572 



Journal of Agriculture. 



[lo Sept., 1910. 



As seen by this table, scabby seed produced 45.7 per cent, and 56.7 

 per cent, clean potatoes on two farms, whereas clean seed produced" 59.5 

 per cent, and 67.3 per cent., or a gain of 13.8 per cent, and 10.6 per 

 cent, respectively. As 10 per cent, represents 2 cwt. per ton of produce, 

 the gain by use of clean seed would be considerable in, say, a twenty acre 

 crop. 



Green Manuring. — At the time the experiments were inaugurated it 

 was decided to put in a plot at each farm for testing the action of green 

 manuring in relation to these diseases, but as no area of suitable size 

 carrying a crop of green material was available, only one row in each plot 

 received green manure. Besides increasing the yield it was often held 

 that green manuring produced a cleaner crop. In many parts of Victoria 

 it is customary to plough in a crop of oats or barley at the time of sowing 

 the potatoes with the special object of increasing the yield, and it was 

 thought by many farmers that this also resulted in the crop coming off 

 a cleaner sample. 



The greater yield was fully borne out by the experiments, an increase 

 taking place of from i to i| tons per acre, but the cleanness 

 was a very variable quantity, increasing in Mr. Shearer's plot by about 

 8 per cent., and decreasing about the same per cent, in Mr. Downey's 

 plot ; while Mr. Summers' plot, where spear grass was used as green 

 manure, the decrease was considerable. 



The following is a table .showing the increase in yield due to green 

 manuring and its effect on Scab:- — 



Name of Grower. 



Downey 

 Shearer 

 Summers 



Plot 1. 



Green 



Manure. 



Yield. 



tns. cwt. 

 4 2 

 6 



2 13 



No Manure. 

 Yield. 



tns. cwt. 



2 17 



4 19 



1 2i 



Increased 



Yield 



by 



Green 



Manure. 



tns. cwt. 

 1 5 

 1 1 



1 lOi 



Iron Sulphate. — The use of iron sulphate has been recommended for 

 the treatment of fungus diseases, as it possesses a slight antiseptic action. 

 It resembles, though in a much lesser degree, the action of copper sulphate 

 or bluestone, which is used as a fungicide in Bordeaux mixture ; it was 

 therefore decided to give it a trial against the Scab in potatoes, and for 

 this purpose it was sown, at the rate of i| cwt. per acre, with the seed 

 at the time of sowing. Two rows at each farm received this substance ; 

 in one it was sown on top of the land after scabby seed untreated wit^^ 

 formalin had been covered, while in the other it was sown in the manure 

 section in the furrow with the formalin-treated seed to try its eftect 

 amongst the special manures. 



In both cases, however, the results from the use of this substance 

 were poor, no improvements taking place on the general sample of pota- 

 toes ; this may have been due to the fact that iron sulphate is easily 

 soluble in water, and might thus be washed out of the soil, or it may 

 undergo chemical change in the soil. ^Vhatever may have been the cause, 

 no good results followed its use, the potatoes from these rows being badly 

 scabbed and about equal in sample to tho.se which received no treatment. 



