214 DURATION OF ORGANIC MANURES, 



course of long time it might be very considerable, or possibly (as 

 asserted by other authority) nearly complete. 



3. According, then/ to the condition of excess of either of the 

 parts necessary for the fertilizing combination above stated, either 

 the organic matter or the lime in soil might be wasting, and the 

 other part for the time remain fixed, and safe from diminution 

 always excepting the portion, large or small, taken up by and re- 

 moved in the crops. 



If I have 'succeeded in establishing the foregoing views of the 

 permanent operation of calcareous manures, it will involve the 

 strong probability, if not certainty, of another result, to which 

 assent would be still more difficult to obtain, without good reasons 

 being shown. 



Though probably all observing and practical farmers would be 

 ready to admit the proposition, that the natural and peculiar quali- 

 ties of good soils, including their measure of productive power, are 

 permanent, (which is but stating, in other words, that the good effects 

 of calcareous manures are permanent), still perhaps few would 

 grant the possibility of permanency of effect to putrescent manures 

 also, when added thereafter. Yet this latter proposition is as legi- 

 timate a deduction from the former, as the former proposition is 

 from the theory which has been maintained of the action of calca- 

 reous manures. The attention of the reader is requested to the 

 argument which will now be offered to sustain this important de- 

 duction. 



"We have all been trained to consider farm-yard and stable-ma- 

 nures, dung, and all vegetable and other putrescent matters, when 

 applied to soils, as having temporary effects only ; and whether the 

 effects lasted for but the first crop, as on acid sandy soils, or for 

 four, six, or even eight years on well constituted natural soils, still 

 the effects were truly, as usually considered, only for a limited 

 time, and would at some period be totally lost ; and the ground so 

 manured would return to the same state of less productiveness, as 

 of the surrounding land, previously equal, and which had received 

 no such manuring. Such views are almost universal ; and the ut- 

 most that would be claimed by the most zealous and sanguine ad- 

 vocate for extending the effect of such manures, would be a protracted 

 though still limited and temporary duration of action. And the 

 actual results would always accord with these opinions, (and also 

 with my theory of the action of calcareous manures), both on good 

 and on bad soils, before making them more calcareous. All natural 

 soils (not excessively and injuriously calcareous) have secured by 

 their natural powers and facilities, and have had fixed in them, as 

 much alimentary or organic matter as their natural ingredient of 

 lime could combine with. If that ingredient had been very small, 

 the soil would be poor; if- large ; and not so large as to be hurtful, 



