Before the Second World War most vegetables for market were grown close to cities and towns to take advantage of shorter and cheaper cartage for perishable crops. Many growers carted their own produce to market. Potatoes and onions, better travellers and storers, could be grown further afield. Main-crop potatoes were grown mainly by farmers in mixed cropping districts; early potatoes were usually associated with other vegetable production in districts that were little subject to frost. There were few vegetables grown for canning. Since the Second World War there have been big changes in the vegetable industry: a great increase in crops for processing and loss of more than 3,000 acres of former market-garden land close to cities. Such areas are mainly at Avondale and Panmure, near Auckland, in the Hutt Valley, near Wellington, and at Marshland, Burwood, Papanui, and the Port Hills, around Christchurch. Except for main-crop potatoes and, perhaps, onions, most vegetables for market are grown intensively or semi-intensively on market gardens of 5 to 50 acres, though there are a few of between 100 and 200 acres. Those below 5 acres, some of which are part-time workings, are often associated with glasshouses or with the growing of specialist crops such as lettuce and celery.

Crop rotation is important in intensive cultivation and it is usual for several kinds of vegetables to be grown. Specialist growers, especially on smaller areas, enrich their soil with heavy applications of organic matter. Some green cropping is done on many market gardens. On some, vegetable production is associated with livestock farming, and the vegetable crops are rotated around the farm. In the Ohakune district particularly, vegetables are grown for one or two years in rotation with pasture. The light volcanic soil in this area quickly loses structure and is liable to severe wind erosion if it is cropped for more than one or two years at a time. Peas for processing are often grown by farmers who use the crop to provide a cash return in the course of ploughing up old pasture and resowing with new grass.

The most prevalent diseases and pests are: Mosaic. (Nicotiana Virus I); Verticillium wilt (V. dahliae and V. albo-atrum); Black root rot (Thielaviopsis basicola); Leaf miner (Gnorimoschema operculella); and Cutworm (Heliothis armigera). A physiological effect causing bronzing of the leaf late in the season and, thought to be a form of chilling, can cause quite severe losses.

by Moore Grant Baumgart, B.SC., Horticultural Division, Department of Agriculture, Nelson.

Research into soil types and recommended fertiliser programmes, and chemical analyses of tobacco and soil, have been made by the Cawthron Institute in Nelson. The growers, the manufacturers, and the Department of Scientific and Industrial Research have a joint Tobacco Research Station. This station has bred varieties for local conditions and types resistant to black root rot. It also produces seed for the growers. There is a local breeding programme and, as well, new varieties from overseas are checked for suitability for local use. Fertiliser trials, disease-control trials, and drying experiments are all carried on. Experiments to prove the practicability of drying leaf in bulk are in progress. Small-scale trials in the 1960–61 season would appear to indicate that this should be possible.

The kilns in general use today are of the down-draught type capable of loading four to five sticks high. Drying takes five days. On unloading, the tobacco sticks are bulk stacked, generally in the grading shed. When the harvesting season is over the leaf is returned to the kiln for conditioning before grading. Conditioning consists of allowing the dry and brittle leaf to take up some moisture from the hot and humid kiln. This allows it to be handled without breaking. Grading is done on the farm and then the leaf is delivered to the factory.

The main variety grown is Virginia Gold – a fluecured type which crops heavily and is good for manufacture. About 95 per cent of the total grown is of this variety, the remainder being mostly Burley – air dried. The crop is grown under contract to the manufacturers. Seed is sown in beds on the farm. The soil in these beds is sterilised against soil pests and diseases. Seed is sown very thinly so that the young plants do not have to be handled before transplanting to the field. This practice reduces the spread of mosaic. Seed is normally sown in late August. Calico covers are fitted to the beds to shade the plants on extremely bright days and also to protect them from frost. Planting out in the field is normally done in November when fear of frost has passed, most of the area being planted by machines. Cultivation is continued while the crop is small enough to allow the passage of tractors. Almost all the area is irrigated. Harvesting begins in late January and continues until the first frosts in late April. Harvesting machines, both imported and locally made, are used on most of the larger farms. When harvesting stops the ground is thoroughly cultivated, often with a rotary cultivator, so that all stalks and trash are buried. Cover crops of short-rotation ryegrass or rye corn are grown in the winter.

The yield per acre has steadily increased with better varieties and better cultural practices: from 600 lb of dried leaf per acre in 1935–37 to 1,200 lb in 1945–47 and 1,600 lb in 1963–64. The total crop for 1963–64 season was over 9 million pounds from 5,800 planted acres. In 1963–64 the amount of domestic leaf used in manufacture was 50 per cent of the total.

The commercial growing of tobacco in New Zealand is at present limited to the Waimea county of Nelson Province. Most of the area is close to the town of Motueka. Soil and climate favour this locality. The best soils for producing heavy crops of good-quality leaf are sandy silt loams of the river valleys. The largest area of this soil type is in the Riwaka district. Tobacco is also grown on heavier soil types in other river valleys in the area. The Motueka district has an annual rainfall of about 40 in., reasonably evenly spread throughout the year. It is very sunny (about 2,500 hours a year) and free from wind. Hot days, with temperatures of up to 90° F, with warm and humid nights, suit tobacco.

As red spider rarely builds up to epidemic proportions, no control is practised. Black root rot (Phytophthora cactorum), a soil-born fungus, has caused great losses of plants. Resistant varieties are being used as replacement plants. Two minor outbreaks of Verticillium wilt (V. albo-atrum) have been recorded. Quarantine measures prevented the first outbreak spreading and it is hoped that the second one has been also confined. It does not seem necessary to spray hops to control insect pests or diseases.

by Moore Grant Baumgart, B.SC., Horticultural Division, Department of Agriculture, Nelson.

Growers, brewers, and Government together operate a Hop Research Station. The station was originally set up to breed satisfactory hops, resistant to Phytophthora cactorum. This has been done, and other projects in the field of hop breeding and drying are under way.

The Hop Marketing Committee, a grower committee with State representation, controls the sale of all hops. This Committee acts under the statutory authority of the Hop Marketing Regulations. One business firm in Nelson is the broker for hops. The representatives of New Zealand Breweries inspect samples and select their needs. The surplus is available for export. Under the regulations New Zealand's needs must be met before any export can be made. No imports are allowed while New Zealand hops are available.