1921.] 



Beport on Potato Trials, 1920. 



353 



up ou certain definite lines in order that they may issue a 

 summarised report of all the trials in the Country. 



It was recognised that, although County Committees might 

 arrange local schemes in their Counties, which would provide 

 much valuable information to local potato growers, trials carried 

 out on uniform lines in every County with seed from one source 

 and with a uniform system of manuring, would supply this local 

 information equally well and, in addition, further reliable infor- 

 mation of national importance. It was for this reason that the 

 scheme was prepared by the Ministry, and provisions made for 

 the supply of seed. 



Number of Centres.— The County Committees adopting the 

 scheme made such arrangements to carry out the trials as were 

 consistent with local conditions. Most Committees selected the 

 Farm Institute — where one existed — for the site of the trials, 

 but selected other centres in their areas as well, the total num- 

 ber of centres at which the trials were conducted being 455. In 

 most cases the cost of the seed and manures alone had to be 

 defrayed from public money, the land and labour being provided 

 by private persons (farmers, small-holders and allotment-holders) 

 in return for the crop produced. It is a pleasure to be able to 

 record the satisfactory working of this plan, which had many 

 points of great value ; it allowed the trials to be carried out on 

 commercial lines under the close attention of growers themselves, 

 and reheved Committees of the responsibility of hiring or buy- 

 ing land, and from further financial transactions — a burden at all 

 times to public bodies. 



Finance. — As the trials w^ere carried out in connection with 

 the Educational pohcy of the Ministry, they were aided by the 

 Department to the extent of two-thirds of the actual deficit cost. 

 At the moment, details of the actual cost cannot be given. 



Results. — Space does not permit of detailed results of every 

 County trial being given in this Report. Most of these results 

 have already been published locally, and it only remains for the 

 Ministry to compile a report which will correctly interpret the 

 sum total of the results from the many trials. 



The correct interpretation of the results obtained from crop- 

 ping trials is always a difficult matter because of errors which 

 cannot be eliminated from field experiments. The value of such 

 experiments depends upon the degree of confidence which can ho 

 attached t^) the results, i.e., on the probability that similar re- 

 sults will be obtained wlien the trials are repeated. It follows. 



