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180 QUEENSLAND AGRICULTURAL JOURNAL. [1 Ave., 1901. 
Questions on Lesson 6. 
. Are all crops grown from seed ? 
- In what other ways are crops produced? Give examples. 
How are Irish potatoes planted ? How sweet potatoes ? 
. Why should some potatoes be cut into setts ? 
. How does the potato sett help the young plant ? 
What is a tuber ? 
How does the sweet potato tuber differ from that of the Irish potato ? 
. What is meant by draining land ? 
. What soils require draining ? 
10. What does the word “ evaporation” mean ? 
11. How does draining improve clayey soils ? 
12. How may land be drained on which springs are found ? 
1 OATH AB ow 
FIRST STAGE. 
7rH Lesson. 
WHAT DRAINAGE DOES FOR THE SOIL. 
I told you in a former lesson that by means of drainage, stagnant water is 
removed from the soil. But the benefit does not stop at drying the soil. 
Stagnant water is cold, and consequently it reduces the temperature of the 
land. What results from a low temperature? The crops produced on the 
land come to maturity later than they would on a warm soil. This is a very 
important matter, because a farmer or gardener who can get his crops to market 
early in the season, always gets a higher price for them than he does when there 
is a plentiful supply in the market. bla he 
Now, by removing the cold stagnant water the temperature of the soil is 
raised, and consequently seeds placed in it germinate quicker and the plant also 
grows quicker and more vigorously. You can easily prove this by a little 
experiment. Flower pots, as you know, have a hole at the base to allow of the 
passage of water, either by passing from the surface to the bottom of the 
soil they contain or by being sucked up from the saucer through the soil 
towards the surface. By this means a proper supply of moisture is kept up, 
and air also makes its way through. But take a pot without a hole, or a jam 
tin. Fill it with soil; plant a seed or two init. Do the same with the other 
pot, or make a lot of fetes in another jam tin. Place both on saucers, and after 
sowing some sort of seed in each, water the soil. The seeds in both pots will 
germinate. As the young plants grow it will be noticed that those in the pot 
in which no holes have been made grow very slowly, and instead of exhibiting 
a healthy green, present a sickly yellowish appearance, whilst those in the other 
pot soon outstrip them and look healthy. Why is this? The water in the 
first pot is unable to get away. The plants are unable to absorb it all, and it 
lies stagnant at the bottom of the pot. The soil is thus rendered cold and stiff, 
and the rootlets cannot force their way through it, and if they do, they find 
themselves in a cold pool which causes them to sicken and renders them unable 
to supply the needful food to the plant. In the other pot, the holes in the base 
enable the superfluous water to get away, and if watering be discontrnued, that 
which is in the saucer will rise by capillary attraction, and so furnish the needful 
supply to the plants. 
The farmer must then get rid of the superfluous water on his land by 
draining it—that is, making channels by which the water can escape to a lower 
level and leave the field dry and warm. 
I have, in the 6th lesson, told you what soils require draining in order to 
get rid of water which is not wanted. 
The draining of land, however, has another effect upon the soil. 
Air can only penetrate the soil to the level of stagnant water, and, as you 
have learnt, plants require air as much as human beings do, so their roots will 
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