BRUSSELS SPROUTS A VALUABLE WINTER CROP IN OTAGO

New Zealand Journal of Agriculture, Volume 78, Issue 1, 15 January 1949, Page 59

BRUSSELS SPROUTS A VALUABLE WINTER CROP IN OTAGO

By

W. G. CRAWFORD,

!, Instructor in Vegetable Culture,

.J Department of Agriculture, Dunedin.

LITTLE is known of the origin of brussels sprouts, but according to literature the vegetable was in demand as a food in Brussels as early as 1213, and its name is derived from association with the Belgian capital. In Otago the history of brussels sprouts culture dates back to 1890. Although there are no reliable records available, it is highly probable that brussels sprouts were, included among the first vegetable crops grown, but not until recent years was this most important crop cultivated in Otago on a commercial scale. Today Otago is the leading brussels sprouts-producing area in New Zealand. Production is confined mainly to Taieri and Oamaru districts, where some 70 acres, with a yield of approximately 350 tons, are grown annually.

THE value of the brussels sprouts crop to Otago market gardeners varies considerably, each year according to market fluctuations, but the return for the last crop was estimated at between £16,000 and £20,000. The distribution of the crop is determined mainly by market prices, but the following list gives some idea of the way in which Otago-grown brussels sprouts are distributed: — Percentage Market of crop Invercargill .. .. 6 Gore ... .. .. .. -2| ' Balclutha ■ . . ... .. r 1J Dunedin .. . . . . 35 Oamaru ... ". . . . 2 ■ - Timaru ’ . . " . . . . 4 - Christchurch . . . . 35 North Island cities . . 14* * When ' transport is normal. Brussels sprouts rank high in importance among . the vegetable crops grown in Otago and every care is taken to maintain a high . standard of cultural practice and to bring production to the highest possible level. Otago’s climate and soil ? conditions seem well suited to the cultivation of brussels sprouts. As with most crops

brussels sprouts will naturally do much better on certain classes of soil than on others, and in Otago the most suitable soils are those ranging from loam to heavy loam. Very light sandy soils and shallow soils, should be avoided. < - - ; In the Otago district' land must be well drained, either naturally or artificially, free working, of a good depth, and in proper physical condition to produce good crops of high quality. Excellent crops are obtained during the first two or - three years where virgin land rich in organic material (grass and rootlets) has been opened up. The organic material assists in keeping the soil’ open during the growing season, in conserving moisture, and ultimately in supplying plant foods. In older land these conditions are attained only through the addition of organic matter to the soil by .working in green crops, etc. As brussels sprouts are gross feeders, ample plant food and moisture are needed. , Exceptionally high yields have been obtained in Otago in seasons when the autumn has been wet and cold, but the winter comparatively dry. Fertilisers In fertile virgin soils the plant foods necessary, for successful cropping are

generally present in sufficient quantity, but elsewhere it may be necessary to apply fertilisers and organic manures. This may be done either by adding artificial fertiliser or by incorporating green crops or animal manure with the soil.

Many methods are adopted for increasing yields: Good cultural practices, disease control, and seed selection all have their bearing on crop production, but Otago growers consider that the intelligent use of fertilisers on ordinary soils is. a most important factor in the economic production of brussels sprouts. ■ ’ .

Because most market gardeners find it difficult, if not impossible, to obtain natural manure such as stable manure, stack bottom, cow byre cleanings, etc., artificial fertilisers have to be used. It is not possible to lay down any hard and fast rule as to what manures to apply, as the type and quantity required depend generally on the previous crops grown on the land: There are, however, certain basic principles practised by Otago growers, who realise that fertilisers improve the quality of the crop considerably and greatly influence the yield. ' .

v Best results over, a number of years have been obtained by using a mixture of superphosphate, 3 parts by weight, blood and bone, 4 parts, and sulphate of ammonia, 1 part. This mixture is used, at the rate of Bcwt. to the acre, by growers throughout Otago with excellent results. It is. applied in two dressings: The first at the rate .of 6cwt. to the acre is made before transplanting the crop; the second, at the rate of 2cwt. to the acre, is made as a topdressing, generally 2 months later, just before inter-row cultivation begins.

Green Manure and Stable Manure Stable and animal manure, usually combined with straw, has been found excellent material for incorporation with the soil for brussels sprouts growing. However, the value of the manure to the crop depends largely on the kind of animal from which the manure was obtained and the percentage of straw incorporated with the manure. , Stable manure is broadcast on the land after the initial cultivation and lightly harrowed in before ridging is done. Green-manure crops are most important for improving the physical condition of the soil, which is necessary for free development of plant roots and high-producing crops. Only by the incorporation of organic material has 'it been possible to prevent the physical condition of the soil from being impaired. There are several crops suitable for employment as green crops, but in Otago those used, in order of importance, include oats,'lupins, barley, and peas. There are, many important factors to be taken into, consideration when determining the most suitable green crop to grow, but generally the value of a

green crop lies chiefly in the quickness of growth . and the amount of humus produced per acre. . Deep-rooting green crops bring plant food from -the subsoil and when incorporated into the topsoil provide additional plant foods for the growing crop. Where -the land is inclined to cake, two green crops can be grown in the ground during the spring and summer. If a system of . crop rotation and green manuring is followed, the physical condition of the soil can be maintained. f ■ > . x/. ' I 1 ' Preparation of Land •• " Because of variations in the soil and the varying - treatment necessary on different classes of . land, there is no set method of cultivation, but the aim is to bring the soil to a fine tilth suitable for the needs of the crop and for the free development of the plant roots. No crop responds better to good cultural conditions of the soil than do brussels sprouts. 1 . The .initial cultivation■ before planting is a most important factor in successful cropping. Deep cultivation is carried out, as • early as possible in

the spring as soon as soil conditions are favourable. The soil is usually cultivated to a depth of 8 or 9in., but this will depend on the depth of the soil. The ground is worked to a fine tilth and a green crop sown for incorporation in the soil to increase the. supply of humus. Growers have found that brussels sprouts thrive, best on virgin soils rich in organic matter, which clearly indicates that' humus in some form is' necessary. It is therefore obvious that for good crops the condition of the soil should be as similar as possible to that of virgin soil. The green crop should be evenly distributed throughout the soil rather than ploughed in in the ordinary way, and the rotary hoe has given excellent results in Otago mar-ket-gardening districts, where the subsoil is mainly sandy. After the green crop has been hoed in the land is generally allowed to lie until 2 weeks before planting, when it is. given a further cultivation with the discs and spring-tooth cultivator. After being worked to a fine tilth the ; soil is thrown up in ridges 2ft. 6in. apart and 8 to Din. high, running in the direction of the water flow. Ridging facilitates drainage and makes for a longer growing season; as the soil is kept much warmer in the autumn and early. winter than where the soil surface is flat. - .

Liming

In Otago liming before initial cultivation is an important part of management where brussels sprouts or any other cruciferous crop is being grown and is seldom neglected by the more experienced growers.. Liming, which is usually carried' out at 2- to 3-year intervals, assists greatly in the prevention of club root, a common disease of brussels sprouts and allied crops. The rate of application is from 20 to 30cwt. of carbonate of lime per acre.

Varieties

Of all the varieties of brussels sprouts cultivated commercially ' in. Otago Scrymger’s Giant has met with the most success if given suitable treatment.- ( ' \

Raising Plants

Late October or early November is considered the best time, to sow brussels sprouts in Otago to produce well-established plants ready for planting out in late December. The more . thorough the cultivation of the land on which plants are to be raised the better plants are likely to be. As plants from poorly-prepared seed-beds seldom yield good crops, great care must be taken in the preparation of the ground. Plants do best when sown in beds raised 6 to Bin. above the level of the surrounding land. To provide favourable conditions for the seed the soil is reduced to a very fine tilth. Where the land has- been used previously for gardening a dressing .of blood and bone and superphosphate is applied at the rate of 6oz. per square yard, and lightly hoed into the-topsoil. A topdressing of lime, |lb. per square yard, also helps, to keep the soil in good condition and assists in the production of healthy, vigorous, stocky plants. . '

The seed should be sown thinly and evenly in rows 6in. apart, running north and south. Beds 4ft. wide are considered the most convenient for working, as the operator can weed any part of the bed without tramping on the bed itself. Successive sowings of seed are made when required up to mid-December. Plants are never allowed to remain in .the seed-beds until they become root bound or are checked.

Planting Out

In Otago the planting of the crop extends over a period of 6 to 8 weeks. However, most of the planting is done from mid-December to mid-January, which is considered the best time for starting plants successfully.

Only plants free from disease, with good root formation, and of strong, vigorous appearance are planted out. Care is taken to see that the crown or heart of the plant is not damaged in any way during handling. Transplanting is all done by hand in Otago and where two or more operators are engaged a small garden spade has been found to be the quickest and most satisfactory implement for - the work. On one-man units an ordinary garden trowel is quite satisfactory. Correct spacing of plants is important, because brussels sprouts require plenty of room for full development. It is usual to allow 2ft. between plants, with 2ft. 6in. between rows. At this spacing approximately 9000 plants are required to plant an acre.

-- Plants should be thoroughly watered in the seed-bed several hours before planting in the field. It is preferable to transplant on a cool day, to avoid excessive wilting. Plants are placed in the soil opening prepared either by a .trowel, or a spade and the soil filled in and pressed firmly around the plant without crushing, or disturbing the roots in the ball of soil attached. If this work is,carried out. when the soil is dry, a good watering to settle the soil round the plants is beneficial. During dry weather the top half of the leaf growth on each outside leaf is removed with a sharp knife to form a balanced condition with the root

system, which may be injured during transplanting., ' , v < Management of Growing Crop Frequent shallow cultivation to keep the soil loose and weeds in check is practised, but deep cultivation, which is likely to disturb the roots of the plants, should be avoided. Brussels sprouts are perhaps the best of all winter vegetables cultivated in Otago, but are by no means an easy crop to grow. The plants must be given the proper cultural conditions. That is, they must have a uniform moisture supply, there must be. adequate available plant food, and they must not receive any check in growth,

particularly during the early growing period. Close, firm sprouts are ret. quired. and if the crop is grown in dry soil during hot -seasons, the atmosphere tends to make the sprouts open. The number of cultivations necessary depends on weather conditions and the ' physical condition of the soil, but cultivation should not extend into the early, wet winter months. The surface soil is kept sufficiently loose to absorb and retain moisture and permit . free root action and extension in search of food. The second application of fertiliser, mentioned earlier, >is applied by hand close to the plants, 6 to 8 weeks after planting, just before cultivation begins.' A practice strongly advocated by growers is the use of the hoe as soon after rain as possible at every opportunity during the summer. The object is to restore the tilth of the land and to conserve moisture. Sprouts form on the stems in the axils of the leaves and these leaves should be removed as the sprouts appear. All bottom and decayed leaves should be removed in late autumn sothat light and air can reach the plants. The usual procedure is to break the leaves off short by bending them down sharply. • The stump of leaf stalk usually left withers and falls, leaving a healed scar. ■ )

Harvesting

The harvesting of the crop extends over a considerable portion of the year. In the Oamaru district harvesting commences usually in May. Owing to its proximity to the sea, the climate of the district is more favourable for the earlier development of the sprouts than that of the Taieri district, where harvesting generally begins 2 to 3 weeks later. Harvesting continues right through the season, from May to September and even later in some seasons. Harvesting should , not be delayed unduly, but in certain soils, particularly the sandy, well-drained loam of the Taieri Plains, the sprouts remain

in excellent condition for longer periods than in ' the Oamaru district, where the climate is usually warmer. As the harvesting of the crop proceeds additional bottom leaves are removed, but those forming on top of the plant are retained, because they are necessary for the well-being of the plant and they also provide protection from frost for young sprouts. The earliest-harvested crops generally command high prices on the local market and are seldom sent out of the Otago Province in any quantity during the months of May and June, when it is the practice to harvest sprouts and pack them in 251 b. cases for sale. Cases reduce to a minimum the risk of bruising and at the same time allow for good ventilation-between the time of harvesting and retail distribution. Crops harvested later are packed in both cental bags and cases. Packing in bags is done mostly for the sake of convenience when produce is to be railed to markets outside the Otago district. Sprouts packed in cases keep better for a longer period than those packed in bags, which sweat badly if held for any length of time.

Pests and Diseases

Information on insect pests and diseases attacking market garden crops is available from x all branches of the Horticulture Division, Department of Agriculture, and consequently only those experienced each year in Otago are mentioned here. Generally brussels 1 sprouts in Otago are affected by few diseases and insect pests other than club root, cabbage aphis, and white butterfly, which seriously affect crop yields. , .

There is not very, much spraying of brussels sprouts done in Otago, but the

information given below on the principal diseases should be of assistance to those desirous of carrying out a spraying programme. For successful cropping in Otago there are several important points which must be kept in mind when dealing with all pests and diseases: Spraying must be done at the correct time; it must be thorough;, and good judgment .must be used.

Disease Control

Club root (Plasmodiophora. brassicae): This fungus disease attacks all cultivated plants of the cabbage family, causing swellings and knots of varying sizes , and shapes to develop on the roots. The plants become yellowish, stunted, and make very little growth. Spores of this fungus enter the plant through the root, cells and feed on the contents. When the . root dies spores are set free in the soil to attack plants of the same family when conditions are favourable. The spores are small, move easily in the soil water, and may cause serious losses if certain preventive measures are not adopted, and the following are recommended: / . .; 1. As . the disease flourishes in acid conditions, ' sweeten the . soil for brussels sprouts growing by applying lime at 2- to 3-year intervals at the rate of 1 to 3 tons per acre; improve drainage where this is not satisfactory.. 2. Practise crop rotation as far as possible by allowing as long an interval 7 as practicable between the growing of host plants. Exclude cruciferous crops from affected land for a period of at least 3 years. ' 7 ' ' 3. Examine all plants carefully when lifting them from . the seed-bed and destroy any showing club root infection. Treat infected seed-bed soil with mercuric chloride. 4. Destroy all infected plants by burning. White butterfly (Pieris rapae) : The caterpillar of this butterfly feeds on the 7 leaves of brussels sprouts and related plants. The caterpillar, which may ,' be up to l|in. long, is dull velvety-green' with -an orange stripe down, the middle of the back. The pest is worse in hot, dry seasons and over the past few years has been troublesome to. growers, resulting.. in heavy losses of produce. • ■ To control the pest plants should be sprayed with arsenate of lead (l|lb. to 100 gallons of Water). Spray the under-sides of the leaves thoroughly. Cabbage aphis (Brevicoryne brassicae) The cabbage aphis. or the green fly, as it is generally called, does considerable damage . to , all cruciferous crops in Otago if unchecked. The pest is particularly troublesome in periods of dry weather, when colonies of the small, greyish-green insect cause leaves of the plants to curl, giving a greyish l appearance to infected plants. To control the aphis plants should be sprayed with nicotine sulphate (1 part to 800 parts of water, plus 3 to 41b. of soft soap to every 100 gallons of solution). . ." y -

CASEOUS LYMPHADENITIS ERADICATED v By Aseptic Conditions in a High-country Shed ... ' i ’HE eradication of caseous lymphadenitis by the adoption of strictly aseptic conditions in the shearing shed has been achieved on the Godley Peaks Station in the Mackenzie Country. Several years ago the station was putting between 1000 and 1200 Merino sheep through the works annually and an average of between 25 and 33 per cent, was being rejected because of lymphadenitis. In the past 2 years, with about the same number of sheep being sent to the works, there have been no rejections because of lymphadenitis.

THIS /Outstanding success is attributed by Mr. John-Scott, owner of the station, to the following: —

1. Olive oil with a 5 per cent, carbolic added for use on the sharpening stones is supplied to shearers. 2. Oil rags consisting of scoured sheepskins, which are changed twice weekly, are supplied to the shearers. 3. Water tins contain a strong solution of carbolic soap. 4. The shearing board is scrubbed down with an antiseptic solution after each day’s operations, even if only a few sheep have been handled in that day. 5. The concrete floors of the count-ing-out pens are sprayed at regular intervals to keep down dust, and after each day’s shearing the pens are thoroughly hosed down. —K. G. GRAY, Inspector of Stock, Department of Agriculture, Fairlie.

Illegal Wool-branding Materials Still Being . Used

MOST farmers are aware that woolbranding materials must be tested and approved by the Department of Agriculture before they can be marketed. It is now a punishable offence to use anything other than approved wool-marking preparations, or to add anything to an approved preparation which will make it harmful to the wool. This / legislation is in the wool growers’ own interests, because brands which will not scour out cause enormous damage and loss in the woollen mills—and in the final analysis this loss has to be borne by the grower of the wool. From complaints still being received from buyers and mills, some farmers apparently are still using harmful. materials, so buyers continue to view all brands with suspicion. Thus the majority of wool growers are suffering for the actions of the. few. The remedy lies in the producers’ own hands— use of only approved branding materials.