Chapter 19

Gypsum 462 Mode in which gypsum acts 462 Salt 465 Antiquity of the use of salt 465 Nature of its action 465 Salt not a necessary plant-food 466 Can soda replace potash? 466 Salt of universal occurrence 467 Special sources of salt 468 The action of salt 468 Mechanical action on soils 470 Solvent action 470 Best used in small quantities along with manures 472 Affects quality of crop 472 Rate of application 473