AGRICULTURAL CHEMISTRY AND GEOLOGY. 161 



manure. The second, one hundred and twelve pounds of Lawes's superphosphate of lime per 

 acre, drilled in dry, and the third plot, one hundred and twelve pounds of Lawes's superphos- 

 phate of lime drilled in a liquid state. The crops were weighed October 4th. The first plot 

 yielded per acre eight tons and fifteen hundredsweight ; the second, thirteen tons and fifteen 

 hundredsweight ; and the third, seventeen tons and seven hundredsweight. In other words, 

 one hundred and twelve pounds of superphosphate per acre, drilled in dry, gave an increase 

 of five tons, and the same quantity applied in a liquid state, an increase of eight tons and 

 twelve hundredsweight per acre. The cost of the superphosphate was $1.80 per acre. This 

 is a good result, although it is usually found that superphosphate has a more marked effect 

 on turnips than on ruta bagas, and even still more than on mangel-wurzel. 



The above yield will appear small to those who are frequently reading of crops of one 

 thousand five hundred to two thousand bushels per acre. The great drought of last year, 

 doubtless, materially injured the crop, especially where no superphosphate was applied. But, 

 as the weather in England last summer approximated more closely to what it usually is in 

 this country, the experiment may be looked upon as pretty correctly indicating what would 

 be the effect of an application of good superphosphate of lime, in a dry and in a liquid state, 

 to mangel-wurzels in this climate. Albany Cultivator. 



Amount of Manure applied per Acre. 



THE following, from the Rural New Yorker, displays the minute quantity of concentrated 

 manure which falls upon a square yard of surface-soil when applied at ordinary rates : 



An acre of land contains forty-three thousand five hundred and sixty square feet, four 

 thousand eight hundred and forty square yards, or one hundred and sixty square rods. By 

 those who have used guano, it is said three hundred pounds is sufficient to manure an acre ; 

 two hundred and two pounds would give just one ounce avoirdupois to the square yard. One 

 cubic yard would give a trifle over one cubic inch to the square foot. A cubic yard of highly- 

 concentrated manure, like night-soil, would, if even and properly spread, manure an acre 

 very well. A cubic yard of long manure will weigh about one thousand four hundred 

 pounds ; a cubic foot not far from fifty pounds. A cord contains one hundred and twenty- 

 eight cubic feet ; a cord and a quarter would give about a cubic foot to the square rod. If 

 liquid manure be used, it would take one hundred and seventy barrels to give one gill to a 

 square foot upon an acre, which would bo equal to about fifty pipes or large hogsheads. It 

 would be quite useful if farmers would be a little more specific as to the amount of manure 

 applied. 



Natural Supply of Ammonia in Ordinary Soils. 



AT a recent meeting of the Royal Agricultural Society, Professor Way, in the course of 

 some remarks on the atmospheric supply of manuring or fertilizing matter, called attention 

 to the large amount of ammonia constantly taken up by the soil, and washing into the land 

 by rain, and to the great importance^ consequently, of exposing the soil in such a manner to 

 atmospheric influences as may best tend to this ammoniacal absorption. Fallowing of land, 

 he remarked, had given way to rotation of crops ; but that there was no such thing as such 

 a simple resting as fallowing was supposed to imply in this case, for an alteration of the soil 

 under the influence of oxygen was constantly going on. Every interval, even, between one 

 crop and another, was in reality a fallow. Land should be laid up as lightly as possible, for 

 the purpose of its aeration. The working of the land, with a view to this abundant aeration, 

 was one important means of improvement. He regarded it as indispensable, to the full de- 

 velopment of the powers of soil, that steam-power should be brought to bear effectively upon 

 its cultivation. The amazing bulk of ammonia locked up in the land itself could not be 

 taken up by plants, and would therefore remain in a form unavailable for vegetation, unless 

 the management of soil tended to release such manuring matter, and bring it within reach 

 of the roots. He had calculated, from data furnished by some rich loamy land of tertiary 

 drift, that the soil within available depths contained ammonia at the rate of one ton (equal 



11 



