27 



remainder is lost. How can we recover more and thus secure a 

 better return for our outlay ? Part of the loss cannot yet be 

 explained, and is under investigation in the laboratory, but part is 

 due to the failure of the plant to take up all the food given to it. 

 A proper balancing of the manure enables the difficulty to be got 

 over to some extent ; in the following two instances the same 

 amount of nitrogen is given in each case, but in one the manure is 

 well balanced while in the other it is not. 



Laboratory experiments were made to see if any stimulant 

 could be administered to the crop to get it to utilise the food 

 materials better, and manganese salts appeared to have this effect, 

 but trials in the field have not yet proved successful. 



The crops are not abnormally large and the varieties used are 

 capable of better growth ; something is clearly standing in the way. 

 Inspection of the soil at once shows that it is too heavy to give the 

 best results; the soil type therefore is one limiting factor. 



Now this difficulty is an old orfe and has long since been met 

 by an old device. Chalk lies below the surface of the land in 

 Hertfordshire and the old practice was to dig down for it and apply 

 it to the land at the rate of 80 or 100 tons per acre. The treatment 

 was effective, but it is costly. More recently economy has been 

 effected by using smaller dressings or by substituting lime, but 

 however the process is modified it has to be adopted in some form 

 or other. Seeing, therefore, that we must have recourse to chalking 

 and liming, a series of laboratory and field experiments was under- 

 taken to see just what the lime and the chalk do in the soil and how 

 much — or rather how little— is needed to effect improvement. These 

 have already been discussed on p. 8. While the laboratory inves- 

 tigations were in progress a field experiment was started. The land 

 was divided into three parts, one receiving, at a cost of £3 6s. 8d. 

 per acre, a dressing of 20 tons of small chalk obtained in the 

 excavation of a sewage filter bed ; one was chalked on the old Hert- 

 fordshire method by the men who make a speciality of this kind of 

 work, approximately 50 tons being given at a cost of £3 7s. lOd. 

 per acre ; and the third was left untreated. This was done during 

 the winter of 1912-13. The effect of the chalk on the physical 

 texture of the soil was manifested in a few months. Cultivation 

 became and has remained easier : the ploughman found his work 

 facilitated, the board running cleaner than on the unchalked land. 

 A considerable proportion of the outlay was recovered in the 1913 

 crop; in 1914, however, neither oats nor barley showed any benefit. 



