194 CONTINUED EFFECTS OF MARL. 



this excess of marl has been moderated in effect ; and those appli- 

 cations now, as the others, show continuing good effects only. The 

 other exception, though not yet well understood, seems more real. 

 It applies only to some small spaces of land, sometimes slightly 

 oozy, on clay sub-soil. The surface of these spots is generally slop- 

 ing, though, in some cases, too level to lose much soil by washing 

 rains. The soil is shallow, and receives the excess of filtrating rain- 

 water from the more level and higher land, in wet seasons, and 

 which is discharged over its surface, when most abundant ; or other- 

 wise beneath the shallow soil, to the lower grounds, or to streams. 

 Such spots, being too wet only in winter and spring, and of small 

 extent, were either not drained at all, or, where covered drains had 

 been made and had failed, they were not renewed. In land of 

 this kind, it seems as if the oozing water dissolves and carries off 

 the organic and nutritive ingredients of the soil. All soil of this 

 character, on the farm named, together makes but some ten or 

 twelve acres, in many small, irregular-shaped spots, and always of 

 small value for tillage, which circumstances caused their being neg- 

 lected. In all such cases, and even after being marled, and an 

 early improvement being thereby produced, these spots have become 

 more poor, and the soil itself seeming to diminish in quantity, as 

 if lost by being washed away, which, however, is not the case. 

 Previous and proper drainage would, no doubt, have prevented the 

 existence of this only known real exception to the continued and 

 unabated good effect of marling. It is stated here thus particularly, 

 not only as due to truth, but also because the facts will be again 

 referred to, in another connexion. 



It should be observed, as to my general practice, and in regard 

 to all land referred to on which no repetition of the first marling 

 of early date has been made, or has been needed and where no 

 abatement of the highest productive power has occurred that the 

 following conditions existed, and were (as I suppose) essential for 

 the results stated : The marling had been heavy (perhaps furnish- 

 ing 1| to 2 per cent, of carbonate of lime to the tilled layer of soil), 

 and the land subsequently kept under sufficiently mild cropping 

 and treatment, which allowed it to be supplied, through its own 

 growth of grass, and by help of atmospheric influences, with more 

 organic or nutritive matter than the cultivated crops took away. 

 On some marled land, on other farms, where the general course, of 

 cultivation was exhausting, and not compensated by enough of 

 natural or other supplies ojf vegetable and alimentary matter, the 

 early increase of product has been subsequently lowered. In some 

 such cases, within my observation, of most scourging tillage, in 

 eight or ten years after marling, and after excellent early effects, 

 the land was reduced to as low a state as before being marled. 



