ioSept., 1908.] Potato Experimental Fields, 1907-8. 



573 



In this group of fields, the most productive, and at the same time 

 economical, amount of manure has been section B (4 cwt. Super.). Indi- 

 vidual fields, notably that of Mr. Herbert at Neerim, shoAV much superior 

 results when nitrogen is added to the light dressing of superphosphate. 

 Mr. Watson's field at Trentham also shows a slight increase in yield in 

 sections D and E over section B. Upon Mr. Beale's land at Kinglake, the 

 light dressing of superphosphate in section A gave the best results. 



Reference to Mr. Seymour's portion of this report will show that exter- 

 nally tlie soils of these three fields were very similar in character. The 

 different action of the fertilisers reveals the necessity for a more complete 

 knowledge on the part of potato growers, and incidentally emphasises the 

 profound value of field experiments. 



Fields at Romsey and Newlyn. 



Upon the two fields belonging to this group, the relative actions of 

 farmyard manure and ai'tificial fertilisers, singly and in combination, have 

 been tested. The results shown below indicate the marked superiority of the 

 former. In drawing comparisons, however, the reader must keep in mind 

 the fact that a great part of the improved yields from the farmyard 

 manure is due to the greater capacity of soils so treated to hold moisture. 

 It is probable that in this direction farm manure is more serviceable thaji 

 as a direct plant food. The dominant fact, however, is that the farm- 

 yard manure has influenced the yield of potatoes to a greater extent 

 than the dressings of fertilisers ; and, as far as the results under review 

 may be accepted, potato growers may safely look upon the figures as 

 demonstrating a principle which the Department of Agriculture has for 

 many years been urging upon their notice. Farm manure not being always 

 obtainable in sufficient amounts may be replaced by crops of peas, beans, 

 vetches or clover, which are subsequently ploughed in for green manure. 



