H.—29.

D. Simple observational experiments to determine the effect of phosphate, phosphate plus potash, phosphate plus nitrogen, and phosphate plus potash plus nitrogen on limed and unlimed ground respectively. In these there are only single plots of each treatment. Thirty-seven experiments laid down in 1931. E. Other observational experiments involving single plots. .Description of Experiments laid down subsequent to 31st March, 1933. —New experiments aim at attacking what I consider the vital question of method of supplying the tree with artificial fertilizers. Five new experiments have been laid down to test the effect of concentrating phosphatic and potassic fertilizers near the tree compared with their broadcast application over the whole of the ground allocated to each tree. These are distributed as follows :—

Eight experiments were established to investigate the injection of fertilizers in solution into the ground. These are simple trials in which a crowbar was used to make the holes into which the solution containing phosphate and/or potash was poured. These experiments are of a preliminary nature pending the receipt of a special injecting outfit as used in America and Germany. When these injectors are available it is hoped that facilities will be provided for more comprehensive trials on this phase of manuring. The simple preliminary or exploratory experiments are grouped as follows :—

Results of Experiments as measured or observed to date. —Up to date the most outstanding feature of the trials has been the effect of nitrogen. Beneficial effect has been by no means universal, but where it has occurred it can be taken as a fair generalization that the trees exhibit in the general colour of the foliage and vigour of new growth signs of nitrogen deficiency. Nitrogen effect where it has occurred on apple trees has been less marked generally than where it has caused visible effects on stone-fruit. It would appear that the colour and general appearance of the trees gives a fair indication of whether or not a nitrogenous fertilizer is likely to influence growth. The most marked effects from nitrogen have occurred on soils which are obviously low in organic matter, and the least effect on soils such as those of the Hastings flats, which have a high content of organic matter. In view of the marked effects on plots receiving nitrogen along with phosphate or phosphate and potash and the absence of effect where the latter are used without nitrogen in some of the trials on stone-fruits in Central Otago, it was deemed advisable to extend these trials so as to include plots receiving nitrogen only. This was done in the spring of 1933. The plots receiving nitrogen only for the first time were not as good as those which had been dressed for three successive seasons. Whether this is due to the cumulative effect of the nitrogen on the older plots or to their association with phosphate and potash can be determined only after a number of seasons. \ Donation of Fertilizers. —About 5 tons of muriate of potash and a similar quantity of sulphate of ammonia were donated by Pacific Potash, Ltd., and Imperial Chemical Industries, Ltd., respectively, during the past season. These donations have materially assisted in enabling the programme of work to be carried out. Acknowledgments. —The enthusiastic assistance of Mr. Dallas, and district officers of the Horticulture Division is acknowledged, and thanks are also due to co-operating orchardists for their continued interest. MYCOLOGY SECTION. G. H. Cunningham, Mycologist. Work for the year has covered the following diseases : — (1) DISEASES 01? SWEDES, TURNIPS, RAPE, AND CABBAGES. Dry-rot (Phoma lingam). Swede seedlings raised from a Station selection of Herning, and rendered dry-rot free by treatment with hot water, were planted out on three areas made available under the Small-farms Plan. Faulty management and unfavourable seasonal conditions eliminated two of these holdings, but the third (Colyton) area produced an excellent crop of seed, which laboratory test has shown to be free from dry-rot. Six selections have been made of swedes of improved strain for mother-seed production for the 1934-35 season. In connection with the recently introduced system of brassioa-seed certification, laboratory tests have been conducted to ascertain the percentage of dry-rot present in commercial seed lines offered for sale in New Zealand. Prel ; minary work has shown that the petri-plate method is preferable to the Copenhagen germinator for testing seed for the presence of this disease. Successful results depend on testing large numbers of seed, a minimum being regarded as 20,000. The disease has been isolated from rape, ohou moellier, and wild turnip, all new hosts (for New Zealand) of the pathogen.

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District. Number of Trials. | Kind of Fruit. i I Auckland .. .. .. 2 Apples. Hastings .. .. .. 1 Apples. Mapua .. .. .. 1 Apples. Central Otago .. .. .. 1 Apricots.

District. Number of Trials. Kind ol Fruit. I I Auckland .. .. .. 1 I Apples. 1 Hastings .. .. .. 2 Apples. Palmerston North .. .. 1 Apples. Motueka .. .. .. 1 Apples. Marlborough .. .. .. 1 Apples. Roxburgh-Ettrick .. .. 1 Apples. Central Otago .. .. .. 1 Apricots.