R. Hojat Ansari, M. Hasanpour Asil, A. Hatamzadeh, B. Rabiei, S.h. Roofigari Haghighat,
Volume 12, Issue 43 (spring 2008)
Abstract
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
Z. Shirkhodaei, F. Aghayari, H. Hasanpour Darvishi,
Volume 23, Issue 4 (winter 2020)
Abstract
There are new technologies such as geographic information systems (GIS) that can be effective in the optimization of irrigation water. Therefore, utilizing these resources in a desirable, effective and efficient manner to ensure sustainable development is one of the most important issues in the today's world. The aim of this study was to determine and evaluate the potential water use efficiency (WUEp) index in the plain scale by using net water requirement data, area under cultivation and yields, and to determine the comparative advantage of wheat and barley plants in Tehran, Alborz, Qom, Qazvin and Zanjan provinces by employing the geographic information system (GIS). The yields of wheat and barley products by weighted average in ArcGIS software were converted to yields in the plains scale. To calculate the potential and actual water use efficiency, we used the OPTIWAT software in order to calculate the net irrigation water and the current irrigation efficiency plains; also, the yields of wheat and barley products in the plains scale were used. Zoning water use efficiency indexes was performed by using the ArcGIS software and Kriging method. Mapping results showed a comparative advantage of crops in the west and northwest of Tehran province, south and southwest of Alborz province, southwest, north- west and center of Qazvin province, center Qom province and also, northern and southern regions of the Zanjan province, in comparison to other areas. Average potential and actual water use efficiency in the whole study area of the provinces for wheat were 1.43 and 0.58 kg m-3, respectively, while these were 1.62 and 0.65 kg m-3 for barley, respectively.
I. Hasanpour, M. Shirvani, M.a. Hajabbasi, M.m. Majidi,
Volume 26, Issue 2 (ُSummer 2022)
Abstract
Low organic matter content and alkaline pH of calcareous soils in arid and semi-arid regions are the main reasons for the low nutrient availabilities for plants in these soils. One way to improve the chemical properties and fertility of calcareous soils is the application of organic substances such as biochar produced from pyrolysis of organic wastes. However, biochars have an almost predominant alkaline pH, which exacerbates plant nutrient deficiencies in calcareous soils when used for a long time. Pyrolysis of some organic wastes under controlled temperature conditions can lead to the production of acidic biochar. The effect of acidic biochars on several chemical properties of two calcareous soils in Isfahan province was investigated in the present study. Treatments included two types of biochar (pine cone and rice husk), three levels of biochar addition (one, three, and six percent), two types of soil (a sandy loam (Tiran) and a clay loam (Lavark)), and two incubation periods (one and six months). The results showed that applying biochar could slightly decrease soil pH but raised soil electrical conductivity. In addition, the amount of organic carbon, total nitrogen, and available concentration of manganese in all treatments and the concentrations of available phosphorus, potassium, iron, zinc, and copper in the most of treatments showed a significant increase compared to the control. Amending soil with biochar at a 6% rate caused the most significant changes in the measured parameters in both soil types. In general, the results of this study indicated that acidic biochar produced from pine cones and rice husk can be used as a suitable conditioner to improve the chemical properties and fertility of calcareous soils.
