LECTURES TO GROWERS

Nelson Evening Mail, Volume LXIII, 5 August 1929, Page 7

LECTURES TO GROWERS

BY MR T. KlfiO AIND MISS LYSAGHT

ORCHARD MANURING

At the invitation of tlio Moutere Hills Fruitgrowers' Uiiitm, Mr J'. I>igt? unci -Miss Lysaght of the Cawthron Institute gave to a gathering oT growers short, lectures with orchard manuring and the bronze beetle. In I lie cuur.se of his lecture, Mr T. Rigg stated Unit in the past many negative or conflicting results had been obtained in manurial experiments on applo trees conducted in England and United Stales of America. Recently the work of the East Mailing Fiui; Stntioii, Knglaiid. had demonstrated that some of these manurial experiments were unsatisfactory because the root-stocks useil for the trees were unstandardised. It had been ascertained that root-Stocks exerted a profound influence on tree individuality and owing to the lack of standardisation a large; experimental error had been introduced into some <;l the manurial •experiments. A number of manurial trials in both England and United Stains of America had however, shown the value of manurial treatment for particular soils. In United States of America nitrogenous manures have given excellent results in the case of old established orchards many of which were in sod. Phosphatic manures, apparently, have seldom given any marked benefit to crop. Pqtassic manures have been found essential in certain parts of California where great 1 isses have been occasioned in the prune plantations as a result of potash deficiency.

In England, a deficiency of potash has been shown to detrimentally affect both vigour of tree and yield of fruit. Definite increase in yield and improvement in the vigour have been reported by both the East Mailing and Long Ashton research stations as a result of liberal potassic manuring. The negative results obtained in a number of experiments in both United States of America and England suggested that manuring of apple trees was frequently unrcmuneralive. under their systems of orcharding. In New Zealand, the use, of the Northern. Spy stock which gives the trees a more restricted root development, the close planting of trees and the utilisation of poor soils for orcharding have all combined to make manurial treatment of more probable value. In certain cases

experience lias already demonstrated that good growth of tree and high yield of fruit cannot be maintained without resort to manurial treatment. On Iho other hand, it, was only to be expected in view of the small demands made by applo trees on the plant foods of (hi; soil, that, little response would be obtained -on fertile soils to manurial treatment. Obviously even on poor sioiia there was a. limit beyond which manurial treatment would prove, unprofitable or even detrimental In yield of fruit It is vvei: known Unit cert:i,i;i orchard

areas of New Zealand have benefited greatly from judicious manurial Ireulment.' Little 'data are available, however, showing the ret urn which has been obtained by imiiiurial frealnienl. Nor is it known what part individual plant foods have played in promoting the welfare of the trees. Such data could only be obtained from the conduct of carefully controlled experiments over a period of years. Several experiments oi this nature have been initiated by the Cnwthron Institute and it was now possible to draw fairly definite conclusions concerning Ibe influence of manurial treatment, in several localities of the Nelson district. .Many points, however, in connection with the efl'ec: of individual plant foods on yield of fruit still remained obscure and much additional work would be required before n final statement could be made.

PEACH CULTUIH

The experiments of the Institute have; shown the great importance of nitrogenous manures for peach culture. On the highly fertile sands of the Motueka Valley—tised for peaches and small fruits'—an increase in yield of one bushel per tree had been obtained as a result of the annual application of three poUNds of nitrogenous manure per tree. I'lie increase in yield represented a total of 120 bushels per acre, which could be safeiv valued at C 36. Little benefit on the 'Motueka sands had been obtained from the use of phosphatic or potassic fertilisers in this experiment. This lack of response to phosphatic fertilisers was in keeping with the results of the soil analyses which had been made by the Institute on Motueka soils and which had revealed very large supplies of available phosphate in the soil. 'I he supply of potash in the Motueka sand, was not high and in the meantime an application of lewt. per acre of sulphate or potash was desirable for peaches. Experiments With peaches on tiie Stoke fine gravelly loam had likewise shown the great importance of manurial treatment. An increase in yield of over 201hs per tree yearly had been obtained in a three year trial from the use of a mixture of 2lbs superphosphate, lib sulphate of potash and 31 bs of nitrogenous manure per tree.

APPLE CULTURI

Mammal experiments on apples had been conductod at Upper Moutere and at Wakatu. The orchard selected for the experiments in tipper Moutere was located ou a Ivpical area of Moutere Kills soil, while' the orchard at Wakatu was situated on a more fertile soil wellsupplied with organic mailer and nitrogen. The manurial experiments at Upper Moutere bad been conducted over a period of six years during which a manurial programme based on the general recommendations of the Institute for the manuring of Moutere Hills orchards had been -used. The manurial programme included the use of cover crops at least twice in "very three years and the use of both phosphatic manure at the rate of 5-6cwts per acre annually and sulphate of potash at the rate of 1 1-4 cwts. per acre annually. In addition lib of nitrogenous manure —such as ammonium sulphate or dried blood—per tree had been used as a spring dressing. last spring the quantity of both phosphatic and nitrogenous manures bad been increased. Careful records of fruit yield on different blocks have shown that during the last two years an increase of over 30tbs fruit per tree per year had been obtained as a, result of the manurial treatment. On the acre basis this represented tin increase of over 100 bushels of fruit per acre per annum and bore striking testimony to ths value of the manurial programme recommended by the Institute for Moutere orchards and"used by the majority of growers ou the Moutere Hills. Great improvement in. growth and vigour of the, treated trees in the Upper Moutere experiments had taken place during the last three or four years. The untreated trees, on the other hand, were in a bad way—growth was practically at a standstill and much dieback was in evidence.

lii tlie experiments at Wakatu, conducted on a soil ot' fair fertility although somewhat low in phosphate, little improvement in yield had been effected eve -iftor manurial treatment for nine jem3. The data suggested that phosphatio and potassic manures had .been, beneficial to yield but that nitrogenous manures on this soil had had no beneficial effect on yield of fruit. The treated trees, however, were superior in growth and general development and were quite free from dieback. The untreated trees although they had produced almost as much fruit as the treated trees were not so vigorous and dieback was becoming very noticeable particularly in the. Dougherty variety. The results of the two sets of experiments indicated that the value of manuring for apples was greatly dependent on the type of soil used for their culture. Although great gains in yield had been obtained on a poor soil, the value of manurial treatment on better soils was more doubtful. On good soils, little manurial treatment should he needed provided good cultivation was maintained throughout, 'the spring and earlv summer.

The use of large amounts of nitrogenous manure for frees of normal development could not be recommended as it tended to lower the quality of the fruit and might indeed adversely affect the yield. For .Moiitere Hills orchards which have been u\u\ev a guod manurial programme for 5 or G years 2lbs per tree of a nitrogenous manure—such as sulphate of ammonia—should not be exceeded in the spring treatment.

COLOUR '.Mr ftigg slated that there was little evidence tit support a theory that potassic manures improved the colouring of fruit. The most important factors concerned in colouring were (1 ) adequate sunlight- -heavy nitrogenous manuring tended to delay maturity by at least a fortnight and by promoting vigorous foliage development In the autumn reduced the amount of sunlight reaching the apples. (2) Suitable moisture conditions an adequate supply of water was required within the tree for the maturation of the fruit and the conversion of starch into sugars.

(3) Suitable temperature conditions. Every variety of apples had particular soil and climatic conditions favouring an attractive appearance of fruit. In the ease of some highly coloured varieties low temperatures at uighl during the ripening period favoured high colour of fruit.

QUALITY IX RELATION TO MANURING Cool storage experiments conducted by Mr L Tiller of the Institute had definitely shown that quality of fruit was in-

fluenccd by the type of soil on which it was grown. Manuring on certain soils had improved greatly the keeping qualities of (he fruit. There was great, invi) for the extension of these investigations so that the exact, effect of both soil and manure on the keeping quality of fruit could be determined. It seemed probable (hat other ailments such as pitting [o!' fruit, scald, iiusseting might be i:, (lueucod by the iii.uiiiria.l programme oi tlic. orchard int. | la England, it Iliad been shown, that high phosphate and potash content oi I the appl,- was associated with good keeping quality of the fruit.