. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. 144 Science of Plant Life proving the chemical composition of the soil and to a less extent its physical condition. Irrigating the land where the water supply is inadequate, and imderdraining it where the soil moisture is excessive, are further means of improving soil conditions for the growth of crops. The soil requires these special attentions for the growth of domesticated plants be- cause they must not only Hve, as do wild plants, but they must, in one form or another, yield a p
. Science of plant life, a high school botany treating of the plant and its relation to the environment. Botany. 144 Science of Plant Life proving the chemical composition of the soil and to a less extent its physical condition. Irrigating the land where the water supply is inadequate, and imderdraining it where the soil moisture is excessive, are further means of improving soil conditions for the growth of crops. The soil requires these special attentions for the growth of domesticated plants be- cause they must not only Hve, as do wild plants, but they must, in one form or another, yield a profitable return. Atmospheric water. The water in the air affects plants directly in several ways. The moistness or dryness of the air determines whether less water or more is required for transpiration, and the amount of water precipitated from the air in the form of rain determines to a large extent the amount of water available in the soil. Atmospheric water condensed in the form of fog and cloud reduces transpiration and also lessens the amount of light that reaches the plant. The distribution of rainfall through the year is of the great- est importance to vegetation. When the period of heaviest rainfall coincides with the hottest part of the year, the con- ditions are best for the rapid growth of plants. If the rain-. FiG. 82. Cross sections of kernels of hard or macaroni wheat. This wheat is grown in dry regions and is valued because of its large content of protein. In the figures the flinty or high protein parts are shaded and the soft or starchy parts are white. When the wheat is grown under the conditions of dry farming, the protein content is highest {A); when regularly irrigated, the same wheat produces soft, starchy grains (C). An intermediate condition is shown by B. This exemphfies the effect of the water balance on the composition of a Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabilit
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbotany, bookyear1921
