. Productive soils; the fundamentals of successful soil management and profitable crop production. Soils. 188 NITROGEN, PHOSPHORUS AND POTASSIUM added to it. It is a soil condition that good soil management maintains and poor management destroys. ^'Helpful soil organ- isms'^ perpetuate themselves, and they remain in the soil so long as the farmer maintains soil conditions favorable to them. But as regards the ^'plant-food elements/' a virgin soil may become depleted, and crops consequently fail. Moreover, some soils are unproductive because they especially lack some one essential element (Chap
. Productive soils; the fundamentals of successful soil management and profitable crop production. Soils. 188 NITROGEN, PHOSPHORUS AND POTASSIUM added to it. It is a soil condition that good soil management maintains and poor management destroys. ^'Helpful soil organ- isms'^ perpetuate themselves, and they remain in the soil so long as the farmer maintains soil conditions favorable to them. But as regards the ^'plant-food elements/' a virgin soil may become depleted, and crops consequently fail. Moreover, some soils are unproductive because they especially lack some one essential element (Chapter VI). The only way to restore a depleted supply. Fig. 124.—Sixty-four bushels of potatoes for nine dollars. When a necessary fertilizer was added to this soil a 64 per cent increase in yield was obtained. of elements, or to nullify the effect of a lack of any one or two ele- ments, is to add plant-food material to the land (Fig. 124). It is entirely possible for the farmer to add fertilizing elements to the soil, and to maintain in''the soil a sufficient available supply, so that his efforts concerning moisture conservation, aeration, tillage, etc., shall not be in vain. Compare Figures 125 and 126. Of the elements essential to plant growth, four are much dis- cussed in relation to crop production, viz., nitrogen, phosphorus, potassium, and calcium (lime).^ Since the liming of soils is so 1 Commonly, the word '4ime" is used instead of calcium, though it is the oxide of calcium (CaO).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Weir, Wilbert Walter, 1882-. Philadelphia London, J. B. Lippincott company
Size: 1815px × 1376px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectsoils, bookyear1920
