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Showing 344 results for Ph

J. Mohammadi, H. Khademi, M. Nael,
Volume 9, Issue 3 (10-2005)
Abstract

In order to achieve a sustainable management of land resources and to improve land quality, quantitative assessment of effective factors and soil quality indicators are required. The aim of this study was to evaluate variability of selected soil quality attributes in central Zagros affected by such factors as region, land use and management practices. Twelve sites were selected in three provinces including Chahar Mahal va Backtiari (Sabzku, Broujen), Isfahan (Semirum), and Kohkeloyeh va Boyerahmad (Yasodje). Different management practices were considered such as: protected pasture, intensive grazing, controlled grazing, dryland farming, irrigated wheat cultivation, legume-farming practice, protected forest, and degraded forest. Systematic sampling with taking 50 samples of surface soil in each site was carried out. The results of univariate and multivariate analysis revealed that all factors significantly influenced the spatial variability of selected soil quality attributes namely phosphatase activity, microbial respiration, soil organic matter, and total nitrogen. The results obtained from discriminant analysis indicated that all selected soil quality parameters could significantly be used as soil quality indicators in order to recognize and discriminate sustainable agricultural and forestry ecosystems and/or optimal management practices.
E. Khosravi, Sh. Dokhani, G. H. Kabir,
Volume 9, Issue 3 (10-2005)
Abstract

The meat productions are the most popular among different food products. On of the serious problems of this kind of products may be the change of the physical and chemical properties. The Restriction of the use of synthetic antioxidants have prompted the extensive research on the effect of the natural antioxidant and replacement of synthetic antioxidant with the natural ones. In this study, the effect of α-tochopherol (vitamin E) and propyl gallate on German sausage was evaluated. Four different German sausages were formulated and prepared in 30 Kg batches as follows: control without antioxidant, sausages plus α- tochopherol (200 or 500 ppm) and sausages plus propyl gallate (200 ppm). Twelve Kg of the samples were filled into cellulosic casings and the other 18 Kg in polyamidic casings. All samples were cooked. One third of the packed samples were stored at (4˚C ± 1) for 10 days and the rest were stored at (– 18 ˚C ± 1) for 6 months. The extent of autoxidation for samples were determind by peroxid and TBA values. During the storage period, autoxidation rates of control samples were more than other treatments. Propyl gallate was more effective in reduction of autoxidation than α- tochopherol treatments. Addition of 500 ppm vitamin E was more effective than 200 ppm. Significant differences were observed among treatments (P< 0.05). The study of the shear strength of the stored susages at the (4 ºC ±1) for the 10 days indicated that the most shear strength is seen in the cellulosic casing samples. The same results obtained for the stored samples at the (-18 ºC ±1) for the 6 months.
N. Davatgar, M. Kavoosi, M. H. Alinia, M. Paykan,
Volume 9, Issue 4 (1-2006)
Abstract

The soil potassium status and effect of soil physical and chemical properties on it were investigated using 109 surface soils (0-30cm) from four regions in Guilan province. Neutral molar ammonium acetate extractable K (K-NH4OAc), boiling molar nitric acid extractable K (K-HNO3) and water soluble K were determined. Results showed that CEC and clay were normally frequency distributed while distribution frequency of other variables such as silt organic carbon and pH were not normal and have significant skew and kurtosis. In addition sand, K-NH4OAc and K-HNO3 has logarithmic normal distribution. Water-soluble potassium was affected by sand, pH, O.C and K-NH4OAc (R2a=0.73**). Ammonium extractable potassium was affected by soluble potassium, non-exchangeable potassium and CEC (R2a=0.72**). Boiling nitric acid was affected by exchangeable potassium and silt (R2a=0.55**). Geographic distribution of K-NH4OAc data shows amount of it in central parts of Guilan, particularly Sepidrood river watershed is more than other regions. Fomanat region soils have the less clay, CEC, K-NH4OAc and K-HNO3. According this study about 68.8 percent of Guilan soils was classified in the range of medium to very low potassium status.
Pourreza, M.r. Ebadi,
Volume 9, Issue 4 (1-2006)
Abstract

In a completely randomized design with 3×5 factorial arrangement, the metabolizable energy and nutrients digestibility of three varieties of sorghum grains (low, medium and high tannin) with and without supplemental phytase were determined and was compared with corn and wheat. Three varieties of sorghum were selected from the 36 varieties according to their tannin content and were grown togther with corn and wheat under the same environmental conditions. Supplemental phytase was added at three levels (0.0, 500 and 1000 FTU/kg) to each grain. The metabolizable energy (ME) and nutrients digestibilities were determined by the mature male Leghorn with the method of Sibbald. The results indicated that different grains had different ME, apparent and true digestibilities regarding dry matter, nitrogen and phosphorus. Medium tannin sorghum had the highest apparent and true metabolizable (AME and TME) energy, whereas the high tannin sorghum showed the lowest AME and TME. The apparent and true dry matter digestibilities of corn was more than the other grains (P<0.001). Medium tannin sorghum had the highest apparent and true nitrogen digestibilies than the other two varieties (P<0.001). Difference between tested grains regarding apparent and true phosphorus digestibilities were not significant. All measured criteria were the lowest for the high tannin sorghum. Adding 500 FTU/Kg phytase caused an improvement (P<0.001) in AME, apparent and true dry matter digestibilities and true nitrogen digestibility. Although added phytase improved apparent and true phosphorus digestibilities and true nitrogen digestibility, but the differences were not significant. The differences between 500 and 1000 units phytase was not significant and the results indicated that 500 FTU/Kg phytase was sufficient to improve the nutritional value of grains under study.
L. Rozbeh Nasiraei, Sh. Dokhani, M. Shahedi, R. Shokrani,
Volume 9, Issue 4 (1-2006)
Abstract

The Two cultivars of kiwi fruit, Hayward and Abbot, with the desirable quality were harvested on time from Valiabad, a region in Tonekabon (Mazanddaran Provicnce). Fruits were graded and packed in the wooden boxes, cartons and low density polyethylene (LDPE) films, the fruits were cold stored in a proper and constant conditions (T= ±0.5 & RH=90-95%) for a period of 6 months. Samples were taken in completely randomised design from each package for intervals of 30±3 days and during storage (6 months). Chemical characteristics such as the total soluble solids(TSS), titratable acidity as citric acid, dry matter, vitamin C and the Physical characteristics such as yield point (Y.P.), yield point strength (Y.P.S.), penetration force (P.F.) and penetration stress (P.S.) were measured. Statistical analysis was performed with the factorial experiment in an unequal completely randomized design and the means compaired by Duncan multiple range test. The results indicated that, cv, Abbot has shorter shelf life, 4 months, compared to Hayward with 6 months storage period. Hayward contained more dry matter than Abbot throughout the storage period. Total soluble solids of cultivars increased and titrable acidity as citric acid decreased during storage. Vitamin C of Abbot was more than Hayward throughout the storage. Total factors in relation to texture and physical properties decreased by time such texture Hayward cv.after six month storage and in Abbot after four month storage was softer. As the final conclusion, wooden bins packaging for longer storage and plastic packaging for monotonous rippening of kiwifruit was the best in compared with other packaging.
S. Ayoubi, M. Karimian Eghbal, A. Jalalian,
Volume 10, Issue 1 (4-2006)
Abstract

Paleosols include soils formed under climatic condition different from the present. Although such soils are widespread in central Iran region, adequate investigations of them are yet to be carried out. Micromorphology is one of the most important tools in plaeoclimatological studies. This investigation was carried out to study microscopic features of two paleosols from Isfahan province to reconstruct the paleoclimatic condition during the Quaternary. The results of this study indicate that strong clay coatings are presented in Sepahanshahr paleosol, indicating moisture regime in the past. This paleosol is polygenetic due to calcite and gypsum accumulation during drier periods compared to clay illuviation condition. Micromorphological features in Segzi paleosol indicate that this area has experienced a swampy environment during the younger Dryas. The overall results from this study indicate that climatic oscillation evidences during Quaternary have been preserved in paleosols from Isfahan region.
N. Farid, P. Ehsanzadeh,
Volume 10, Issue 1 (4-2006)
Abstract

A major source of photoassimilates deposited into the seeds is the closest photosynthetic source to the latter sinks. While the contribution made to grain yield by floral parts and the adjacent photosynthetic surfaces has been determined for a number of crop plants, such information lacks regarding safflower. Thus the present study was aimed at estimating the contribution of photosynthesis of safflower head and the two adjacent leaves to the grain yield of this oil seed crop. A 4-replicate RCBD field experiment was conducted at Lavark Research Farm, Isfahan U. of Tech., using four genotypes (Nebraska10, Kouseh, Arak2811 and K12) and three levels of shading (heads only, heads and the two adjacent leaves and control) on safflower heads following pollination, using khaki paper bags. Genotypes differed in terms of days to heading and maturity, height, number of heads per plant, number of seeds per head, 1000-seed weight, seed weight per head and grain yield per plant. Shading on safflower head and the two adjacent leaves led to a significant decrease in number of seeds per head, 1000-seed weight, seed weight per head, grain yield per plant and harvest index. There was not a significant difference between the two levels of shading treatment. It could be concluded that, with the environmental conditions experienced during spring 2003 at Isfahan, the photosynthetic products of safflower head and the two adjacent leaves may contribute to grain yield per plant by as much as 37 percent.
A. A. Vali,
Volume 10, Issue 1 (4-2006)
Abstract

Saline soils and halophytic vegetations are common features and part of the habitat pattern in deserts and steppes. The saline area is developing in arid lands. Investigation effects of halophytes on soil characteristics and adaptive mechanisms of the various halophyte types is essential for controlling saline environments. Juncus gerardi is a perennial grass-like halophyte and Halocnemum strobilaceum is a succulent halophyte shrub. The distribution of these species is mound like in the field. The soil samples of the mounds for investigating the effect of these species on plant root environment were compared with near regions in Korsiah saline area in Darab. Also the consentration some ions of live and dead organs and tissues of these species were studied for recognition of their adapive types. The results show that Juncus gerardi decrease salinity in 0-30 cm of topsoil, therefore the Ec decreased 37%. But salinity increased significantly in 30-60 cm depth. The identification of ions in plant tissues showed that the concentration of ions is low in dry matter. This is 0.33% of dry matter for Sodium. This is a way to rescue from dry conditions by selective absorption of ions. The comparison of root environment of Halocnemum strobilaceum with near regions showed a significant decrease in salinity in 0-30 cm and 30-60 cm depth decreased 27% and 40% respectively. The identification of ions concentrations in plant tissues reflect the high amounts of ions, therefore the plant tissues composed of 8.18% of Sodium. The comparision of ion concentrations in different live and dead tissues of plants a Significant increase of the amounts of ion in the dead tissues in comparison with the live tissues. Therefore this species excrete much quality of salts in their dead tissues and organs and so combat this problem.
Sh. Ayobi, M. H. Alizadeh,
Volume 10, Issue 2 (7-2006)
Abstract

Conventional soil survey methods for soils within the watersheds in Iran require a significant budget with many soil surveyors and much time. Additionally, no accurate and reliable information exists on the spatial variability of superface soil parameters in order to predict the soil loss by different models (RUSLE, PISAC, EUPOSEM, MORGAN). Also information on planning and management activities is lacking. These limitations call for methods of estimating soil properties using minimum sampling derived from important terrain parameters. This study was performed to develop soil-landscape models in three geological units (E2Sc, Ku, Plc), in a part of Mehr- watershed, Sabzevar. Six soil variables selected for this study were topsoil clay, gravel, sand, organic matter content, field capacity and bulk density measured at 316 sites on a regular 100m grid. Topographic attributes were calculated by a digital elevation model with 100m spacing. Finally, multiple linear regression analyses relating soil to topographic attributes were performed and then models were validated by additional sample points (78 of 316). The developed regression models showed significant relationships between surface soil properties and topographic attributes such as elevation, slope, aspect, wetness index, stream power index and sediment transport index. The mean errors and root mean square errors in the validation of the models were low and acceptable. The regression equations could explain only 26 to 72 % of the variability measured in the soil attributes in the watershed scale with 100m spacing.
M. Kh. Pirouzi Fard,
Volume 10, Issue 2 (7-2006)
Abstract

In the present study, the effects of sodium metabisulphite concentration (2, 4, 6, 8, 10%), dipping time (2.5, 5.0, 7.5, 10 min.) mixing of the solution including: continuous mixing , once per 2.5 minutes , once per 5.0 minutes and without mixing (I, II, III, IV) and pH of the solution (4.62, 3.62, 3.42) on the absorption of sulphure dioxide by halved Riogrande variety tomatoes prepared for sun drying were investigated. The experiment design was completely randomized plots with the order of 5, 4, 4 and 3 treatments, each with four replications. The results showed that increasing the solution concentrations, dipping time, mixing and decreasing pH increased the rate of SO2 absorptions. The increment of SO2 in tomato under the effect of the above mentioned factors have been shown in different tables and figures. The mathematical models of relationship among the rate of absorption of SO2 , the concentration of sodium metabisulfite solution, dipping time, also the effect of metabisulfite solution pH were developed. Significant differences were found in these increments in all the treatments (α= 0.01).
J. Kolahdooz Shahrudi, H. Seyedoleslami, R. Ebadi, B. Hatami,
Volume 10, Issue 2 (7-2006)
Abstract

The predatory beetle Cybocephalus fodori minor has recently been reported in Iran. Also few studies have been reported on life cycle of Cybocephalus beetles, especially on that of C. f. minor. Thus, the life cycle and feeding rate of this predatory beetle was studied on pistachio oyster shell scale, Lepidosaphes pistaciae under laboratory conditions (temperature: 25 ± 2 °c relative humidity: 65 ± 5% and photoperiod: 16:8 L: D/h). Life cycle of C. f. minor was completed at six stages including egg, three larval instars, pupa and adult. Duration of the development for one generation (not considering preoviposition period) was 43-46 days for males and 38- 42 days for females. The developmental time length for the egg, larval instars1-3, pupa, male and female adults longevity, preoviposition and postoviposition periods was 8.8 ± 0.1, 5.2 ± 0.1, 34 ± 0.1, 6.8 ± 0.1, 17.3 ± 0.3, 59.2 ± 2.2, 65.8 ± 3.1, 6.8 ± 1.6 and 3.5 ± 0.5, respectively. Average fecundidity (number of eggs laid by a female per her life time) was 64.7 ± 6.2. Sex ratio in the laboratory and in the field was 1:1. Daily feeding rate for the female and male adults, larval instars feeding on adult female scale was 7.1 ± 3.5, 6.9 ± 2.2, 1.8 ± 0.2, 3.7 ± 0.2 and 5.9 ± 0.3, respectively. These parameters were also determined when those stages were fed on the eggs and second nymphal stages of pistachio oyster shell scale. Adult beetles over 60 days exhibited the highest feeding on this scale.


B. Hatami, A.f. Mirlohi, M.r. Sabzalian,
Volume 10, Issue 2 (7-2006)
Abstract

Endophytic fungi, Neotyphodium spp. symbiotically infect host grasses, Fescue arundinacea Schreb. and F. pratensis Huds. and Mealybug, Phenococcus solani Ferris attacks some forage plants. To evaluate the role of these fungi to control this pest, four genotypes of F. arundinacea and two genotypes of F. pratensis were used. Plant tillers were split into two sections, one section of which was freed from endophyte using a fungicide mixture. The mixture contained 2 grams of active ingredients of Propiconazol and 1 ml of Folicur per liter of water. New tillers from endophyte-infected and endophyte-free plants were transferred into the field. The number of mealybugs was measured after the first visible sign of infestation on roots. To count mealybug, one plant hill of each plot was randomly selected. Hay yield of each plot was measured by clipping the plants 5 cm above ground level. Correlation of hay yield and other growth characteristics with the number of mealybugs on roots as an index for mealybug damage on infested plants was determined. The results indicated that endophyte-free plants were highly infested with mealybug, P. solani compared with endophyte-infected plants that were completely free of P. solani, correlation coefficients showed that there was significant negative correlation between forage yield and mealybug numbers, indicating mealybug damage on infested plants. It seems that endophytic fungi are effective biocontrol factors for some root feeding pest such as mealybug, P. solani.
R. Arefi, H. Nahvi, A. Hemat,
Volume 10, Issue 3 (10-2006)
Abstract

The objective of this research was to design and develope a Pick and Position system to displace spherical-shaped fruits, with minimum damage to flesh, from one specific place to another. A mechanical gripper (end-effector) suitable for grasping spherical-shaped fruits with 5-9 cm in diameter was designed and developed. The primary goal of the gripper design was to take and release the fruit without bruising it in a specified time sequence. A slider-crank mechanism was used to drive the gripper. To achieve suitable timing in gripping and releasing of the fruit, the slider was driven by a cam. The kinematic and dynamic analysis of the gripping unit was done and its motion was simulated using Working Modwl software. In the next step, a four-bar mechanism (arm) was designed and developed to displace gripper between two specified locations. After kinematic analysis, equation of motion of the arm mechanism was derived and its dynamic analysis was performed. The gripper was assembled on the arm mechanism and the performance of the gripper and arm mechanism was investigated. It was observed that the system had the ability to pick and release the oblong fruits, such as apple, between two specified locations. The performance of the system for larger size fruits could be improved by some modifications on the gripper fingers.
M. M. Jowkar, H. Salehi,
Volume 10, Issue 3 (10-2006)
Abstract

Tuberose is one of the tropical and subtropical bulbous cut flowers cultivated extensively in most floricultural regions of Iran. Although it has a high potential for a long vase life after harvest, tuberose declines rapidly at home. In order to overcome this problem, two experiments were conducted on a local cultivar, “Goldorosht-e-Mahalat”, using a completely randomized design. To find a suitable preservative which provides the longest vase life for tuberose, the experiment was carried out by applying the carelessness of most consumers: not recutting stem ends nor changing the vase solutions. In the first experiment the preservative solutions were: sucrose (1, 2 and 3%), silver thiosulphate (0.4, 0.8 and 1.2 mM), silver nitrate (50, 100 and 150 mgl-1), citric acid (150, 300 and 450 mgl-1) and tap water as the control. In the early days of the experiment, silver thiosulphate caused severe burning of the florets, silver nitrate caused the wilting of the florets and bent the end of the flower spikes and sucrose didn’t have any positive effect, but decreased the vase life. The longest vase life belonged to citric acid, after which the control (tap water) was placed. The second experiment was conducted to determine the role of the water quality and citric acid. The treatments were: sterilized distilled water, citric acid made with sterilized distilled water (150, 300 and 450 mgl-1) and tap water as the control. The longest and the shortest vase life belonged to sterilized distilled water and the control (tap water) respectively. The citric acid prepared with sterilized distilled water had a desirable effect on the vase life of cut tuberose flowers. This effect increased with the increment of the acid up to 450 mgl-1.
J. Amiri, M. Rahemi,
Volume 10, Issue 3 (10-2006)
Abstract

This research was conducted to investigate the changes of GA3-like substances in the stratified (0, 10, 20, 30 days at 10oC) and non-stratified seeds of two olive cultivars, namely ‘Arbequina’ and ‘Zard’. In the first experiment stratified seeds of these cultivars (10 g) were extracted with ethanol (80%), purified by ethyl acetate, and then separated by thin layer chromatography (TLC). To compare the biological activity of separated zones, lettuce hypocolyl assauy was used. The results obtained in this part of study indicated that the amount of GA3-like substances increased as the stratification period increased. In the second experiment extracts were made from different parts of non-stratified seeds of both cultivars. The result of the second experiment showed that the GA3–like substances of embryos of non-stratified seeds were higher than other parts of the seed.
M. Arab-Abousaadi, E. Rowghani, B. Hassanzadeh,
Volume 10, Issue 3 (10-2006)
Abstract

The effects of different levels of metabolizable energy and energy to protein ratios on the performance of Fars native laying hens were examined during the second laying phase. In a feeding trial, 216 Fars native hens 42 weeks old were randomly allotted to 9 experimental diets using 6 replicated groups of 4 birds per cage. The diets were formulated with 3 levels of ME (2700, 2900 and 3100 kcal/kg diet). At each level of energy, 3 energy to protein ratios (195, 215 and 239) were considered. The diets were fed ad libitum for a period of 20 weeks (42-62 weeks). The results indicated that there were no significant differences in egg production, egg weight, body weight gain and livability at the end of the experiment (65 week of age) (P>0.05). Daily feed intake was significantly lowered in hens fed the first (ME=3100 Kcal/kg, CP=15.87), second (ME=3100 Kcal/kg, CP=14.43), third ration (ME=3100 Kcal/kg, CP=12.99) and fifth (ME=2900k Kcal/kg, CP=13.5%) as compared with the seventh ration (ME=2700 Kcal/kg, CP=13.82). Feed intake and feed conversion ratios (FCR) significantly decreased as the dietary energy level increased (P<0.05). Feed consumption at the highest energy level was significantly lower than that at the lowest energy concentration. FCR was influenced by dietary energy level. Hens on the diet with 3100 Kcal ME /kg had lower FCR compared to 2700 Kcal ME/kg. The feed cost per 1 Kg egg production increased significantly with the elevation of dietary energy and protein levels (P<0.05).The results showed that a diet containing 11.31% CP and 2700 Kcal ME/kg adequately satisfied the maintenance and production requirements of Fars native hens during the second phase of production. Also, this ration was more economical.
A. Hassanoghli, A. Liaghat, M. Mirabzadeh,
Volume 10, Issue 4 (1-2007)
Abstract

Increased chemical compounds in soil are the most important results of irrigation with domestic wastewater and treated effluents which contain some nutrients such as phosphorous (P). This process could increase the soil fertility, leading to the decrease of chemical nutrient consumption and consequently the cost of agricultural production. A research project was carried out in Tehran region for two years in order to investigate the capabilities of soil and plant in absorption and storage of wastewater contaminants, namely, phosphorous, and also the transmission of them to drain depth as a result of irrigation practice. To do the research, a series of lysimeters based on a statistical factorial experiment in the form of randomized complete design (3x3x3) were used. Raw and treated domestic wastewater, obtained from Ekbatan Housing Complex, and well water (control) were used to irrigate raw edible vegetables including parsley, carrot and tomato. The results showed that the amount of phosphorous leaching through soil to drain depth was between 0.90% and 3.56%, and between 1.03% and 4.15% of the phosphorous concentration in raw wastewater and treated one entered into the soil, respectively. Also, mass balance analyses showed the average phosphorous reduction ranged from 97.2% to 99.9% of the phosphorous entered with wastewater. During two years of study, the maximum concentration of PO4 measured in drained water was about 0.21 mg/L obtained from lysimeters irrigated with raw wastewater. This was much lower than the permissible PO4 amount for discharging the effluents to the surface water resources (6 mg/L PO4 is permitted by Iranian Environmental Protection Organization).
A. R. Hoseinpur, H. Shariatmadari,
Volume 10, Issue 4 (1-2007)
Abstract

Hamadan province is one of the most important alfalfa (Medicago sativa) producing regions in Iran. However, little is known about P status in this region and no suitable extraction method has yet been introduced. This experiment was carried out to determine the available phosphorus by nine chemical extractants in some soils of the Hamadan region. The treatments consisted of 15 soils and 2 P levels (0 and 200 mg P kg-1 as Ca(H2PO4)2.H2O ) in a factorial experiment in a randomized design with three replications. Alfalfa plant were harvested in three cutting. The results indicated that the amount of extractable phosphorus decreased in the following order: Collwell>Bray 2>0.1 N HCl>Bray 1>Olsen>AB-DTPA>Mehlich 1>Mehlich 2 > 0.01 M CaCl2 The amounts of P extracted by all methods except that by 0.01 M CaCl2 method, showed significant correlation. The results of correlation studies showed that in the first cutting, Collwel method, in the second cutting AB-DTPA, Olsen, Collwel, Bray 1, Bray 2 and Mehlich 2 and in the third cutting, AB-DTPA, Olsen, Collwel, Bray 1, and Mehlich 2 methods seems to be suitable extractants for assessing available P of soils in Hamadan province.
A. Halajnia, G. H. Haghnia, A. Fotovat, R. Khorasani,
Volume 10, Issue 4 (1-2007)
Abstract

Study of phosphorus reactions over time and the role of organic matter in the calcareous soils are important for the development of P fertilizer and manure management practices. The objective of this study was to determine the effect of applied manure on P availability and its chemical forms in the soil, over time. Eight samples were collected from semi-arid calcareous soils of Mashhad plain. The samples were treated with two levels of inorganic P (0 and 300 mg P kg-1 soil as KH2PO4) and two levels of organic matter (0 and 1% cattle manure). The experiment was conducted in a completely randomized design with factorial arrangement. The treated soil samples were incubated for 2, 5, 10, 30, 60, 90 and 150 days, then analyzed for available P (Olsen-P). The result showed that only 17% of added phosphorus was available in P treatment at the end of experiment. In manure treated soils, this figure reached 34% for the same period of time. Application of manure along with P increased the recovery of applied P and CBD-P (Citrate-Bicarbonate-Dithionite). This may be due to the formation of P-organic complexes with Fe oxides. Application of manure in soil increased NaCl-NaOH-P considerably compared with P and P+OM treatments. It can be concluded that P originating from manure compared with inorganic-P may be more available for plants over the time.
N. Etemadi, K. Razmjoo, A. Khalighi, Z. Zamani, H. Lesani,
Volume 10, Issue 4 (1-2007)
Abstract

Turfgrasses are the most important cover plants in the world. Quality evaluation of the turfgrasses is usually done by experienced evaluators using color texture, density and uniformity. The results obtained by different evaluators may be different, leading to researcher’s concern. Therefore, some quantitative methods have been used for increasing the aquracy and stability in results. In this study, three color evaluating methods including, spectrophotometery (chlorophyll content), chlorophyllmeter SPAD-502, and evaluator person, as well as leaf texture by evaluator person compared with leaf width were used for 75 populations of Cynodon dactylon L. and Tifdwarf cultivar. The results showed that there were significant differences between populations for the color and leaf texture. There were no significant corelations between measuring color by using specterophotometery, chlorophyllmeter-502, and evaluator. Use of SPAD-502 instrument for measuring leaf color of bermudagrass is not recommended due to small leaf width of this species. However, there was significant corelation between visual evaluation and leaf width in measuring leaf texture. Therefore, when no experienced evaluator is present, leaf width maybe used for measuring leaf texture.

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