02951naa a2200289 a 450000100080000000500110000800800410001910000160006024501070007626000090018330000090019250000860020152019070028765000250219465000170221965000320223665000350226865000160230365000230231965000240234265300160236665300210238265300240240370000240242770000160245177301940246710509272019-07-31       2012    bl uuuu     u00u1 u    #d1 aSAWCHIK, J.  aImpact of winter cover crops on soil properties under soybean cropping systems.h[electronic resource]  c2012  a8 p.  aTambién publicado en: Agrociencia Uruguay, v. 16, n. especial, p. 288-293, 2012.  aABSTRACT. Agricultural systems in Uruguay exhibit a high frequency of soybean in crop rotations. This could adversely affect soil organic carbon (SOC) storage in the long term. The introduction of winter annual cover crops (CC) in these systems may improve SOC balance as well as reduce the impact of rainfall on soil erosion rates. The objective of this study was to evaluate the impact of the inclusion of CC on SOC storage and soil physical properties under continuous soybean (Glycine max [L.] Merr) cropping systems. A ? eld experiment was established in 2003 in a vertic Argiudoll. A split plot design was used with CC and non CC as whole plot arranged in four randomized complete blocks. Cover crops were: oats (Avena sativa L)., annual ryegrass (Lolium multi? orum L.). Two termination dates comprised split plots: 60 or 30 days before soybean planting. Mean annual forage production over eight years was higher (P ? 0.05) in oats compared to annual ryegrass for both termination dates. The inclusion of CC increased SOC concentration at the 0-7.5 cm depth, and at the 7.5-15 cm depth in the annual ryegrass treatment. Oats and annual ryegrass had 60 and 80 % more particulate organic carbon (POC) concentrations at the 0-7.5 cm, respectively than no cover crop treatment. No signi? cant differences among treatments were observed for mineral associated organic C-MAOM at any depth. Nitrogen mineralization potential under ryegrass had a three-fold increase compared to the no cover crop treatment. Both CC treatments showed a higher (P ? 0.05) percentage of macropores compared to the no cover crop treatment. In most of the years soybean grain yield was not affected by cover crops treatments. However, late termination dates often reduced soybean yields. The inclusion of CC in high frequency soybean cropping systems may enhance soil C storage, and improve related soil physical properties.  aAGRICULTURA CONTINUA  aAVENA SATIVA  aCARBONO ORGÁNICO DEL SUELO  aCULTIVOS DE COBERTURA INVERNAL  aGLYCINE MAX  aLOLIUM MULTIFLORUM  aSISTEMAS DE CULTIVO  aCOVER CROPS  aCROPPING SYSTEMS  aSOIL ORGANIC CARBON1 aPÉREZ BIDEGAIN, M.1 aGARCÍA, C.  tIn: INTERNATIONAL SOIL TILLAGE RESEARCH ORGANIZATION. 19., SOCIEDAD URUGUAYA DE CIENCIA DEL SUELO, 4., 2012, Montevideo, UY. [Oral presentation]: paper no. 376. Montevideo, UY: ISTRO, 2012.