Ontario Teachers' Manuals: Nature Study Part 47

5. Early and late sowing: Three plots are required. Plant the same amount of seed in each and cover to the same depth. Plant No. 1 as early as the soil can be made ready; No. 2, two weeks later; and No. 3, two weeks later than No. 2. Compare the quality and the yield.

6. Effect of sowing clover with grain the first year: Only two plots are required. Sow the same amount of wheat or oats on each plot. On one plot put a moderate supply of red clover and none on the other. Weigh (or estimate), as in Experiment 3 above, the straw and the grain produced on each.

7. Effect of a clover crop on the grain crop succeeding it the following year: The same two plots must be used as in No. 6. When the grain was cut the previous autumn, the plots should have been left standing without cultivation until spring. When the clover has made some growth, spade it down and prepare the other plot in the same way. Rake them level and sow the same amount of grain in each again. Weigh the crops produced on each.

8. Test quality, yield, and time of maturity of several varieties of the same species. Samples of such varieties of wheat as Red Fife, White Fife, Preston, Turkey Red, Dawson's Golden Chaff, White Russian, etc., may be obtained from the Central Experimental Farm at Ottawa, if not available in the district.

9. Effect of different fertilizers (1) on the same crop, (2) on different crops: This can be done either out-of-doors in small plots or indoors, using pots or boxes.

(1) Effect on the same crop: For example, oats on plots four feet square. The following standard fertilizers may be used: stable manure, nitrate of soda, muriate of potash, and bone meal.

On plot No. 1, a dressing of stable manure,

On plot No. 2, four oz. nitrate of soda,

On plot No. 3, four oz. muriate of potash,

On plot No. 4, eight oz. bone meal,

On plot No. 5, two oz. nitrate of soda, two oz. muriate of potash, and four oz. bone meal.

On plot No. 6, use no fertilizer. Record results.

(2) Effect on different crops: Try a series of experiments similar to the above, using (a) peas instead of oats, (b) using corn, (c) using cabbage, (d) using potatoes.

FUNCTION OF PARTS OF PLANTS

This may be introduced in Form III and continued in the next Form.

Already the attention of the pupils has been directed to the essential organs of the flower, namely, stamens and pistil. They have noticed the two kinds of flowers on pumpkins, corn, and many trees. They have seen that only the pistillate flowers produce fruit and seeds, and that when the staminate flowers have shed their pollen, they die. They have seen the yellow dust that the stamens contain and have seen bees laden with it as they emerge from the heart of the flower. Have them watch the bee as it enters the flower and notice how it invariably rubs some part of its pollen-covered body against the pistil. When on the moist, sticky top of the pistil, these little pollen-grains soon begin to grow, sending a delicate tube down to the bottom of the pistil to the ovary.

Inside the ovary are little bodies called the ovules that are moistened by a fluid that comes from this delicate pollen tube, and at once they begin to enlarge and eventually become the seeds. The coverings surrounding them complete the true fruit.

The use of the root in supporting the plant in its normal position is apparent to every pupil. To demonstrate the firm hold it has upon the soil, have the pupils try to pull up some large plants by the roots.

They will then notice the branching roots of some plants and the long conical roots of others. Compare the colour and other surface features of the root and stem. To prove its feeding power, try two plants of equal size, taking the root off one and leaving it uninjured in the other. Set them side by side in moist earth and notice which withers.

Take all the leaves off a plant and keep them off for a few weeks. The plant dies if its leaves are not allowed to grow. Keep it in the dark for a long time, and it finally dies even when water and soil are supplied. The leaves, therefore, are essential and require sunlight in doing their work. Their complete work will be considered later.

HOW THE PLANT GETS ITS FOOD FROM THE SOIL

When seeds germinate, the lower end of the caulicle, which becomes the root, bears large numbers of root-hairs. Inside the root-hairs is protoplasm and cell sap. These root-hairs grow among the soil particles which lie covered over with a thin film of moisture. It is this moisture that is taken up by these root-hairs, and in it is a small amount of mineral matter in solution which helps to sustain the plant. The transmission of soil water through the delicate cell walls of these root-hairs is known as _osmosis_.

GERMINATION OF SOME OF THE COMMON GRAINS

Make a special study of corn, wheat, and buckwheat. Take three plates and put moist sand in each to a depth of about half an inch. Spread over this a piece of damp cloth. Put in No. 1, one hundred grains of corn; in No. 2, the same number of grains of wheat; and in No. 3, the same number of grains of buckwheat, peas, or beans. Cover each plate with another piece of damp cloth and invert another plate over each to prevent drying out. Keep in a warm room and do not allow the cloths to become dry. If one of the cloths be left hanging six or eight inches over the side of the plate and dipping into a dish of water, the whole cloth will be kept moist by capillarity. Note the following points:

1. Changes in the size of the seeds during the first twenty-four hours.

2. In which variety germination seems most rapid.

3. The percentage vitality, that is, the number of seeds which germinate out of one hundred.

4. The nature of the coverings and their use. (Protection to the parts inside)

5. The parts of the seed inside. (Buckwheat, pea, or bean divides into two parts, which become greenish and are called seed leaves. Wheat and corn do not divide thus.)

6. The first signs of growth. A little shoot or tiny plant begins to develop at one end of the seed. Note which end bears this tiny plant.

7. Note the development of this embryo plant and the formation of stem and root.

8. Of what use is the bulky part of the seed? To answer this, let the pupils separate the white part of a kernel of corn, which is attached to the embryo plant, from the pulpy ma.s.s surrounding it. Set five such plants in moist sand and also five germinating seeds not so dissected.

Pupils will discover that the ma.s.s surrounding the embryo is for the nouris.h.i.+ng of the embryo plant. It is a little store of food prepared by the mother plant for the little ones that grow from the seeds. Note that it disappears as the plant grows.

To further show the great value of this stored plant food, put a large-sized pea in a pot of moist moss or sawdust for a few days. When it has germinated and its root is a couple of inches long, place the pea in a thistle tube or small funnel, with the root projecting down the tube into a gla.s.s of water in which the funnel tube rests. Place all in a sunny window and note how much growth the plant is able to make without any food except that which the seed contained.

9. Note the development of the root and root-hairs. It is by means of these root-hairs that the plant absorbs moisture. The branching form of the root gives greater support to the plant and increased area for absorption of water by means of root-hairs.

To show the direction taken by the root and also by the shoot, take a gla.s.s jar with straight sides like a battery jar (a large fruit jar will do); line it inside with a layer of blotting-paper and then fill it with moist sawdust. Drop seeds of sunflower or squash down between the paper and the gla.s.s. The moisture from the blotting-paper will cause them to sprout, the shoot or stem always taking an upward direction and the root turning downward quite regardless of the position in which the seeds were placed.

10. Apply this study to seed planting: Plant seeds of wheat in four pots of soil, No. 1, half an inch deep; No. 2, two inches; No. 3, four inches; No. 4, six inches. Repeat this experiment, using buckwheat. What seeds are up first? What seeds last? Which are best after a week? After three or four weeks? From this experiment could you recommend a certain depth for the planting of wheat and buckwheat?

11. Does the kind of soil make any difference? To answer this have different pupils choose different soils, such as (1) coa.r.s.e sand, (2) fine sand, (3) wet clay, (4) humus or leaf mould, (5) mixed soil or loam; and let each put in grains of wheat, two inches deep.

Allow five other pupils to plant seeds of buckwheat, under similar conditions. Treat all pots alike as to time of watering and quant.i.ty of water used on each and give them all equal light and heat. Note which come up first. Which are highest in one week, in two weeks, in four weeks?

12. This study may be continued in the garden by planting one plot each of corn, wheat, and buckwheat. Plots ten feet by twenty feet are large enough. Observe the rate of development in the plots. Which seems to mature most quickly? Which blossoms first? In what respect are the leaves of these plants alike or unlike? How do the stems differ?

Examine the blossoming and seed formation. When the grains are ripe, collect a hundred of the best looking and most compact heads of each grain and also a hundred of the smallest heads of each. Dry, sh.e.l.l, and store the two samples of each grain in separate bottles. These samples are for planting the following spring.

13. To show the need of moisture in germination: Fill two flower-pots or cans with dry sand; put seeds of sunflower in each, covering them an inch deep. Put water in one pot and none in the other. Examine both pots after two or three days.

14. To show that heat is needed for germination of seeds: Plant sunflower seeds in two pots as above; place one in a warm room and the other in a cold room or refrigerator; water both and observe result in three days.

15. To show that air is necessary for germination: Fill a pint sealer with hydrogen (the gas collected over water in the usual way, as shown in any Chemistry text-book). Put a few sunflower seeds in a small sponge or wrap them loosely in a piece of soft cloth. Keeping the mouth of the jar which has been inverted over water and filled with hydrogen, under the surface of the water, introduce the sponge containing the seeds, by putting it under the water and pus.h.i.+ng it up into the jar. Seal the jar without letting the gas get out. Put some seeds in another jar in a wet sponge and leave the jar uncovered. Compare results after several days.

Here is a second experiment to prove this. Boil some water in a beaker in order to drive out all the air, put a few grains of rice in the water, and then add enough oil to make a thin covering on the water.

This covering will prevent air from mixing with the water again. Put some rice in a second beaker without boiling or adding the oil. Leave the beakers side by side in a warm room for a week. The seeds will not germinate in the boiled water. It is not always easy to get rice that will germinate, but when it has been procured, the experiment is easy and very interesting. Any other seeds, such as those of pond lily and eel-gra.s.s, that germinate readily under water, will do as well as rice.

WEEDS

Pupils in this Form should learn to identify a large number of weeds and weed seeds. The collecting and mounting of weeds and weed seeds the previous summer and autumn will have helped to prepare them for this work. In the spring, when flower and vegetable seeds are coming up in the garden, it is often difficult for pupils to distinguish the weeds from the useful plants. To help in this work of distinguis.h.i.+ng the good from the bad, the teacher should arrange for a plot having, say, ten rows, one row for each variety of weed selected. Each row should be designated by a number instead of a name. The identification of these growing weeds by name may be given as a problem to the pupils. This plot should remain until the pupils have observed the manner of growth of each variety, the blossoming and seed formation, and then the root growth, as they are being uprooted previous to the ripening of the seed.

Each pupil should prepare a brief description of each of the ten varieties studied, and make drawings of the plant and its parts, especially the leaf, flower, seed, and root. They should learn the best methods of eradication and add these in their notes. _Farm Weeds_ will be of great value in such weed studies.

VINES

Suitable garden vines for study are climbing nasturtium, scarlet runner bean, and j.a.panese hop. Their growth and method of climbing should be compared with that of the sweet-pea and morning-glory already studied.

Observe particularly the kind of leaves and their arrangement, also the flowers and fruit. Observe also the gourd family--melon, cuc.u.mber, and squash--their tendency to climb, and the nature of their flowers and fruit.

WILD FLOWERS

In schools where the studies with garden plants, such as have been indicated, can be carried on, there will not be as much time for the study of wild flowers as in those schools where no garden plants are available. A definite list of wild flowers for study should be arranged by the teacher early in spring.