. Productive soils; the fundamentals of successful soil management and profitable crop production. Soils. CHAPTER XII . NITROGEN, PHOSPHORUS AND POTASSIUM IN RELATION TO SOIL FERTILITY An Important Controllable Factor.—^'Sufficient available plant-food elements'' is a fifth positive factor determining soil fertility (Chapter VII). The maintenance of fertility may be. Fig. 123.—Feed the soil and you feed the crop. When this peat soil was supplied with the necessary elements of plant food this splendid crop of corn was the result. accomplished in a large measure by maintaining in the soil a good
. Productive soils; the fundamentals of successful soil management and profitable crop production. Soils. CHAPTER XII . NITROGEN, PHOSPHORUS AND POTASSIUM IN RELATION TO SOIL FERTILITY An Important Controllable Factor.—^'Sufficient available plant-food elements'' is a fifth positive factor determining soil fertility (Chapter VII). The maintenance of fertility may be. Fig. 123.—Feed the soil and you feed the crop. When this peat soil was supplied with the necessary elements of plant food this splendid crop of corn was the result. accomplished in a large measure by maintaining in the soil a good available supply of the important elements (Fig. 123). ^ Outside the irrigated sections the source of ''water'' is the rain- fall; thus, so far as the farmer is concerned, the water problem is mainly a question of conserving and controlling this moisture for crop use. As regards " air,'' it is free and abundant—and the supply of carbon dioxide contained in it remains practically the same. With drainage and good tillage a lack of air in the soil need never be a cause, either directly or indirectly, of low yields. ''Good tilth" can neither be bought nor sold, leached out of the soil or 187. 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
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectsoils, bookyear1920
