PRUNE GROWING.

Auckland Star, Volume XLIV, Issue 102, 30 April 1913, Page 8

PRUNE GROWING.

• _ A PROMISING INDUSTRY FOR THE DO_C NION. CLIMATE — SOIL — VARIETIES — PRUNING—DRYING—YIELDS. ;By 8.N.) The prune is a fruit of high commercial value, and it is astonishing that its cultivation has not been more widely undertaken in these regious, for the fruit is popular with cons timers, and large quantities arc imported from California, a young country, .where the natural con- I ditions are certainly not more favourable than in New Zealand. The inline, likp the cherry, has its home in Franco, a land of high culture and wonderful production, and the well-known French article is produced in a climate very similar to that of the Dominion. The prune, which is really a variety of plum, has a wider range of climate ih.in ' the cherry. The cherry will grow! on the Australian tableland*, where the climate is comparatively cool] uii|til after picking time, but it j is never seen on the warm coastal j lands or in the hot inland plains. The I prune does not mind the heat so much, and it thrives in California, in a climate that is decidedly warm. But the prune I certainly produces the finest fruit and yields the heaviest crops in a strictly temperate climate, and there is very little of New Zealand that does not come •under this heading. I want it to be thoroughly understood that I write with knowledge of the country and its natural conditions, and. writing with that knowledge, I say, unreservedly, that there arc many parts of the Dominion which arc as well adapted to prune cultivation as any part of France, where the industry has been so successful. A little brains, however, must be mixed with the cailtivation of the prune. The site of the orchard should be wisely chosen. All fruits require protection from frosts and high winds, and where there is no natural protection shelter belts should be provided — indeed, the shelter belt is essential to successful fruit cultivation under almost all conditions. -With this condition, prune culture should be successful in Central Otago, and in the neighbourhood of Oamaru, Timaru and Tcmuka. The Canterbury Plains arc -rather subject, to frosts and high winds, and there is little natural protection; but the conditions arc belter in Nelson and Marlborough, and in parts of the Wellington and Taranaki provinces. Hawke's Bay lies so .well to the sun that it ought to 6tiit the prune very well, and it should thrive in parts of the Auckland province. The prune prefers a naturally rich soil, it is a strong-growing tree, and requires plenty of nourishing food. If possible, the trees should be planted on a slope, for there is more natural protection, and frosts are lees felt on rising ground, and the. natural drainage is better; but a gentle slope is to be preferred, both for the sake of cultivation and because the soil might wash away in heavy rains if a precipitous site G|hould be chosen. The aspect should be to the north-east, with natural protection from the south-west, and shelter belts should be planted to serve as breakwinds on the north and east. If new, the soil should be sweetened, but not impoverished, by cultivation;, before planting the orchard; and the land ought to be clean —don't, for example, plant an orchard in land infested with couch-grass. It is the custom to plough to a depth of about nine inches, but it would be wise to subsoil, as affording better drainage and better conditions for root development. Personally, the writer holds that the land should be trenched before an orchard is planted. Thorough drainage is expensive, but under New Zealand conditions some attempt at drainage should be .made, il" only by running surface drains or subsoiling between the rows of trees. The young trees are bought when they are a year old, the idea being that they feel the shock of removal less at that age. The trees, which should be out of the grcund for as short a time as possible, should be planted at least twenty I feet apart, but twenty-four feet would be better, as allowing more room for I cultivation and spraying. The prune is a strong grower and should have plenty of room. The holes should be roomy, and the tree should be planted n little deeper than it stood in the nursery, the roots should be enread out to their na-

tur.il position, and any roots bruised or tangled-up in transit should be cut away or straightened out. The soil should be beaten down firmly round the trees. In this connection, it is worthy of note that in recent experiments iv England, where the soil was rammed hard roun-d the planted tree, as though it we're a fencing-post, the tree throve better for the treatment. While the young trees are coming on surface crops may be grown between the rows, 'but with these crops manure should always be applied, so that nothing may be abstracted from the soil that would be of service to the tree when it comes into bearing. In the off season a crop of pcis or vetches may be grown to be ploughed in: and in some parts of New ; Zealand a crop of peas can be grown almost throughout the year. The growing of surface crops will necessitate tho thorough cultivation of the soil, and this will be of benefit to the young orchard. If no surface crops arc grown, the land should be ploughed twice a year, and worked -with the cultivator j whenever weeds appear —no weed should ihe allowed to grow, and the soil should ! never be allowed to cake. Surface cropi [ling should cease when the trees are in ; bfarinjj. iyut cropping for green manuring | should go on for ever. In the bearing stage the trees will require just as much j cultivation as when they .were growing, and the tendency should be to take the soil towards the trees—this will leave a j deprt —ion between the rows that would I serve as a drain in case of emergency. The cultivation of an orchard should begin early in the season. In this work spring-tooth cultivators, set-tooth cultivators, disc harrows, ami smoothing harrows all have their place; the springtooth cultivator is much favoured by Australian growers. The prune may be grafted or budded on the Myrobolan stock, the Marianna plum, and the peach etock. The last two do well on sandy soil, but the Myrobolan stock would suit New Zealand conditions best. The Myrobolan does not sucker, and it takes kindly to soil that is inclined to be cold and wet. Marianna stocks can be grown from cuttings, but the Myrobolan stock should be grown from the pits. All stocks should really ho seedlings, for seedlings make the best root sj-stcm, and scions grafted on a seedling have a better chance to make a strong, healthy tree than scions grafted on v roote-d cutting. Some growers prefer to buy one-year-old trees, from the nursery, plant them, and twelve months | afterwards graft or bud with their own ;scions. By this means they make sure of ■ the variety, and have the further advantsgc of using scions from trees already I acclimatised to tho district. The varieties of prune in most favour are the Prune d'Agen and Robe de Sergeant. At Batlow, in New South Wales, where the climate is very temperate and rather like that of the Dominion, the Silver, Sugar, and Golden varieties have done particularly well, and these varieties might he planted with success in districts to-the south of Hawke's Bay. The young tree requires to be well pruned: it should be cut back to about three buds, and it should be cut back hard for several years until it has acquired the right habit of growth, and finally topped back to give strength to the limbs and prevent the tree from growing beyond bounds. There is less pruning of the cross branches than with the cherry, but above all things the grower must see to it that the main limbs are strong and robust, for the prune is a heavy bearer, and weak limbs •would soon break under the weight of the fruit. A low and rather rounded top enables the fruit to be picked with ease, and affords facility for spraying, and a compact shape gives the tree strength and symmetry. Prunes do not bear continuously like the cherry, but take a rest every three or four years; that, however, should be no excuse for stinting them in the matter of manure. Prunes grow vigorously and bear enormous crops, and to do this they should be supplied with some manure .which includes a good deal of lime and potash, but on poor land a good dressing of farmyard manure might be best. On land of this description, or where an old orchard is being replanted, the young trees should receive a dressing of two or three pounds of bonedust at planting; but on better land they ought not to want manure until they ecme into bearing, and then it should be given liberally. Green manuring is good and I very necessary, but it docs not return to the" soil all that the vrana tak«s from lift.

When the prune crop is ripe it will stand oil the trees better than the cherry. The selling of the fruit in its natural state has helped to keep the prune-drying industry back in Australia, lint the dried product should be the ultimate object of the prune grower, and for this purpose it is not necessary that there should be immediate access to a market, for the dried fruit will keep and carry anywhere.

For drying, the fruit β-hould be j thoroughly ripe when picked, and it j should be handled with care. It is then ! immersed in a solution consisting of lib ; of caustic soda to ten gallons of boiling I water, for from five to ten seconds, according to 'the toughness of the skin, or just long enough to slightly crack the skin. With a stronger lye-dip the prunes would not require such a long immersion, tut the skins must not be cracked too much, or they will present a rough appearance and be liable to go sugary. In dipping, the fruit should be placed in wire or pert orated metal baskets. The tank should be a.bout 24 inches deep, with about IS inches of the boiling solution, and the solution should be kept boiling. The fruit is then spread on trays to dry, and silvcT or light-coloured prunes ehould he put into the fumigator just long enough to 6et the colour well. After this the prunes are placed in the sun or evaporator. In the latter the temperature should be about 130 degrees' to start with, gradually increased to 180 or 200 degrees, the process to last from one to two days, according to' the size of the fruit. If t-he temperature is too high at ■the start the prunes are liable to buret and be spoilt. The evaporator is much to be preferred in most parts of the Dominion, and it has the further advantage that fru'rt so dried is less liable to become inoth-infeoted than if dried in the sun. If the fruit is put in canvas bags as soon ac ronroved from the evaporator there i« no risk at all from insects of any d<«cription. If the fruit is to be dried in the sun, trays of the following dimensions should be used: 2ft x 3ft, 4ft x 3ft, or 6ft x 3ft. The latter sizes are the most popular, and the trays are so made that they can .be stacked at night time or if rain ehould come on. The drying ground should be a clean patch of grass, and the trays ehould be placed with pathways between them, r=o that they may be handled with expedition. The drying process lasts several Aaye, according to the weather, and before putting the fruit into canvas or calico hags, it should be sorted over, and any not properly dried ehould be redried. Sun-drying is common, though not universal, in hot climates; but 1 would reI commend the evaporator as 'best suited :to New Zealand conditions. The fruit, when dried, ehould be pliable, and when removed from the evaporator it should be allowed to lie in sweating boxes for at least four weeks, and it ehould be turned at least once each week. Then it is redipped in a solution of boiling water, to which a little salt and a quantity of broken or damaged prunes have been added. Then again dried. After which it is graded, and neatly packed in boxes .with white paper. iPrune growing is a sound industry. It is estimated that it costs from £G0 to £70 per acre to bring a prune orchard into bearing, and £12 per acre per annum to work it when in bearing. As to the returns: From a prune orchard of four acres in New South Wales 74001b of fruit was obtained in 1912, which wae sold at 0d per lb, or £185. This is a low price, and the yield in New Zealand would certainly be qiiite as high as in New South Wales. For the anterprovincdal trade the Prune d'Agen in ite green state would carry all over tie Dominion, but this variety should 'be twice grafted.