Impact of agricultural practices on plant diversity of winter wheat fields

des the direct effects of plants in providing the food, fibers, wood and medicines, plants conserve and protect the regional biodiversity and therefore play an important role to providing biodiversity goods and services for human being. For assessing the plant diversity and effect of arid zone agricultural practices on plant diversity, a study was conducted in Shirvan, Mashhad and Gonabad. These three regions are related to Razavi and Northern Khorasan provinces and differed in mean annual air temperature and precipitation. In each region, high and low input fields of winter wheat and a natural system for comparison were selected. Use of agricultural inputs was criteria for selection of low and high input fields in each region. In grain filling stage of wheat growth (90 stage of zadoks), sampling of plants were done by use of quadrates in five replicates in each system. Plants in each quadrate were counted and species richness of plants was determined. Results showed that plant diversity changed and declined in agricultural systems, also whole plant species was affected by agricultural practices and decreased. Based on results, important weeds of winter wheat fields were not observed in natural systems. As a whole, agricultural practices result in reduction of plant diversity and this effect was greater in regions that had temperature and humid stresses.