in this study, precipitated calcium carbonate (pcc) was modified using cationic starch, and its effect on optical and physical properties of paper was examined in comparison with unmodified filler afterwards. to determine the filler retention in paper, both modified and unmodified fillers were added to pulp suspensions by 20, 30, and 40 percentages. for comparing the utilization effect of modif...

in rainfed areas of iran, cereal yields are low, variable and mainly as a result of inadequate and erratic seasonal rainfall and associated management factor, such as late sowing date (or late crop germination). in order to investigate the effects of single irrigation and nitrogen on bread wheat (triticum aestivum l. var. sabalan) a field experiment was conducted as split plot arranged in a ran...

in order to study the effect of different levels of nitrogen and sulfur fertilizers on yield, yield components, content of some elements, qualitative and quantitative traits of spring safflower (serin cv.) an experiment was conducted at agriculture and natural resource research station of ardabil in 2008. this experiment was carried out in factorial experiment in completely randomized block des...

curly top disease is one of the important diseases of sugar beet. spatial pattern and population variation of leafhoppers circulifer haematoceps, and c. tenellus, vectors of sugar beet curly top virus, were studied in hamadan province, iran for three years (2007- 2009). sampling was carried out at the early stage of the plant growth, in accordance with planting date for 9 weeks, in 7- 10 day in...

background and objectives: over the last decade, climate change has been one of the most challenging issues in the scientific papers. studying the impacts of climate change on crop productivity at regional scale will depend on the right estimate of future climate. this estimation is being implemented by climate models and most of them by general circulation models (gcms). this study aims at pre...

in order to determine the best traits related to indirect increasing of grain yield, five wheat genotypes (zagros, tajan, durum cul., kohdasht and n-81-18 line) were evaluated by using randomized complete block design (rcbd) with 4 replications in research field of gorgan university of agricultural sciences and natural recourses. the studied traits included leaf area index (lai), crop growth ra...

this research was conducted at the agricultural college of tehran university in 2005 to analyze the effect of use of cytokinin as well as of calcium on durability of rose (illona cultivar). cuttings were taken from rose biennial mother plants, then treated by cytokinin of 0, 0.1, 1and10 micromole per liter and calcium of 0,10,20 and 30 milimole per liter. cut flowers, after harvest, were kept i...

effects of different paclobutrazol concentrations (0, 250, 350 and 450 mgl-1) and plantlet density (80, 100 and 120 plantlet/m2) on minituber production per plantlet in potato cultivar ‘sante’ were investigated in a factorial experiment based upon a randomized complete block design of 4 replications. paclobutrazol (cultar with 250 g/l of active ingredient) was used as foliar application at earl...

drought and salinity are the most important environmental stresses that are causing adverse effects on natural ecosystems. there are species among iranian natural germplasm that are resistant to environmental harsh conditions. restoring of degraded ecosystems, promoting of biodiversity and increasing of species richness will provide by identifying of these species. almond species with broad eco...