Showing 126 results for Wheat
A.h Hosseinzadeh, I Bernousi, M Mardi, M Bihamta, S Omidi, B Yazdi Samadi,
Volume 13, Issue 47 (4-2009)
Abstract
Fusarium head blight (FHB) is one of the most destructive diseases of wheat causing significant reduction in grain yield and quality. Development of resistant varieties is an effective, economical and enviromentally safe way to control FHB disease. A major QTL (quantitative trait locus) for Fusarium head blight resistance, Qfhs.ndsu-3BS, derived from cv. Sumai 3, has been identified and verified by several research groups via molecular marker analysis. The resistant cv. Sumai 3 was crossed to susceptible cv. Falat, then three backcrosses were followed by one self-fertilization. Three simple sequence repeat (SSR) markers, Xgwm 389, Xgwm493, Xgwm533, were used for marker assisted selection (MAS) in BC1 and BC2 generations.The probability of linkage between markers and Qfhs.ndsu-3BS was calculated using a binomial probability function based on the assumption that a molecular marker at a specific distance from Qfhs.ndsu-3BS in the population would carry the donor-parent allel as a function of the distance between marker and QTL and the number of backcrosses/selfs used in deriving the population. Microsatelite locus Xgwm 493 was significantly associated with Qfhs.ndsu-3BS.
M Mehrabi Koshki, D Zafari, B Sharif Nabi,
Volume 13, Issue 47 (4-2009)
Abstract
Recent studies have shown the controlling effects of Trichoderma species and extract of a few plant species of the Brassicaceae family on some phytopathogenic fungi. In this study, using a completely randomized blocks design in the field, controlling effect of biological agents comprising mustard flour, Trichoderma koningii T18, T. virens T59, T. brevicompactum T30, T. harzianum T56, mixture of four Trichoderma isolates, mustard flour + mixture of four Trichoderma isolates and two commercial biological product of Trichodermin B and Subtilin were evaluated against wheat common bunt caused by Tilletia laevis. According to the infection index, all treatments were able to reduce infection percentage and showed significant differences (P<0.01) compared to control (infected with T. laevis without any biological agent) in which heads infection was 43.5%. Treatments of Mustard flour and mustard flour + mixture of four isolates, reduced the disease by 89.9% and 87.4% respectively. Consequently, it seems that wheat common bunt could be controlled by application of non-infected seeds and by treating seeds using mustard flour without using chemical fungicides.
A Farahnaki, A Dehghn, Gh Mesbahi, M Majzobi,
Volume 13, Issue 48 (7-2009)
Abstract
Salad dressing is a semisolid emulsion and a colloidal system with high consumer demand. Food polysaccharides (e.g starch) are used in the formulation of salad dressing to improve its physical properties and sensory attributes. In this research, 10% mixture of wheat or maize starches were used to produce pregelatinized starches by a double drum drier, followed by milling and sieving. The pregelatinized starches (10%) were applied in the formulation of a salad dressing instead of native starch. Viscosity (at 25 and 35◦C), Hunter color parameters of the samples were evaluated and compared. Pregelatinized starches were more effective in increasing viscosity of the samples compared to corresponding native starches, and the effect of maize starch was greater than wheat starch. Significant differences were recorded in terms of color parameters of the samples. Pregelatinized starch caused higher L values (lighter samples) while the native starch samples were creamy-light yellow. In general, it can be concluded that the pregelatinized starches had better functional properties in salad dressing compared to native starches, and the produced pregelatinized starches can be used instead of native starch in the formulation of salad dressing.
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.
M Malakouti, M Babaakbari, S Nezami,
Volume 13, Issue 49 (10-2009)
Abstract
To increase grain yield, nitrogen use efficiency (NUE) and nitrogen apparent recovery fraction (NARF) in wheat (Triticum aestivum L.), an experiment was carried out in Karaj Soil and Water Research Station farm for two consecutive growing seasons in 2004-05 and 2005-06. The experimental design was RCBD with 6 treatments (T1= Control T2= 150 kg ha-1 of N as urea in 3-split applications T3= 1/3 N as SCU as the base fertilizer + 2-split urea applications T4= 150 kg ha-1 N as SCU as the base fertilizer T5=150 kg ha-1 of N as urea in 2-split applications and T6=1/3 N as complete fertilizer as the base fertilizer +2-split urea applications) in the first year and 7 treatments (T1= Control T2= 180 kg ha-1 of N as urea in 2-split applications T3= 180 kg ha-1 of N as urea in 3-split applications T4= 180 kg ha-1 N in 5-split urea applications T5 = pre-plant urea + 4-split urea applications T6= 1/3 N as SCU as the base fertilizer +4-split urea applications and T6=1/3 N as complete fertilizer as the base fertilizer +4-split urea applications) in the second year with 3 replications. In the second year, N rate was increased from 150 to 180 kg ha-1, adding the existing extra nutrients in complete macro and fertilizers to other treatments and N split-application was increased up to four times. After harvesting, grain yield, NUE and NARF were measured. The results of first year revealed that the yield, NUE and NARF for T2 (5145 kg ha-1, 13.8 kg kg-1, 41.2%, respectively) and T6 (5067 kg ha-1, 13.2 kg kg-1, 38.2.2%, respectively) were increased significantly at 1% level. In the second year, the maximum grain yield (6335 kg ha-1), NUE (16.2 kg kg-1) and NARF (50%) were obtained again from T6 treatment. Higher yield, NUE and NARF in the second year were mainly due to higher N rates and more N split applications. The economic returns for these substitutions, even without considering any fertilizer subsidies, the averages turned out to be 14, 8 and 4 in these treatments, respectively. Overall results revealed that the substitution of complete macro and SCU fertilizers with pre-plant urea is advisable in wheat production areas. Therefore, it is recommended that the experiment be further tested and evaluated in some wheat growing provinces.l results.
N Ghanavati, M Malakouti, A Hossein Por,
Volume 13, Issue 49 (10-2009)
Abstract
Correlation between components of Q/I and wheat (Triticum aestivum L.) growth indices was studied in a greenhouse experiment during 2003-04 growing season. Eighty soil samples (0 – 30 cm depth) were collected randomly in farms around the Abyak region, Ghazvin province. Twenty-one samples were then selected based on soil texture and NH4OAC-K. The research included treatments of 21 soils and two potassium (K) levels (0, 100 mg/kg) and was conducted in a factorial manner in a randomized complete block design with three replications for studying correlations between Q/I and treatments. Effect of potassium application on the wheat growth was found to be significant at 5% level. The effect of soil properties on wheat growth was also found to be significant at 1% level. However, the interaction of K and soil was not significant. There were no significant differences among the different equilibrium time intervals. The soil potassium buffering capacity (PBCK) values were strongly correlated with CEC (r =0.996**), clay content (r = 0.921**) and moisture saturation percentage (r = 0.811**). Final equation derived from stepwise regression for prediction of PBCK was as follows: PBCK = 7.419 CEC –19.743 R2adj = 0.782** The equilibrium potassium activity ratios (ARke) were strongly correlated with soluble potassium (r =0.846**), NH4OAC-K (r =0.730**), SP (r = 0/794*), OC (r = -0.477ns) and clay content (r=-0.602*). Similarly, readily exchangeable potassium (ΔK0) was strongly correlated with ammonium acetate extractable potassium (r = 0.871**), soluble potassium (r = 0.778**), saturation percentage (r = 0.551*), organic carbon percentage (r=-0.045ns) and clay content (r=-0.206ns). There was no significant correlation between ΔK0 and ARKe with potassium uptake values by wheat. In contrast, there was a strong correlation between PBCK values and potassium uptake by wheat (r = 0.729**), and relative wheat yield (r = 0.735**). There was no significant correlation between Q/I parameters when KCl and K2SO4 were used, and the soil physicochemical properties. However, Q/I parameters obtained from KCl showed a higher correlation with wheat plant's growth indices.
A Khodashenas, A Koocheki, P Rezvani Moghadam, A Lakzian , M Nassiri Mahallati,
Volume 14, Issue 52 (7-2010)
Abstract
Among the biodiversity of soil microorganisms, bacteria have the basic role in soil functions. In order to determine the diversity and abundance of soil bacteria in arid regions, and also to study the effect of agricultural practices on them, a study was conducted in winter wheat fields on Shirvan, Mashhad and Gonabad. In each region, high and low input fields of winter wheat and a natural system for comparison were selected. Use of agricultural inputs was criteria for selection of low and high input fields in each region. Soil sampling was done on fields and natural systems and organic matter content, abundance and diversity of soil bacteria were measured in soil samples. Species richness and abundance of soil bacteria was affected by region and so that natural system of Gonabad has the minimum of species richness among the studied systems and the differences of other systems was not significant. Abundance of soil bacteria in 1 g dry soil was maximum in Gonabad and minimum in Shirvan. Abundance of soil bacteria was affected by organic matter and in low and high input systems of Gonabad and low input system of Mashhad was greater than other systems. Overall, 19 species of bacteria that belonged to 4 genus were detected. Results showed that species richness and abundance of soil bacteria in studied systems were relatively low and agricultural practices have not significant impact on these organisms, so that species richness and abundance of soil bacteria were improved in agricultural systems of Mashhad and Gonabad. Pattern of bacterial diversity showed that regional and agricultural stresses were affected on bacterial function so that in high level of stresses, species richness decreased and function of soil bacteria was restricted to decomposition of organic matter. Therefore, organic matter of soil must be increased and agricultural stresses must be decreased to improve of soil bacterial functions.
Sh. Javanmardi , R. Fotovat , J. Saba,
Volume 14, Issue 53 (10-2010)
Abstract
Osmotic adjustment is generally regarded as an important adaptation of wheat to drought. Because it helps to maintain turgor and cell volume, osmotic adjustment is often thought to promote growth, yield, or survival, of plants in dry soils. However, a physiological rationale for such views is lacking. This study was conducted to determine the effect of osmotic adjustment and some of its components on the wheat yield. Ten bread wheat cultivars were grown in pots under different watering levels using a split plot design. During grain filling stage, RWC, leaf sugar content, proline content and osmotic regulation were estimated by sampling flag leaf under normal and stress conditions. Main stem was used for measuring sugar content of different parts of stem. Although there were some differences in osmotic regulation in wheat lines, there were no relationships between yield and osmotic regulation. It was shown that these components probably have a little share in wheat osmotic regulation.
J. Abedi- Koupai , S. S. Eslamian1, S. A. Gohari , S.a Gohari , R. Khodadadi ,
Volume 14, Issue 54 (1-2011)
Abstract
Channel lining is essential to increase resistance against scour, reducing water losses and as a result increase water conveyance efficiency. Since the canal lining has significant costs, selection of type of lining must be made with great care and with considering engineering properties. One of the conventional lining for water conveyance cannel is concrete lining. Because of advantages of concrete lining including durability (about 40 years) and low maintenance costs, this type of lining is the best option in many regions, however the construction expenses is high. So far many researches have been published about the types and the durability of concretes containing synthetic pozzolans. Due to high production of wheat in our country, nano particles of wheat ash sheath (NPWAS) were used. In this study the mechanical properties of concrete (compressive strength, tensile strength and durability) incorporating nano-particles of wheat ash sheath were investigated. The results showed that the compressive and tensile strength of samples incorporating 20 percent of NPWAS has not statistically significant difference (P<0.05) with the values of tensile and compressive strength of control samples. Therefore, the optimum replacement percentage of NPWAS was 20 percent by weight of cement. Moreover, results of durability of concrete samples showed that concrete containing 20 percent NPWAS were more durable than control samples in the magnesium sulfate solution. NPWAS with having 90.56 percent of silicon dioxide, high pozzolanic activity and ability to perform substantial chemical reaction with calcium hydroxide would decrease porosity and increase resistance of concrete.
M. Zahedifar , N. Karimian , A. Ronaghi , J. Yasrebi , Y. Emam ,
Volume 14, Issue 54 (1-2011)
Abstract
The effect of phosphorus (P) (0, 25, and 50 mg kg-1 soil as Ca(H2PO4)2) and organic matter (OM) (0, and 2% w/w feedlot cattle manure) on P and zinc (Zn) distribution in different parts of wheat plant (Triticum aestivum L.) at various growth stages and its relationship with soil P and Zn were determined in greenhouse condition. In all pots, shoot P concentration decreased as plant growth proceeded. Phosphorus concentration of shoot and flag leaf decreased from 7th to 9th stage of growth, whereas that of spickle increased. Spickle P uptake and Zn uptake of stem, shoot, flag leaf, and spickle increased with proceeding of wheat growth. Phosphorus uptake of shoot increased from 3th to 9th growth stages, whereas P uptake of stem and flag leaf decreased from 7th to 9th growth stages. Soil P and Zn concentrations increased with application of P and OM and plant growth. The trend of P and Zn changes in shoot, stem and flag leaf was similar. It is, therefore, concluded that analyzing flag leaf for P and Zn concentrations be used for prediction of plant nutritional status of those nutrient elements in cases where such information is needed.
F. Salehi, M. J. Bahrani, S. A. Kazemaini, H. Pakniyat, N. A. Karimian,
Volume 15, Issue 55 (4-2011)
Abstract
Crop residues are beneficial substances that can bring about important changes in soil biological, chemical and physical properties and can also increase or stabilize crops yield. A field experiment was carried out at Research Station of College of Agriculture, Shiraz University, Shiraz, Iran, to determine the effects of wheat (Triticum aestivum L.) residue rates in combination with N levels on some soil properties in common bean (Phaseolus vulgaris L.) cultivation for two years (2008-2009). The experiment was conducted as split split-plot arranged in a completely randomized blocks design with three replications. Treatments were two red bean cultivars as main plots, N levels (0, 34.5, 69, and 103.5 kg ha-1) as sub-plots and residue rates (0, 25, 50 and 75%) as sub sub-plots. The results showed that application of crop residues significantly increased soil organic carbon, N, K, and P contents. Heavy crop residue (75%) application had no effects on these soil properties. Thus, retaining 50% crop residue was optimum for proper soil quality. Increased N application increased soil N, decreased P and K contents, and had no effects on organic carbon.
K. Enayati, M.j. Rousta, A. Vakili,
Volume 15, Issue 56 (7-2011)
Abstract
Soil structure and aggregate stability affect soil erodibility. There is a necessity for increasing aggregate stability against erosive factors such as wind and water. This study was conducted on surface soil samples (0-20cm) collected from agricultural land susceptible to erosion located in Chahoo, southeast of Fars province. The experimental design was CRD with 10 treatments and was replicated 3 times as follows: control plot (without addition of soil amendments), pure gypsum, chopped wheat straw, farm yard manure, gypsum+wheat straw, gypsum+ farm yard manure (1% w/w), cement at levels (0.3% w/w), (0.6% w/w), (0.9% w/w), gypsum +cement (0.9% w/w). After one, four and seven months, the amounts of soil aggregates in 53-4000 µm sizes were determined by wet sieving and MWD was calculated. The results of aggregate size distribution in every stage of the experiment showed that application of farm yard manure and wheat straw separately or in combination with gypsum through reduction in aggregates with diameters of <106 µm has caused an increase in aggregates with diameter of >106 µm. Based on the results of this research, the effect of these treatments, which increased MWD of the aggregate, results from the amount of aggregates with diameters larger than 1000 µm. According to the results of this study, it is suggested that these treatments be considered suitable to increase the stability of sensitive silt loam soils.
A. Heydari,
Volume 15, Issue 57 (10-2011)
Abstract
Performance of proper deep tillage can reduce negative effects of soil compaction. The objectives of the research were to determine the effects of deep tillage application on soil physical properties and wheat yield. Therefore, in 2006-2007 an experiment was conducted at Tajarak Agricultural Research Station of Hamedan on a soil with clay loam texture. In this research, four tillage methods were used. These methods were: 1) subsoiling with 30cm soil depth + conventional tillage (moldboard plowing) 2) subsoiling with 50cm soil depth + conventional tillage, 3) plowing by combined plow (chisel plow + roller) with 30cm soil depth and 4) conventional tillage (plowing by moldboard plow to 25-30cm soil depth). Randomized complete block design with four treatments and replications was used to analyze data and compare the treatment means. Before and after the application of the tillage treatments, parameters of cone index, bulk density and infiltration rate were measured in soil. Also before yield harvesting, components of yield (grain number in panicle, panicle number in plant and 1000 grain weight) were measured. To measure grain yield in experimental plots, in each plot ten square meter area from the yield was harvested. Result indicated that effect of different tillage treatment on soil resistance was not significant. Effect of deep tillage methods on bulk density and infiltration rate was significant. Deep tillage methods increased water infiltration rate in the soil and decreased soil bulk density. Effect of different deep tillage methods on wheat yield was not significant. However, application of chisel plow increased the wheat yield by 25%. It may be concluded the subsoiling treatment does not affect the crop yield in intensive and fully irrigated field condition. The results of this study indicated that if there is a compacted layer at 30cm soil depth, and with the same climate and soil as those in the experimental site, the application of chisel plow due to economical consideration (low fuel consumption and high field efficiency) can be recommended for soil preparation and cultivation of irrigated wheat.
L. Rahimi, N. Aliasgharzad, Sh. Oustan,
Volume 15, Issue 58 (3-2012)
Abstract
Azotobacter chroococcum can improve mineral nutrition of plants through N2 fixation and plant growth promoting capabilities. Fourteen strains of A. chroococcum were isolated from rhizosphere of wheat plants grown in different field conditions around Tabriz, northwest of Iran. In a pot culture experiment with sterile soil, wheat plants (Triticum aestivum cv. Falat) were inoculated with 14 bacterial strains. Positive control received nitrogen fertilizer without bacterial inoculation and the negative control was left un-inoculated and without N- fertilizer. Totally, 16 trearments with four replications were arranged in a completely randomized design. The plant growth indices and N and P concentrations of shoot and root were determined at the harvest time. Results showed that the inoculation with Azotobacter strains caused a significant increase in shoot and root dry weights. Bacterial inoculation significantly enhanced the concentration and content of N in shoot and root. Phosphorus content was only enhanced (p<0.05) in the root. Translocations of N and P from root to shoot were markedly increased in bacterial treatments compared to the positive and negative controls. Moreover, strains 1 and 48 which showed relatively higher phosphate solubilizing capability and phosphatase activity in in-vitro assay also brought about higher P content and concentration in shoot and its translocation from root to shoot.
A. H. Khoshgoftarmanesh, E. S. Razizadeh, H. R. Eshghizadeh, H. R. Sharifi, Gh. Savaghebi, D. Afiuni, M. Tadayonnejad,
Volume 15, Issue 58 (3-2012)
Abstract
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
A. Haghverdi, B. Ghahraman, M. Kafi, K. Davari ,
Volume 15, Issue 58 (3-2012)
Abstract
The objective of current study was to perform screening experiment, (phase zero of response surface methodology) the analysis of salinity and water tensions for spring wheat in Mashhad region and derive water production functions. The experiment was performed in the Research Field of Agricultural Faculty of Ferdowsi University of Mashhad in 2009-2010. Two water sources were selected: saline water (10 dS/m) and water without salinity limitation (0.5 dS/m). A single replicate factorial experiment with four variables and water requirements in different growth stages, was done with each variable having two levels, 20% and 100% of water requirements. The central points of experiment area with two replications were added for estimating the curvature in the fitted response surface. The results showed the water requirements in heading and flowering were the most important variables. The fitted water production functions estimated the yield of saline and non saline plots with correlation coefficients equalsing 0.95 and 0.99. In general, the obtained results proved the efficiency of the screening experiment in identifying the relative importance of variables and excluding the ineffective variables
J. Asghari Meidani, E. Karimi, S. B. Mousavi,
Volume 16, Issue 60 (7-2012)
Abstract
This study was conducted to study and compare the effects of different tillage systems on soil physical properties and wheat yield in dryland conditions. The experiment was carried out in Maragheh Dryland Research Station with 5 treatments and 4 replications based on RCBD for 3 years (2001-2003). The results showed that difference between the treatments in terms of wheat yield was significant, and stubble chopping and chisel plow tillage in fall + sweep in spring + seed drill planting had the maximum yield (i.e. 1452 kg/ha), lower value for yield (1.077kg/ha) blonged to T1 treatment. Also the results showed that spike/plant and spike length were the main characters in yield increase. For the soil bulk density and water content, the difference between treatments was significant and in planting and flowering stages stubble chopping and chisel plow in fall + sweep in spring + planting by seed drill had the highest soil water content and the lowest bulk density
Mahin Karami, Majid Afyuni, Amir Hossein Khoshgoftarmanesh, Mohammad Ali Hajabbasi, Hossien Khademi, Ali Abdi,
Volume 17, Issue 64 (9-2013)
Abstract
Zinc (Zn) is an essential trace element for plants as well as for animals and humans. There is a significant relationship between soils, plants and humans Zn status in a certain agro-ecosystem. The objectives of this study were to assess Zn status of soils in 3 arid and semiarid provinces of Iran and to model the relationship between wheat grain Zn and agro-ecosystem parameters. About 137 soil and wheat samples were collected randomly from the agricultural soils of Fars, Isfahan and Qom and were analysed in laboratory. Modeling the relationship between wheat grain Zn and agro-ecosystem parameters was done using least square based and robust methods. The results indicated that total Zn concentration of soils (range, 21-149 mg kg-1 mean, 75.2 mg kg-1) was in normal ranges. The DTPA-extractable Zn concentrations were below the critical level (0.8 mg kg-1) in 16% of the surveyed fields. The Zn concentration in 80% of wheat grains was sufficient (more than 24 mg kg-1) with respect to plant nutrition (range, 11.7-64 mg kg-1 mean, 31.6 mg kg-1). However, Zn bioavailability for consumers was generally low in more than 75% of the samples. This is because of high phytic acid to Zn molar ratio (more than 15). Soil DTPA-extractable Zn and available P were entered in to most of regression models significantly. Regression analysis showed that most of models fitted to wheat grain Zn concentration and soil Zn and influenced by agro-ecosystem parameters had a weak prediction power, despite their high determination coefficient. This means that factors other than those considered here have a strong influence on the uptake of Zn by wheat in these soils.
Majid Hejazi Mehrizi, Hossein Shariatmadari, Majid ََafyuni,
Volume 17, Issue 64 (9-2013)
Abstract
Application of sewage sludge has been considered as an organic fertilizer in arid and semi-arid regions of Iran. This study was conducted to investigate cumulative and residual effects of sewage sludge on soil inorganic fractions and their relation to phosphorus (P) availability. Two levels of application (50 and 100 Mg ha-1) and three consecutive times of sewage sludge application (1, 3 and 5 years) with a control treatment were studied in a randomized complete block split plot design with three replications. Composite soil samples were collected from 0-30 depth at the end of 5th year of application. Increasing the rate and application year of sewage sludge enhanced dicalcium phosphate (Ca2-P), octacalcium phosphate (Ca8-P), apatite (Ca10-P), aluminum phosphate (Al-P), iron phosphate (Fe-P) and available P but decreased occluded P (OC-P). Residual effect of sewage sludge application resulted in increased inorganic fractions in blocks treated for 1 year compared to control. Positive correlations were observed between inorganic P fractions and Olsen P, wheat yield and P uptake (except OC-P). We concluded that inorganic P fractions and P availability increased in sewage sludge amended soil.
Vajiheh Dorostkar, Majid Afyuni, Amirhossein Khoshgoftarmanesh,
Volume 17, Issue 64 (9-2013)
Abstract
Limited information is available about the effect of preceding crop residues on bioavailability of zinc (Zn) in calcareous soil and its accumulation in wheat grain. In this experiment, residues of five crops including safflower (Carthamus tinctorius L.), sunflower (Helianthus annuus L.), bean (Phaseolus vulgaris L.), clover (Trifolium pretense L.) and sorghum (Sorghum bicolor L.) were incorporated into a calcareous Zn-deficient (0.5 mg kg-1) soil. A treatment without crop residue was also used in the experiment. This experiment was conducted in research greenhouse of Isfahan university of technology in 2010. Two wheat cultivars (Triticum aestivum cvs. Backcross and Kavir) differing in Zn-efficiency were studied in the experiment. Incorporating crop residues into the soil resulted in an increase of grain Zn concentration in both wheat cultivars although this increase was dependent on the preceding crop type. The greatest increase of grain Zn concentration occurred in the sorghum residues treatments. Although application of crop residues significantly decreased grain phytic acid to Zn molar ratio (as Zn bioavailability criteria for consumers), this ratio was still higher than 15, the critical Zn bioavailability level for consumers in foods. According to the results, despite the increase in the total Zn content, the bioavailability of Zn in wheat grain was not affected by crop residue treatments.
