JWSS - Journal of Water and Soil Science

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The effect of N levels and planting densities on quantitative and qualitative characteristics of grain yield in grain sorghum (cv. Kimia) was studied in summer 1998 at Kushkak Agricultural Research Station, Shiraz University. The experiment was a spilt plot with 4 replications in which 4 levels of planting densities (7.7, 10, 15.4, 20 seeds m^-2) were applied as main plots and 4 levels of N (0, 40, 80, 120 Kg N ha^-1) as subplots.

 N application rates up to 120 kg N ha^-1 increased grain yield (7240 kg ha^-1), but due to increased planting density (5336 kg ha^-1) the highest yield obtained from 15 seeds m^-2. Interaction of N and planting density was also significant. Application of 80 kg N ha^-1 and highest planting density produced 8702 kg ha^-1 of grain. Different grain yields in different levels of N and planting densities were due to increased number of grains per basic branches of panicle and increased number of panicle per m^-2. The trend of variation of crop growth rates (CGR) was similar to the trend of grain yield. Nitrogen application increased grain protein contents but planting density had no significant effect on grain protein. Phenolic compounds (tannins) decreased with increasing N application and with decreasing planting density. A negative correlation was observed between increased N content and increased phenolic compounds.

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It is believed that various types of field bean, including pinto, white and red, differ in adaptability to high temperatures and may, thus, differ in response to delay in planting. In order to evaluate this response, an experiment was conducted during 1996 at the Agricultural Research Station, Isfahan University of Technology, using a randomized complete block design with split-plot layout. Main plots consisted of four planting dates (April 28, May 13 and 28 and June 13) and sub-plots included four genotypes of common bean (red bean, c.v. Naz pinto beans, experimental lines 11816 and 16157 and a white bean, experimental line 11805).

 Number of branches per plant, number of pods per branch and per unit area, number of seeds per pod of main stem and branch, number of seeds per main stem, per branch and per unit area, 100-seed weight and seed yield significantly reduced, while harvest index significantly increased by delay in planting and consequent increases in temperature and reduction in time for growth. The lower harvest index obtained with early planting was the result of the lower efficiency of the produced vegetative growth due to the coincidence of seed filling period with high temperatures. Pinto bean line 11816 ranked the highest for number of branches per plant and harvest index among the genotypes evaluated and produced the highest seed yield (3030 kg ha^-1). Although red bean Naz ranked the highest for number of pods and seed per main stem and per unit area, it had the lowest harvest index and 100-seed weight and, consequently, produced the least seed yield (2254 kg ha^-1). The results obtained indicate that delay in planting adversely affects bean seed yield. Pinto bean line 11816 may have higher yield potential among the genotypes studied at all planting dates under conditions similar to the present experiment. No specific relationship was observed between apparent seed characteristics and plant tolerance to heat.

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To prepare a sheetable dough, potato granule and potato puree of Agria and Marfona potato-cultivars, corn flour, emulsifier ,shortening, water,starch, salt, garlic and pepper powder were used. Dough was sheeted to thickness of 1-2 mm and formed to desirable shape. These slices were baked at 125^oC for 30 minutes. Prepared potato chips were packed in air or nitrogen atmosphere and stored in dark at 25^oC. Peroxide value, bending strength and color of the samples were determined in 30 day intervals. Peroxide value was detected just at the end of the third month. Peroxide value in chips packed in nitrogen atmosphere was less than that in chips packed in air atmosphere. Atmosphere of packages had a significant effect on the bending strength of the chips (p<0.01). The bending strength of chips packed in nitrogen atmosphere was more than that of chips packed in air atmosphere. Storage time had significant effect on bending strength (p<0.01). Storage time and cultivar effects on lightness and darkness of chips (L in hunter lab system) were significant (p<0.01). Storage time and cultivar effects on yellowness and blueness (b) of chips were significant (p<0.05). Storage time, cultivar and packaging atmosphere had no significant effect on redness and greenness (a) of chips (p<0.05)

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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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In order to study the effects of salinity of irrigation water on the growth and quality of 10 bermudagrass cultivars under saline soil, a factorial plot experiment using a complete randomized block design with three replications was carried out at College of Agriculture, Isfahan University of Technology in 2002-2003. Ten cultivars under five levels of irrigation water salinity (3.30, 6.93, 10.2, 14.8, 17.8 dsm^-1) were studied. During experiment, visual appearance of color (1 to 9, best 9), and leaf area, shoot and root dry weights and length and number of stolones were measured. Results showed that salinity of irrigation water affected color of different cultivars, such that with increase in the level of salinity, color decreased. Cultivars showed better color in August, but lower color in January. Annual mean indexes showed that ISF2 and Tifdwarf had highest and lowest color, respectively. Also, with increase in salinity levels, leaf area, foliage dry weight, length and number of stolones reduced. With increase in salinity of irrigation water from 3.30 to 10.2 dsm^-1 root dry weight increased, but reduced in higher salinity levels. Due to significant interaction effects between salinity and cultivars for most traits, the responses of cultivars were different. Large differences observed between cultivars for most of traits indicated high genetic variation among the studied bermudagrass cultivars. Under high level of salinity conditions, JP2 and Tifway for foliage dry weight, 3200W18-4 and ISF2 for root dry weight, and cultivars Midlawn and 3200W18-4 for leaf area, were recognized as more tolerant than others.

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In this experiment the response of persimmon fruit, cv. Karaj, to astringency removal by ethanol and the effects of this treatment on some important fruit characteristics were investigated. Fruits were harvested at three different dates and at each date based on the previous results, and then modified treatments were applied. The best ethanol astringency removal treatment in this study was 10 ml of 38% ethanol per kg fruit for 48 hours. The period after ethanol treatments had no effect on the reduction of soluble tannin concentration, although it resulted in the reduction of flesh firmness and increased soluble pectin. Ethanol treatments and also temperature conditions reduced flesh firmness and increased ground color of fruits however, the effect of ethanol treatments was more than temperature conditions. Temperature conditions increased ethylene production, thus reducing the flesh firmness and increasing the ground color index of fruits. Ethanol treatments did not increase the ethylene production, and it seems that its effects on some characteristics are due to ethanol itself or factors other than ethylene.

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Variations in theaflavin and thearubigin content during fermentation and the effects of these variations on brightness and total color in black tea were evaluated at the Tea Research Center in Lahijan in the year 2004.  Percentages of theaflavin (TF), thearubigin (TR), total color and brightness were determined in two clones 100 and in the natural Chinese hybrid during flushing in the months of June, August and October and different fermentation time (30, 60, 90, 120 and 150 minutes). It is evident from the results obtained that apart from genetic differences in the clones under study, changes in climatic conditions during different periods of flushing and fermentation time can to a great extent influence the amount of TF, TR, total color and brightness in black tea. Results obtained also indicated significant interacting effects of clones, different flushing and fermentation times on the quality-determining characteristics of black tea. No significant correlations were found between TR and brightness however, significant correlations were found between other characteristics studied at the 1% probability level. On the basis of regression analysis with fermentation time (independent variable) and each of the characteristics studied (dependent variable), linear relationships were detected between fermentation time and brightness and TF content. Multi-variable regression analysis between brightness (dependent variable) and TF and TR (independent variables) showed that more than 56% of variations in brightness in black tea was related to TF and TR. Also multi-variable regression analysis between total color (dependent variable) and TF and TR (independent variable) indicated that more than 43% of variations in total color in black tea can be attributed to TF and TR percentages

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To optimize the use of sulfur in drying of apricot, four following treatments including: sulfiting and drying, sulfiting- blanching and drying, blanching- sulfiting and drying, and finally sulfiting- drying to % 50 of initial moisture- blanching and finish drying were studied. The levels of sulfur addition were from 0 to 1500 ppm, SO2 and drying was carried out at 50 to 74 °C. The quality of dried apricots was judged by extent of browning development and hardness determination. A response surface statistical design was applied to evaluate the quality of slabs and to determine optimum drying conditions. The results showed that sulfite was the major factor in controlling dried apricot quality. At present of sulfur, the role of temperature can be neglected. The amount of used sulfite has no significant effect on drying time of apricots. Blanching reduced drying time of product significantly. By increasing the drying temperature, loss percentage of SO2 was reduced for all treatments. Blanching and then sulfiting, increased loss in residual sulfur of products significantly. Application of sulfiting– drying method, using 900 ppm of SO2 at 50 to 68 °C was found to be the best treatment because of production of slabs whit average hardness and color texture equal to 1.44 N/m2 and 0.07 Od respectively.

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Saffron is one of the most important crops in Iran and the quality of its dried stigma is highly depended on the processing and storage conditions. In this study, the effect of different storage conditions in terms of temperature (20, 30 and 40°C) and water activity (0.32, 0.52 and 0.75) during 12 weeks storage on color strength, aroma and bitterness of saffron were investigated. In order to study of moisture (water activity) different saturated solution of MgCl2, Mg(NO3)2, MgBr2 and NaCl in the various temperatures were used. Results showed the color strength decreased as temperature increased. Increasing of water activity resulted in deterioration of crocin and consequently decreasing of color. Furthermore, after 12 weeks of storage, the color strength had a noticeable decrease, the bitterness also decreased but the aroma increased.

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Sun drying is a well-known food preservation technique that reduces the moisture contents of agricultural products. Shrinkage, rehydration ability and color of food materials during air drying adversely affect the quality of the dried products. Since all fresh tomatoes can not be consumed at the time of harvest, preservation provides a larger market, allowing consumers to buy the preserved tomato through the year. A natural convection solar dryer consisting of a solar air heater and a drying chamber was manufactured in this research. Tomato slices were dried in the solar dryer and compared with open sun drying. Also, tomato slices were dried in a laboratory oven (operated at temperature 50, 60, 70, 80°C). With increasing the temperature, the time required to arrive certain moisture content is decreased. Also results showed that drying time in the solar dryer is shorter than open sun drying. In other words, drying time was reduced 17 to 45% by the solar drying in comparison to open – sun drying. The experimental shrinkage data showed a linear behavior with moisture content. Also, the experimental data didn't show a strong effect of temperature on the rehydration ability of the product. Thus, the effect of temperature and method of sun drying on the shrinkage phenomenon and the rehydration ability can be neglected. Tomato slices dried at 50°C had better appearance (lightness and red color) than at 80°C.

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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.

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