The nitrogen cycle is an ecochemical pathway distributed on a global scale and including multiple organisms. Reactions comprising the nitrogen cycle are catalyzed by complex protein machines, some of which — like the nitrogen fixing system in legumes — may arguably be Irreducibly Complex (IC). The focus of this paper is not on these systems, but the overarching cycle in which they participate, ...

Constructed wetlands could be components of low-tech systems to treat and reuse wastewater in arid region. A key function of the wetland would be to provide additional N removal. To improve design criteria, a sequential model of nitrogen transformations (organic N! ammonium; ammonium!nitrate; nitrate!nitrogen gas) was successfully calibrated and verified for a wetland in Kingman, Arizona. A seq...

a factorial experiment based on a randomized complete block design with three replications was carried out in order to study the effects of tuber size, nitrogen fertilizer and harvest date on yield and yield components of potato. this experiment was conducted in a grower’s farm in uraki village located in chabahar city, in 2011. in this experiment, the treatments were two levels of tuber size (...

abstract- crop residue is applied to amend soil properties and increase crop yield. in this study, the effects of rapeseed residues and different rates of nitrogen on grain yield and yield components of sunflower and weed dry matter were investigated. the experiment was conducted at the experimental farm of college of agriculture, shiraz university, located at badjgah, shiraz, iran in 2007-2008...