9 Sept., 1907.] 



Potato Experimental Fields. 



549 



during the four vears in the different plots is shown in the following 

 table : — 



With continuous wheat cropping there was an annual loss of i,8oo 

 lbs. of humus per acre whilst on the rotation plan of maize, oats, and 

 barley there was a gain of above 1,500 lbs. and in the other rotation with 

 clover over 2 tons. As humus is one of the principal sources of nitrogen, 

 in the case of continuous wheat growing the annual loss of nitrogen was 

 146 lbs. over and above that utilised by the wheat crop or for every i lb. 

 used by the crop 5 .lbs. were lost to the soil whilst in the clover rotation 

 there was an annual gain of 6i\ lbs. 



A glance at the above table will show what an important factor clover 

 is in the renovation of the soil. Heavier yields of potatoes and a better 

 quality of tubers are largely bound up in this question of a proper system 

 of rotation and especially one including clover. If larger areas of the best 

 potato lands of the State were utilized for dairying and grazing, a little 

 more than half the present area of potatoes would produce as heavy a 

 return of marketable tubers. 



Selection of Seed. 



The importance of the selection of potatoes for seed recei\ed careful 

 attention during the harvesting of the crop, 1905-6. The varieties were 

 culled and notes were made of the proportion of rejects. This selected 

 seed was used in the 1906-7 fields and reference to two or three lots will 

 suffice to show the influence of a proper system of selection on the quality 

 and yield of the crop. , The .varieties which have suffered most through 

 want of care are the red skinned. This may be accounted for by the fact 

 that they have been longest in cultivation ; the practice of taking small 

 or undersized tubers for seed year after year without any regard to the 

 plant which produced them is responsible for much of the decline of this 

 variety. 



One parcel of seed of this variety was taken from a plot planted by 

 Mr. Jellie of Woodford with the following results: — 

 Average yield — 6 tons per acre. 



Wild plants, 25 per cent. 



both rejected. 



Yellow tleshed jjlants, 50 per cent, j 

 The return of market and seed tubers per acre was i| tons and of 

 Tejects 4I tons. The selected seed was planted in Mr. Park's plot at 

 Romsey, and the results are most striking. The gross return of the section 

 was 7 tons 10 cwt., made up as follows: — 6 tons 18 cwt. marketable 

 seed, and 12 cwt. small. The money value of market and seed potatoes 

 at 50s. per ton and of small at 20s. would work out as follows per 

 -acre : — £ s. d. 



Market and seed, 6 tons 18 cwt. at 50s. per ton . . 17 5 



Small, 12 cwt. at 20s. per ton . . . . . . 12 



Total 



17 17 



