Jan. 2, 1920.] Agricultural Gazette of N.S.W. 71 



Plants obtained their food from the air, water and soil. Those chemical elements 

 which the plant required for its nutrition and which must therefore be regarded as part 

 of its food were carbon, hydrogen, oxygen, nitrogen, sulphur, phosphorus and perhaps 

 chlorine, and the metallic elements potassium, calcium, magnesium and iron were also 

 necessary. The lack of any one of these or its presentation in unsuitable form might 

 cause a physiological disease, and it was the work of the horticulturist to remedy defects 

 in sou by the judicious application of artificial manures. In general the elements most 

 likely to be lacking were nitrogen, phosphorus, potassium and calcium, of which a deficient 

 supply was supplemented by the use of such artificial fertilisers as ammonium sulphate 

 to supply nitrogen, superphosphate to supply phosphorus, potassium sulphate to supply 

 potassium, and lime to supply calcium. When buying superphosphate or potash the 

 labels on the fertiliser bags were sometimes confusing. The higher percentages in the 

 guarantee meant nothing; a guarantee of 4 to 5 per cent, of potash was a guarantee of 

 4 per cent., and it would be the same if it said 4 to 50 per cent. 



Lime was obtainable in two forms — quicklime and carbonate of lime. The effects of 

 quicklime in breaking up clay and of carbonate of lime in neutralising soil acidity were 

 pointed out and the influence of the presence of lime on the health of plants indicated. 

 In applying fertilisers easily soluble in water the danger of producing too dense a medium 

 around the delicate root hairs -was dwelt upon. Fungi might be divided into five main 

 classes, and in each class there were members which were dangerous plant parasites. A 

 member of each class and its method of attack was described and remedies suggested. 

 Reference was made to the finger-andtoe disease of cabbage, diseases diie to bacteria, 

 Irish blight of potatoes, downy mildew of grape vines, and ripe rot of oranges, 

 passion fruit and apples. 



Another meeting was held on 17th November, when a lecture by Mr. H. J. 



Rumsey, on the subject of seasonal vegetables, was well attended. 



Lower Portland. 



A meeting of the above branch was held on 5th November, when there was 



an attendance of eleven members. 



A paper was read by Mr. Chkistie on the subject of lime. He had used it, he said, in 

 almost every form with beneficial results, and had found that limed land held the moisture 

 better than unliraed land. Lime had the power of liberating potash and phosphoric 

 acid which were present in the soil, and making them available for plant food. For 

 light soils which were sour or deficient in lime, he preferred carbonate of lime or agri- 

 cultural lime, which was not so caustic in its action as stone lime, though the latter was 

 better for breaking up heavy clay soils. He had used gypsum for grape vines beneficially. 



Departmental Note. — The Chief Inspector states that lime causes unavailable potash 

 to become available for plant use bj' chemical action ; it does not directly affect phosphoric 

 acid in the same way, but the improvement which it makes in the condition of the soil 

 causes chemical nitrifying agencies to become more active and consequently the fertility 

 of the soil is improved. , 



At one time it was the custom to apply heavy dressings of lime, but it is now considered 

 that better results are obtained by small applications at more frequent intervals. The 

 Department generally recommends a dressing of about 1 ton per acre, and this is repeated 

 yearly if the condition of the soil renders it necessary. 



Under special conditions (such as in cases where the soU is of a heavy nature and it is 

 required to fit it for special crops) heavier dressings are recommended. The price of lime, 

 however, makes heavy applications for ordinary purposes too costly. 



March. 



A meeting of the above branch was held on 17th September, when a paper 



on orchard pests and methods of destroying them was read by Mr. G. Mitchell. 



Mr. Mitchell said the worst and most common orchard pests might be divided into 

 two classes, fungi and insects. Black spot, shot hole and powdery mildew were the 

 worst of the first class; while the second class had to be divided into two types, one of 

 which (like aphis, San Jose scale, red spider and others) sucked their nourishment from 

 the leaves and fruit, while the other (like codlin moth, pear slug, vine moth and some 

 large beetles) devoured the leaves and fruit by bitirg. 



