FERTILIZERS. 261 



II. Fertilizers of the vegetable kingdom. 



There are two classes of fertilizers, one derived from the vegetable, the other from the animal 

 kingdom. The organic fertilizers, however, are often of a mixed kind : barnyard manures, for 

 example, consist mainly of vegetable matter, the straw and hay, intermixed with a small quan- 

 tity of animal matter. The excrementitious matters of some animals may, indeed, be regarded as 

 purely of animal origin, as guano, inasmuch as the birds fed entirely upon fish. Some fertilizers, 

 again, are purely of vegetable origin, as sea plants, peat, and all decomposing vegetables. 



8. Green Crops, etc. 



As a general thing, vegetable matters are not active fertilizers, and yet they are efficient, and 

 may be relied upon. Those which may first be considered are green crops, consisting of the 

 immature or unripe vegetables, as buckwheat and clover in blossom. When in this state, and 

 . ploughed under, the plant decomposes, or decays gradually, and furnishes a supply of nutriment 

 for a lengthened period. Many advantages arise from the use of green crops : the matters of 

 the soil are brought up from a depth to which the roots penetrate — and they are of that kind, 

 and in the proportion which vegetables require ; they are intermixed with the soil more evenly, 

 and hence become more accessible to the growing plant ; there is, too, less expense attending the 

 care of green crops, especially where the field is distant from the homestead. There is no ad- 

 dition to the soil of the expensive fertilizers, as the phosphates and alkalies ; these are only brought 

 within the reach of the succeeding crop. When clover is the crop selected, it is maintained that it 

 takes from the atmosphere important elements, which become a clear gain to the soil and succeed- 

 ing crop. Turf, when turned over, furnishes, in part, the same elements as clover and buckwheat. 

 One of the results of ploughing in green crops is to improve the mechanical condition of the soil. 



Questions have arisen as to the time when these crops should be ploughed in, and a difference 

 of opinion exists upon the subject : probably these differences are not very important, and as 

 to time much will depend upon circumstances j convenience has to be consulted. Many light 

 soils have been reclaimed by the aid of clover, and no doubt soils so light as to have been aban- 

 doned and thrown out to commons, may, by clover and plaster, be brought back to a fertile 

 condition, with less expense of time and money than by any other means. 



Another question, in regard to clover, has been agitated, namely, whether it should be fed 

 oflF by cattle or mowed before it is turned under. It seems to me that it turns entirely on great- 

 ness of the crop ; if it is very heavy it should first be mown : the roots in such a case are large, 

 and will supply all the necessary nutriment to the succeeding crop. Where the whole plant is 

 turned under, if the herbage is large, its course of decomposition is irregular, and it becomes 

 infested with mould, which is never congenial to wheat. It is to be remembered that the use 

 of green crops for manures does not do away with the necessity of supplying, at the proper 

 time, inorganic matters, in some form or other. There is a great liability to commit an error 

 here, especially in New-York, where wheat lands have great power of endurance. The error, 

 it is true, may not become very serious, unless persevered in : it may be theoretical ; reflection 

 will lead to the correction of the error. 



