 |
| Titel |
Effect of Cropping System and Contouring or Download Sowing on Soil Water Erosion under no Tillage |
| VerfasserIn |
J. Marioti, J. Padilha, I. Bertol, F. T. Barbosa, J. C. Ramos, R. S. Werner, E. Vidal Vázquez, M. S. Tanaka |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250068789
|
|
|
|
|
|
| Zusammenfassung |
| Water erosion is the main responsible factor of soil and water losses, thus also causing soil
degradation, especially on agricultural land, and it is also one factor of degradation outside
the place of the origin of erosion. No tillage agriculture has been practiced in the last few
decades for the purposes of water erosion control in various regions of Brazil. However, it has
been shown that no tillage does not adequately control water erosion unless other
complementary conservationist practices such as contour tillage or terracement. Although the
erosion problem is widely recognized, there are still difficulties in estimating their magnitude,
the environmental impact and the economic consequences, especially when it occurs in a
conservation system like no tillage. The aim of this study was to quantify runoff and soil
losses by water erosion under five different soil tillage treatments at Santa Catarina State,
Southern Brazil. A field study was carried out using a rotating-boom rainfall simulator
with 64 mmh-1 rainfall intensity for 90 minutes. Four rainfall tests were applied
over the experimental period, one in each of the successive soybean and maize
crop stages. Both soil cover by surface crop residue and soil cover by soybean and
maize plant canopy were measured immediately before each rainfall test. Soil and
water losses were smaller when sowing in contour than when sowing downslope.
Contouring has promoted an average reduction of 42% in soil losses and 20% in
water losses. Maize crop has promoted an average reduction of 19% in soil losses
and 12% in water losses, in relation to the soybean crop. Therefore runoff rates
and soil losses were higher in the downslope plots and in the soybean crop. Soil
cover by previous crop residue was an important factor for reducing soil losses.
Runoff rates were influenced by the soil water content before each rainfall test (R2=
0.78). The highest runoff occurred during the third simulated rainfall test, with
the 83% of the total rain applied; immediately before the test the soil moisture
was 36%. The smallest losses occurred in the fourth test, with 55% of the total
rain applied where the soil moisture immediately before the rainfall test was 25%. |
|
|
|
|
|
|