19!21.] LimNG. 347 



of pots 10 and 11, i.e., those treated with hmestone below 

 1/100 in., very few plants died. 



Several American experiments* have been conducted in order 

 to ascertain the degree of fineness to which limestone should 

 be ground. The results obtained regarding the desirable degree 

 of fineness vary from 1/50 in. to 1/100 in. 



In certain circumstances coarsely ground limestone might meet 

 crop requirements. There are conditions, however, in farming 

 practice which would appear to make the finest possible grinding 

 advisable. A high degree of fineness facilitates thorough in- 

 corporation with the soil. This is of greater importance with 

 the application of small quantities than it is with heavy dress- 

 ings, and ground limestone is often applied in relatively small 

 dressings. Again, the trefoil pot experiment, referred to above, 

 sliows that during the season of application the coarser particles 

 may liave but little if any beneficial eft'ect upon the crop. There 

 are occasions when it is particularly important to supply lime 

 in such form as will assist the plant during the season of 

 appHcation. In many cases it would be applied at that point 

 in the rotation when the grass and clover seeds are sown. In 

 such a case the degree of fineness of the limestone, and there- 

 fore its availability for the plant during the first year, wdiich is 

 often a critical period, might decide whether the laying of the 

 land dow^n to grass was a success or failure. 



Eeference has already been made to the fact that in many 

 districts farmers have lost faith in ground limestone on account 

 of its failures." Most of these " failures," however, can be 

 explained readily as arising from the improper use of ground 

 limestone. For example, in the hilly districts of Wales many 

 cases have come under observations where unsucccsslul attempts 

 have been made to improve pasture land by the application of 

 5 or G cwt. per acre of ground limestone. The distinctive feature 

 of the soils in the cases examined were (a) richness in organic 

 matter, (h) a high degree of acidity, and U') a particularly^ high 

 lime requirement. 



During the years 1914-15 the ^Agricultural Department of this 

 C()Il(\m' cai'ried out an exp(n-im(nit+ to ascertain the most suitable 

 manu.rial treatment for upland pastures. The report states that 



*Lyon, Fippiii and Buckmann, "Soils, their Properties and Maiia^^enient," 

 p. 540. Maryland Aj^ricultural Exporiincnt Station. Bulletin No. l'.>3, p. 45. 

 Pennsylvania Experiment Station. Bulletin No. 14*.), p. 21. A^^ricultural 

 Experiment Station of the Rhode Island State CoUo^ro. Bulletin No. ISO. 



t "'The Iin|)rovement of Upland Pastures," hy Jones and Stapledon. 



