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Titel |
Quantification of tillage, plant cover, and cumulative rainfall effects on soil surface microrelief by statistical, geostatistical and fractal indices |
VerfasserIn |
J. Paz-Ferreiro, I. Bertol, E. Vidal Vázquez |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1023-5809
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Digitales Dokument |
URL |
Erschienen |
In: Nonlinear Processes in Geophysics ; 15, no. 4 ; Nr. 15, no. 4 (2008-07-23), S.575-590 |
Datensatznummer |
250012710
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Publikation (Nr.) |
copernicus.org/npg-15-575-2008.pdf |
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Zusammenfassung |
Changes in soil surface microrelief with cumulative rainfall under different
tillage systems and crop cover conditions were investigated in southern
Brazil. Surface cover was none (fallow) or the crop succession maize
followed by oats. Tillage treatments were: 1) conventional tillage on bare
soil (BS), 2) conventional tillage (CT), 3) minimum tillage (MT) and 4) no
tillage (NT) under maize and oats. Measurements were taken with a manual
relief meter on small rectangular grids of 0.234 and 0.156 m2,
throughout growing season of maize and oats, respectively. Each data set
consisted of 200 point height readings, the size of the smallest cells being
3×5 cm during maize and 2×5 cm during oats growth periods. Random
Roughness (RR), Limiting Difference (LD), Limiting Slope (LS) and two
fractal parameters, fractal dimension (D) and crossover length (l) were
estimated from the measured microtopographic data sets. Indices describing
the vertical component of soil roughness such as RR, LD and l generally
decreased with cumulative rain in the BS treatment, left fallow, and in the
CT and MT treatments under maize and oats canopy. However, these indices
were not substantially affected by cumulative rain in the NT treatment,
whose surface was protected with previous crop residues. Roughness decay
from initial values was larger in the BS treatment than in CT and MT
treatments. Moreover, roughness decay generally tended to be faster under
maize than under oats. The RR and LD indices decreased quadratically, while
the l index decreased exponentially in the tilled, BS, CT and MT treatments.
Crossover length was sensitive to differences in soil roughness conditions
allowing a description of microrelief decay due to rainfall in the tilled
treatments, although better correlations between cumulative rainfall and the
most commonly used indices RR and LD were obtained. At the studied scale,
parameters l and D have been found to be useful in interpreting the
configuration properties of the soil surface microrelief. |
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