Nov. 2, 1920.] Agricultural Gazette* of N.S.W. 787 



Laivrence. — Expeiiuients sown 5th and 6th September ; soil, light loam of 

 medium fertility. The results of the trials were very poor, but considering that 

 the rainfall recorded during growth (four months) was 1-48 inches, it is 

 surprising that the crop was not a complete failure. 



The results are not of very great value in the selection of varieties for 

 main crop sowings, as the season was far from an average one. They are, 

 however, of value in demonstrating the drought-resisting qualities of varieties 

 and the action of fertilisers. Carman No. 1 appears to be an exceptionally 

 hardy variety. 



The increases in yield from fertilisers were not so marked as in other 

 localities, in all probability due to a big percentage of it remaining undissolved 

 in the soil. This would apply particularly to P7, which, containing bonedust, 

 requires a plentiful supply of moisture to become completely available. 



Summary of Experi nents. 



A summarisation of the foregoing experiments discovers four outstanding 

 features. There will be noted (1) the consistency of the yields of white- 

 skinned varieties, not only on the elevated Dorrigo and Eastern Dorrigo 

 plateaux where the season was favourable, but on the alluvial soils of the 

 river Hats, where extreme drought conditions prevailed ; (2) the evident 

 drought-resisting qualities of Carman No. 1 ; (3) tbe consistent pro- 

 ductiveness of Factor, Up-to-Date and Lang worthy; and (4) the strong 

 evidence in favour of the use of artificial fertilisers and of P7 in particular. 

 All the trials were conducted on comparatively fertile soils and where the 

 benefit of manuring would not be expected to be very pronounced. The 

 results, however, show very substantial increases in all cases. This may 

 possibly be because the fertilisers supplied the necessary plant foods in a form 

 more readily available than that in which they were already present. This 

 would particularly apply when the supply of moisture was deficient and 

 the demands of the plants were heavy owing to a short growing period. 



The two main factors in successful potato production within control of the 

 grower are — (1) good soil preparation and (2) good seed. Concerning the 

 former, too much stress cannot be laid on the importance of ploughing the 

 land some months before planting to permit of the storage of moisture and 

 the improvement of its physical condition through the ameliorating eflfects of 

 frosts and soil ventilation. Keeping the surface well mulched by use of the 

 harrows after the soil has received its first ploughing is of primary importance 

 in the conservation of soil moisture ; this has, too, a controlling effect on 

 weed growth. This operation is necessary after rain in any quantity, and 

 particularly after heavy falls, which break down the crumb structure and 

 cause the soil to set. 



With the increasing prevalence of drought conditions on the coast better 

 cultural methods will have to be adopted, and storage of soil water must play 

 a more important part in crop production. 



Too much attention cannot be given to the selection of seed. The North 

 Coast farmer is, with the exception. of the Dorrigo grower, dependent on 



