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Manitoba from the Air
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Agriculture Near a Large Slough in Southwest Manitoba

This large-scale colour infrared photo shows the whole of one section fringed by parts of other sections to north, south, east, and west. A light-coloured north/south gravel road 1 can be seen in the east with another gravel road leading off to the east 2. In the northwest another gravel road 3 leads to a group of farm buildings 4 protected by thick shelterbelts of deciduous trees to the north 5 and west 6.

Much of the western centre is occupied by a large slough 7. Water that reflects little infrared radiation appears black, but in the south are red swirls 8 caused by algae growth at, or close to, the water surface. A patch of more dense vegetation is seen in the west 9. A road crosses the western end of the slough 10, but by the time the photo was taken it was little used, indicated by pink vegetation on its surface. The slough is ringed by emergent vegetation 11—marshes and willows (Salix spp), the latter having a mottled texture 12. In the east several hummocks casting rounded shadows 13 are muskrat dens. Light-toned linear areas back from the shore 14 are salt deposits resulting from evaporation. In this hot dry windswept area, shelterbelts have been planted between fields, especially in the south 15.

For ease of identification letters designate individual fields:

a)     this is a large field with a pink colour characteristic of canola. A central lighter area 16 may be the result of a delay of a few days when seeding.[i]

b) and c) these fields are fallow with considerable weed growth; rounded patches of weeds 17 are located south of field c).

d)      the crop growing in this field has been cut along the edges 18.

e)     the distinctive pattern in this field indicates that a crop has been cut.

f)      the bright red of this field indicates a healthy crop, some of which has been cut in the south 19.

g)     the dark green of this field indicates fallow with red vegetation existing along drainage rills 20 leading to the slough.

h) and i) both fields support a healthy crop with dark-toned patches indicating some form of stress 21.

j)      this large field supports a very variable crop; the light-coloured linear area 22 that extends into field g) may indicate a former shoreline of the slough.

Fields in the section to the south are separated by north/south field shelterbelts of deciduous trees 23.


[i] Information from Jack McKinnon, Prairie Agri photo, Carman

Figure 14.28

Agriculture Near a Large Slough in Southwest Manitoba