Potato Growing. 



489 



to nitrogen and potash. The quantity required depends, of 

 course, on the condition of the land, for manuring is effected 

 merely to supply the deficiencies of the soil. It may require 

 none, or much, and each field must be judged on its merits 

 or requirements. As a guide, take a wheat stubble which 

 would ordinarily be sown with a root crop ; then on average 

 soil, fairly well farmed, 15 to 20 tons of good, well-rotted 

 farmyard manure, 4 to 5 cwt. of superphosphate, 1 to cwt. of 

 sulphate of potash, and 1 cwt. to 2 cwt. of sulphate of ammonia 

 will give a good marketable crop. More ammonia may be 

 applied, but where the cultivation is good and the variety 

 vigorous there is a tendency to produce too many coarse 

 tubers. On land after restorative crops and in good con- 

 dition, smaller dressings suffice ; on land in very poor heart 

 more should be applied. Half the ammonia should be applied 

 at about the time of planting, and the other half at the first 

 moulding, or if sulphate of ammonia be used it should be 

 applied at the second dressing, between the rows, as it scorches 

 the leaves ; the moulding will bring it to the plants. It is 

 obvious that a late heavy-cropping variety requires more 

 manuring than a first early, which crops lighter. 



The time for applying farmyard manure is a question on 

 which even good growers differ. Most potatoes are now put 

 in " on the ridge," though there are districts where " flat" plant- 

 ing prevails. On the flat it is necessary to get the dung well 

 incorporated with the soil before planting, and its application 

 is made in autumn or winter. Theoretically, and to a great 

 extent practically, the nitrates are washed out of the land 

 during the winter ; but many conversant with the fact prefer to 

 apply the dung in autumn, even when well rotted, so as to 

 ensure thorough incorporation, as practice has shown them that 

 they get better crops thereby. These, however, generally 

 manure very liberally — up to 30 tons per acre — and mainly 

 grow early or second early varieties, on light land in dry 

 climates, the object of the heavy manuring being very largely 

 to retain moisture. 



On the ridge system the manure is either applied in late 

 autumn or early in winter, to be turned in in the first ploughing, 

 to decay sufficiently, not to be too long to hinder subsequent 



