251 



Mr. Woolley manured a piece of land in the proportion of two 

 hundred loads of good stable manure to the acre, applying upon 

 an adjacent tract of the same soil his marl in the ratio of about 

 twenty loads per acre. The crops, which were timothy and 

 clover, were much heavier upon the section which had received 

 the marl: and there was tliis additional fact greatly in favour of 

 the fossil manure over the putrescent one, that the soil was also 

 entirely free from iceeds, whWo the stable manure had rendered its 

 own crop very foul. 



This greensand stratum at Poplar Swamp seems to be almost 

 entirely free from any sulphate of iron or other astringent mate- 

 rial, and, as a consequence, the crops seem not to be scorched by 

 an extra dose, however lavishly applied. 



There can be no doubt that twenty loads of marl per acre 

 must be regarded as an unnecessarily bountiful dressing, but 

 computing the relative cost of the two manures, when employed 

 in the ratio above stated, we find a considerable disparity in fa- 

 vour of the greensand. Placing the home value of farm-yard 

 manure at one hundred cents for each two-horse load, and that of 

 the marl at twenty-five cents per load, we have the expense of 

 manuring one acre, tivo hundred dollars; of marling the same, 

 Jive dollars. 



This being an experiment, an extravagantly large dressing of 

 manure was employed, but not exceeding the usual average ap- 

 plication more than the twenty loads of marl surpassed what was 

 necessary. 



Experience has already shown that land once amply marled 

 retains its fertility with little diminution for at least ten or twelve 

 years, if care be had not to crop it loo severely; while with all 

 practicable precautions, the stable manure must be renewed at 

 least three times in that interval to maintain in the soil a corre- 

 sponding degree of vigour. 



Marl from Mr. Woolley's middle bed possesses this 



Composition. — In 100 parts : 



Greensand, ... 86 



Clay, .... 12 



Quartzose sand, - - 2 



100 



