Figure 1
Location of the study area in the Alto Ipanema catchment (Pernambuco, Brazil)
Abbildung 1. Lage der Untersuchungsfläche im Einzugsgebiet des Alto Ipanema (Pernambuco, Brasilien)
Figure 2
Schematic representation of the monitoring procedure: thermocouple sensors, infrared camera, soil cover treatments (dried elephant grass straw, dried cashew tree leaves and coconut powder on removable frames as well as the bare soil)
Abbildung 2. Schematische Darstellung des Monitoringverfahrens: Thermoelementsensoren, Infrarotkamera und Bodenbedeckungsvarianten (Elefantengrasstroh, Kaschubaumblätter und Kokusnusspulver auf entfernbaren Rahmen sowie der vegetationslose Boden)
Figure 3
Soil surface temperature recorded with thermocouples for the bare soil and for the three types of mulch: elephant grass straw (top), cashew tree leaves (middle) and coconut powder (bottom).
Abbildung 3. Mittels Thermoelementen gemessene Oberflächentemperatur des Bodens vom nackten Boden und drei Mulchvarianten: Elefantengrasstroh (oben), Kaschubaumblätter (Mitte) und Kokusnusspulver (unten).
Figure 4
Soil surface temperatures of the different soil mulching covers and respective densities, and for bare soil, for both day and night periods
Abbildung 4. Oberflächentemperatur des Bodens bei verschiedenen Mulchauflagen und Mengen sowie dem nackten Boden während des Tages und der Nacht
Figure 5
Soil surface temperature variations for both day and night periods compared to the bare soil (recorded with the thermocouple), of the different mulching treatments. Mean values from data recorded between 10:00 a.m. of October 31, 2014 and 8:00 a.m. of November 4, 2014.
Abbildung 5. Die Abweichungen der Oberflächentemperatur des Bodens der Mulchvarianten vom nackten Boden während des Tages und der Nacht (mittels Thermoelement gemessen). Es werden Mittelwerte der vom 31. Oktober 2014, 10:00 Uhr, bis zum 4. November 2014, 8:00 Uhr, aufgenommen Daten gezeigt.
Table 1
Mean values of soil surface temperatures for different mulching covers, for day and night periods
Table 1. Mittelwerte der Oberflächentemperatur des Bodens der verschiedenen Bodenbedeckungsvarianten für die Tag- und Nachtperioden
| Soil cover treatment | Mulch density (t ha−1) | Mean temperature (°C) | |
|---|---|---|---|
| Day | Night | ||
| Bare soil | 0 | 39.13a | 22.18f |
| Elephant grass straw | 2 | 36.69ab | 25.77bcd |
| 4 | 32.87cd | 23.71e | |
| 8 | 30.02def | 26.64ab | |
| Cashew tree leaves | 2 | 32.01cde | 26.13abc |
| 4 | 29.41ef | 27.01a | |
| 8 | 30.31def | 26.56ab | |
| Coconut powder (coir dust) | 2 | 34.09bc | 26.25abc |
| 4 | 31.26cdef | 25.32cd | |
| 8 | 28.22f | 24.18d | |
[i] Mean temperature values followed by different letters on the same column do not differ in 5% level of significance, by Tukey test. The day period was considered from 6h00 to 17h59 and night period from 18h00 to 5h59.
Figure 6
Box plot of soil surface temperatures recorded with the thermo-couples of the different soil cover treatments
Abbildung 6. Box-Plots der Oberflächentemperatur des Bodens der verschiedenen Bodenbedeckungsvarianten
Table 2
a) Basic statistics of soil surface temperature register from October 31 to November 4, 2014; b) Data obtained from the soil surface thermograms of the different soil cover treatments, recorded at 10:00 a.m. and 2:00 p.m. of October 31, 2014 (see Figure 7)
Table 2. a) Grundlegende Statistiken der Temperaturdaten vom 31. Oktober 2014 bis zum 4. November 2014, 8:00 Uhr; b) Daten der Thermogramme der Bodenoberfläche der verschiedenen Bodenbedeckungsvarianten, aufgenommen vom 31. Oktober 2014, 10:00 Uhr, bis zum 4. November 2014, 8:00 Uhr (vgl. Abbildung 7)
| a) | |||||||
|---|---|---|---|---|---|---|---|
| Soil cover treatment | Mulch density (t ha−1) | Temperature (°C) | |||||
| Mean | Mode | Median | Max. | Min. | S.D. | ||
| Bare soil | 0 | 30.4 | 24.0 | 24.6 | 53.1 | 18.4 | 10.2 |
| 2 | 31.1 | 25.3 | 27.7 | 52.0 | 23.0 | 7.3 | |
| Elephant grass straw | 4 | 28.2 | 34.4 | 25.7 | 41.4 | 21.0 | 5.7 |
| 8 | 28.2 | 29.9 | 27.5 | 35.9 | 24.2 | 2.7 | |
| 2 | 29.0 | 32.5 | 27.6 | 39.5 | 24.0 | 3.9 | |
| Cashew tree leaves | 4 | 28.1 | 29.2 | 27.3 | 34.0 | 25.0 | 2.1 |
| 8 | 28.3 | 30.6 | 28.1 | 36.2 | 24.6 | 2.8 | |
| 2 | 30.0 | 23.1 | 26.8 | 47.2 | 23.1 | 5.9 | |
| Coconut powder (coir dust) | 4 | 28.2 | 23.1 | 25.6 | 43.0 | 22.4 | 4.5 |
| 8 | 26.4 | 24.6 | 24.6 | 33.0 | 22.9 | 2.6 | |
| Max stands for maximum. Min stands for minimum. S.D. stands for standard deviation. | |||||||
| b) | ||||||
|---|---|---|---|---|---|---|
| Soil cover treatment | Mulch density (t ha−1) | Temperature (°C) | ||||
| 10:00 a.m. | 2:00 p.m. | T14:00−T10:00 | ||||
| T10:00 | TM-TBS | T14:00 | TM-TBS | |||
| Bare soil | 37.9 | 54.1 | 16.2 | |||
| Elephant grass straw | 2 | 32.6 | −5.3 | 40.2 | −13.9 | 7.6 |
| 4 | 29.4 | −8.5 | 37.2 | −16.9 | 7.8 | |
| 8 | 28.9 | −9.0 | 33.5 | −20.6 | 4.6 | |
| Cashew tree leaves | 2 | 28.0 | −9.9 | 33.7 | −20.4 | 5.7 |
| 4 | 29.6 | −8.3 | 33.0 | −21.1 | 3.4 | |
| 8 | 29.2 | −8.7 | 31.3 | −22.8 | 2.1 | |
| Coconut powder (coir dust) | 2 | 28.2 | −9.7 | 31.3 | −22.8 | 3.1 |
| 4 | 28.6 | −9.3 | 29.9 | −24.2 | 1.3 | |
| 8 | 27.8 | −10.1 | 29.4 | −24.7 | 1.6 | |
| T10:00 stands for temperature at 10:00 a.m. T14:00 stands for temperature at 14:00 p.m. TM stands for temperature of mulching treatment. TBS stands for temperature of bare soil. | ||||||
Figure 7
Thermograms of the soil surface for the different soil cover treatments, recorded at 10:00 a.m. and 2:00 p.m. of October 31, 2014.
Abbildung 7. Thermogramme der Bodenoberfläche der verschiedenen Bodenbedeckungsvarianten, aufgenommen vom 31. Oktober 2014, 10:00 Uhr, bis zum 4. November 2014, 8:00 Uhr.
Figure 8
Daily fluctuations of the difference between the soil surface temperature of mulching treatments (TMS) and bare soil (TBS). Thermal data (spatially averaged) obtained from the thermograms recorded with the infrared camera.
Abbildung 8. Die täglichen Schwankungen der Differenz von der Oberflächentemperatur der Mulchvarianten (TMS) und des nackten Bodens (TBS). Die Daten der Thermogramme wurden mittels Infrarotkamera aufgenommen.