82 CALCAREOUS MANURES-PRACTICE. 



CHAPTER IV. 



THE EFFECTS OF CALCAREOUS MANURES ON ACID SOILS REDUCED BY CULTIVATION. 



Proposition 5 — continued. 



My use of marl has been more extensive on impoverished acid 

 soils than on all other kinds, and has never failed to produce striking im- 

 provement. Yet it has unfortunately happened that the two experiments 

 made on such land with most care, and on which I relied mainly for evi- 

 dence of the durable and increasing benefit from this manure, have had 

 their effects almost destroyed by the applications having been made too 

 heavy. These experiments, like the 4th and 6th, already reported, were 

 designed to remain without any subsequent alteration, so that the measure- 

 ment of their products, once in every succeeding rotation, might exhibit 

 the progress of improvement under all the different circumstances. As 

 no danger was then feared from such a course, marl was applied heavily, 

 that no future addition might be required ; and for this reason, I have to 

 report my greatest disappointments exactly in those cases where the most 

 evident success and increasing benefits had been expected. However, 

 these failures will be stated fairly, and as fully as the most successful re- 

 sults; and they may at least serve to warn from the danger of error, if 

 •not to show the greatest profits of judicious marling. 



It should be observed that the general rotation of crops pursued on the 

 farm, on all land not recently cleared, was that of four shifts, (corn, wheat, 

 and then the land two years at rest and not grazed,) though some excep- 

 tions to this course may be remarked in some of the experiments to be stated. 



Experiment 8. 



Of a poor sandy acid loam, seven acres were marled at the rate of only 

 ninety bushels (37 per cent.) to the acre ; laid on and spread early in 1819. 



Results, 1819. In corn — the benefit too small to be generally perceptible, 

 but could be plainly distinguished along part of the outline, by comparing 

 with the part not marled. 



1820. Wheat — the effect something better — and continued to be visible 

 on the weeds following, until the whole was more heavily marled in 1823. 



Experiment 9. 



In the same field, on soil as poor and more sandy than the last described, 

 four acres were marled at one hundred and eighty bushels, (37 per cent.) 

 March 1818. A part of the same was also covered heavily with rotted barn- 

 yard manure, which also extended through similar land not marled. This 

 furnished for observation, land marled only — manured only — marled and 

 manured — and some without either. The whole space, and more adjoin- 

 ing, had been heavily manured five or six years before by summer cow- 

 pens, and stable litter— of which no appearance remained after two years. 



Results, 1819. In corn. The improvement from marl very evident — but 

 not to be distinguished on the part covered also by manure, the effect of 

 the latter so far exceeding that of the marl as to conceal it. 



1820. In wheat. Jn 1821 and 1822, at rest. 



1823. In corn— r>A by -i^ feet. The followin.g moasurements were made 



