Nitrogen use efficiency

Cassman KG, Peng S, Oik DC, Ladha JK, Reichardt W, Dobermann A, Singh U. 1998. Opportunities for increased nitrogen use efficiency from improved resource management in irrigated rice systems. Field Crops Research 56 7-38. 

Goins, G. D., Yorio, N. C., Wheeler, R. M. (2004). Influence of nitrogen nutrition management on biomass partitioning and nitrogen use efficiency indices in hydroponically grown potato. J. Amer. Soc. Hort. Sci., 129, 134-140. 

Berendse F. and Aerts R. (1987) Nitrogen-use efficiency a biologically meaningful definition Fund. Ecol. 1, 293-296. 

Cassman K. G., Dobermann A. D., and Walters D. (2002) Agro-ecosystems, nitrogen-use efficiency, and nitrogen management. Ambio 31, 132-140. 

Let us assume that 100 units (dry weight basis) of plant detritus is undergoing decomposition in a wetland. The carbon content of detrital matter is 40 units assuming 40% carbon content (dry weight basis). Carbon and nitrogen use efficiency is set at approximately 40% for aerobes and 10% for anaerobes. Based on the above assumptions, 16 units of carbon are assimilated by aerobes and 4 units of carbon by anaerobes. To maintain C N ratio of 10 in their biomass, aerobic microbes and anaerobes would require 1.6 units and 0.4 units of nitrogen, respectively. 

The proportionate declirie iri the cbnsumpffofTof ammonium nitrate has resulted from massive development of urea production in developing countries and the introduction of complex fertili rs based on ammonium phosphates. However, considering the hi er nitrogen use efficiency of ammonium nitrate compared with urea, ammonium nitrate may be the more eco-nonnical nitrogen source in many situations. 

Research and development companies such as the Spanish Alkol Biotech, the Brazilian Granbio, or the American Arcadia Biosciences Inc. focus on the development of hybrid energy crops (eg, energy cane) with high yields, to use sugar beet for the production of cellulosic ethanol, as well as on nitrogen-use efficiency to reduce consumable inputs. 

Interestingly, the reported recovery efficiencies in Greek experiments with wheat rose with higher nitrogen applications, while those for barley and corn, predictably, fell as fertilization rates increased see Simonis, A. D. 1989. Studies on nitrogen use efficiency of cereals. In Jenkinson and Smith (29), pp. 110-124. 

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