02494naa a2200289 a 450000100080000000500110000800800410001902400320006010000180009224501230011026000090023350000650024252015880030765000270189565000210192265000110194365300090195465300150196365300230197865300270200165300170202865300130204565300170205870000140207570000180208977300970210710495602019-11-11       2003    bl uuuu     u00u1 u    #d7 a10.2136/sssaj2003.18312DOI1 aFABRIZZI,K,P.  aSoil Carbon and Nitrogen Organic Fractions in Degraded vs. Non-Degraded Mollisols in Argentina.h[electronic resource]  c2003  aArticle history: Received: Dec 5, 2001/Published: Nov, 2003.  aAbstract: The use of no-tillage has notably increased in the Pampas region of Argentina during the last 10 yr. Two tillage experiments with contrasting previous agricultural use, degraded and non-degraded soils, were evaluated in the southeast of Buenos Aires province, Argentina. The objectives were to: (i) quantify the effects of tillage and N fertilization on quantity and vertical distribution of C and N in the soil organic matter (SOM) and particulate organic matter (POM) fractions as well as potentially mineralizable N (PMN), and (ii) evaluate these fractions as indicators of soil quality. Tillage systems were conventional tillage (CT), minimum tillage (MT), and no-tillage (NT) (main plots), and N fertilization rates were 0, 120, and 150 kg ha?1 (subplots). Total organic C (TOC), total N (TN), POM-C, POM-N, and PMN were measured at 0- to 7.5- and 7.5- to 15-cm soil depth. In Exp. I (degraded soil) TOC was greater under NT (27 g kg?1) than under CT (24 g kg?1) in the 0-N treatments. No differences in TOC and TN were found in Exp. II at 0 to 7.5 cm (non-degraded soil). Carbon in POM and POM-N were greater under NT in the fractions of 212 to 2000 and 53 to 212 ?m at 0 to 7.5 cm, but they were similar or greater under CT at 7.5- to 15-cm depth in Exp. I. Stratification of TOC, TN, and POM were observed under NT in Exp. I. Potentially mineralizable N was greater under NT (62 mg kg?1) in Exp. I, however, no differences in PMN were observed in Exp. II. Carbon in POM 212 to 2000 ?m and PMN were the more sensitive indicators of tillage effects, mainly in Exp. I.  aCONSERVACION DE SUELOS  aMANEJO DE SUELOS  aSUELOS  aCORN  aNO-TILLAGE  aNO-TILLAGE SYSTEMS  aORGANIC MATTER IN SOIL  aSOIL QUALITY  aSOYBEANS  aZERO TILLAGE1 aMORON, A.1 aGARCÍA, F.O.  tSoil Science Society of America Journal, November 2003, Volume 67, Issue 6, Pages 1831-1841.