in order to study the effect of biological and chemical fertilizers of nitrogen and phosphorus on some physiological, morphological and phenological traits of sunflower this study was carried out in eivanegharb (ilam province) in summer of 2011. treatments were arranged in split factorial based on rcbd with three replications. the main plot include 4 levels of phosphorus and nitrogen chemical f...

To study the effect of chemical and biological fertilizers on growth and essential oil content of lavender (Lavandula angustifolia Mill.), the present work was conducted in 2012-2013 at the experimental field of Alborz Research Station of the Research Institute of Forests and Rangelands, Karaj, Iran. The experiment was conducted in factorial in the form of a randomized complete block design wit...

this research, for lowering the use of chemical fertilizer, was carried out using combinations of biological and chemical fertilizer on bean in rasht region in 2012 growing season. the experiment was conducted based on randomized complete blocks design with 12 treatments and three replications. experimental treatments included: control (no fertilizers and no inoculants), chemical fertilizers (n...

The niche theory predicts that environmental heterogeneity and species diversity are positively correlated in tropical forests, whereas the neutral theory suggests that stochastic processes are more important in determining species diversity. This study sought to investigate the effects of soil nutrient (nitrogen and phosphorus) heterogeneity on tree species diversity in the Xishuangbanna tropi...

this research was carried out at agricultural and natural resources research center, isfahan, islamic republic of iran (kabootar abad) for two years (2006-2007). the experiment was conducted as a split plot arranged in randomized block design with four replications. treatments were four levels of n fertilizer [110, (160 = soil and water research institute recommendation), 210 and 260 kg ha-1] a...

The evaluation of the Kjeldahl digestion method was investigated by comparing measured values of total nitrogen, phosphorus and potassium using three salt and catalyst mixture in Standard Kjeldahl digestion method and Salicylic acid Modification method with certified values of plant material as well as comparison was made for determination of total nitrogen from steam distillation method verses...

Root cortical aerenchyma (RCA) is induced by hypoxia, drought, and several nutrient deficiencies. Previous research showed that RCA formation reduces the respiration and nutrient content of root tissue. We used SimRoot, a functional-structural model, to provide quantitative support for the hypothesis that RCA formation is a useful adaptation to suboptimal availability of phosphorus, nitrogen, a...

Nutrient limitation to primary productivity and other biological processes is widespread in terrestrial ecosystems, and nitrogen (N) and phosphorus (P) are the most common limiting elements, both individually and in combination. Mechanisms that drive P limitation, and their interactions with the N cycle, have received less attention than mechanisms causing N limitation. We identify and discuss ...