82 



Notes on Manures for April 



[Apr. 



NOTES ON MANURES FOR APRIL. 



E. J. Russell, D.Sc, 

 Rothamsted Experimental Station. 



Manures for Potatoes. — This is the season when manures 

 must be applied for potatoes. The best preparation is a good 

 dressing of farmyard manure in the previous autumn in 

 England, or in spring where the winter rainfall is heavy as, 

 probably, in Wales. Where sufficient dung was not available 

 in autumn the remainder is applied in the drills. 



Artificials must always be added. Satisfactory results have 

 been obtained by the application at the time of planting of 

 1 cwt. of sulphate of ammonia. 4 cwt. of superphosphate, and 

 1 cwt. of sulphate or muriate of potash per acre. If, however, 

 the soil and climatic conditions are such that 9 or 10 tons of 

 potatoes per acre may be expected then the following mixtuie 

 would be justified: IJ cwt. of sulphate of ammonia, 4 cw^t. of 

 superphosphate, and IJ cwt. of sulphate or muriate of potash. 



In special cases even higher dressings can be used, but only 

 when direct experience shows a definite advantage. Cases are 

 on record when a shortage of dung was satisfactorily counter- 

 balanced by increasing the sulphate of ammonia to 2J- cwt., 

 with corresponding increases in the superphosphate to 6 cwt. 

 and in the sulphate of potash to 2 cwt. per acre. 



Some farmers have asked whether anything is gained by 

 adding magnesium compounds to a potato manure. Certain 

 Scotch farmers have used magnesium in the form of oxide or 

 carbonate, and claim to have obtained satisfactory results. One 

 of the successful Scotch growers in Hertfordshire has applied 

 magnesium compounds. The writer w^as unable to find, how- 

 ever, that any advantage was gained thereby, but precise evi- 

 dence is lacking. Magnesium sulphate or chloride could be 

 more readily obtained: the effect is being tested durmg the 

 present season at Rothamsted. 



Sulphate of ammonia is generally found better for potatoes 

 than nitrate of soda, nitrate of lime or nitrolim, ond should 

 therefore be used unless there is evidence that the nitrate 

 would be more effective. Whenever there is any reason to fear 

 scab sulphate of ammonia and superphosphate w^ould be 

 necessary, but in soils wdiere smh does not generally give 

 trouble, and in certain other cases also, a mixture of basic slag 



