1922.] 



The Agricultural Value of Sea- Sand. 



595 



Shell-sand from Perranporth is being delivered on farms near 

 Truro (a distance of 9 miles) at 6s. per ton, and as it contains 

 nearly 6 cwt. of lime (CaO) to the ton of sand it makes the cost 

 of the lime about £1 per ton on the farm. Sand from Padstow 

 is being sent inland by rail and dehvered at the railway stations 

 at the following prices per ton: — Bodmin 9s. 8d., Otterham 

 83. 6d., Launceston 10s., Camelford 8s. 2d., Liskeard 9s. 8d. 

 This sand contains not less than 8 cwt. of hme per ton, so that 

 the cost of the ]ime in it is not more than 25s. per ton at points 

 so far distant from the source as Launceston and Liskeard. 

 Ground hmestone at these two places is at present somewhere 

 about 353. per ton and as this contains not more than 11 cwt. 

 of lime (CaO) per ton of limestone the lime in it must be some- 

 thing like 63s. per ton. This certainly compares very unfavour- 

 ablv with the cost of the lime in the sea-sand, so that Cornish 

 farmers would be well advised to ascertain the respective charges 

 on the various forms of lime available — burnt lime, ground lime- 

 stone and sea-sand. Taking a few of the most important centres 

 in the county the prices may be compared as follows : — 



Per fan of Material. Per toji of Lime (CaO) in 



Burnt Ground Sea-sand, Burnt 



Lime, Limestone, G5-75 7 j . Limestone. Sea-sand. 



95% pure. 95°/„pure. CaCOg." 



Penzance 45/- "iO/- 5/- 47/4 75/2 12/- 



Truro 43/- 38/- 6/- 45/3 71/5 20/- 



Liskeard 40/- 35/- 9/8 42/- 65/9 23/6 



Launceston 40/- 35/- 10/- 42/1 65/9 24/3 



The excessive cost of the limestone is largely due to the fact 

 that, unlike burnt lime, its railway freight does not come under 

 the agricultural rate. Thus, while burnt lime at the kiln, 

 Newton Abbot, is 30s. per ton, ground limestone is only about 

 ITs. 6d. per ton^ yet at Penzance, Truro, etc., the difference in 

 price is only 5s. per ton. 



This leads naturally to the question of the comparative 

 manurial values of the three substances. In the first, burnt 

 lime, we have the lime in what is considered its most active form, 

 the oxide, while in the other two the lime is present as a car- 

 bonate. As far as the mechanical condition is concerned the 

 gTound limestone is much finer than the sea-sand and it would 

 therefore be considered quicker in action and, possibly, of slightly 

 greater value. Beyond this there seems to be no advantage in 

 lime or limestone over sea-sand. 



Action on Various Crops. — A good deal of information is 

 available as to the action of sea-sand on various crops. Experi- 

 ments have recently been carried out by the Cornwall County 



B 2 



