management strategies to increase nitrogen use efficiency (nue) in agriculture

use of nitrogen fertilizers has contributed much to the remarkable increase in food production that has occurred during the past 50 years. however, environmental and economic challenges due to nitrogen application in agricultural have increased regard to nitrogen use efficiency (nue). studies conducted around the world shows that only half of nitrogen fertilizer inputs is taken up by crops. unfortunately, in iran, very little information exists about nue on a large scale for cereal. however, look at the statistics of nitrogenous fertilizers it can be found that overuse of fertilizers may be due to their low efficiency. therefore, to estimate of nue during 10 years (1378-87) was used from partial factor productivity (pfp) for this purpose. the results show that, pfp was 38 kg kg-1 and less than 6 units global average (44 kg kg-1). obviously pfp must be increased by about 8% in the year until the year 1400 at least it equal global average. thus, it seems that nitrogen fertilizer management methods at the farm scale are the need to review, to reduce nitrogen losses to the environment. in this regard, improving farm management practices, experiences of other countries and using advanced technologies highly will help. because most technologies have synergistic effects on plant response to nitrogen, hence they must be applied in an integrated manner.