226 AGRICULTURAL REPORT. [1T428, 429, 430 



428. Stimulant Action of Ammonia. — Beyond this, however, ammonia pos- 

 sesses in an eminent degree, the property of stimulating soils, or, in other 

 words, of rendering available to plants in a short space of time, a large supply of 

 mineral nourishment. Not only is it powerfully active in the process of decom- 

 position of rocks, in a manner analogous to carbonic acid ; but it (or rather its 

 sa lt s — combinations with acids; H361, — also possesses the property of dissolv- 

 ing a number of substances insoluble in either pure water or carbonic acid, 

 thus rendering them immediately available to plants. 



Ammoniacal salts, when applied by themselves, are therefore highly exhaust- 

 ive of the soil, though, for the time being, they may enable it to produce heavy 

 crops. On the other hand, when applied at the same time with other, true 

 manures, ammoniacal salts are to be highly recommended, as rendering the 

 manure most rapidly effective. 



429. Leaf- Producing Powers of Ammonia. — Experience seems to prove, that 

 as a general thing, the presence of an abundant supply of ammonia in the soil 

 is pre-eminently favorable to the development of the leafy portion of plants, 

 and is, therefore, particularly beneficial and important during the period prior 

 to bloom and fructification, in which the development of the leaf and stalk takes 

 place. An abundant supply of ammoniacal manure in the early stages of veg- 

 etation, is calculated to insure a good and vigorous "stand ;" while on the other 

 hand, an over-supply at a later period, may retard blooming and fructification, 

 and cause the plant to "run to weed." It is highly probable that the tendency 

 of cotton to " run to weed " in newly cleared bottom land very rich in vegetable 

 mould, is due to this cause in part at least £n 447). It is well known that 

 the most decidedly favorable effect is produced by this class of manures, on 

 those crops whose surface of leaf is comparatively small — such as wheat, and the 

 cereals generally ; while their effect is less noticeable with plants naturally very 

 leafy, which possess a large surface for the absorption, from the atmosphere, of 

 the ammonia they require. In coincidence with this rule, we observe that the 

 same land which causes cotton to "run to weed," will produce the most abund- 

 ant crops of corn. — It appears likewise, that an abundant supply of ammonia is 

 not favorable to the development of bulbs and tubers, such as the turnip, for 

 instance; and it will be observed that the sweet potato, likewise, prefers sandy 

 soils, poor in vegetable matter and ammonia. In rich, black bottom soils, espe- 

 cially when they are heavy, a great deal of leaf is formed, but the patotoes are 

 small and wiry. 



430. Peruvian Quano. — I may as well mention here, Peruvian Guano, con- 

 cerning which there has been a good deal of discussion among agriculturists, 

 as to whether it is to be regarded as a mere stimulant, or as a true manure. 

 Some of these differences of opinion have undoubtedly been owing to variations 

 in the material employed ; for the greater part, however, they are probably 

 attributable to different conditions of the land to which it was applied. 



It must be remembered that whenever the soil contains a sufficient quantity 

 (in an available condition) of any nutritive ingredient, for the wants of the 

 present crop, that crop cannot in any way be benefitted by the further addition 

 of the same ingredient. The surplus will simply remain idle, until, perhaps, 

 called for by the succeeding crop. 



Peruvian Guano contans chiefly ammoniacal salts, and the phosphates of lime 

 and magnesia ; also small quantities of soda and potash, sulphuric acid, etc. 

 As it is not generally employed in very large quantities, the amount of the latter 

 ingredients which it brings into the soil, will not generally exercise a very per- 

 ceptible influence, if a soil is in tolerable condition, for the reasons above given ; 

 its chief action will be stimulant, due to the ammoniacal salts, which cause a 

 rapid assimulation of nutritive ingredients by the plant, while the re^tof the 

 ingredients will remain comparatively inert. Should the soil, however, have 

 been in want of phosphates, the guano will serve still another purpose, and the 

 difference between the land thus manured and that which has received nothing, 



