlated
with mean CWSI values. An average threshold CWSI value of 0.17 before irrigation produced the maximum yield and it could be
used to initiate the irrigation for watermelon. 相似文献
10.
A. Garcia y Garcia T. Persson L.C. Guerra G. Hoogenboom 《Agricultural Water Management》2010,97(7):981-1206
Studies on irrigation scheduling for soybean have demonstrated that avoiding irrigation during the vegetative growth stages could result in yields as high as those obtained if the crop was fully irrigated during the entire growing season. This could ultimately also lead to an improvement of the irrigation water use efficiency. The objective of this study was to determine the effect of different irrigation regimes (IRs) on growth and yield of four soybean genotypes and to determine their irrigation water use efficiency. A field experiment consisting of three IR using a lateral move sprinkler system and four soybean genotypes was conducted at the Bledsoe Research Farm of The University of Georgia, USA. The irrigation treatments consisted of full season irrigated (FSI), start irrigation at flowering (SIF), and rainfed (RFD); the soybean genotypes represented maturity groups (MGs) V, VI, VII, and VIII. A completely randomized block design in a split-plot array with four replicates was used with IR as the main treatment and the soybean MGs as the sub-treatment. Weather variables and soil moisture were recorded with an automatic weather station located nearby, while rainfall and irrigation amounts were recorded with rain gauges located in the experimental field. Samplings for growth analysis of the plant and its components as well as leaf area index (LAI) and canopy height were obtained every 12 days. The irrigation water use efficiency (IWUE) or ratio of the difference between irrigated and rainfed yield to the amount of irrigation water applied was estimated. The results showed significant differences (P < 0.05) between IR for dry matter of the plant and its components, canopy height, and maximum leaf area index as well as significant differences (P < 0.05) between MGs due to IR. Differences for the interaction between IR and MG were significant (P < 0.05) only for dry matter of pods and seed yield. In general, seed yield increased at a rate of 7.20 kg for each mm of total water received (rainfall + irrigation) by the crop. Within IR, significant differences (P < 0.05) on IWUE were found between maturity groups with values as low as 0.55 kg m−3 for MG V and as high as 1.14 kg m−3 for MG VI for the FSI treatment and values as low as 0.48 kg m−3 for maturity group V and as high as 1.02 kg m−3 for maturity group VI for the SIF treatment. We also found that there were genotypic differences with respect to their efficiency to use water, stressing the importance of cultivar selection as a key strategy for achieving optimum yields with reduced use of water in supplemental irrigation. 相似文献
11.
《Agricultural Water Management》2001,46(3):241-251
Mismanagement of nitrogenous fertilizers has caused serious nitrate (NO3) contamination in many flood-irrigated regions of the western US. Low-volume irrigation practices, such as drip irrigation, can offer an alternative approach for controlling NO3 leaching and agricultural water use. The objectives of this study were to compare NO3 movement through soils under flood and drip irrigation practices for sugarbeet production, and to evaluate the agronomic feasibility of implementing drip irrigation. A field experiment was conducted during the sugarbeet (Beta vulgaris L.) growing seasons of 1996 and 1997 in southeastern Wyoming, where NO3 contamination is a continued concern and sugarbeet is a major cash crop. Three drip irrigation regimes, corresponding to 20, 35, and 50% water depletion of field capacity (designated as D1, D2, and D3, respectively), were compared against flood irrigation. The irrigation plots were treated with 112, 168, and 224 kg N ha−1 (designated as F0, F1, and F2, respectively). Sugarbeet (SB) yields and sugar contents under drip irrigation were higher (3–28%) than those with flood irrigation; yields and sugar contents for the drip systems were in the order of D1>D2>D3. For all of the irrigation applications, there was an increasing trend in yields with increasing fertilizer rates. Drip regime resulted in greater residual soil NO3 (RSN) for both 1996 and 1997 seasons as compared to flood practices. Values of RSN in both years followed the trend: F2>F1>F0. Soil NO3 in all three drip regimes was higher (1.6–2.4 times) than that with flood irrigation. In the overall root zone, NO3 concentrations between D1 and D2 were comparable, whereas both of those levels were lower than D3. Greater NO3 concentrations with D3 were observed at all depths. The amount of applied irrigation water with the drip system was lower than that for flood irrigation. Agronomic water use efficiency (WUE) and fertilizer use efficiency (FUE) for drip irrigation were always higher than those for flood irrigation. In 1996, WUE and FUE maintained an order of D1>D2>D3. There was a decreasing pattern in FUE values with increasing fertilizer rates. The overall results indicated that SB production could be sustained with lower water and fertilizer use by using drip irrigation. The p-values (≤0.05), based on both F-test (pf) and two-tailed student’s t-test (pt), suggested a significant difference between the yield means obtained under drip and flood irrigation practices. As compared to the flood irrigation, the least p-values were obtained with D1 followed by D2 and D3, respectively, thus, confirming that D1 was the most effective treatment. The p-values for SB yields under comparative fertilizer treatments and same drip application showed no significant difference between the means, thus, suggesting the feasibility of using lower fertilizer rate while sustaining the targeted yield under drip irrigation. The comparative estimation of water losses by drainage between flood and drip irrigation suggested that the later practice reduced the quantity of water leaching beyond the root zone. Among the three drip treatments, the lowest drainage amount was observed with D1 as a result of its higher irrigation frequency and smaller quantity of water input during each application. 相似文献
12.
《Agricultural Water Management》2005,72(1):59-68
In a greenhouse pot experiment conducted in Turkey during 2001, onion seedlings were transplanted on May 31 at the density of five plants per pot. On this date the soil water content of all pots were at field capacity. The pots were weighed daily until harvest (December 2), and the data were used to determine the daily evapotranspiration and quantity of irrigation. Eight irrigation treatments were applied, designated as I1 full irrigation (non-deficit treatment), and I2, I3 and I4 no irrigation in the vegetative growth periods, yield formation and ripening, respectively, and I5, I6, I7 and I8 received 0.0, 0.25, 0.50 and 0.75 times the soil water depletion in the treatment I1 on the same day. For each treatment, the following parameters were analysed and compared: applied irrigation depth, daily and seasonal evapotranspiration, bulb yield, yield response factor (ky), irrigation water use efficiency (IWUE) and water use efficiency (WUE). The findings indicated that onion plants were very sensitive to lack of soil water during the total growing season and the yield formation period, but rather insensitive in the vegetative and ripening periods. High water use and water use efficiencies were observed with increasing levels of irrigation, or no irrigation in the vegetative period. 相似文献
13.
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
14.
《Agricultural Water Management》2004,67(1):63-76
The aim of this study carried out in Van, Turkey was to determine the most suitable irrigation frequencies and quantities in summer squash (Cucurbita pepo L. cv. Sakız) grown under field conditions. Irrigation quantities were based on pan evaporation (Epan) from a screened class-A pan. Irrigation treatments consisted of two irrigation intervals (I1: 5 days; I2: 10 days), and three pan coefficients (Kcp1: 0.45; Kcp2: 0.65 and Kcp3: 0.85). Plants were adequately watered from seed sowing to first fruit emergence, then, scheduled irrigations were initiated at 5- and 10-day intervals.Irrigation quantities applied to the treatments varied from 279 to 475 mm; seasonal plant water consumption or evapotranspiration (Et) of irrigation treatments varied from 336 to 539 mm; and the summer squash yield varied from 22.4 to 44.7 t ha−1. The highest total yield was obtained from I1Kcp3 treatment. However, Kcp2 treatments had the earliest yield. Treatments irrigated with higher amount of water generally gave lower irrigation water use efficiency (IWUE) values than others. Et/Epan ratios of treatments ranged from 0.12 to 1.16. Moreover, irrigation treatments had significant effects (P<0.01) on yield and there were significant positive linear relations among irrigation water, plant water consumption, fruit traits and yield.In conclusion, Kcp3 treatment with 5-day irrigation interval is recommended for summer squash grown under field conditions in order to get higher summer squash yield. However, if the irrigation water is scarce, it will be suitable to irrigate summer squash frequently using Kcp1 values. 相似文献
15.
This study was conducted to determine the effect of different supplemental irrigation rates on chickpea grown under semiarid climatic conditions. Chickpea plots were irrigated with drip irrigation system and irrigation rates included the applications of 0 (I 0) 25 (I 25), 50 (I 50), 75 (I 75), 100 (I 100), and 125 % (I 125) of gravimetrically measured soil water deficit. Plant height, 1,000 seed weight, yield, biomass, and harvest index (HI) parameters were determined in addition to yield-water functions, evapotranspiration (ET), water use efficiency (WUE), and irrigation water use efficiency (IWUE). Significant differences were noted for plant height (ranging from 24.0 to 37.5 cm), 1,000 seed weight (ranging from 192.0 to 428.7 g), and aboveground biomass (ranging from 2,722 to 6,083 kg ha?1) for water applications of I 0 and I 125. Statistical analysis indicated a strong relationship between the amount of irrigation and yield, which ranged from 256.5 to 1,957.3 kg ha?1. Harvest index values ranged between 0.092 and 0.325, while WUE and IWUE values ranged between 1.15–4.55 and 1.34–8.36 (kg ha?1 mm?1), respectively. 相似文献
16.
Potato water use and yield under furrow irrigation 总被引：3，自引：0，他引：3
Field experiments were conducted to study the effects of plant-furrow treatments and levels of irrigation on potato (Solanum tuberosum L.) water use, yield, and water-use efficiency. The experiments were carried out under deficit irrigation conditions in a sandy loam soil of eastern India in the winter seasons of 1991/92, 1992/93, and 1993/94. Two plant-furrow treatments and two levels of irrigation were considered. The two plant-furrow treatments were F1 - furrows with single row of planting in each ridge with 45 cm distance between adjacent ridges, and F2 - furrows with double rows of planting spaced 30 cm apart in each ridge with 60 cm distance between adjacent ridges. The two levels of irrigation (LOI) were I1 - 0.9 IW/CPE and I2 - 1.2 IW/CPE, where IW is irrigation water of 5 cm and CPE is cumulative pan evaporation. Treatment F2 produced highest tuber yield in all years with average value of 10,610 kg ha -1 and 12,780 kg ha -1 at LOI of I1 and I2, respectively. On average, six irrigations with a total of 25 cm, and seven irrigations with a total of 30 cm were required for both treatments F1 and F2 at LOI of I1 and I2, respectively. Treatment F2 resulted in a significantly higher number of branches and tubers per plant, foliage coverage and water-use efficiency for both irrigation levels than treatment F1. Average daily crop evapotranspiration was found to range from 1.1 to 3.4 mm and from 1.2 to 3.9 mm for treatment F1 and from 1.1 to 3.6 mm and from 1.2 to 4.0 mm for treatment F2 at LOI of I1 and I2, respectively. 相似文献
17.
Using a correlation between trunk diameter fluctuation (TDF) and stem water potential (SWP) it appears possible to determine water deficit threshold values (WDTV) for young cherry trees. This correlation must be based on a significant effect between SWP and at least one variable associated with the vegetative or reproductive growth of the trees. The objectives of this study are: (1) to determine the effect of several irrigation treatments on vegetative and reproductive growth and the SWP of young cherry trees; (2) to determine the correlation between TDF and SWP, and; (3) to propose a first approximation of SWP and TDF water deficit threshold values for young cherry tree plants. The experiment was carried out between September and April of the 2005-2006 and 2006-2007 seasons, in Quillota, in the Valparaiso region, central Chile. The irrigation treatments consisted of applications of 50% (T50), 100% (T100) and 150% (T150) of potential evapotranspiration (ET0) over the two growing seasons, using a randomized complete block design (RCB). The effect of irrigation scheduling was observed on: apical shoot growth rate (GRAS), branch cross-sectional area (BCSA), canopy volume (CV), annual length of accumulated growth (ALAG) and productivity. This effect showed that the T50 treatment caused lower SWP (measured pre-dawn), vegetative growth and productivity. The fruit quality variables (cracking and size) were not affected by the different treatments. Combining the vegetative growth, productivity and SWP results shows that the water deficit threshold value, as a first approximation, is between 50% and 100% of ET0, and therefore the critical SWP for defining irrigation frequency should be close to −0.5 MPa. Upon applying a post-harvest drought period (14 days without irrigation), a linear correlation was determined both between SWP and maximum daily trunk shrinkage, MDS (R2 = 0.69) and between SWP and trunk growth rate, TGR (R2 = 0.57). Using these correlations and the SWP reference value, reference values were obtained for MDS (165 μm) and TGR (83 μm day−1), which would permit automated control of water status in young cherry trees. 相似文献
18.
Plant age and size, seasonal growth patters and crop load, among other factors, have been reported to decrease the usefulness of trunk diameter variation (TDV) derived indices as water stress indicators in olive trees. Our hypothesis, however, is that indices derived from TDV records in old, big olive trees are sensitive enough to detect levels of water stress in trees of orchards under deficit irrigation that, although severe, are below the threshold for fruit shrivelling. This is of importance for the production of good quality oils, since fruit shrivelling may affect oil quality. The aim of this work was to assess different TDV-derived indices as water stress indicators in 40-year-old ‘Manzanilla’ olive trees with heavy crop load. We derived the maximum daily shrinkage (MDS), daily growth (DG) and daily recovery (DR) from TDV records taken during the 2008 dry season both in well-irrigated FAO trees and in deficit-irrigated RI trees. Measurements of volumetric soil water content (θv), leaf water potential (Ψl), stomatal conductance (gs), net CO2 assimilation rate (A), water and oil accumulation in the fruits and yield parameters were made for both treatments. The trunks did not grow during the experimental season, either in the FAO or RI trees, likely because of the heavy crop load. Therefore, DG was useless as water stress indicator. For MDS and DR, which were responsive to the increase of the trees’ water stress, we calculated the variability, quantified by the coefficient of variation (CV), the signal intensity (SI) and the sensitivity (SI/CV) values. In addition, we derived reference equations for irrigation scheduling from the relationships between MDS values in the FAO trees and main meteorological variables. Values both of SI-MDS and SI-DR were steady until September 9, despite of increasing differences in θv between treatments from early in the dry season. The Ψl vs θv values showed an outstanding capacity of the RI trees to take up water from the drying soil, and the Ψl vs gs values showed a near-isohydric behaviour of those deficit-irrigated trees. These results explain, at least in part, the lack of response of MDS and DR on that period. Both SI-MDS and SI-DR peaked for the first time on September 9, 16 days before the appearance of fruit shrivelling. Our results suggest that using TDV-derived indices as water stress indicators for irrigation scheduling in old olive orchards with medium to low plant densities, i.e. with large root zones, may be useless in case the irrigation strategy is aimed at keeping the soil close to field capacity. Nevertheless, the MDS and DR indices may be useful indicators for the avoidance of fruit shrivelling in deficit irrigated olive orchards for the production of good quality oil. Reliable reference equations for scheduling irrigation with the signal intensity approach were obtained from the regression of MDS values vs the daily maximum values of both the air temperature and the vapour pressure deficit of the air. 相似文献
19.
Camelina sativa (L.) Crantz is a promising, biodiesel-producing oilseed that could potentially be implemented as a low-input alternative crop for production in the arid southwestern USA. However, little is known about camelina’s water use, irrigation management, and agronomic characteristics in this arid environment. Camelina experiments were conducted for 2 years (January to May in 2008 and 2010) in Maricopa, Arizona, to evaluate the effectiveness of previously developed heat unit and remote sensing basal crop coefficient (K cb ) methods for predicting camelina crop evapotranspiration (ET) and irrigation scheduling. Besides K cb methods, additional treatment factors included two different irrigation scheduling soil water depletion (SWD) levels (45 and 65 %) and two levels of seasonal N applications within a randomized complete block design with 4 blocks. Soil water content measurements taken in all treatment plots and applied in soil water balance calculations were used to evaluate the predicted ET. The heat-unit K cb method was updated and validated during the second experiment to predict ET to within 12–13 % of the ET calculated by the soil water balance. The remote sensing K cb method predicted ET within 7–10 % of the soil water balance. Seasonal ET from the soil water balance was significantly greater for the remote sensing than heat-unit K cb method and significantly greater for the 45 than 65 % SWD level. However, final seed yield means, which varied from 1,500 to 1,640 kg ha?1 for treatments, were not significantly different between treatments or years. Seed oil contents averaged 45 % in both years. Seed yield was found to be linearly related to seasonal ET with maximum yield occurring at about 470–490 mm of seasonal ET. Differences in camelina seed yields due to seasonal N applications (69–144 kg N ha?1 over the 2 years) were not significant. Further investigations are needed to characterize camelina yield response over a wider range of irrigation and N inputs. 相似文献
20.
Abdelmonem Mohamed Amer 《Agricultural Water Management》2011,98(5):815-822
Surface irrigation analysis and design require the knowledge of the variation of the cumulative infiltration water Z (L) (per unit area) into the soil as a function of the infiltration time t (T). The purpose of this study is to evaluate water infiltration and storage under surface irrigation in an alluvial clay soil cultivated with grape yield, and to determine if partially wetted furrow irrigation has more efficient water storage and infiltration than traditional border irrigation. The two irrigation components considered were wet (WT) and dry (DT) treatments, at which water applied when available soil water reached 65% and 50%, and the traditional border irrigation control. Empirical power form equations were obtained for measured advance and recession times along the furrow length during the irrigation stages of advance, storage, depletion and recession. The infiltration (cumulative depth, Z and rate, I) was functioned to opportunity time (to) in minute for WT and DT treatments as: ZWT = 0.528 to0.6, ZDT = 1.2 to0.501, IWT = 19 to−0.4, and IDT = 36 to−0.498. The irrigation efficiency and soil water distribution have been evaluated using linear distribution and relative schedule depth. Coefficient of variation (CV) was 5.2 and 9.5% for WT and DT under furrow irrigation system comparing with 7.8% in border, respectively. Water was deeply percolated as 11.88 and 19.2% for wet and dry furrow treatments, respectively, compared with 12.8% for control, with no deficit in the irrigated area. Partially wetted furrow irrigation had greater water-efficiency and grape yield than both dry furrow and traditional border irrigations, where application efficiency achieved as 88.1% for wet furrow irrigation that achieved high grape fruit yield (30.71 Mg/ha) and water use efficiency 11.9 kg/m3. 相似文献