187 



Scientific Agricull ure. 



supplied with organic matter, its retentive power for water and fertilisers may be 

 seriously reduced on account of the destruction of the organic matter by the action 

 of too much lime. Soils may sometimes be injured by applications of impure forms 

 of lime, which harden like cement in the soil, or of those which contain an excessive 

 amount of magnesia. 



It has been shown that even upon many upland and naturally well-drained 

 soils apparently in good condition otherwise, the sourness (acidity) is so great that 

 most varieties of plants will not thrive. Lime is the most economical and effective 

 substance thus far used for correcting this condition. According to experiments 

 made by the Rhode Island Agricultural Experiment Station on acid soils in that 

 State, the plants tested may be classified with regard to their behaviour toward lime 

 as follows : Plants benefited by liming— spinach, lettuce (all kinds), beets (all kinds), 

 okra (gumbo), salsify (vegetable oyster), celery, onion, parsnip, cauliflower, cucum- 

 ber, eggplant, cantaloupe, asparagus, kohl-rabi, cabbage, dandelion, Swedish turnip, 

 pepper, peanut, English or flat turnip, upland cress (pepper grass), martynia 

 rhubarb, common pea, pumpkin, summer squash (scalloped), golden wax beau, red 

 Valentine bean, horticultural pole bean, bush Lima bean, lentil, Hubbard squash, 

 saltbush, hemp, tobacco, sorghum, alfalfa, clover (red, white, crimson, and alsike), 

 barley, emmer, wheat, oats, timothy, Kentucky bluegrass, Canada pea. Cuthbert 

 raspberry, gooseberry, currant (White Dutch), orange, quince, cherry, Bui' bank- 

 Japan plum, American linden, American elm, sweet alyssum, mignonette, nastur- 

 tium, balsam, pansy, poppy, and sweet pea ; plants but little benefited by liming— 

 Indian corn, spurry,* rye, carrot, chicory, Rhode Island bent, and redtop; plants 

 slightly injured by liming— eotton, tomato, cowpea, zinnia, phlox (Drumrnondi), 

 Concord grape, peach, apple, and pear; plants distinctly injured by liming— -lupine, 

 common sorrel (Rumex acetosella), radish, velvet bean, castor bean, flax, blackberry, 

 black-cap raspberry, cranberry, Norway spruce, and American white birch. Other 

 plants said to be injured are the chestnut, azalea, and rhododendron. 



Many kinds of lime are available for agricultural use, among which are 

 caustic or burnt lime, or quicklime, which should contain at least 90 per cent of 

 actual lime (CaO) and is the most concentrated form of this material ; gypsum, or 

 land plaster, in which the lime is in the form of the mild sulphate ; ground limestone 

 and chalk, in which the lime is in the form of the mild carbonate ; different kinds 

 of marl, containing varying proportions of sand and clay and from 5 to 95 per cent 

 of carbonate of lime ; wood ashes, which contain from 30 to 35 per cent of lime in the 

 form of carbonate ; limekiln ashes, containing about 40 per cent of lime ; and waste 

 lime from gas houses, sugar-beet factories, etc., the composition of which varies with 

 the process of manufacture. 



It is impossible to state definitely for all locations and conditions what kind 

 of lime is cheapest to use. Caustic or quick lime is the most concentrated and 

 consequently the most economical to handle. On account of its caustic properties it is 

 more vigorous in its action than the milder sulphate (gypsum) or carbonate (limestone, 

 chalk, wood ashes, marl, etc). There may be special reasons, however, why some of 

 the latter may be preferable. For instance, gypsum, on account of its peculiar 

 composition, has been found to be a specially valuable corrective of black aikali. 



The frequency with which liming should be practised depends, among other 

 things, upon the character of the soil and the rate of application, the number of 

 years involved in the rotation practised, the plants grown and their order of suc- 

 cession. As a general rule, it may be stated that from | to 1£ tons of lime per acre 

 every five or six years is sufficient. Applications of 2 or 3 tons may, however, be 



* It has been reported in England that spurry is injured by liming, but such results have not 

 been obtained in Rhode Island, 



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