2001 August 14, Tuesday. 45 kilometers North of Julia Creek.
Today, the Gulf Savannah Grassland, we have been passing through sunk away into a flood plain. At present the sand is dry as any country we have seen thus far, and tufted grass grows evenly throughout the broad plain. Clues to the activity in the area lie in the pockmarked texture of the earth, made from cattle hooves at a time when the ground was shallowly submerged for some months during the wet season.
Such a change in water levels compared to the surrounding area has the potential to improve soil content, by encouraging the production of organic matter, which decomposes into valuable soil. However, as long as the climate remains as harsh as it is, with extreme wet summers and scorching winters, vegetation cannot thrive. Tall shade trees are unable to grow because their roots would be rotted out in their first wet season. Accordingly, neither will the shrubs and smaller plants which thrive in the shelter they offer.
If soil from the plain was taken to a moderate climate, lush plants could be grown in it. With conditions as they are, tough brown grass is intercepted only by stunted, prickly shrubs – on average less than ten per kilometre. Because of the sandy top to the ground, it dries out quickly, and herbaceous plants which might grow as the wet receded, would be parched to dust, leaving no trace after the first week of heat.
What do plants need water, earth, and light for? What can happen to a plant or tree which has too much of each of these?