HORTICULTURE.

New Zealand Journal of Agriculture, Volume XXX, Issue 5, 20 May 1925, Page 349

HORTICULTURE.

SOIL-TREATMENT. The effects on the land of continuous cropping, of one kind was well known to our forefathers. The bad results were overcome by laying the land down in grass and clover for a period, and thus allowing it to recuperate. In more intensive methods of culture the difficulty was avoided by a suitable rotation of crops. Potatoes subject to early and late blight would be followed by an entirety different crop possibly peaswhich was not at all subject to the same diseases, and would . then die out for want of a host, the heavy, demand on plant-nutriment in the soil being made up by generous applications of manures. Much of the land in this country —too much, possibly- — devoted to horticultural crops is very high-priced owing to its situation within town boundaries — circumstances which compel the grower to confine his attention- to those crops only that give a maximum return. A position which is more acute still is where the crop is grown in land under glass. .Scientists have devoted a great deal of time during recent years to meet the position/ and our correspondence shows a keen demand for this class of information. In the application of steam to the . soil, under right conditions, we have , a wonderfully effective remedy, the only objection to which is its cost, although where there are a sufficient number of growers of crops

under glass in a locality they might well co-operate in securing an outfit for mutual use. Small quantities of soil may be sterilized by baking it in a pan in an oven before sowing the seed, or placing the box over a sink and pouring a gallon or two of boiling water into it as fast as the soil will take it up, afterwards standing it aside till sufficiently dry for sowing. With chemicals we have much less certain, agents, although good work has been done. While many chemicals when applied to - the soil act to a certain extent both as a fungicide and an insecticide, it is well to clearly, ascertain the character of the primary trouble to be dealt with before selecting a chemical remedy. For instance, eelworm, insect larvae, and fungus in the soil require distinctive treatment* Where eelworm is the main trouble, experience has shown carbon bisulphide to be the best chemical remedy. Use it at. the rate of 6 oz. per square yard, pouring it into a number of holes about 5 in. deep ; then fill and tamp the holes. Afterwards water the ground if the surface is loose or dry. A good method of doing this is to mark off the land in lines 1 ft. apart, cross-mark them by the same distance, and make the holes at the intersections, pouring in two-thirds of a fluid ounce of the chemical, an assistant following filling in and tamping the holes. For a glasshouse 100 ft. by 25 ft. 10 J gallons of carbon bisulphide would be required. A useful non-poisonous fungicide for this purpose is a 1-100 solution of formalin (formaldehyde), applying about 1 gallon of mixture per square foot. Two or three weeks should elapse before sowing or planting the land so treated. Growers who are not suited by these methods might try the " Cheshunt Compound.” It contains 2 oz. copper sulphate (bluestone) and 11 oz. ammonium carbonate reduced to a fine powder and thoroughly mixed. Store it in a dry state in a tightly corked glass or stone jar for at least twenty-four hours before using. A solution is prepared by dissolving 1 oz. in a little hot water, and making up to 2 gallons with water. Water the infected soil, after which immediate planting may follow. Infected soil may be treated after seeds or plants are in position. This is . specially recommended for fungi causing “ damping-off ” and root troubles. As tomato-growers will now be commencing another season, the foregoing information will be useful to many. During the season just past “ damping-off,” black-stripe, fusarium wilt, and sclerotinia were very troublesome in places. Fruit affected with the latter disease was very noticeable. It is quite true that “ prevention is better than cure," and the best treatment is good drainage and cultivation, and a carefully considered use of manures. Many’ growers engaged in intensive culture on heavy land might well use more lime, especially for the tomato crop. - VEGETABLES AND POTATOES. Broad beans may be sown now, and in suitable localities sow peas and plant out lettuce. For early planting seed potatoes should be secured now, spread in trays for sprouting, and stored in a light airy place. Should the potato-moth be about, dip them in a mixture composed of i|lb. arsenate of lead and 50 gallons water.' Where new land in grass has to be broken in, a commencement should now

be made by skim ploughing and allowing it to lie until the turf is killed. Where available, manure from the cow-sheds and stables should be carted out, and a liberal dressing applied to land that is to be planted out in early potatoes and main-crop cabbage and cauliflower. Plough it in, and commence that thorough preparation which is so ■ necessary. THE SMALL-FRUIT SECTION. The pruning of the small-fruit section will now demand attention. Black currants should be pruned to induce an abundance of strong young wood in the bushes ; this may be done by cutting back old wood to a bud near the base. Red and white currants require an almost opposite treatment. It is best not to top the main growth in these bushes after the first year or two ; maintain an open centre and remove all, suckers. To allow gooseberries to become crowded is fatal to best results. Prune to keep the growth well spread out, and renew the laterals by shortening to base buds those that are old or weak. The carryingout of these simple directions would bring about great improvement in many plantations of these useful berries. Raspberry-canes are usually cut out as soon as they have fruited ; if this has not been carried out it should be done now, taking care to cut low down, removing also canes that are out of place, and cutting down those that are weak. Owing to the prevalence of cane-wilt and anthracnose, carefully carry out the old canes and burn them. Much the same treatment is suitable for the loganberry, which- is now so popular, with the further addition of training in the new running canes. These are usually divided into four bundles, two being wrapped round and left on a lower wire and secured, and the other two in a similar manner on the upper wire of the trellis. —W. C. Hyde, Horticulturist. New Rabbit Districts. — The constituting of the following rabbit districts, for the purposes of Part 111 of the Rabbit Nuisance Act, has been gazetted : ’ Mairoa, Arapae, and Oparure (all in Waitomo County), and Akitio (in the county of that name). •. ■ ■ ‘ . Honey-export Control.— For the purpose of enabling the New Zealand Honey Control Board effectively to exercise a limited control over export,, shipment of honey to Europe has been prohibited 'save by license from . the Minister of Agriculture, subject to such conditions as may be approved by the Board.

Wheat and Oats Threshings. — Returns of actual threshings up to 20th April received by the Government Statistician from threshing-mil! owners showed that until .then 2,810,292 bushels of wheat and 2,991,913 bushels of oats had been threshed out. The average yields per acre in cases where particulars of areas were furnished (covering 99 per cent, of total. threshings) . worked out at 34-05 bushels for wheat and 39-73 bushels for oats. The figures for the Canterbury, Otago, and Southland Land Districts respectively were as follows : Canterbury— Wheat, 2,283,580 bushels threshed, averaging 34-66 bushels per acre . oats, 1,636,211 bushels threshed, ■ averaging 38-84 bushels per acre. Otago-Wheat, 427,192 bushels, averaging 31-89 bushels per ' acre; oats, 691,796 bushels, bushels per acre. Southland —Wheat, 42,602 bushels, averaging acre;-) oats, 515,403 bushels, averaging 43-77 bushels per acre.