CH. viii] Effect on Crops 145 



Superphosphate has two remarkable effects on the 

 crop: it favours root development in the early stages 

 of plant growth, and it hastens maturity in the later 

 stages. It is specially useful for swedes and turnips, 

 and gives returns even when the soil seems rich in 

 phosphates. Fig. 30 shows the results obtained at 

 Rothamsted: unmanured turnips failed to swell and 

 remained like radishes, turnips manured with super- 

 phosphate and potash swelled to a considerable size 

 even without nitrogenous manure, while when this was 

 added still further growth was obtained. 



After a wet winter a dressing of 3 cwt. of super may 

 considerably assist the young winter corn to form roots. 

 Nitrate of soda or sulphate of ammonia should be given 

 at the same time. 



Its effect on maturity is well seen on the barley plots 

 at Rothamsted. Wherever phosphates are withheld the 

 crop ripens badly : where they are supplied it ripens well. 

 Indeed cases are on record elsewhere where the ripening 

 has gone on too quickly, so that the crop has suffered in 

 consequence. 



At Rothamsted the barley on the permanent plots 

 stands greatly in need of phosphates: the results are 

 plotted in Fig. 31. 



Phosphates also increase the feeding value of fodder 

 crops and for this reason must be liberally used wherever 

 recourse is had to folding or where many head of stock 

 are kept. Addition of superphosphate to the seeds ley 

 often leads to improvement in the sheep grazing the 

 aftermath. , 



In horticultural practice superphosphate proves very 

 valuable for inducing hard growth in plants that are 

 becoming too sappy. 



R. s. 10 



