H.—34.

Soil-injection Trials. So far no significant differences have been observed between any of the treatments, nor were there any significant differences in yields recorded when the crops were weighed in the 1935 season. Results, by Districts, of Manurial Trials. Auckland District. —Apples : On appearance, the complete manure plots are distinctly ahead of the remainder of the treatments in vigour and yield. In another experiment on young Granny Smith trees there are no visible effects from the use of varying quantities of nitrogen at 3 lb. and 6 lb. per tree respectively. Two out of the three liming-experiments continue to show a good response to liming. Peaches : The trees receiving nitrogen were outstanding in vigour and quantity and quality of fruit. Tauranga District. —Lemons : The interim results of the two trials being conducted have been published in the N.Z. Journal of Agriculture, August and September, 1935. The trial of various combinations of phosphate, potash, and nitrogen has now been brought to a conclusion, and the final results will be published at an early date. The liming trial is being continued for a further year. At the end of the first five-year period the limed plots had yielded 1,106 lb. of fruit per tree, as compared with 990 lb. from the unlimed plots. Hastings District. —Apples : In none of the experiments in this district has any difference been recorded from the various manurial treatments applied. Mapua District. —Apples : Nitrogen has increased yields in two replicated experiments, while in the other trial no determination of manurial responses was obtainable owing to severe spray injury. The difference in yield and in trunk-circumference measurements in the limed and unlimed plots has not been significant. No differences in responses have been observed from concentrated versus broadcast applications of fertilizer. Motueka District. —Apples : In two observational experiments the trees receiving complete manure are superior in vigour to the remainder, while no differences between " lime " and " no lime " treatments were observed. Christchurch District. —Apples : A " complete " manure has given the best results. Lime appears to show no response. Roxburgh-Ettrick District. —Apples : No significant differences in yield were recorded on the replicated trial, but on observational plots nitrogen appears to have given a marked improvement in the vigour of the trees and potash also appears to have been beneficial where applied in association with nitrogen. Peaches : On bearing peach-trees the response from nitrogen was outstanding, and there has also been a response from potash in combination with nitrogen. Apricots : Plots receiving nitrogen were superior in appearance and growth to the remainder of the treatments. Lime appears to give no response. Central Otago. —Apples : In three observational experiments responses to nitrogen have been marked both on foliage and upon yields. In one experiment where varying quantities of nitrogen— viz., 2 lb., 4 lb., and 6 lb. of sulphate of ammonia—were used on Dunn's the larger quantities resulted in a good setting of fruit in spite of the fact that this season was what would normally have been the " off " cropping-season. In one other experiment no response to nitrogen was observed, but insufficiency of soil-moisture is considered to have been a limiting factor. Peaches : Nitrogen appears to improve foliage and growth, which is also reflected in improved quality and yield of fruit. In one experiment lime has appeared to increase size of fruit and advance ripening. Apricots : Plots not receiving nitrogen have commenced to degenerate, whereas on nitrogen plots there is improved foliage, growth, and amount of fruit. In two of these trials benefit was also secured by the lessening of frost injury on the nitrogen plots. When varying dosages of nitrogen were used—viz., 3 lb., 6 lb., and 9 lb. of sulphate of ammonia—the degree of frost resistance and the subsequent fruit-setting was proportionate to the quantity of nitrogen applied. General Comments. In this series of trials, with the exception of Hawke's Bay, nitrogen appears to be the most important element in fruit-tree manuring. Since, however, the complete manure plot is invariably the best in the.majority of trials, it would appear that the elements phosphate and potash are also contributing to the improvements which have been obtained. ■ This has been particularly noticeable during the past season, and it would therefore appear that the effect of phosphate and potash are slow to become apparent in contrast to nitrogen which shows up fairly quickly in nitrogen-deficient soils. In Central Otago responses to nitrogen have been outstanding, but more particularly on stone-fruits. Carbonate of lime has given very little response, except in certain cases, such as in some North Auckland experiments, where the beneficial effect of lime upon the growth of the trees and upon the establishment of cover crops has also been noted. In Hawke's Bay during the five years the experiments have been in progress no responses whatever have been obtained from the treatments applied. The various experiments comparing the concentration of fertilizers about the trees with the broadcasting of the applications have so far given no results. No results have yet been secured from the experiments investigating the effects of injecting fertilizers in solution into the soil.

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