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Distribution of Fertilizers from Aeroplanes.—Measurements on the ground spread of fertilizers and seed dropped from aeroplanes were carried out on several occasions during the operations of aerial top-dressing in the Wairarapa. One specially detailed trial was carried out on Ohakea Aerodrome. The trials showed that the fertilizer was spread in bands roughly parallel to the lines of flight of the aircraft and that there were sometimes marked gaps between the bands of fertilizer. However, it was shown that with correct distances between flight lanes, a sufficient degree of skill of the pilot, and accurate ground control it is possible to obtain a most satisfactory distribution of fertilizer. All the measurements conducted in the past year have been of screened superphosphate distributed from aircraft of the Royal New Zealand Air Force. It is hoped in the near future to measure the ground spread that light, privately operated aircraft are obtaining with commercial fertilizers. Rukuhia Soil Research Station Developmental work has continued to occupy an important place during the year. New areas have been prepared for peat research, for fertilizer-placement trials, and for pasture-production measurement trials. With some improvement in the staff position it has been possible to stabilize existing projects and to derive important interior conclusions from several of them. Many farmers from peat lands have visited the Station's experimental plots and have appplied suggested procedures for drainage, soil preparation, and fertilizer treatment to their own farms with striking success. Another activity which has received mucli attention from farmers in the Auckland Province is the experimental work on spray irrigation of permanent pasture. The past summer has been favourable for demonstrating the benefits of irrigation and numerous irrigation plants have now been installed on private farms. The use of radio-active isotopes of elements important in plant nutrition is a new and rapidly growing method of investigation of problems of fertilizer application and uptake from soils. Special equipment and laboratory facilities have been installed at the Station so that this method may now be applied to any problems that can be best solved by this means. A preliminary study of the fate of phosphatic top-dressing applied as superphosphate has yielded useful information and has confirmed previous evidence of the exceedingly high phosphate " fixing " power of the Horotiu sandy-loam soil of the Waikato. Techniques of Measuring Pasture Responses.—A comparison of four techniques of measuring pasture response to fertilizers has shown that while all give similar differences between treatments, the " mowing only " is preferable on the score of simplicity and ease of operation. Responses to 4 cwt. of superphosphate alone on Hamilton clay loam varied from Bto 10 per cent, and to superphosphate and lime from 16 to 21 per cent. There is no response to potash on this soil type. Kinds of Phosphates.—A comparison of thirteen different kinds of phosphates at equivalent rates of application has shown none significantly better than superphosphate in pasture-production on Hamilton clay loam. Thermophos, an American fused product, gave the highest actual yields. Fertilizer Placement.—When serpentine-superphosphate was used with swedes on Hamilton clay loam and on Horotiu sandy loam and the fertilizer was placed in seven different positions relative to the seed, the greater yields were obtained where the fertilizer was placed close to the seed. With potash and nitrogen fertilizers there appears to be less difference in yields between treatments.

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