CHAPTER VIII 



Ground Limestone 



Use in General. Trace the history of agriculture back as 

 far as possible, and you will find that man has been familiar with 

 the use and value of calcium compounds in the treatment of 

 certain soils which had failed to produce their usual crops. The 

 Roman farmer dug marl to use in treating his fields before he 

 planted them, and whether he originated the practice or whether 

 the idea was handed down to him by earlier agricultural peoples 

 is still a matter of doubt. Nor were the Romans the onh^ people 

 of that earl}^ date who practiced the liming of their lands when the 

 soil failed to produce. The custom has been followed in China 

 for long ages, except that there it was muck dressing that was 

 practiced, but since the beneficial part of the muck was its calcium 

 carbonate content, the process was essentially the same. 



We have records to show that the farmers of England have 

 made a practice of spreading chalk or marl on their soils for nearly 

 two centuries, and we are also in possession of the observations 

 made on the results achieved. Dr. C. G. Hopkins in his work, 

 Soil Fertility and Permanent Agriculture (p. 160), says: 



An English record of 1795 mentions the "prevaihng practice of sinking 

 pits for the purpose of chalking the surrounding land therefrom." 

 On the famous Rothamsted Experiment Station it has been found that the 

 fields that had received liberal applications of this natural limestone a century 

 ago are still moderately productive, while certain fields remote from the 

 chalk pits Avhich show no evidence of such applications are extremely un- 

 productive. 



There are according to Hopkins no early records which state 

 that the easily pulverized limestones and marls were burned to 

 improve their fertilizing value. The burning of limestone to 

 quicklime was probably first practiced with the idea of finding 

 an easy method of pulverizing the resistant rocks so that they 

 could be successfully applied to the soil. The treatment of soils 

 with ashes maj^ also have been in part responsible for the idea of 

 burning limestone before using it. 



The early farmers of England, as might be expected, appear 

 to have been the first to make use of chalk on the soil in order to 

 increase its productivity. This is easily explained by the great 

 deposits of chalk outcropping on the southern counties. That 

 the generous applications of calcium carbonate-bearing compounds 



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