

54 MANURES. 



Immense beds of astringent clay, denominated spurious 

 marl, from its pernicious effects when applied in large quanti- 

 ties to the soil, are to be found in the marl regions of New 

 Jersey. This bad effect on the soil and vegetation, is owing 

 mainly to the astringent ingredients combined with it, such as 

 copperas and alum-earth, which produce a powerful acid re- 

 action. But these pernicious qualities can be corrected, and 

 the marl or clay rendered subservient to the agriculturist in 

 the production of his crops. Professor ROGERS, in his Re- 

 port, says, that if this clay be dug several months before it is 

 to be used, and spread out in broad, shallow, flat heaps, exposed 

 to the action of the atmosphere, and where the rains may pene- 

 trate it, carrying off the copperas and alum-earth, which it is 

 known readily dissolves in water; and as the green mineral 

 does not dissolve in water, it sustains no loss in its fertilizing 

 qualities by its exposure to the rains. This clay contains a por- 

 tion of the green granular material of the true marl but the ope- 

 rator should be very careful in his experiments. A year or two 

 will be sufficient to determine its value, the time of its expo- 

 sure to the atmosphere, the best method of its preparation, and 

 the quantity and manner of its application. But the following 

 simple and effective process is to be preferred. 



Add to every heap of this spurious astringent marl, a small quantity of 

 freshly burnt lime, and mingle them thoroughly together. The sulphuric acid 

 of the copperas or alum-earth, or of both, if present, will pass over to the lime, 

 and form sulphate of lime, (gypsum or plaster,} the value of which, as a stimu- 

 lant to vegetation, is well understood; the other ingredients, the oxide of iron 

 and clay, will, oil being liberated, contribute also towards improving the tex- 

 ture of the soil should it be sandy. A bushel of lime to every hundred bushels, 

 or five tons of the mass (we would recommend double the quantity of lime) 

 will, in most cases, be sufficient to neutralize all the astringent matter present, 

 and to convert it into, or rather replace it by, gypsum. The dressing of an 

 acre of such a mixture will contain of the green-marl, of gypsum, and of un- 

 combined lime, or more truly lime now in a state of carbonate, in all proba- 

 bility fully enough to impart to the soil a most decided improvement in its fer- 

 tility. 



This marly clay is not only easily divested of its injurious 

 properties by the action of lime, or exposure to the atmosphere, 

 but it may also be rendered of vast advantage, by adopting the 

 practice of the English farmers that is, making a compost of 

 the substance with the common manure of the farm. See Eng- 

 lish Farmers' Reports, No. IX. When a field is over-limed, 

 the best remedy is the application of putrescent and vegetable 

 manures. So when a field has become sterile by an over-dose 

 of this marly clay, a certain remedy will be found by applying 

 to each acre a few bushels of lime which will very speedily 

 correct the acidity in the soil communicated by the astringent 

 clay. 



Directions for the Selection and Proper Mode of Applying the Green-sand Marl. 

 la seeking for the marl stratum in neighbourhoods where it is supposed to 



