THE FLOEAL WORLD AND GAEDEN GUIDE. 107 



beiDg compared with good artificial manure, as the average amount 

 of water in guano is only 13'09 per cent. It is evident, therefore, 

 that a manure which contains sucb high fertilizing properties with- 

 out the water, must be of very great value, inasmuch that it is so 

 portable that a large amount is saved in the single item of carting. 

 It will be evident that that manure is of the greatest value which 

 contains the largest percentage of the substance most required by 

 the crops, and which is not contained in the soil, or in only very 

 small proportions. This constituent appears to be nitrogen, it 

 having been repeatedly proved from carefully made experiments 

 that the increase in the crops has been in exact proportion to the 

 quantity of nitrogen applied in the shape of manure. jN'ow, as good 

 guano is largely composed of this substance, it is of course one of 

 the most valuai3le aids to the agriculturist. 



There are, however, other methods by which land may be manured 

 than the visible substances placed upon it by the farmer. Most 

 persons are not aware that soils are able to imbibe a vast amount 

 of manure from the atmosphere, if put in a proper condition. They 

 will absorb from the air nitrogen in the form of ammonia and nitric 

 acid, and the atmosphere itself gives to the land every year in the 

 form of rain a very large quantity of these substances. This at 

 once raises the subject of draining, for if land is clogged up with 

 water to the surface, it is unable to benefit by the valuable manures 

 which descend in the rain, which, instead of soaking through the 

 ground, is compelled to run off the surface without giving half their 

 manuring value to the crops. Again, undrained land is unable to 

 extract the manures from the air, for this process is only carried on 

 by reason of its porosity ; and therefore, if the water cannot pass 

 readily away, the ground remains full, the air is unable to pass 

 among it, and thus it is unable to derive any benefit from it. 



This power possessed by soil of manuring itself from the air 

 constitutes the real value of fallowing, and this has caused the 

 introduction of mistaken theories, among which may be classed 

 Jethro Tull's plan. This agriculturist had got hold of an idea, 

 which was, that he could, by continually pulverizing the soil, render 

 the particles so fine that they would pass through the pores of the 

 roots and enter into the structure of the plant, and thus do away 

 •with the necessity of manuring. It is not necessary to point out 

 here the absurdity of such a notion, as every one knows that the 

 substances extracted by plants from the soil are in the form of fluid ; 

 but yet the practice which it gave rise to was in a great measure 

 sound. He obtained crops without manure in the sense in which it 

 is generally used, and yet not without manure in a scientific sense, 

 for he manured his land from the atmosphere. The plan he adopted 

 was to prepare the whole field by thoroughly digging and forking it. 

 The wheat was then dibbled in in rows of three together, each row 

 being one foot apart ; then a space of three feet was left without 

 anything planted in it, and then three more rows, and so on. As 

 soon as the wheat was up, the one-foot spaces between the rows 

 were forked over repeatedly with a fork about six inches wide, so 

 that it did not come nearer than three inches to the wheat, which 



