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101.
A methodology for up-scaling irrigation losses 总被引:1,自引:1,他引:0
This paper presents a methodology for up-scaling field irrigation losses and quantifying relative losses at the irrigation
area level for potential water savings. Two levels of analysis were considered: First, the field level where irrigation is
applied. Second, the irrigation area level, where the field level losses are aggregated, or up-scaled, using average loss
functions. In this up-scaling approach, detailed crop-soil-water modelling can capture the variability of physical parameters
(such as soils, crops, water table depth, and management practices) at the field level which are then used to derive loss
functions for aggregating losses at higher scales (irrigation area level). This allows potential field-level adaptations and
water management changes made by individual farmers to be assessed for impact at the larger irrigation area level. The APSIM
farming systems model was used for simulation of crops (wheat, rice, and soybean) and their interaction with the wider system
processes at the field level. Given the climate, soil, and management information (sowing, fertilisation, irrigation, and
residue management), the model simulates infiltration, the soil moisture profile, plant water uptake, soil evaporation, and
deep drainage on a daily basis. Then, by placing the field level analysis in the context of the wider irrigation system or
catchment, it is possible to correlate field level interventions (e.g. water savings measures) with water requirements at
these higher levels. Application of this method in the Coleambally Irrigation Area in NSW, Australia, demonstrated that an
exponential function can describe the relationship between deep drainage losses and the water table depth for different soil,
crop, and water table depth combinations. The rate of loss increase (slope of the curve) with the water table depth is higher
on lighter (higher intake rates) soils than on heavy soils and is more pronounced in areas under rice cultivation. We also
demonstrate that this analysis technique can assist in identifying spatial distribution of losses in irrigation areas, considering
water table depth as an additional factor, leading to targeted areas for water-saving measures. 相似文献
102.
Majid Talebi Zahra Hajiahmadi Mehdi Rahimmalek 《Journal of Crop Science and Biotechnology》2011,14(3):173-178
In the present study, genetic diversity of 48 individual plants from four Iranian cultivated populations of alfalfa (Medicago sativa L.) was evaluated using sequence-related amplified polymorphism (SRAP) markers. Fourteen SRAP primer combinations produced
193 fragments of which 95 were polymorphic. The number of polymorphic fragments detected per primer combination ranged from
3 to 10 bands with an average of 6.78 bands. Average polymorphic information content (PIC) was 0.343 for all primer combinations.
Although the AMOVA (analysis of molecular variance) results showed a significant difference in the genetic diversity among
the populations (P < 0.0001), the genetic variation mainly caused by the variation of intra population accounted for 93.17%
of the total genetic variation. Unweighted pair-group method arithmetic average (UPGMA) analysis of the marker data clearly
separated the populations of subtropical (Yazdi) and semi-cold (Hamadani and Nikshahri) as well as Kodi, an improved population.
It can be concluded that SRAP markers are useful for studying diversity and relationships among and within alfalfa populations. 相似文献
103.
Zahra Khan-Mohammadi 《Archives of Agronomy and Soil Science》2013,59(7):753-762
The aim of this study was to provide data to assess the additive effects of soil salinity on the toxicity of Cd to soil alkaline phosphatase (EC 3.1.3.1). Two soils (Langroud acid soil and Shervedan calcareous soil) were artificially salinized with NaCl. The natural and salinized soils were treated with CdSO4 solutions to give a Cd concentration in the range 3–5000 mg kg?1. Soil alkaline phosphatase activity was measured after 3 days of incubation. Salinity enhanced the extractable Cd concentration in both Langroud and Shervedan soils. The percentage of soil alkaline phosphatase activity inhibited by Cd was significantly increased from 27.8 to 45 in the Langroud acid soil as salinity increased from natural levels to 28 dS m?1. An increase in the inhibition percentage was not observed in the Shervedan soil. Lower values for the ecological dose causing 50% inhibition (ED50) under saline conditions in the Shervedan soil supported the hypothesis that Cd may be more toxic to soil alkaline phosphatase when the soil is more saline. We conclude that Cd toxicity to soil alkaline phosphatase is salinity dependent and that higher Cd concentrations under saline conditions are probably responsible for the enhanced Cd toxicity to soil alkaline phosphatase. 相似文献
104.
Zahra Tahernezhad Zeyn-alabedin Musavi Mohammad Javad Zamani Mohammad Jafar Aghaei Bahram Rostam Foroudi 《Genetic Resources and Crop Evolution》2013,60(3):905-911
Variation of high molecular weight glutenin subunits (HMW-GS) in 28 Iranian Aegilops tauschii (2n = 2x = 14, DD) accessions studied by sodium dodecyl sulphate electrophoresis method (SDS-PAGE). The results showed high variation of HMW-GS in the accessions. The range of frequency in 14 HMW-GS combinations was 3.57–25 % in the accessions. AMOVA showed the molecular variance between the geographic areas was lower than within the geographic areas. According to Nei’s genetic diversity, the highest diversity levels were in Semnan, Golestan and Azarbayjan, on the other hand the lowest levels of diversity were found in Khorasan, Gilan and Mazandaran accessions. Hence, the Caspian Sea South East accessions also Azerbayjan in Iran have more diversity. AMOVA did not show variance between strangulata and tauschii but there was more genetic diversity in ssp. tauschii subspecies in comparison of ssp. strangulata according to Nei’s gene diversity and Shannon information index. It showed Iranian Ae. tauschii have a good potential for bread making quality improvement in bread wheat. 相似文献
105.
The aim of this work was to determine metal accumulation by plants growing on three molybdenum-mine zones and their tolerance strategies. The plants from tailing, extracting and non-contaminated zones were sampled with their corresponding soils. The results show that molybdenum (Mo) and copper (Cu) were at toxic levels in soils and their levels varied in 44 collected species from 21 families. Ajuga chamaecistus and Cramb orientalis L. excluded Mo and Cu, respectively. Achilla tenuifollia as Mo-hyperaccumulator with total Mo (1979 mg kg?1) and then Erodium ciconium with 1308 mg kg?1 Mo and Conyza Canadensis with 618 mg kg?1 Cu were moderate metal accumulators. They stored considerable levels of metals in their leaves vacuoles and elevated the levels of phytochelatins, cysteine and glutathione and induced antioxidant enzymes. In conclusion, this study indicated that some collected plants excluded metals. In metal-accumulators, antioxidant enzymes, phytochelatins and sequestration of excess metals were involved in their tolerance mechanism. 相似文献
106.
Journal of Plant Diseases and Protection - Pot experiments with winter wheat were conducted for two successive years to study the relationship between the cereal cyst nematode, Heterodera... 相似文献
107.
A monoclonal antibody blocking enzyme-linked immunosorbent assay (B-ELISA) was developed to detect antibodies to Mycoplasma bovis in cattle sera. The assay was highly specific and sensitive and there was no cross-reaction detected. This method revealed a high prevalence of antibodies (60%) to M. bovis in dairy cattle in North Queensland. The diagnostic potential of this B-ELISA for the detection of antibody to M. bovis was compared with its detection by PCR. There was a strong positive correlation between PCR and B-ELISA titers. Thus, the B-ELISA appears to be a valuable and reproducible tool in the serodiagnosis of M. bovis infection in cattle. 相似文献
108.
Amin Bigham Sadegh DVM PhD Zahra Shafiei DVM PhD 《Journal of Equine Veterinary Science》2008,28(6):341-344
This study was performed to compare the onset and duration of analgesia produced by either a lidocaine−MgSO4 or lidocaine−distilled water combination administration in the caudal epidural space of horse. Seven healthy adult horses, aged 11.7 ± 1.4 years (mean ± SD), body weight (kg) 567 ± 32.5 (mean ± SD), were selected for this study. Caudal epidural anesthesia was produced in all horses by administering 2% lidocaine (0.22 mg/kg) diluted in 1 mL distilled water and repeated with 2% lidocaine (0.22 mg/kg) diluted in 1 mL 10% MgSO4 2 weeks later. Time to onset (minutes), duration (minutes), and cranial spread of epidural analgesia were recorded. Heart rate (HR), respiratory rate (RR), and body temperature (°C) were recorded. Measurements were taken at 0 (as a baseline value before epidural administrations) and at 5, 10, 15, 30, 60, and 75 minutes after the epidural administrations of each treatment. Statistical analyses included paired Student t test and analysis of variance (computer program SPSS, Analytical Software, version 15.00). Statistical significance was set at P < .05. Onset of analgesia was significantly different (P < .001) between lidocaine-distilled water (2.38 ± 0.47 minutes) and lidocaine−MgSO4 (4.62 ± 0.54 minutes). Duration of analgesia after lidocaine−MgSO4 (186.0 ± 7.0 minutes) was longer than lidocaine-distilled water (54.5 ± 7.3 minutes). No significant differences were recorded for HR, RR, and body temperature in comparison with baseline values for each group. Using the lidocaine−MgSO4 combination for obstetric and surgical procedures could commence relatively soon after epidural injection and could be completed without readministration of anesthetic agent. 相似文献
109.
Ramin Heydari Zahra Tanha Maafi Wilfrida Decraemer 《European journal of plant pathology / European Foundation for Plant Pathology》2014,140(2):329-340
Several species of trichodorid nematodes cause economically important disease on plants. Trichodorus comprises most of the trichodorid species. Trichodorus golestanensis n. sp. is described from a forest park in northern Iran. The new species belongs to the T. lusitanicus morpho-species group and is characterized in male by three ventromedian cervical papillae of which two at level of onchiostyle region, three ventromedian precloacal supplements, the posterior one just anterior to retracted spicules and ventrally curved spicules with mid-blade indentation provided with a few bristles. Females are distinguished by well developed triangular vaginal sclerotized pieces in lateral optical view, a rhomboid-shaped vagina and a transverse slit-like vulva in ventral view. Molecular analysis using the sequence of D2-D3 expansion segment of 28S rDNA differentiated the new species and confirmed the relationships of T. golestanensis n. sp. with T. andalusicus and T. asturanus. The sequences of D2-D3 regions were also provided for previous trichodorid records from Iran T. gilanensis, P. teres and N. minor together with discussion of their relationship. 相似文献
110.