92 MINERAL OR ORGANIC MATTER ALONE. 



Second, When the land, in consequence of the excess of 

 organic matter of a particular kind, causes the grain to tiller 

 much, and to fall or lodge, the use of unaided mineral manures 

 is indicated. 



In practice, this tendency to straw is counteracted by taking 

 two or more corn crops in succession to bring it down by rais- 

 ing turnips with peat ashes alone, where these are easily ob- 

 tained by growing potatoes with wood ashes or with artificial 

 admixtures of saline substances or by paring and burning pre- 

 paratory to any crop. It is obvious that both skill and judg- 

 ment are required in determining when and how often any of 

 these practices ought to be resorted to, with a view not only to 

 the benefit of the crop which is immediately to follow, but also 

 to the future good of the land ; for though it may be clear that 

 one or other of these forms of treatment is the most advisable 

 for a given time, it is quite certain that a continuance of such 

 procedure will by-and-by that is, in proportion as the organic 

 matter becomes exhausted both diminish the crops and injure 

 the land. 



c I merely mention, as a third result of observation, that, on 

 many soils, organic matter alone or, generally, substances rich 

 in nitrogen applied alone succeed well, and, without any ad- 

 mixture of mineral matter, add largely to the crops the land is 

 made to produce. The reason of this is, in most cases, exactly 

 the converse of that to which I last adverted. The soil being 

 more or less rich in mineral and poor in organic matter of the 

 proper kind, is most grateful for an addition of the latter, and 

 for a time returns large profits upon every application of it. 



6. Why saline substances are not always useful in inverse pro- 

 portion to the quantity of them contained in the soil f 



But the general rule above stated, (2,) that a substance 

 is productive of benefit when applied to the land in inverse pro- 

 portion to the quantity of the same substance already existing 

 in the land, is susceptible of modifications of much importance, 

 and which must be kept constantly in mind if we are to be able 

 to explain the many appearances which, in ordinary farming, 

 and especially in the kind of field experimenting we are now 



