EFFECTS ON ACID CLAY SOIL. 129 



born soil at best is very unfit for the corn crop ; and its highest 

 value is found under clover, and in wheat on clover, of which some 

 proofs will be found in the next experiment. The first crop of 

 clover, however, after marling, has not since been equalled. 1835.] 

 [My subsequent distant residence prevented my observing this 

 field when under any matured crop, until in 1842, when in wheat. 

 The then growth on the unmarled space was certainly not more than 

 one-fourth as much as that of the surrounding ground. 1842.] 



Experiment 7. 



Another piece of land of twenty-five acres, of soil and qualities 

 similar to the last described (Exp. 5 and 6), was cleared in 1818, 

 and about 6 acres marled in 1819, at about three hundred and fifty 

 bushels. The course of cultivation was as follows : 



1820. Corn benefit from marl very unequal supposed to vary 

 between twenty-five and eighty per cent. 



1821. Wheat the benefit derived greater. 



1822. At rest. 



1823. Ploughed early for corn, but not planted. The whole 

 marled at the rate of six hundred bushels (40 per cent.), again 

 ploughed in August, and sown in wheat in October. The old 

 marled space more lightly covered, so as to make the whole nearly 

 equal. 



1824. The wheat much improved. 

 1825 and 1826, at rest. 



1827. Corn. 



1828. In wheat, and sown in clover. 



1829. The crop of clover was heavier than any I had ever seen 

 in this part of the country, except in some very rare cases of rich 

 natural soil, where gypsum was used and acted well. The growth 

 was thick, but unequal in height (owing probably to unequal 

 spreading of the marl), standing from fifteen to twenty-four inches 

 high. The first growth was mowed for hay, and the second left to 

 manure the land. 



1830. The clover not mowed. Fallowed in August, and sowed 

 wheat in October, after a second ploughing. 



1831. The wheat was excellent, almost heavy enough to be in 

 danger of lodging. I supposed the product to be certainly twenty 

 bushels, perhaps twenty-five, to the acre. 



As it had not been designed to make any experiment on this 

 land, the progress of improvement was not observed with much 

 care. But whatever were the intermediate steps, it is certain that 

 the land, at first, was as poor as that forming the subjects of the two 

 preceding experiments in the unimproved state (the measured pro- 

 ducts of which have been given), and that its last crop was at least 

 four times as great as could have been obtained, if inarl had not 



