Two Iwate Climates and Two Crops
A student compares two places in Iwate Prefecture. Kamaishi, on the Sanriku coast, has a January average of 2°C and an August average of 24°C, with annual precipitation of 1,500 mm and winter snowfall of about 20 cm. Morioka, inland, has a January average of -2°C and an August average of 24°C, with annual precipitation of 1,300 mm and winter snowfall of about 200 cm. The student also has a map showing that Kamaishi sits in a narrow valley opening to the sea, while Morioka lies in the broad Kitakami basin. The class is asked to recommend which area is better for rice paddies and which for apple orchards. A classmate says, "Morioka is colder in winter, so it must have a shorter growing season." The teacher asks the class to use at least two climate variables and one landform feature, and to distinguish between what the data show and what they merely suggest.
1. Compare the two places and infer which is more suitable for rice paddies and which for apple orchards. Explain using at least two climate variables.
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Morioka is the stronger candidate for rice paddies. Its August average is the same 24°C as Kamaishi, so summer heat is not lacking, and the Kitakami basin provides broad, flat land suitable for paddies. Its lower annual precipitation, 1,300 mm against 1,500 mm, does not by itself make it drier for rice, because rice paddies depend on irrigation from rivers and snowmelt, and the basin's rivers can supply that. Kamaishi's narrow valley limits large paddies. For apples, Morioka is also plausible because apples need winter chilling and good drainage, and the basin's cold winter and snowfall fit that. But the data only suggest this: the table gives no information on soil, slope, or growing-season length. A careful answer distinguishes the strong inference, that the basin's flat land favors paddies, from the weaker inference, that cold winters automatically favor apples.
2. A classmate says, "Morioka is colder in winter, so it must have a shorter growing season." Is this reasoning complete? Explain.
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The reasoning is incomplete. A colder winter does not by itself prove a shorter growing season, because the growing season depends on spring and autumn temperatures, frost dates, and the length of the frost-free period, not only on January cold. The data show that both places have the same August average of 24°C, which suggests that summer warmth is similar. Morioka's heavy snowfall, about 200 cm against 20 cm in Kamaishi, can delay spring fieldwork by keeping the ground cold and wet, so it may shorten the usable season in practice. But that is an inference, not a direct measurement. The classmate has confused one indicator with the whole concept. To test the claim, the class would need monthly temperature data for April, May, and October, plus frost dates. The correct conclusion is that winter cold is relevant but not sufficient evidence.
3. How could a map of the Kitakami basin change your conclusion about rice?
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A map could confirm or weaken the landform argument. If the map shows wide, gently sloping plains with rivers and existing irrigation channels near Morioka, the case for rice paddies becomes much stronger, because rice needs level fields and reliable water. If it shows that the basin is narrow, fragmented by hills, or poorly supplied with water, the climate advantage would matter less. The map could also reveal flood risk: paddies need water, but fields too close to a river may be damaged in heavy rain. The student should look at contour spacing, river networks, and the distance from fields to settlements. In that way, the map tests the inference drawn from the climate table. The conclusion would change from "Morioka is probably better for rice" to a more precise statement about which parts of the basin are suitable.