02097naa a2200181 a 450000100080000000500110000800800410001902400380006010000190009824501270011726000090024452015160025365000100176965000160177965000170179570000230181277300800183519886392014-07-17       2014    bl uuuu     u00u1 u    #d7 a10.1080/01904167.2014.8887362DOI1 aFAGERIA, N. K.  aComparison of conventional and polymer coated urea as nitrogen sources for lowland rice production.h[electronic resource]  c2014  aNitrogen (N) is one of the most yield limiting nutrients in lowland rice production. Improving N use efficiency is essential to reduce cost of crop production and environmental pollution. A greenhouse experiment was conducted with the objective to compare conventional and polymer coated urea for lowland rice production. Grain yield, straw yield, panicle density, maximum root length, and root dry weight were significantly increased in a quadratic fashion with the increase of N rate from 0 to 400 mg kg−1 soil. Nitrogen source X N rate interactions for most of these traits were not significant, indicating that lowland rice responded similarly to change in N rates of two N sources. Based on regression equations, maximum grain yield was obtained with the application of 258 mg N kg−1 soil and maximum straw yield was obtained with the addition of 309 mg N kg−1 soil. Nitrogen use efficiency (grain yield per unit of N applied) was maximum for polymer coated urea compared to conventional urea. Root length and root dry weight improved at an adequate N rate, indicating importance of N fertilization in the absorption of water and nutrients and consequently yield. Polymer coated urea had higher soil exchangeable calcium (Ca) and magnesium (Mg), Ca saturation, Mg saturation, base saturation, and effective cation exchange capacity compared to conventional urea. There was a highly significant decrease in soil exchangeable potassium (K) with increasing N rates at harvest of rice plants.  aArroz  aNitrogênio  aOryza sativa1 aCARVALHO, M. C. S.  tJournal of Plant Nutrition, New Yorkgv. 37, n. 8, p. 1358-1371, July 2014.