1921.] 



Liming. 



345 



(a) Mechanical Composition. 



Chemical Composition. 





Percentage. 



Percentage. 



Moisture 



2-7 



Nitrogen 



•31 





lOG 



Total Phosphoric Acid 





Gravel 



... 171) 



(P2O5) 



•089 



Coarse Sand ... 



... ir,-5 



Citric-soluble Phosphoric 





Fine Sand 



... 150 



Acid ... 



•OOG 



Coarse Silt 



... 15-4 



Total Potash (K2O) ... 



•78 



Fine Silt 



1(')G 



Citric-soluble Potash ... 



•05 



Clay 



4-4 



Total Lmie (CaO) 



•23 







Total Magnesia (MgO) 



•20 







Carbonate 



Nil. 



The limestone was ground in a mortar and separated by sieves 

 into four fractions of the degree of fineness indicated below : — 



Fraction A. Particles below \ in. and above tV hi. diameter.* 

 Fraction B. „ „ tt in. ., n 



Fraction C. ,, „ i"- „ „ too in. „ 



Fraction D. ,, in. 



The pots were filled with soil and seed was sown on May loth, 

 1920. Pots 1, 2 and 3 for control received no limestone, while 

 the soil in Pots 4 to 11 inclusive received an admixture of 0.3 

 per cent, ground limestone (approximately equivalent to 3 tons 

 per acre). No manure was added to any of the pots. The treat- 

 ment is indicated in greater detail in the following table : — 



No limestone. 



0-3 per cent, of limestone, jjarticles ^ in. to jV i". 



„ „ tV in. „ iz in. 



V 11 '1 5"5 in. ,, in. 



,, ,, below i^iy in. 



Eighty seeds of trefoil were sown in each pot. By May 23rd 

 the seedlings appeared in all pots. They did not, however, 

 thrive in any pot. In fact they were of a poor colour, appeared 

 to be in a very critical state, and made but very slight progress 

 up to June 10th. At this date, however, the plants in pots 

 10 and 11 appeared to have greatly improved in colour and were 

 making headway. The plants in the other pots did not improve 

 much for another fortnight. On June 28th the plants were 

 thinned down to 40 individuals to each pot. 



^ That it is practicable to grind limestone so that the greater })art of it 

 would pass through a 100 mesh to inch sieve is shown by llie following 

 results recently obtained by the writer in examiniiig a sample of grtuinii 

 limestone : — 



Particles ^ in. to yV in. ... ... <>ll p(M- i>ont. 



Vt in- V 5V in l-'i:? 



M tV in- V ttto in '" I"* „ 



„ below in !)1()S 



Pots 1, 2 and 3 

 Pots 4 and 5 ... 

 Pots G and 7 ... 

 Pots 8 and 'J ... 

 I^ots 10 and 1 1 



