GYPSUM, OR PLASTER OF PARIS.
The fertilizing properties of this article were discovered by a German laborer in a quarry, who observed the increased luxuriance of the grass by his path, when the dust fell from his shoes and clothes. This led to experiments which demonstrated its fertilizing power. With the protracted controversies on gypsum we have nothing to do; certain important facts are established which are valuable to agriculturists.
Gypsum is valuable as an application to the soil, at from three fourths to one and a quarter bushels to the acre. On poor land, for a flax crop three bushels per acre, applied after the plants were up, and when wet, produced a great crop. It should be applied only once in two years, or in very small quantities every year. Applied as a top-dressing, it will do no good until a considerable quantity of rain has fallen upon it. If it be applied in the spring, and the summer prove a dry one, its greatest effect will be felt the next season. Its most marked effects are on poor soils; on land already rich it seems to produce but little effect; on dry, sandy or gravelly soils, it will increase a clover crop from one fourth to two thirds; sowed among clover and immediately plowed in, it acts powerfully. Plants of large leaves feel its influence much more than those with small ones, hence its excellence on clover, potatoes, and vines. Some soils contain enough plaster already: the farmer must determine by analysis or experiment. On the compost heap it is valuable in small quantities; it is also useful on all long, coarse, or fresh manures of the previous winter. Seeds rolled in it before planting vegetate sooner and stronger. Mixed with an equal quantity of ashes and a little lime, and applied to any crop immediately after hoeing, or when just coming up, it adds materially to its growth. It is better to apply it twice—on first coming up, and immediately after first hoeing; small quantities are best;—it will ten times repay the cost and labor. Upland pastures and meadows, except clay soils, are greatly benefited by it. A time-saving method of sowing plaster on fields of grass or grain, is to sow out of a wagon driven slowly through the field, the driver being guided by his former tracks, while two men sow out of the wagon. It is customary to put plaster and ashes, mixed, around the hills of corn, or throw it upon the plants. Sown on the field of hoed or hill crops, its effects are much greater than when only put on the hill. It should be sown equally over the whole ground.