Abstract

ALESSO, Carlos Agustín; PILATTI, Miguel Ángel; DEL CARMEN IMHOFF, Silvia  and  GRILLI, Mariano. Spatial variability of soil chemical and physical attributes in a flat Pampa Santa Fe field. Cienc. suelo [online]. 2012, vol.30, n.1, pp.85-93. ISSN 1850-2067.

The processes and properties that regulate crop performance and yield vary in space and time. The assessment of the magnitude and spatial structure of their variation is required in order to apply site-specific crop management (SSCM). Our aim was to assess the intra-field spatial variability of some chemical and physical topsoil properties of a typic Argiudoll of the center of Santa Fe for the use of the SSCM. Sixty soil samples of the top layer (0-20 cm depth) were taken in a 475 x 100 m plot. Sampling was distributed in three transects separated by 50 m with 20 points every 25 m. Disturbed soil samples were used to analyze N of nitrates (NNO 3), total organic C (COT), total N (Nt); available P (P), sand (Arena), clay (Arcilla) and soil reaction (pH). Soil bulk density (Ds) was determined on non-disturbed soil samples taken at 0-10 and 10-20 cm depths. Summary statistics were calculated and the spatial dependence was determined with sample variograms and envelopes obtained by permutations. Coefficients of variation (CV) for COT, Nt, Arena, Arcilla, Ds 0-10, Ds 10-20, and pH were low (CV < 15%) while they were moderate for P and N-NO3 (15 < CV < 35%). Moderate spatial dependence with a range of 96 m was only observed for N-NO3. The other soil properties had no autocorrelation because their variation occured at distances shorter than 25 m. In this study, the low variability and lack of spatial dependence of the soil properties did not allow modeling their spatial distribution as well as the development of reliable soil maps that would allow the use of the SSCM.

Keywords : Argiudol; Geostatistic; Site-specific Management.

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