JWSS - Journal of Water and Soil Science

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Evaluation of nutrient status in soil is important from nutritional, environmental and economical aspects. Potassium is a very important plant nutrient not only because of its large demand, but also because of its important physiological and biochemical functions in plant. In order to evaluate K availability and common K extractants in the central region of Isfahan Province, surface soil samples from 26 important soil series were taken, out of which 16 soil samples were selected for further study based on their ammonium acetate extractable K and texture. Available K was extracted from the soil samples by NH₄OAC (4 methods), CaCl₂ (2 methods), NaCl (2 methods), NaOAC, AB-DTPA, Mehlich I, Mehlich III, Morgan-Wolf and HNO₃. A green house experiment using corn (Zea mays L.) variety Single-cross 704 as the test plant with 2 treatments (zero and 150 mg/kg K) and three replications was performed with the 16 selected soils to correlate K uptake with K extracted by different extractants.

 From XRD analysis, the dominant clay mineral was found to be Illite. Based on the amount of potassium extracted by these extractants from the soils the extractants used in this research may be divided into three groups: relatively weak extractants including CaCl₂, Mehlich I and Morgan-Wolf relatively strong extractants including NH₄OAC, NaCl (2N), Mehlich III, AB-DTPA, NaOAC and NaCl (1N), the strongest and weakest extractants in this group were NH₄OAC and NaCl (1N), respectively and finally, a very strong extractant which includes only HNO₃. In each group, the quantities of extracted K showed high correlation with each other. A high and significant correlation was observed between the quantities of K extracted by NH₄OAC, AB-DTPA and HNO₃. The amount of K extracted by 2N NaCl, 1N NaOAC, 1N NH₄OAC, and AB-DTPA was significantly correlated with K taken up by plant and its K concentration. 2N NaCl and 1N NaOAC were selected as the most suitable extractants for K based on their high correlation coefficients with plant uptake (0.79** and 0.72**, respectively) and K concentration in plant (0.86** and 0.85**, respectively). Yield, relative yield and plant response were not significantly correlated with K extracted by different extractants indicating that available K of the selected soils was not a limiting factor for corn growth therefore, it was impossible to determine the critical level of K for corn by the selected extractant.

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Rice bran is the most important by-product of rice milling. It is a valuable source of edible oil in most rice producing countries. Rice bran oil is used in babyfood, biscuit, poultry, fish and farm animal feeds. The storage of rice bran without 'heat processing will result in hydrolysis and auto-oxidation of lipids, and to its decreased physicochemical, organoleptic and nutritional quality. Rice bran is rich in carbohydrates, free amino acids, lipids and different enzymes. The enzymes have destructive effects on the quality of rice bran components. Heat processing is an effective method to reduce the microbial and enzymatic activity of bran. This study was carried out using a factorial experiment by completely randomized design with three replications to investigate the effect of heat treatment and storage time on rice bran crude oil properties.

The parboiling treatment was effective on the rice kernel strength. The bran produced from parboiled rice milling had lower endosperm components. This type of bran had a lower starch but a higher oil percentage. The results of color of rice bran oil samples determined by Lovibond showed that the oil from parboiled rice bran before and during storage had better color than the other samples. Iodine value of bran oil from parboiled paddy decreased during the storage period. The results from studies on fatty acid composition of oil samples determined by gas chromatography (G.C.) showed that the quantitative trend of fatty acids of the control sample remained the same as that in the rice bran samples with the treatment process.

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Systemic properties of pyroquilon, an anti-blast systemic chemical, used in controlling rice blast disease caused by Pyricularica grisea, was investigated through in vivo tests. Rice plants were treated with pyroquilon as granules in soil. Leaf and stem tissues were collected at different times after treatment and pyroquilon was extracted from tissues and detected by gas chromatography. Treated rice plants were also exposed to disease infection in blast nursery at different times and disease incidence was evaluated one week later. Pyroquilon was detected in leaf tissue one day after treatment (DAT), reached maximum during 4-7 DAT, and then reduced gradually to a nondetectable level after 28 DAT. In stem tissue, change in pyroquilon content was similar to but its quantity was less than that of leaf tissue. On inoculated plants, disease was controlled up to 60% at 2 DAT and completely controlled during 4-28 DAT. The results indicated that pyroquilon could be taken up and systemically translocated in rice plants after applying as granules in soil. Extent of disease control was a good function of pyroquilon content in leaf tissue (R²=0.93) and 2 ppm of compound in leaf could provide 90% control of the disease. In contrast, disease control was not a good function of pyroquilon content in stem tissue (R²=0.30).

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Potato (Solanum tuberosum L.) has relatively weak root system and requires high nitrogen fertilizer which is costly and may pose environmental pollution. This study was conducted to compare root morphological characteristics and nitrogen uptake of some potato cultivars growing in Iran. A greenhouse experiment using a completely randomized design with 3 replications and 8 potato cultivars including: Arinda, Agria, Premiere, Diamant, Concord, Marfona, Marodana and Nevita was conducted at Isfahan University of Technology, Isfahan. Virus-free seed tubers were planted and grown up to flowering stage. The plants were then harvested and their root length (RL), root average diameter (RAD) and root surface area (RSA) were determined using a Delta-T Scan image analysis system and Windias software. Root length density (RLD), root length and shoot weight ratio (R/S) were also calculated. Dry mater production and nitrogen accumulation (total nitrogen uptake) (PNA) were also determined. Soil inorganic nitrogen was measured before planting and after harvest. All measured parameters, except RAD, were significantly (p<0.05) affected by cultivar. Large differences observed between cultivars for all traits indicated genetic diversity among the studied potato cultivars. The highest and the lowest values of RL, RLD, RSA, R/S, RDW and PNA were found in Marfona and Nevita respectively. Based on cluster analysis, cultivars were divided into four different groups. Under the condition of this study, Marfona was superior whereas Arinda, Nevita, Marodana and Agria were inferior. Due to the high differences in root morphological characteristics and nitrogen uptake among potato cultivars, plant breeders may produce cultivars with larger root volumes and high nitrogen uptake.

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A 2-year vineyard survey failed to the provide evidence that Uncinula necator (Schw.) Burr. survived winter as mycelium in dormant infected buds in Khorassan province. Ascospores of U. necator, were collected by a volumetric spore trap operating constantly in a vineyard for 55 days after the bud burst. The first powdery mildew colonies were consistently found on the leaves of the shoots (7.30 cm long) growing on the vine. Cleistothecia were found on all plant parts infected during the previous growing season. More than 35-45 % of the cleistothecia borne on the leaves and stems died during winter. Most of the ascospore discharge occurred between the bud burst and the blooming time. Ascospores were periodically released from cleistothecia on the leaves kept in vineyard from October to May, while the ascospores germinating on the glass slides germinated from October to January and then germination slowed down to zero in early March and the water content potential of ascospore cytoplasm decreased constantly during this period as well. The mass required to fracture the ascocarp wall during maturation was measured to be approximately 5g in autumn, 3g in winter and 2.5 g in early spring. The most rapid decrease in the strength of the ascocarp wall occurred during a 4-week period before dehiscence in the field. The effect of the pathogenic property ascospores on healthy leaves demonstrated their role as a primary inoculum source. Cleistothecia appear to be the principal means of overwintering of U. necator in Khorassan province vineyards.

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The effect of Rathayibacter tritici on the movement of Anguina tritici larva and nematode function as vector of ear rot bacterium was conducted in the laboratory (Agarose plates) and greenhouse conditions. The results showed that the contact of nematode larva with high concentration of bacterium or long duration of nematode-bacteria contact can decrease the movement and the efficiency of nematode function as the vector of the disease, and in some cases it resulted in the mortality of the nematode. No differences were detected in the mobility of larva in the concentrations less than 10² CFU and less than 0.5 hour of nematode-bacteria contact times and their controls (exposed to water alone). Movement of the nematodes appeared to be random under these conditions. It can be concluded that Rathayibacter tritici did not act as an attractant to Anguina tritici larva. These results suggest that the attachment of a large number of bacteria to nematode (as an essential vector of the bacterium) would induce nematode weakness and mortality. So it is possible that ear rot bacterium can parasite ear cockle nematode, or the nematode is a host for this bacterium .

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To evaluate the effect of plant density and detopping on grain yield, protein content biological yield harvest index, growth indices, number of cob in each plant, No. of row per ear, No. of grain in each row, thousand seed weight of corn (Zea mays L. ar. SC 704), an experiment was conducted at the experimental statues of Research Center of Uremia Agricultural College in 2004. The Treatment design was split plot in randomized complete block design with four replications. The main plots included plant density at three levels (53000, 66000, and 88000 Plants/ha) and the subplets comprised three levels: (1) no detopping (control) (2) removing canopy only and (3) removing canopy and three leaves above the node. Analysis of Variance of data showed that both detopping treatment and plant density influenced the number of kernel per ear ,1000 grain weight, ear weight, total dry weight of biomass, seed yield and harvest index. Canopy detopping led to a marked increase in photo assimilateion import grains. The highest plant density evaluated, 88000 plants per hectare with detopping of three above leaves had the highest number of cobs per square meter. In plant density of 53000 plants per hectare and canopy detopping treatment, the number of grain per ear was greater than other densities. The efficiency of harvest index increased under corn detopping compared with control, and this increase with an increase in photosynthesis contributed to grain yield. It was concluded that major increase in grain yield under high plants density and tassel detopping was due to improvement of physiological indices.

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One of the properties of systemically acquired resistance in plants is their concomitance with the biochemical changes including enhancement of activities of defense-related enzymes. The leaf extract of Reynoutria sachalinensis (F. Schmidt) Nakai is known to be an effective compound for the control of a few plant diseases particularly powdery mildew of cucurbits (caused by fungal pathogen Podosphaera fusca), by inducing host defense responses. In the present investigation, the effects of this extract on some defense responses of cucumber plants were studied via in vivo tests. Changes of defense responses in the extract treated-cucumber plants, with or without pathogen inoculation, were studied and compared with those of non-treated control plants. Results indicated that specific activity of peroxidase increased significantly in treated tissues. Enhancement of enzyme activity showed the same patterns in both the pathogen inoculated- and non-inoculated-plants thus the pathogen attack did not affect the enzyme activity. Specific activity of phenylalanine ammonia-lyase in the non-inoculated extract treated-plants showed a transient fast increase during 24 hours after the treatment, whereas in the inoculated ones, it showed a permanent slow increase probably due to the interaction between extract treatment and pathogen attack. Phenolic content of extract treated-plant tissues, despite small fluctuations, did not show any definite pattern of changes.

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  Two hundred fifty seven bacterial isolates were collected from colza root and rhizosphere in Golestan, Mazandaran, Guilan and Tehran provinces. Antagonistic effect of bacterial isolates on Rhizoctonia solani, the causal agent of colza damping off, was studied using dual culture method. The results showed that, 60 isolates had the ability to inhibit the growth of R. solani on PDA medium. On the basis of the biochemical, physiological and morphological tests, isolates P1, P2 and P3 were identified as Pseudomonas fluorescens. Biocontrol mechanism studies showed that isolates produced antibiotics and volatile metabolites prevented the mycelial growth of the fungus. The isolates produced some of antimicrobial metabolites including hydrogen cyanide, protease and siderophore. Isolate P3 was more effective to inhibit the growth of the fungus in-vitro. The effect of isolates on disease reduction in comparison with control was significantly different. None of the isolates were able to prevent disease occurrence completely. Isolates applied as soil treatment had a significantly higher disease control as compared to seed treatment method. Isolate P3 had considerable effect on reduction disease in the greenhouse conditions. All isolates were capable of colonizing canola roots and so increased canola growth in free-causal agent conditions.

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  A factorial experiment, based on RCB design, with three replications was conducted to evaluate the effects of rhizobial inoculation, urea, and weeds on soybean performance in the field. The factors under study consisted of inoculation and non-inoculation, three levels of 0, 150, and 300 kg/ha urea, and weed-control and weed-infestation. Results showed that weed-control, inoculation and urea application increased biological and seed yield. The highest effect on yield was due to weed control, followed by inoculation and urea application. Inoculation, weed-control and urea application of 300 kg/ha enhanced protein percentage in soybean grains. In this case, inoculation had the highest effect on protein percentage, followed by urea application and weed control. In contrast, only weed-control significantly increased seed oil percentage. Seed filling rate increased as a result of inoculation, but, seed filling duration was not affected by inoculation. Weed-control improved seed filling rate and duration. Urea application induced seed filling duration, but had not any effect on seed filling rate.

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Polyphenol oxidase (PPO) activities were measured spectrophotometrically in tomato(Roma VF: resistant to Fusarium oxysporum f.sp. lycopersici and susceptible to Meloidogyne javanica) roots inoculated with nematode and fungi in four biological life stages of nematode. PPO specific activity showed a significant decrease in treatments (nematode + fungi) as compared with control plants. Results showed that nematode is able to change or suppress induction of this enzyme in spite of fungal induction. Nematode in all biological stages suppressed the induction of PPO activity in tomato roots but in young adult formation stage the suppression was higher than other life stages including giant cell formation, egg-laying and penetration. Native polyacrylamide gel revealed the presence of five isozymes of PPO with R_m values of 0.26, 0.31, 0.44, 0.50 and 0.63. Isoforms with Rm values of 0.26, 0.44, 0.50 and 0.53 showed significant changes in nematode + fungus inoculated tomato plants compared to plants inoculated with fungus alone. Based on the results obtained in this study, nematode infection resulted in suppression of tomato defenses against the fungi (as secondary pathogen) and intensified the fungal disease. Five PPO isoforms with R_m values of 0.26, 0.31, 0.44, 0.50 and 0.63 were shown in native polyacrylamide gel among which the isoform with R_m value of 0.31 had a thicker band in tomato plants inoculated with nematode or fungus alone. Two isoforms with R_m values of 0.44 and 0.53 in nematode-inoculated plants were similar to the corresponding bands in the healthy control. Isoforms with R_m values of 0.26, 0.44, 0.50 and 0.53 in nematode-fungus-inoculated tomato plants showed significant changes compared to plants inoculated with the fungus alone. Nematode infection of root tissue caused suppression of PPO specific activity and induced changes in PPO isoforms with R_m values of 0.26, 0.44, 0.50 and 0.63 more significantly than isoform 0.31.

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To compare the allelopathic potential of some Guilan province rice cultivars with allelopathically approved IRRI rice cultivars, a factorial experiment was conducted in completely randomized block design with 3 replications on the Experimental Farm of Agricultural College of Guilan University in spring 2005. Two factors including a) seven rice cultivars (traditional cultivars of Hashemi, Ali Kazemi, and Tarom and 2 modern cultivars of Khazar, and Dorfak and two IRRI cultivars of Dollar and IR64), and b) two types of planting, (including monoculture and mixed culture of each cultivar with Barnyardgrass) were used. A monoculture of Barnyardgrass was also used as a control. Growth rate (GR) and leaf area index (LAI) of Barnyardgrass were determined after 2, 4, 6, and 8 weeks of transplantation (WT), in mixed and monoculture treatments. In addition, after 3, 6, and 9 WTs the type and number of weeds in 1 m2 of each plot was determined. Rice plant samples were taken in 2, 4, 6, and 8 WTs, and were extracted in the Lab to be tested for germination for barnyardgrass and redroot pigweed seeds in Petri dishes. The filed research results showed that GR, LAI, number of weeds and yield of barnyardgrass grown with Dollar cultivar were lower than the others, which indicates higher allelopathic properties of this cultivar. Rice cultivars water extract evaluation of Petri dish also showed that Dollar cultivar has higher allelopathic potential than the other cultivars. Increasing the concentration of the water extracts increased the suppression of treated seedlings. From starting to geramination stage of the rice cultivars, allelopathic effects of the water extracts decreased. Leaves had the highest level of allelopathic potential in comparison to other organs. In other words, the pure extract of Dollar cultivar taken form samples in 2 and 6 WTs had the highest allelopathy potential among the cultivars and samples.

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In order to study yield component and determinate the contribution of stem reserves to corn yield under effect of different densities and interference periods of sorghum, a factorial experiment based on randomized complete block design with three replications was conducted in 2002 on the Research Farm of the Faculty of Agriculture Tabriz University. Experimental factors were sorghum interference at different periods (0,14,28,42 days after corn emergence and also during plant life corn) with three densities (4,8,12 plants m-2). Characteristics of study were yield, yield component and the contribution of stem reserves to corn grain yield. The results showed that with increasing sorghum density and interference, corn yield components (except the number of grain rows) were decreased, due to shading and competition between plants for using available resources. Maximum grain yield and grain number per ear was obtained at pure corn plantation. With increasing sorghum density and interference periods grain yield decreased, and maximum corn yield loss was 38%, which occurred at the highest sorghum density and interference. Dry matter remobilization and contribution of stem reserves were significantly influenced by sorghum densities and interferences in corn grain yield. The highest contribution of dry matter remobilization and stem reserves to corn yield was obtained at maximum density and complete interference of sorghum. The least contribution of reserves was shown in pure corn plantation. This might be related to shading and competition between plants for light and other resources.

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In order to study the effects of salt stress and leaf feeding by ascorbic acid on antioxidant enzyme activity, proline accumulation and lipid peroxidation on leaves and roots of Brassica napus L. cvs. Okapi, an experiment was conducted as a factorial in a completely random design with three replications. Plants were exposed to salt stresses by NaCl solution (200 mM) and foliar were treated by ascorbic acid solution (25mM). Catalase, Superoxide dismutase and peroxidase activity were assayed in shoot and root. Also, malondialdehyde content and proline and chlorophyll in leaves were determined. The results showed that the activity of all antioxidant enzymes (except for SOD in roots) were increased significantly in plants under salt stress, and ascorbic acid application, as a antioxidant decreased their activity in leaves, but in roots it was not effective. Total protein content in leaves and roots decreased significantly under salinity condition. Ascorbic acid treatment increased total protein content under salt stress in both roots and shoots. Measurement of malondialdehyde content in leaves and roots showed that lipid peroxidation was increased by active oxygen species due to salt stress, and ascorbic acid reduced lipid peroxidation only in leaves. Chlorophyll content was also decreased by salinity compared to control. According to the result of present study, ascorbic acid application decreases deleterious effect of salinity.

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In mountainous basins, snow water equivalent is usually used to evaluate water resources related to snow. In this research, based on the observed data, the snow depth and its water equivalent was studied through application of non-linear regression, artificial neural network as well as optimization of network's parameters with genetic algorithm. To this end, the estimated values by artificial neural network, neural network-genetic algorithm combined method and regression method were compared with the observed data. The field measurement were carried out in the Samsami basin in February 2006. Correlation coefficient (r) mean square error (MSE) and mean absolute error (MAE) were used to evaluate efficiency of the various models of artificial neural networks and nonlinear regression models. The results showed that artificial neural network and genetic algorithm combined methods were suitable to estimate snow water equivalent. In general, among the methods used, neural network-genetic algorithm combined method presented the best result (r= 0.84, MSE= 0.041 and MAE= 0.051). Of the parameters considered, elevation from sea level is the most important and effective to estimate snow water equivalent.

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Micronutrients such as Fe and Zn in adequate level are essential for plant growth cycle and impose a vital role in increasing yields of most agricultural crops. Using organic wastes such as sewage sludge, compost and manure is a proper practice for returning organic matter and some nutrients into the soil, particularly in arid and semi-arid regions. The objective of this study was to determine the effects of sewage sludge, compost and cow manure on availability of Fe and Zn in soil and their uptakes by corn, alfalfa and targetes flower. A completely randomized design with three treatments (sewage sludge, compost and cow manure at 25 Mg/ha) was used. Application of sewage sludge, compost and cow manure significantly increased availabile Fe and Zn of the soil. The application of organic wastes increased the dry matter yield of the plants. Fe and Zn concentration of plants shoots in organic amendments treatments were significantly greater than blank. The highest mean concentration of Fe in plant tissues was obtained in the cow manure and the highest mean concentration of Zn in plant tissues was obtained in the compost treatment.

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In order to evaluate the effects of nitrogen fertilizer levels on grain yield and nitrogen use efficiency in corn cultivars, a split plot experiment based on randomized complete block design with three replications was conducted at the Research Farm of Islamic Azad University of Ardabil during 2006-2007 cropping seasons. Factors consisted of nitrogen fertilizer at four levels (0, 80, 160 and 240 kg/ha) and corn cultivars at three levels (SC-310, SC-404 and DC-370). The results showed that grain yield was significantly affected by nitrogen levels, corn cultivar and nitrogen level × corn cultivars. The highest grain yield was related to application of 240 kg/ha nitrogen with SC-404 cultivar. Nitrogen levels of 160 and 240 kg/ha had similar yields, but more yield than 80 kg/ha. With increasing of nitrogen levels, plant height, the number of grains per ear rows significantly increased. Comparisons of means showed that increasing the application of nitrogen fertilizer decreased nitrogen use efficiency. Nitrogen use efficiency decreased from 17.13 kg/kg with application of 80 kg/ha nitrogen fertilizer to 12.4 kg/kg in application of 240 kg/ha nitrogen fertilizer. Nitrogen use efficiency was affected by corn cultivar. Nitrogen use efficiency in SC-404 was higher than SC-301. In conclusion, in order to increase grain yield and nitrogen use efficiency, SC-404 hybrid should be applied with 160 kg N/ha in climatic conditions of Ardabil Plain.

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This study was conducted in Rudasht Research Farm Isfahan, to evaluate tolerance to iron (Fe) deficiency of 30 spring wheat genotype, using split plots in a randomized complete block design with three replications. Main plot consisted of two Fe levels (0 and 20 kg Fe ha-1 applied as FeEDDHA at planting and beginning of vegetative growth). Grain yield increased by 14% following the application of 20 kg Fe ha-1 as FeEDDHA. Application of Fe significantly increased grain yield of all wheat genotypes except for Rushan. The result indicated that Mean Productivity (MP), Geometric Mean Productivity (GMP) and Stress Tolerance Index (STI) were the most suitable indices for identifying and selecting Fe-deficiency tolerant wheat genotypes. By using both treatments with and without added Fe, grain yield showed significant (P < 0.01) positive correlation with MP, GMP and STI. The STI could divide the studied wheat genotypes in different groups based on both their response to fertilization and grain yield potential. Therefore, the STI was the best index to identify Fe deficiency tolerant genotypes. Based on the three indices, Ghods and Falat genotypes were the most tolerant and sensitive genotypes to Fe deficiency, respectively

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Sediment sources fingerprinting is needed as an autonomous tool for erosion prediction, validation of soil erosion models, monitoring of sediment budget and consequently for selecting soil conservation practices and sediment control methods at the catchment scale. Apportioning of eroded-soil into multiple sources using natural tracers is an integrated approach in soil erosion and sediment studies. The objectives of this study, as a first work, are to assess spatial variations of biochemical tracers and theirs validation in discriminating sediment sources under different land uses and water erosions at catchment scale and to apply them as fingerprints to determine relative contributions of sediment sources in Zidasht catchment, Iran. In view of this, 4 enzyme activities as biochemical tracers were measured in 42 different sampling sites from four sediment sources and 14 sediment samples. The results of discriminant function analysis (DFA) provided an optimum composite of two tracers, i.e. urease and dehydrogenase that afforded more than 92% correct assignations in discriminating between the sediment sources in the study area. Sediment source fingerprinting model was used based on optimum composite of two tracers resulting from DFA to explore the contributions of sediment from the four sources. The results showed that the relative contributions from rangeland/surface erosion, crop field/surface erosion, stream bank and dry-land farming/surface erosion sources were 11.3±5.3, 8.1±3.8, 75±8.5 and 3.6±2.5, respectively. Therefore, we can conclude that fingerprinting using biochemical tracers may help develop sediment fingerprinting models and as a first step facilitate a more complete tool for fingerprinting approach in the future.

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