Showing 23 results for Variation
G. Saeidi,
Volume 5, Issue 4 (1-2002)
Abstract
Flax (Linum usitatissimum L.) is an oilseed and widely adapted crop. Oil of regular genotypes of flax is used in industry because of its unique fatty acid profile. New, mutant genotypes of flax have oils similar to sunflower oil which can be used as edible oil. This experiment was conducted to investigate the genetic variation of agronomic traits and productivity in different edible and industrial oil genotypes of flax in Isfahan. The genotypes were evaluated in augmented design.
Based on the results, the average numbers of seedling/m2 in edible and industrial oil genotypes were 178 and 367 with variation coefficients of 70 and 10%, respectively. Maturity also showed variation and varied between 89 to 116 days in edible oil genotypes and between 89 to 128 days in industrial oil genotypes. Plant height varied between 57 to 86 and 49 to 73 cm in edible and industrial oil genotypes, respectively. Seed yield also had considerable variations and varied between 429 to 2651 and 779 to 2389 kg/ha with variation coefficients of 35 and 25 in edible and industrial oil genotypes, respectively. Seed yield per plant showed a high and positive correlation with basal branches (r=0.77**) and bolls per plant (r=0.93**), but high and negative correlation with stand (r=-0.66**). Regression analysis revealed that approximately 96% of the variation in seed yield per plant was attributed to variation in bolls per plant, seeds per boll and seed weight and they were determined as the major yield components, respectively. Bolls per plant was the most important yield component and contributed to 87% of the variation for seed yield per plant.
F. Shahin Nia, A. Rezai, A. Saedi,
Volume 6, Issue 2 (7-2002)
Abstract
The variation and path coefficient analysis of bread-making quality traits have been studied for 145 genotypes of breeding lines, cultivars and landrace varieties of wheat (Triticum aestivum L.). Bread-making quality traits of genotypes was evaluated indirectly by protein percentage, SDS and Zeleny sedimentation tests, hardness index, test weight, bread volume, grain moisture, and water absorption percentage. Hardness index, Zeleny and SDS sedimentation tests had the highest coefficient of variability (13.51%, 11.83% and 11.03%, respectively). Factor analysis for the genotypes, based on qualitative traits revealed two factors, which explain 98.23% of total variation and were named grain protein index and bread volume factors. The result of correlation analysis indicated positive and significant relationship between protein percentage, SDS sedimentation test and other bread-making quality traits. On the first and second steps of stepwise regression analysis, protein percentage was the most effective trait in explaining different qualitative trait variations. Path analysis also showed the direct and significant effects of protein percentage, Zeleny sedimentation volume, grain moisture and water absorption percentage, and bread volume on SDS sedimentation test. According to cluster analysis based on qualitative traits, the cultivars and landrace varieties, from the view poit of protein quality and quantity, had the highest potential among other groups (generally breading lines).
T. Najafi Mirak, A. Zali, A. Hossainzadeh, Gh. R. Rasoulian, A. Saeidi,
Volume 7, Issue 4 (1-2004)
Abstract
Russian Wheat Aphid (RWA) is a serious pest of wheat, barely and other small grains in cereal-producing regions of the world. The use of resistant cultivars is an effective management strategy to control this pest. In this study, 15 lines and 13 cultivars of durum and bread wheats along with two resistant and susceptible controls were used to evaluate their reaction to RWA under greenhouse conditions, using completely randomized design with four replications. Three seedlings at each plot were considered as an experimental unit. Five aphid nymphs (4-5 ages) were placed on each plant at 1-2 leaf stage. Leaf rolling and leaf chlorosis percentages were measured 21 days after infesting and used to screen the genotypes. Despite the relatively high linear correlation between two resistance components, leaf rolling and leaf chlorosis, estimated as 80%, analysis of variance indicated significant differences among genotypes. Eight durum lines DW9, DW14, DW4, DW2, DW7, DW8, DW12 and DW3 and one bread wheat cultivar (Azadi) were significantly more resistant than the resistant control (Halt). One durum line (DW13) and two bread wheat cultivars (Shiroodi and M-75-7) had higher leaf rolling and leaf chlorosis than the susceptible control (Sholeh). So they were selected as the most susceptible to the biotype of D. noxia. under study. Orthogonal comparison showed that durum lines were more resistant than bread wheat cultivars. These results were confirmed by Cluster Analysis based on leaf rolling and leaf chlorosis.
M. Farshadfar, E. Farshadfar,
Volume 8, Issue 2 (7-2004)
Abstract
Agropyron is one of the most resistant plants to biotic and abiotic stresses. It plays an important role in forage yield in rangelands. Genetic variability based on different markers is the important step in crop improvement. In order to evaluate the genetic variation of different Agropyron species based on morphological and chemical traits, this experiment was carried out in the Agriculture and Natural Resources Research Center of Kermanshah. The tiller numbers, spike length, spikelet numbers, length of flag leaf, width of flag leaf, plant height, peduncle length, ash percentage, organic matter, fiber, dry matter, fat and crude protein were registered. Statistical analysis of data was done by SPSS software. According to cluster analysis the tetraploid genotypes were classified into 5 clusters. Based on principal components analysis the length of flag leaf, spike length and plant height, and among the chemical traits of the ash percentage, organic matter, and crude protein had the highest portions of variance. The genetic parameters such as PCV, GCV, ECV, Hb and Ga for length of flag leaf were 0.274, 0.169, 0.215, 0.382, 3.05 and for spike length were 30.96, 21.64,22.139, 0.48, 5.786 and for plant height were 0.16, 0.084, 0.136,0.276, 6.054, respectively.
F. Rafeie, G. Saeidi,
Volume 9, Issue 2 (7-2005)
Abstract
To study the genetic variation of different traits, 66 isolated lines from different Iranian safflower landraces of Isfahan, Azarbaijan, Khorasan, Kordestan, Central provinces along with 13 foreign genotypes and two local populations of Kooseh and Arak-2811 were evaluated in a simple lattice design with two replications. The experiment was conducted at the research farm, Isfahan University of Technology in the year 2001.
The results indicated that there was significant differences among the genotypes for all the traits including days to 50% flowering, maturity, plant height, yield/plant, seed yield and its components and relative resistance to the powdery mildew disease (p<0.01). Seed yield of genotypes varied from 1285 to 3524 Kg/ha. The seed yield of local population of Kooseh which was dominant growing cultivar in Isfahan province and one of the latest in maturity and tallest genotype was 2317 Kg/ha, however, some genotypes were earlier in maturity and had the less plant height and more seed yield than Kooseh. Seed oil content was measured for the 20 high yielding isolated lines by the Soxhlet method and varied from 24.62% (in one of the isolated lines from Kordestan landrace) to 37.55% (in one of the isolated lines from Kooseh). The genotype of Kooseh had seed oil content of 35.99%. Based on the results of cluster analysis, the genotypes were classified in to 3 the distinct clusters and they were significantly different for all of the traits, except for days to 50% emergence. One of the clusters had the maximum seed yield, seed yield/plant, branches/plant, capitula/plant, seeds/capitulum and the minimum of seed weight. It was implied that the genotypes of this cluster which were isolated from local populations could be used for improving the seed yield. The cluster analysis also indicated that in isolated lines from different provinces, there was no special pattern between the genetic and geographical diversity.
B. M. Ashour, A. Arzani, A. Rezaei, S. A. M. Mirmohammady Maibody,
Volume 9, Issue 4 (1-2006)
Abstract
The Genetic basis of grain yield and related characteristics were studied by a generation mean analysis in five crosses of winter wheat (Triticum aestivum L.). “Roshan”, “Mahdavi”, “Inia”, “Atila” and “Goscoyin” cultivars along with their F1, F2, BC1 and BC2 populations were evaluated by a split-plot design with crosses as the whole plot in a randomized complete block design with two replications and generations were applied as the subplots. Analysis of variance revealed significant differences among generations for studied characteristics including the grain yield per plant, the number of spikelet per plant, the number of spikelet per spike and grain weight per spike. For the majority of traits and crosses, F/DH1/2 was less than one, indicating that the sign and magnitude of gene actions were different. Estimates of broadsense and narrow sense heritabilities were low for the grain yield per plant compared with other traits, rating from 28.5% to 58.6% and 24% to 48,5% for the five crosses, respectively. Genetic components of generation means were calculated by fitting different models and choosing the best model indicated that the impact of additive, dominance and epistasis genetic components in controlling the traits depend on the cross and the trait under study.
S. H. Tabatabaei, H. Fardad, M. R. Neyshabory, A. Liaghat,
Volume 10, Issue 1 (4-2006)
Abstract
To determine the water application efficiency in furrow irrigation more accurately, consideration of seasonal and spatial variation of infiltration properties are needed. In addition, the effectiveness of different farm management on infiltration are significant. The main objective of this research was to simulate the seasonal variation (SV) of infiltration coefficients in Kostiakov-Louise equation (KLE) in a cracking soil under two traditional farm managements. Farm studies carried out in a clay-loam soil in Karaj. The two management treatments were soil without wheat residual and soil with wheat residual by a 5 ton/ha rate. There were 22 furrows with 0.75 m width in the farm. KLE infiltration coefficients were measured using inflow-outflow and two point’s methods in six furrows. The results of this study indicated that the SV of a and k coefficients were not significant, but variation of f0 was significant which was simulated with a logarithmic model. The effectiveness of SV on cumulative infiltration (Z) was also evaluated and indicated to be significant that were simulated with a logarithmic model too. Finally, dimensionless parameter such as Z* were developed to predicate Z parameter in different irrigation time, irrigation events and different residual management. Base on the result, although residue management causes a significant difference between value of f0 and Z in two treatments, but it doesn’t effect on trend of variation during the season. It means that the trend of variation is independent of residue in soil. It is probably done because of change in some of soil physical properties such as soil bulk density and aggregate stability.
E. Farahani, A. Arzani,
Volume 10, Issue 4 (1-2007)
Abstract
An experiment was conducted to investigate the genetic diversity in the cultivars and F1 hybrids of durum wheat, using agronomic and morphological traits. Evaluation of consistency between choosing parents of crosses based on morphological and agronomic observations and genetic distance obtained from cluster analysis were objectives of this study. Fourty- two genotypes were evaluated using a randomized complete block design with three replications in 2003. Agronomic characteristics comprised days to 50% flowering, days to 50% pollination, days to maturity, plant height (cm), spike length (cm), grain weight per spike (gr), number of grain per spike, number of spike per m2, grain yield (t/ha), biological yield (t/ha), 1000 grain weight, test weight (gr/L) and harvest index were measured in the studied genotypes. The results of analysis of variance showed significant differences among genotypes for all the studied traits. The results also revealed that grain yield had the highest coefficient of variation (CV= 21.6%), followed by spikes per m2 (CV= 20%) and number of grains per spike (CV= 18.9%). Lowest coefficient of variation was observed in days to maturity, days to 50% pollination and days to 50% flowering. Moreover, correlation analysis indicated that grain yield correlated with harvest index, biological yield, grain per spike and grain weight per spike. Cluster analysis of genotypes based on agronomic traits defined desirable clusters. These clusters have desirable characteristics and are beneficial for breeding objectives. Results of evaluation of consistency between choosing parents based on observation and those of cluster analysis showed varing degrees of consistency in 12 conducted crosses, ranging from highly similar parents in Eupoda6×Chahba88 to relatively distinct parents in PI40100×PI40099 cross.
M. H. Banabazi, S. Esmaeilkhanian, S. R. Miraei Ashtiani, M. Moradi Shahrbabak,
Volume 10, Issue 4 (1-2007)
Abstract
Genetic variation within and between five Iranian sheep populations including Sanjabi (SAN), Kordi Kordistan (KKO), Kordi Khorasan (KKH), Mehraban (MEH) and Moghani (MOG) was assessed using six microsatellite markers (McMA2, McMA26, MAF64, OarAE64, OarCP26 and OarFCB304). The PCR reactions were successfully perfomed with all primers except OarAE64. All locus-population combinations were at Hardy-Weinberg equilibrium except McMA2 in MOG population (P<0.005). Polymorphism criteria showed that the five studied loci were polymorphic in all populations. The lowest DA genetic distance (0.234) was observed between KKH and KKO and the highest (0.388) between SAN and MOG populations. The dendrograms based on DA distances were drawn using unweighted pair-group method using an arithmetic average (UPGMA) and neighbor-joining (NJ) method. KKO, KKH and SAN were grouped together at one cluster and MEH and MOG at another by both methods. The average expected heterozygosity for each populations (as interpopulation variation) ranged from 0.744 to 0.847 for KKH and MEH, respectively. The estimated time of divergence for two Kordi populations (KKO and KKH) was 445 years that complies with historical evidences. The findings of this research confirmed that microsatellite variation could be a useful tool for screening of investigating biodiversity among domestic animals.
A.r. Khanahmadi, Gh. Rahimi, A. Nejati-Javaremi, S. Esmaeilkhanian,
Volume 11, Issue 40 (7-2007)
Abstract
In order to detect genetic variation of native fowls in Mazandaran native Fowls breeding station, blood samples were collected from 100 male and female of birds (1:11). The DNA of the blood samples was extracted according to an optimized salting out protocol. The extracted DNA was amplified through polymerase chain reaction (PCR). Of the twenty random primers (10 mer) were used in this study, fourteen yielded satisfactory PCR. The total 63 polymorphic and 77 monomorphic bands were detected for the 14 primers. The number of bands displayed for each primer ranged from 4 to 16 with 200-2100 base pairs. The highest and lowest percentages of polymorphism band were observed for primer 9 (72%) and primer 14 (16%) respectively. The band sharing frequency was calculated for each primer, which ranged from 79 to 96. The genetic similarity within population and genetic variation were estimated as 89 and 11 percentage respectively. In conclusion, the existence of high level of polymorphism after ten generation of selection may indicate the accuracy of genetic evaluation program, suitable selection strategies and also large enough effective population size in this breeding flock.
M. Golestani, H. Pakniyat,
Volume 11, Issue 41 (10-2007)
Abstract
To investigate genetic variation, and identification of tolerant genotypes according to quantitative indices of drought tolerance, 8 sesame genotypes were tested in a randomized complete block design with three replications under optimum and limited irrigation at the Research Station of College of Agriculture, Shiraz University. Based on the potential yield and yield under stress, quantitative indices of drought tolerance such as mean productivity (MP), geometric mean productivity (GMP), harmonic mean (HM), stress tolerance index (STI), stress susceptibility index (SSI) and tolerance index (TOL) were determined. The result of analysis of variance exhibited highly significant differences among the genotypes for all the indices measured, and yield under optimum and limited irrigation, indicating the existence of genetic variation among genotypes, and thus the possibility of selecting drought tolerant genotypes. Mean comparison displayed that the highest potential yield, stress yield, MP, GMP, HM and STI were related to the genotype number 5. Correlation analysis between indices, mean potential and stress yields indicated that every four indices are suitable for screening the genotypes. Based on these indices and higher yields under optimum and limited irrigation the best drought tolerant genotypes were identified to be genotypes number 4 and 5. Multivariate biplot indicated that the genotypes number 4 and 5 were located next to the vectors of drought tolerance indices, including MP, GMP, HM and STI. Cluster analysis showed genetic distance among genotypes. As a result, genotypes number 4 and 5 were identified as drought tolerant and genotypes number 1, 2 and 3 as susceptible to drought.
H. Jalilvand,
Volume 11, Issue 42 (1-2008)
Abstract
This study was down in Forest Park of Noor. In order to determination of tree ring response to climatic variations, 35 cores were taken from dominant natural stand of common ash (Fraxinus excelsior L.). The guide of this study was finding which climatic variables are effective in the ring width growth of ash in current growing year and previous years (one, two and three years before current growing year) by multiple regression models at the North of IR-Iran. Totally, 85 annually, monthly seasons and seasonal growth climatic variations of precipitation, temperature, heat index, evapotranspiration and water balance were analyzed. The best multiple regression models were explained 83 percent of total variance of the growth of common ash. The results show that the growth of common ash was related to the previous year's climatic variations than that of the current year. The most effective role of climatic variations was due to the first and second preceding years (55%). Evapotranspiration of July and September, and precipitation of May in the second and precipitation of March in the third previous years, all were positively affected the growth of this species. This study revealed that ash is interested in warmer condition on early and middle of seasonal growth in present of available humid, and precipitation in the months of early growing season (Ordibehesht-Khordad of two previous years).
A Sarhadi, S Soltani, R Modaers,
Volume 12, Issue 46 (1-2009)
Abstract
Low flow estimation and its characteristics play an important role in hydrologic studies. However, some low flow events are ignored compared with the lowest annual low flow that may have high risk. These events are taken into consideration by the use of partial duration or peak over threshold models. In this study, a 7-day low flow was applied for frequency distribution and threshold, and the lower events were considered as the number of low flow event ( ) to study seasonal variation of low flows together with two graphical methods. The results showed two major low flow seasons, and for other times of the year, the low flow events are negligible. At last, the region was divided into homogeneous groups based on seasonal variation of low flows.
M.m Majidi, A Arzani,
Volume 13, Issue 47 (4-2009)
Abstract
Sainfoin (Onobrychis viciifolia Scop.) is a perennial legume widely adapted to environmental conditions and has been successfully used as a pasture and hay forage in Iran. This experiment was carried out to investigate yield potential and genetic variation of morphological, agronomic and qualitative traits using 10 Iranian sainfoin populations. The experiment was conducted as a randomized complete block design with four replications ON Research Farm, Isfahan University of Technology. Results indicated that there are significance differences between populations for most of the traits. The estimates of heritabilities for forage yield, number of stem per plant, number of node and qualitative traits were over 50 percent. The high phenotypic and genotypic coefficients of variability for economic traits showed that a broad genetic diversity in this germplasem can be exploited in breeding programs. Significant differences were found among cuts and cut × population interaction for all characters. The third harvest produced 41.6 percent of total hay yield. Evaluation of traits related to forage quality revealed that the highest proportion of leaf to stem belong to Sarab and Oromieh populations (6.28 and 6.82, respectively). Crude protein percentage was significantly different among cultivars and Golpayegan population had the highest value for Crude protein percentage. Feridan, Khonsar and Golpayegan populations produced the highest dry matter yield in the first, second and third cut, respectively. These populations were found as the high potential accessions, which can be used as a source for agronomic and plant breeding research in the region.
S Mahbob Sharemi, A Forghani, H Ramezanpor,
Volume 13, Issue 49 (10-2009)
Abstract
Surface charge of soils is measured using two different approaches: ion adsorption and potentiometric titration. Most models of surface charge chemistry of soils have been derived from the data obtained by potentiometric titration. The Uehara and Gillmanُs model was used to estimate the surface charges at some soil pH range in three forest soils of Lahidjan region. The selected soils (Typic Udorthent, Typic Hapludalf, Ultic Hapludalf) were formed on three different types of parent rocks. So, the effect of parent rocks on surface charge characteristics was investigated. Soil samples were characterized through their organic carbon, clay percentage, pH in water and 1 M KCl, cation exchange capacity (CEC), point of zero charge of variable charge components (pH0), zero point of net charge(ZPNC) and charge variation. All soils had a significant amount of negative charge at soil pH. A Typic Hapludalf contained the lowest value of pH0 and the largest amount of negative charge at soil pH. The pH0 values were less in the surface than in the subsurface horizons. The ZPNC values were not obtained by the interpretation of charge variation curves and estimated lower than 2.5, which refers to high amount of negative charge in these soils. Differences in negative charge development in a pH range from 3 to 6 were largest for horizons rich in organic carbon and least for those with significant amounts of layer silicate minerals. Data obtained from charge variation curves of the studied soils also showed that the values of AEC were low and below 1 cmol/kg soil.
F. Gavazi, E. Maroufpoor,
Volume 21, Issue 1 (6-2017)
Abstract
The main purpose of this study is investigation of hydraulic properties in drip irrigation tape. In this study, 10 types of drip irrigation tape were tested, and the effect of 4 temperatures of water, 13, 23, 33 and 43 °C, was investigated according to the standard ISO 9261 and ISO IRISI. Initially all experiments were performed in standard temperature (23°C) in order to obtain qualitative evaluation indexes of tapes. The results obtained were as follows: According to the Cv, 8 models of tapes were ranked as good and 2 models as medium. According to the difference between the actual and nominal flow rates, 3 models were ranked as good, 3 models as medium, 3 models were acceptable and 2 models were unacceptable. According to the EU, 9 models were ranked as excellent and T3 was ranked as good. According to the UC, UC of all models was more than 70% and their flow rate variation follows normal distribution. According to qvar, flow rate changes in 3 models were acceptable, 2 models were ranked as good and 5 models were unacceptable.
M. Khoshravesh, M. Valizadeh,
Volume 21, Issue 2 (8-2017)
Abstract
Construction of a dam in the upstream of Tajan basin, as one of the human activities in order to provide drinking water, hydropower, agriculture, flood control or other purposes, can be effective on other sectors such as water resources. The purpose of this study is investigating the impact of Rajaei dam on groundwater resources in Sari-Neka plain during 26 years period (1985-2011) using geostatistical method, parametric and non-parametric tests. The results of statistical tests showed that groundwater table variation during 26 years has experienced insignificant upward trend. Quality factors such as EC, TDS, TH, Cl, SO4, Mg, Na and SAR had significant downward trend at 5% confidence level for Pearson and Kendall test. The Quality changes of groundwater resources in the region had good condition due to construction of dam. The results of spatial analysis for the study area using Kriging interpolation method in the three years for 1985, 1999, 2011 showed that in 1999 (the year of exploitation of the dam) most of the quality factors had reached the highest level from 1985 until the dam operation (1999) and then decreased to 2011. The results of this study showed that, agricultural activities after dam construction, operation of irrigation system and drainage network design of Rajaei dams, have raised the water table in northern part of the region and consequently had a significant impact on the quality of water resources.
H. Dabbaghi, M. Khoshravesh, M. A. Gholami Sefidkouhi,
Volume 22, Issue 2 (9-2018)
Abstract
Emitter clogging for using agricultural wastewater increases the operating costs and reduces the motivation of farmers. The new method to reduce the emitters clogging is the use of a Merus ring that does not have the problems of chlorination and pickling methods, such as pollution and high cost. Due to the importance of agricultural wastewater use, this study investigated the emitters clogging and the effect of Merus ring on the emitter's efficiency in a trickle irrigation system. The treatments including irrigation water (well water and wastewater) and modified water (irrigation with Merus ring and irrigation without Merus ring), as the main factor and the emitters type treatment including Irritec (D1), Corona (D2), Axios (D3), Netafim (D4), Polirood (D5), and Paya (D6) as the sub treatments were performed in three replications. The results showed that the agricultural wastewater caused the emitters clogging in irrigation water and modified water treatments, but over time, the Merus ring had a positive effect on the evaluation parameters of the emitters. For agricultural wastewater, in the first and last irrigation periods, the average discharge of emitters with the Merus ring was 0.05 and 0.33 Liter per hours, respectively, more than the treatment without the Merus ring. The uniformity coefficient of emitters in the first and last irrigation periods, in well water with the Merus ring, was 0.31%and 6.67%, respectively, more than that in the well water without the Merus ring. Also, the uniformity coefficient of emitters in the first and last irrigation periods in agricultural wastewater with the Merus ring was 0.85% and 12.10%, respectively, more than that in agricultural wastewater without the Merus ring. At the end of irrigation period, the results showed that Netafim and Axios had the best and weakest efficiency, respectively. In general, the emitters used in the treatment of well water with the Merus ring had the highest discharge and the emitters used in the treatment of wastewater without the Merus ring had the lowest discharge.
S. Jahanbakhsh Asl, B. Sari Saraf, T. Raziei, A. Parandeh Khouzani,
Volume 23, Issue 4 (12-2019)
Abstract
In this study, the temporal and spatial variation of snow depth over the mountainous region of Zagros, in the western Iran, for the period 1979–2010 was investigated for the cold season when the probability of snow occurrences was high. For this purpose, daily gridded snow depth data relative to Era-Interim/land were retrieved from the European Centre for Medium-Range Weather Forecasts (ECMWF) and used for spatiotemporal analysis of snow in the region. Furthermore, monthly maximum, minimum and mean air temperature relative to the weather stations distributed over the region were also used to investigate the relationship between snow depth and air temperature variability in the region. In each grid point, the rate of temporal changes in the snow depth was estimated using the Sen’s slope estimator, while the modified Mann-Kendall Test was applied to assess if the change identified was statistically significant. The results showed that in almost all of the studied months, especially February and March, the snow depth was significantly reduced in the region, which was statistically significant at 5% significant level. Unlike the observed statistically significant decreasing trend in the depth snow in the region, a significant increase in the maximum, minimum and average temperature was observed for all the studied months and the stations. The result suggested that the observed decrease in the snow depth in the region was related to the increasing trend in the temperature during the study period, which could be attributed to the global warming and climate change.
F. Haghnazari, M. Ghanbarian Alavijeh, A. Sheini Dashtegol, S. Boroomand Nnasab,
Volume 25, Issue 1 (5-2021)
Abstract
Changes in soil infiltration cause changes in irrigation efficiencies; therefore, estimating it in calculating irrigation efficiencies provides a more accurate estimate of irrigation performance indicators. In a study conducted on ARC2-7 farm in Amirkabir agro-industry in the 2010-2011 crop year, during four irrigations; two furrows were selected in terms of uniform infiltration and variable infiltration with a length of 140 and a width of 1.83 m. In the furrow assuming uniform infiltration two flume type II, at the beginning and end of it, were installed and the cumulative infiltration was determined by the volume balance method. The furrow with variable conditions was divided into four sections by installing five flumes. By examining the spatial variations of the mean cumulative infiltration, its value decreased from the first to the fourth section for the first irrigation by 15% and for the subsequent irrigations by 13%. Temporal changes of cumulative infiltration decreased by 27 and 30% for the first and second sections and by 26% for the third and fourth sections. An 11% increase in the average weight of the aggregate diameter and a 7% decrease in bulk density indicate physical changes in the soil. Surface runoff losses increased from 8 to 18.77% in the furrow assuming uniform infiltration and from 10.91 to 19.77% in the furrow with variable infiltration, and application efficiency decreased by 6%.