A simple approach for regulating saline groundwater inflows to natural streams in irrigated agricultural areas     

Muhammad Nadeem Asghar  Muhammad Kaleem Ullah  Muhammad Mohsin Hafeez 《Irrigation and Drainage Systems》2008,22(3-4):239-252

Stream salinity management is of prime importance for ensuring environmental sustainability of rivers, streams, lakes and other water bodies. Saline groundwater inflows are the main cause of deteriorating quality of stream flows; especially during periods of low flows. The Murray-Darling Basin is a good example for reducing groundwater recharge from irrigated agricultural areas with successful implementation of land and water management plans (LWMPs). In most cases, these plans help minimize the influence of saline groundwater flows on the stream salinity, as a preventive measure. As a remedial measure, this paper introduces a simple but an innovative approach for regulating saline groundwater inflows to natural streams in irrigated agricultural areas. The approach uses the flap gate with an automatic lowering and raising mechanism. During low stream flow, this gate is kept in a raised position. Depending upon the upstream inflows, the ponding situation will develop hydraulic gradient away from the stream; groundwater inflows to the creek will become minimal. During high stream flows, the gate is kept in a lower position to let the diluted water flows through the stream uninterrupted. To install, operate and manage such gates on multiple sites along the stream(s), the individual control panels can be joined into a central control station via telemetric link up. This approach, which holds a key for successfully regulating groundwater induced salinity to natural streams, should be considered in conjunction with other LWMPs to improve stream salinity in an irrigated agricultural area.  相似文献   

Comparison of different classical and molecular methods to identify superior self-compatible almond (Prunus dulcis Mill.) genotypes and evaluation of their traits     

Asghar Estaji  Ali Ebadi  Akbar Ghorbani  Roghaie Allabakhsh 《The Journal of Horticultural Science and Biotechnology》2016,91(1):36-42

Almond [Prunus amygdalus Batsch syn. Prunus dulcis (Mill.) D.A.Webb] trees are either self- or cross-incompatible, which results in lower fruit set and yields. Flower bagging, fluorescence microscopy, and polymerase chain reaction (PCR) were used to discriminate between self-compatible genotypes obtained from crosses of the self-incompatible female parents (‘121’ and ‘4’) with the self-compatible male parent (‘Tuono’). This study was performed on 80 almond genotypes. The results of this study showed that, in the first cross (‘121’ × ‘Tuono’), genotypes 5, 11, 13, 14, 17, 20, 27, 29, 31, 35, and 38 were identified as being self-compatible and, in the second cross (‘4’ × ‘Tuono’), genotypes 1, 2, 10, 11, 12, 15, 21, 23, 25, 32, 37, 38, and 40 were found to be self-compatible. There were some promising genotypes based on self-compatibility and nut and kernel characteristics; for example, genotype 40 had the highest mean fruit and kernel weights at 2.9 and 1.3 g, respectively. PCR can be used to identify self-compatible genotypes at the juvenile stage. Flower bagging under favourable climatic conditions not only discriminated between self-compatible almond genotypes, but can also be used to measure fruit set percentages. Flower bagging and fluorescence microscopy can be used to determine the level of self-incompatibility. Fluorescence microscopy identified self-incompatible genotypes, even under unfavourable conditions. In general, a combination of all three methods is recommended to increase the accuracy of detecting self-compatible genotypes of almond.  相似文献   

Evaluation of infiltration models with different numbers of fitting parameters in different soil texture classes     

Salman Mirzaee  Ali Asghar Zolfaghari  Manoochehr Gorji  Miles Dyck  Shoja Ghorbani Dashtaki 《Archives of Agronomy and Soil Science》2013,59(5):681-693

In this study, the ability of eight different infiltration models (i.e. Green and Ampt, Philip, SCS (US-Soil Conservation Service), Kostiakov, Horton, Swartzendruber, Modified Kostiakov (MK) and Revised Modified Kostiakov (RMK) models) were evaluated by least-squares fitting to measured infiltration data. Six comparison criteria including coefficient of determination (R²), mean root mean square error (MRMSE), root mean square error (RMSE), the F-statistic (F), C_p statistic of Mallows (C_p) and Akaike information criterion (AIC) were used to determine the best performing model with the least number of fitting parameters. Results indicated that R² and MRMSE were not suitable for model selection. A more valid comparison was achieved by F, C_p, AIC and RMSE statistics. The RMK model including four parameters had the best performance with the majority of soils studied. RMK was better than the MK model in approximately 51.6, 57, 68.5 and 70.6% of soils, when using F, C_p, AIC and RMSE statistics, respectively, and for the other models, a higher per cent of soils was obtained. The RMK model was the best for loam, clay loam and silty clay loam soils, but the MK model was the best for silty loam soils.  相似文献   

Organic amendments differ in their effect on microbial biomass and activity and on P pools in alkaline soils     

Muhammad Asghar Malik  Khalid Saifullah Khan  Petra Marschner  Safdar Ali 《Biology and Fertility of Soils》2013,49(4):415-425

Organic amendments could be used as alternative to inorganic P fertilisers, but a clear understanding of the relationship among type of P amendment, microbial activity and changes in soil P fractions is required to optimise their use. Two P-deficient soils were amended with farmyard manure (FYM), poultry litter (PL) and biogenic waste compost (BWC) at 10 g?dw?kg^?1 soil and incubated for 72 days. Soil samples were collected at days 0, 14, 28, 56 and 72 and analysed for microbial biomass C, N and P, 0.5 M NaHCO₃ extractable P and activity of dehydrogenase and alkaline phosphomonoesterase. Soil P fractions were sequentially extracted in soil samples collected at days 0 and 72. All three amendments increased cumulative CO₂ release, microbial biomass C, N and P and activity of dehydrogenase and alkaline phosphomonoesterase compared to unamended soils. The increase in microbial biomass C and N was highest with PL, whereas the greatest increase in microbial biomass P was induced with FYM. All three biomass indices showed the same temporal pattern, with the highest values on day 14 and the lowest on day 72. All amendments increased 0.5 M NaHCO₃ extractable P concentrations with the smallest increase with BWC and the greatest with FYM, although more P was added with PL than with FYM. Available P concentrations decreased over time in the amended soils. Organic amendments increased the concentration of the labile P pools (resin and NaHCO₃-P) and of NaOH-P, but had little effect on the concentrations of acid-soluble P pools and residual P except for increasing the concentration of organic P in the concentrated HCl pool. Resin P and NaHCO₃-P_i pools decreased over time whereas NaOH-P_i and all organic P pools increased. It is concluded that organic amendments can provide P to plants and can stimulate the build-up of organic P forms in soils which may provide a long-term slow-release P source for plants and soil organisms.  相似文献   

Moisture diffusion coefficient of reaction woods: compression wood of Picea abies L. and tension wood of Fagus sylvatica L.     

Asghar Tarmian  Romain Remond  Hadi Dashti  Patrick Perré 《Wood Science and Technology》2012,46(1-3):405-417

The moisture diffusion coefficient of compression wood in spruce (P. abies) and tension wood in beech (F. sylvatica) was examined. The results indicated that the diffusion coefficient measured under steady-state condition (cup method) could well characterize the drying kinetics of the reaction woods. The compression wood offered more resistance to the moisture diffusivity when compared with the corresponding normal wood. The thick cell wall rich in lignin explains the small mass diffusivity in compression wood. In contrast, the mass diffusivity in beech is almost always higher in tension wood than in normal wood, in spite of similar density values. The high moisture diffusion in tension wood can be explained by the ease of bound water diffusion in the gelatinous layers (G-layers).  相似文献   

New report of Alternaria alternata causing leaf blight of tomato in Pakistan     

K. P. Akhtar  M. Y. Saleem  M. Asghar  M. A. Haq 《Plant pathology》2004,53(6):816-816

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A wind tunnel experiment to investigate the effect of polyvinyl acetate,biochar, and bentonite on wind erosion control     

Zanyar Feizi  Mohammad Reza Mosaddeghi  Ali Asghar Besalatpour  Mojtaba Zeraatpisheh  Jesús Rodrigo-Comino 《Archives of Agronomy and Soil Science》2019,65(8):1049-1062

Due to the heavy costs of wind erosion control measures, the correct selection of technical methods is indispensable for a sustainable land management in arid and semiarid regions. Thus, the main goal of this research was to investigate the feasibility of using the clay minerals (i.e., bentonite), polyvinyl acetate and palm biochar for reducing the wind erosion in deserts surrounding the cities. The treatments were sprayed uniformly onto the containers (5 × 35 × 105 cm, 0.37 m²) with sand (collected from sand dunes surrounding Isfahan city, central Iran) in 3 replicates. The experiments were conducted in a wind tunnel with sequential repetitions after 1, 10, and 20 weeks. Among the studied treatments, the bentonite planters demonstrated to be the most effective soil erosion control measure by reducing soil loss and improving sand ablation. On the contrary, the palm biochar had less influence on the soil erosion control and only a slight effect on the threshold speed. For the future, further studies are required to select the best and most relevant soil erosion control measures under field conditions considering all the environmental aspects in arid regions of Iran.  相似文献   

Integration of ANP and Fuzzy set techniques for land suitability assessment based on remote sensing and GIS for irrigated maize cultivation     

Javad Seyedmohammadi  Fereydoon Sarmadian  Ali Asghar Jafarzadeh  Richard W. McDowell 《Archives of Agronomy and Soil Science》2019,65(8):1063-1079

Land suitability assessment can inform decisions on land uses suitable for maximizing crop yield while making best use, but not impairing the ability of natural resources such as soil to support growth. We assessed the suitability of maize to be produce in 12,000 ha land of Dasht-e-Moghan region of Ardabil province, northwest of Iran. Suitability criteria included soil depth, gypsum (%), CaCO₃ (%), pH, electrical conductivity (EC), exchangeable sodium percentage (ESP), slope (%) and climate data. We modified and developed a novel set of techniques to assess suitability: fuzzy set theory, analytic network process (ANP), remote sensing and GIS. A map of suitability was compared a map created using a traditional suitability technique, the square root method. The coefficient of determination between the land suitability index and observed maize yield for square root and ANP-fuzzy methods was 0.747 and 0.919, respectively. Owing to greater flexibility to represent different data sources and derive weightings for meaningful land suitability classes, the ANP-fuzzy method was a superior method to represent land suitability classes than the square root method.  相似文献   

Tree-Temperature Monitoring for Frost Protection of Orchards in Semi-Arid Regions Using Sprinkler Irrigation   总被引：1，自引：0，他引：1  

Ali Asghar Ghaemi  Mohammad Rafie Rafiee  Ali Reza Sepaskhah 《中国农业科学(英文版)》2009,8(1):98-107

Automated over-tree sprinkler irrigation systems were developed and tested in two orchards located in two separate locations in southern Iran （a 0.17 ha peach orchard and a 0.24 ha orange orchard） to protect peach blossoms and orange trees leaves and fruits from low temperature damage. The experiment used a system that monitored the trees and air temperatures using two thermistors. The water application rate by the irrigation system was determined by an energy balance as implemented by the software FROSTPRO, In the peach orchard, the system was tested during three frost events during the spring of 2003 and three other events during the spring of 2004. The system successfully kept peach flowers above the critical temperature, i.e., -4.0℃ in spring 2004 （control block -4.12℃, and sprinkled block ＋0.5℃） during all events. Similar results were obtained in the orange orchard during three frost events in the winter of 2004, during which the tree temperatures were at least 2.5℃ above the critical temperature. Results from field tests show that the system can effectively protect the peach blossoms from damage. Determination done after the frost events showed a 12% blossom kill in the sprinkled blocks while in the unsprinkled control block a 41.5% blossom kill. Calculations indicated that when using variable application rates, the amount of water used can be reduced by 54.3%. Spatial distribution of minimum temperatures during the three frosts was also studied in Jahrom, Iran. Results showed a significant temperature control in the experimental block, especially in the central part of the orchard, but the block margins （about 3.6% of the total area） were at the risk of low temperature due to the wind drift effects.  相似文献   

Resistance of <Emphasis Type="Italic">Solanum</Emphasis> species to <Emphasis Type="Italic">Cucumber mosaic virus</Emphasis> subgroup IA and its vector <Emphasis Type="Italic">Myzus persicae</Emphasis>     

Khalid Pervaiz Akhtar  Muhmmad Yussouf Saleem  Muhammad Asghar  Mushtaq Ahmad  Nighat Sarwar 《European journal of plant pathology / European Foundation for Plant Pathology》2010,128(4):435-450

Sixty-nine tomato genotypes representing nine Solanum species were evaluated for resistance to Cucumber mosaic virus (CMV) subgroup IA and its aphid vector Myzus persicae. Resistance was assessed by visual scoring of symptoms in the field under natural conditions, and in the greenhouse by artificial inoculations through aphid M. persicae and mechanical transmissions in the year 2007 and 2009. Considerable variation in responses was observed among the evaluation methods used. Field evaluations were found liable to errors as different levels were observed for the same genotypes in the different years, however mechanical inoculation was found to be the most useful in identifying CMV subgroup IA resistance, in contrast aphid transmission was most useful in identifying insect transmission resistance. All genotypes observed as highly resistant to CMV subgroup IA in the field or through vector transmission became systemically infected through mechanical inoculations. Using mechanical inoculation, six genotypes (TMS-1 of S. lycopersicum, LA1963 and L06049 of S. chilense, LA1353, L06145 and L06223 of S. habrochaites) were found resistant and another six (L06188 and L06238 of S. neorickii, L06219 of S. habrochaites, L05763, L05776 and L06240 of S. pennellii) were found tolerant showing mild symptoms with severity index (SI) ranging 1-2 and with delayed disease development after a latent period (LP) of 18–30 days. However, these genotypes were found to be resistant to highly resistant in the field and through inoculation by M. persicae; and they also supported low population levels of M. persicae except TMS-1. Another nine genotypes (LA2184 of S. pimpinellifolium L., LA2727 of S. neorickii, LA0111, L06221, L06127 and L06231 of S. peruvianum L., LA1306, L06057 and L06208 of S. chmielewskii) showing a susceptible response after mechanical inoculation were highly resistant, resistant and tolerant after M. persicae transmission. The resistant genotypes, identified in the present study can be exploited in the breeding programmes aimed at developing tomato varieties resistant to CMV subgroup IA and broadening the genetic base of CMV-resistant germplasm. The differences observed between mechanical and aphid transmission suggests that one should consider both evaluation methods for tomato germplasm screening against CMV subgroup IA.  相似文献