Showing 14 results for Water Stress
M. M. Nakhjavani Moghaddam, B. Ghahraman,
Volume 9, Issue 3 (10-2005)
Abstract
In order to determine the water production functions for winter wheat (Variety, C73,5), an experiment was conducted in through of a complete randomized block design with 9 treatments and 3 replications in Mashhad region. While the first treatment (as a control treatment) was selected on the basis of irrigation in all growth stages of growing season, six treatments were selected on the basis of an irrigation cut in the six stages of growth season and two remaining treatments were also selected on the basis of a constant reduction of irrigation to the amount of 20 and 60 percent. In general the water stress was caused that the amounts of depth percolation were calculated negatively which was an indication of the water uptake from below the root zone. According to results, models of the yield in per unit of area had a higher correlation coefficient of determination in relation to the models of the yield in per unit of water. The derived sensitivity coefficients indicated that the winter grain formation and flowering stages were respectively the most sensitive stages of the growth season stages to the water deficit. There are some differences between these computed sensitivity coefficients and the amounts reported by the other researchers. Probably the variety, degree of stress, the climatic conditions and some unknown factors may explain these differences.
M Babaeian, M Haydari, A Ghanbari,
Volume 12, Issue 46 (1-2009)
Abstract
In order to study the effects of foliar micronutrient application under water stress at three stages of growth on proline and carbohydrate concentrations, grain yield and yield components of sunflower (Alster cultivar), a field experiment in split plot design with three replications was conducted in 2007. Alster cultivar was considered under water stress at three stages of growth (heading, flowering and grain filling) as main plot and seven micronutrient treatments, Fe, Zn, Mn, Fe+Zn, Fe+Mn, Zn+Mn and Fe+Zn+Mn, as sub plots. Results showed, water stress at three stages of growth significantly decreased grain yield, biological yield, 1000 weight seeds, cap diameter and cap weight of sunflower (Alster cultivar). The impact of water stress was more pronounced when applied at grain filling. Use of foliar micronutrient increased grain yield in water stress. On the other hand, use of Mn foliar application had the highest positive effect on yield components and grain yield. Free proline and total soluble carbohydrate concentration were increased under water stress at all of the three stages of growth. The highest concentration of these two components was found on the flowering stage. Foliar micronutrient also increased accumulation of the two components.
S Safae Chaykar, H Samie Zade, M Esfahani, B Rabiei,
Volume 13, Issue 48 (7-2009)
Abstract
In order to study the correlation of agronomic, morphologic and physiologic traits and their effects on grain yield of rice genotypes in two environments (favorable irrigation and water stress), 49 genotypes were evaluated using a completely randomized block design with 3 replications in two experimental conditions. All practices and conditions were the same for the two experiments with the exception of irrigation, where under stress conditions no irrigation was applied at tillering stage. Comparison of means showed significant differences between genotypes in each environment. Also, differences between yield and yield components of each genotype under two conditions were significant. The results of phenotypic correlations showed that the highest positive and significant correlation with grain yield belonged to number of panicle per plant (0.95) in irrigation conditions and to number of filled grains per panicle (0.92) in water stress conditions. Stepwise regression analysis for grain yield introduced number of panicle per plant, relative water content (RWC), flag leaf length and number of spikelet per panicle, respectively, as effective traits in grain yield in irrigation conditions, however, in stress conditions, number of filled grain per panicle, number of panicle per plant and relative water content were effective traits in yield. The results of path analysis showed that the number of panicle per plant had the highest positive and direct effect on grain yield in the two environments. Factor analysis introduced four factors in the two conditions named yield and crop production, phenologic, harvest index and plant shape and appearance quality of grains factors. Therefore, to select high yield and drought tolerant genotypes, we need to consider number of filled grain per panicle, number of panicle per plant and relative water content. In addition, traits such as panicle length, number of spikelet per panicle, flag leaf length and width that showed significant correlations with grain yield in stress conditions should also be considered important and second to the above mentioned traits.
M Alimohamady, A Rezaee, A.m Mirmohamady Meybodi,
Volume 13, Issue 48 (7-2009)
Abstract
This study was conducted in Research Farm of Isfahan University of Technology to evaluate some of the agronomic and physiological traits and grain yield potentials of ten bread wheat cultivars using a split plot design with three replications. Main and sub plot consisted of optimum and stress moisture treatments (irrigation after 70±3 and 130±3 mm evaporation from class A pan) and wheat cultivars, respectively. The results of analysis of variance revealed significant effect of moisture treatments on all traits except 1000-grain weight, harvest index, specific leaf weight, assimilate redistribution and difference of peduncle weights at heading. Significant differences were found among genotypes in the stress condition except for chlorophyll b and chlorophyll a to b ratio. Significant differences were detected among genotypes in optimum moisture condition for all characters, except for chlorophyll b, chlorophyll a to b ratio, harvest index and assimilate redistribution. Grain yields in two moisture conditions had significant positive phenotypic and genetic correlations with harvest index, number of grain/spike, RWC, chlorophyll a and sum of chlorophylls a and b and had significant negative correlation with RWL. Significant positive correlation was observed between peduncle weight at heading stage and difference of peduncle weights at stages heading and maturity with grain yield and RWC in moisture stress condition. The results of path analysis for phenotypic correlation coefficients between grain yield and their corresponding traits in the regression model showed that in stress condition harvest index had the highest direct and positive effect on grain yield and in non stress condition chlorophyll a had the highest direct and positive effect on grain yield. Results of stepwise regression analysis in non stress condition revealed that chlorophyll a, plant height and harvest index explained more than 90% of grain yield variability. Based on stepwise regression analysis in non stress condition, RWL, harvest index and RWC explained 95% of grain yield variability.
H.r. Memari, E. Tafazoli, A. Kamgar-Haghighi, A. Hassanpour, N. Yarami,
Volume 15, Issue 55 (4-2011)
Abstract
Many experiments have been carried out to decrease the negative effect of drought stress and obtain suitable growth under water deficit conditions. Application of plant growth regulators (especially growth retardants) is one of the proposed methods. This study was conducted to investigate the effect of Cycocel application on growth of two olive cultivars (Shengeh and Roghani) under water stress condition. The design of experiment was completely randomized with six replications (Factorial arrangement). Treatments included irrigation intervals (2, 4, 6, 8 weeks) and Cycocel concentrations (0, 500,1000,2000,4000 mg per litter). Some indices such as height, chlorophyll, leaf area, root, and shoot weight (fresh and dry) were measured. Results indicated that interaction of C.C.C treatment and irrigation intervals on height of olive cultivars was not significant, probably due to the response of these cultivars to concentrations of C.C.C. Although drought stress decreased the number of leaves in both cultivars, the application of CCC (500 mg per litter) thwarted the adverse effects of drought stress. Cycocel increased chlorophyll content significantly (500 mg per litter in Roghani and Shengeh and 6 weeks irrigation interval). Cycocel application decreased leaf area, but in Shengeh cultivar increased leaf area in 6 week irrigation interval. Overall, the results indicated that the application of Cycocel with concentration of 500 mg per litter in 6 week irrigation intervals in both cultivars (Roghani and Shengeh) was the best treatment for controlling the adverse effects of drought. Also, results indicated that such changes were dependent on Cycocel concentration and drought level.
Gh. Omidi Ardali , M. J. Bahrani,
Volume 15, Issue 55 (4-2011)
Abstract
The optimum levels of soil moisture and nitrogen are important to obtain higher yields. To investigate the effects of water stress, nitrogen levels and application times on yield and yield components of sunflower (Helianthus annuus L.), the cultivar Euroflor at different growth stages, a two year study (2006-007) was conducted at Research Fields of College of Agriculture, Shiraz University (Badjgah) using a split factorial design with four replications. Treatments were water stress at three levels, (non-stress and stress at flowering and seed formation) as main plot and three N levels (0, 70, 140 kg ha-1) and N application times (split application at planting and stem elongation, planting and heading, and stem elongation and heading) as subplot. Number of seed per head, 1000-seed weight, seed yield, Oil yield and HI were measured. Results showed that the effects of water stress and N rates on yield and yield components were significant, but the effects of N application times and interaction between water stress, nitrogen rates and application times were insignificant. Overall, the crop showed more sensitivity to drought stress at flowering time, and 70 kg N ha-1 is recommended for the region.
N. Besharat, A. Tajabadi Pour, V. Mozafari,
Volume 18, Issue 67 (6-2014)
Abstract
To study the effects of soil phosphorus (P) application on growth and water relations and nutrient concentration of pistachio seedlings (Badami-e-Zarand) under water stress, a greenhouse experiment was conducted. Treatments were arranged in a factorial manner as a completely randomized design with three replications. Treatments consisted of six P levels (0, 30, 60, 90, 120 and 150 mg P Kg-1 soil as H3PO4) and three irrigation intervals (2, 4 and 8 days). Results showed that as water stress increased, growth parameters significantly decreased. As irrigation interval was increased to 8 days, shoot and root dry weights, shoot/root ratio, leaf area and leaf number and stem height decreased. Photosynthesis parameters were significantly decreased by increasing water stress. Also, P and Zn concentrations decreased as irrigation interval increased. Analysis of variance indicated that P application had no significant effect on growth parameters, transpiration rate and photosynthesis. It seems that Olsen extractable P (5.35 mg kg-1 soil) was sufficient for optimum growth of pistachio seedlings and thus, no growth responses were observed from P application in this experiment. Application of phosphorus significantly increased P and decreased Zn concentrations.
J. Abedi Koupai, M. Salehi-Sirzar, S. S. Eslamian, J. Khajeali, Y. Hosseini,
Volume 18, Issue 68 (9-2014)
Abstract
In order to investigate the effect of pest and water stresses on different growing stages of cowpea (Vigna sinensis) and pest occurrence, an experiment was conducted in Khazaneh Research station of Isfahan University of Technology. The experiment was carried out in a factorial complete randomized block design, in two different farms, with and without insecticide application. The treatments included severe water stress (50% water requirement), moderate water stress (75% water requirement) in four stages of cowpea growth, the first stage (from seed germination until flower in, second stage (from flowering until pod-filling), third stage (from pod-filling until harvesting) and the whole period of cowpea growth, in three replications. There was a control treatment in each farm with no stress in the whole period of cowpea growth, in three replications. The results showed that water stress had no significant effect on percentage of protein and mineral material. Result also showed that water stress had a significant effect (P≤ 0.01) on population of insects. Water stress significantly (P≤ 0.01) reduced the population of nymphs and adults of Empoasca decipiens Paoli and leaf minor damages, but water stress increased population of Thrips tabaci Lind. Considering the duration of first stage of growth (63 days), it is concluded that this stage had less sensitivity to water stress than the other stages. In regions, where farmers encounter water shortage for cowpea planting, the best performance can be obtained when moderate water stress (75% water requirement) is applied at the first stage of growth.
Y. Choopan, A. Khashei Siuki, A. Shahidi,
Volume 21, Issue 4 (2-2018)
Abstract
Limited water resource in arid and semi-arid areas is one of the most important problems in the agricultural sector. Therefore, the use of non-conventional water resources becomes more important. For this reason, a study was conducted on barley to evaluate the effect of irrigation with sugar plant wastewater as a factorial randomized complete block design field experiment. Treatments include water well I1, wastewater I2, combined water and wastewater I3 (the ratio of seven to one, according to local practice) in two levels of without water stress S1 and %75 water stress S2 and treatment I1S1 was considered as control. The results showed changes in surface tension of %1 had a statistically significant effect on plant height, grain yield and root length. As well changes of irrigation water in the level of %1 had a statistically significant effect on plant height, grain protein yield and root length. Maximum grain yield was obtained in treatment I1S1 with the weight of 4034 kg per hectare and lowest grain yield was obtained in treatment I2S2 with the weight of 1564 kg per hectare. The lowest and highest percentages of protein content were observed in treatment I1S1 for 12.37% and treatment I2S2 for 13.47%, respectively. The plant height showed the highest amount in control treatment, i.e. 82.87 Cm.
M. A. Ansari, A. Egdernezhad, N. A. Ebrahimipak,
Volume 23, Issue 4 (2-2020)
Abstract
This study was conducted to evaluate AquaCrop for the simulation of potato yield and water use efficiency (WUE) under different water stress values at five levels (E0, E1, E2, E3 and E4, indicating 100, 85, 70, 50 and 30 percent of crop water needed, respectively) in three times during growth cycles (T1, T2, and T3, indicating 50, 100, and 150 days after sowing, respectively). The results showed that AquaCrop had overestimated and underestimated error for the simulation of yield and WUE, respectively. Based on RMSE and NRMSE values, the errors for yield and WUE were acceptable. The maximum and minimum error were also 0.3 (E1T3) and 3.15 (E1T2), respectively. The results obtained for WUE showed that the maximum and minimum were 0.53 (E3T2) and 0.03 (E4T2), respectively. The average differences between simulated and observed results (ADSO) of WUE for E1, E2, E3 and E4 were 0.24, 0.25, 0.19, and 0.44 ton.ha-1, respectively; the ADSO of yield for T1, T2, and T3 was 0.19, 0.36, and 0.22 ton.ha-1, respectively. Therefore, AquaCrop showed a high error for WUE when water stress was increased and crop was in its initial crop growth.
A. H. Nasrollahi, H. Ahmadi, Y. Sabzevari, S. Nouri,
Volume 24, Issue 2 (7-2020)
Abstract
The Plant Water Resistance Index (CWSI) is a tool that can be used for the rapid monitoring of plant water status, which is a key requirement for the accurate product irrigation management.The purpose of this study was to calculate the CWSI index for bean hares in the Khorramabad region for two methods of surface irrigation and drip tape irrigation. For this purpose, a design was implemented in the form of randomized complete block design and split plot experiment. The main factors included drip tape irrigation (T) and surface irrigation (F), and the cultivars of Chibi cultivars including COS16 (C), Sadri (S) and diluted (K) served as sub-plots. By using the field measurements, the position of the upper and lower base lines was estimated for each treatment in different months and used to calculate the CWSI index. The results showed that CWSI values calculated in the surface irrigation during plant growth period were always higher than those in the drip tape irrigation. The highest value of CWSI index was obtained for the Sadri variety, which was equal to 0.20 and 0.26, for the type and surface method, respectively. Statistical analysis showed that the effect of irrigation method on the amount of water stress index was significant at 5% level, but there was no significant difference between different cultivars. According to the results of this study, the threshold values for CWSI were considered to be 0.19 and 0.24 for surface and drip tape irrigation respectively, and relationships were presented based on the differences in vegetation and air temperature to determine the irrigation time.
F. Alizadeh, A. H. Nasrolahi, M. Saeedinia, M. Sharifipour,
Volume 25, Issue 1 (5-2021)
Abstract
In areas with high rainfall distribution, proper irrigation management, including complementary irrigation, is one of the effective strategies to increase crop production. In order to investigate the effect of supplementary irrigation in different growth stages on the yield and water productivity of Autumn rapeseed, an experiment in the form of a complete randomized block design with five irrigation management treatments including rainfed (I1), single irrigation at flowering stage (I2), single Irrigation at pod filling stage (I3), two irrigation at pod filling stage and flowering (I4), three irrigation at flowering, and pod filling and grain Filling stages (I5) was carried out at Lorestan University Research Field. Results showed that there was a significant difference between the effects of different irrigation treatments at 1% level. The lowest grain yield, biological yield and oil yield were obtained in I1 treatment with 44.62%, 50.95% and 53.58% decrease, as compared to I5 treatment. The results also showed that by applying irrigation at pod filling stage, grain yield and oil yield were increased by 13.22% and 20.23%, as compared to I1 treatment. The highest total productivity for the grain yield and oil yield was obtained in I5 treatment with 0.252 and 0.073 kg / m3. In general, due to the fact that drought stress in rapeseed calving stages reduces yield, the higher the number of irrigations in rapeseed calving stages, the more the yield.
S. Jamali, H. Banejad, A. Safarizadehsani, B. Hadi,
Volume 26, Issue 1 (5-2022)
Abstract
This research was conducted to study the effect of deficit irrigation and saline water on yield and yield components of Peppermint in the experimental research greenhouse of Ferdowsi University of Mashhad from 2018 to 2019. This research was performed as a factorial experiment based on the randomized complete design with three replications. In this research, irrigation levels consist of 4 levels (100 (I1), 80 (I2), 70 (I3), and 55 (I4) percent of FC) and saline water factors consist of 4 levels (0.9 (EC1), 1.9 (EC2), 2.5 (EC3), and 3.4 dSm-1 (EC4)). The result showed that a decrease of the water to 15, 30, and 45 percent have resulted in the reduction of shoot fresh weights (to 15.8, 28.4, and 30.1 percent), shoot dry weights (to 7.1, 11.5, and 11.5 percent), and root dry weights (to 4.6, 9.2, and 9.2 percent), respectively. Also, results showed that irrigation with EC2, EC3, and EC4 has resulted in a decrease in shoot fresh weights (to 12.7, 28.5, and 34.0 percent), shoot dry weights (to 3.6, 11.6, and 11.6 percent), and root dry weights (to 6.7, 12.4, and 14.6 percent), respectively. The result indicated that interaction effects of salinity and water stress decreased peppermint water productivity, as the highest and lowest peppermint water productivity with 3.54 and 2.06 Kgm-3 were in the EC1I4 and EC3I1 treatments, respectively. Results revoluted that maximum dry yield and peppermint water productivity were in the EC1I4, so this treatment was recommended for irrigation of peppermint.
F. Meskini-Vishkaee, A.r. Jafarnejhadi, M. Goosheh, B. Delsooz Khaki, M. Javadzadeh,
Volume 27, Issue 3 (12-2023)
Abstract
One of the most common approaches for farm irrigation management is using soil readily available water and allowable depletion coefficient. The objective of this study was to determine wheat crop response coefficients, critical moisture content, and soil allowable depletion coefficient using a physically based method in three dominant soils under wheat cultivation in Khuzestan province. Treatments included full irrigation and water stress at three levels low, moderate, and high. The highest and lowest values of wheat crop response coefficient were related to silty clay loam (Ky=1.26) and clay loam (Ky=0.96), respectively. Critical soil moisture content was observed in loam soil (0.25 cm3cm-3)> silty clay loam (0.23 cm3cm-3)> clay loam (0.22 cm3cm-3), respectively. Despite the higher critical moisture content in loam, the most soil allowable depletion coefficient was also calculated in loam (0.54). Soil allowable depletion coefficient in silty clay loam and clay loam were 0.44 and 0.42, respectively. The results confirmed the simultaneous effects of soil and plant properties on the availability of soil water for the plants.
