alternative assessment approaches received considerable attention soon after a discontent with traditional, one-shot testing. these approaches, however, have been used only to improve learners’ linguistic ability despite communicative models of language which pointed that knowledge of language also involves pragmatic ability (bachman, 1990; bachman & palmer, 1996). the present study tries t...

Yield gap analyses of individual crops have been used to estimate opportunities for increasing crop production at local to global scales, thus providing information crucial to food security. However, increases in crop production can also be achieved by improving cropping system yield through modification of spatial and temporal arrangement of individual crops. In this paper we define the croppi...

The US egg industry is being pressured from many directions to change its production practices, particularly to address concerns about hen welfare in conventional cage systems. Responding to similar pressures, in 1999, the European Union banned conventional laying cages starting in 2012. This now impending European ban has led to the development of several alternative housing systems. These inc...

agroforestry is one the aspects of sustainable agriculture in which multiple cropping of perennial trees in mixture with crops guarantees the environmental, economical and social sustainability in rural communities. high demands for forage in northern provinces of iran lead to agroforestry in citrus orchards as a potential mean for forage production through agroforestry systems. this research w...

nitrogen is one of the most important nutrients in crop production, but it's losses to the environment is harmful. the sundial model (simulation model of n dynamics in the soil) was used to quantify the cycle of n and it's losses in different production systems of sugar beet (beta vulgaris l.) in former khorasan province, east of iran. the data were collected from traditional, semi-me...

The biogeochemical liabilities of grain-based crop production for bioenergy are no different from those of grain-based food production: excessive nitrate leakage, soil carbon and phosphorus loss, nitrous oxide production, and attenuated methane uptake. Contingent problems are well known, increasingly well documented, and recalcitrant: freshwater and coastal marine eutrophication, groundwater po...