Topping and Suckering

New Zealand Journal of Agriculture, Volume 60, Issue 1, 15 January 1940, Page 60

Topping and Suckering

Tobacco Notes

’ 1 I OPPING should begin as soon as TOPPING cent, of begin soon in 70 per cent, of the crop is in blossom. With a small plantation it is advisable to leave the remaining 30 per cent, of young and backward plants to be topped later, after they have matured and flowered in the usual way. As time may not allow of this procedure where a large tobacco crop is concerned, all plants of a size which promise to be of commercial value should be topped along with the main

crop, irrespective of their being in blossom or not. Many New Zealand tobacco growers do not give enough thought and care to this seasonal operation. A poor tobacco crop may be brought up to almost normal standards by the adoption of wise and proper topping; on the other hand, a good crop may be seriously damaged by careless topping. Topping cannot be standardised, as so much depends on the variety of tobacco

grown, the soil, and the climatic conditions prevailing both before and during the time topping is in progress. Points in Topping The two most important points to remember in topping are:— 1. In a wet season topping should be done lightly, allowing the plants to

retain practically their full complement of leaves. / . 2. If the season has been dry, with indications of dry conditions continuing until, well after topping has been completed, heavy topping should be done that is to say, the crop of a variety carrying 18 leaves to the plant should be reduced to 10 leaves, and to a similar proportion in other varieties. A crop grown during a dry season is invariably poor; the plants are stunted, and the leaves small, thin, and papery. This type of crop ripens prematurely, often so rapidly that it cannot be coped with, and the result is that a large quantity of the leaf becomes ripe on the plant. Such leaf eventually becomes a total loss to the grower. Leaf harvested under seasonal conditions of this kind lacks body to such an extent that it breaks down under the curing process, and is then of very little value. Heavy and Light Topping By heavy topping the plant food previously drawn upon by the seed head

and top leaves is diverted to the 10 ■leaves remaining on the plant, which quickly fill out and grow to normal size, texture, and quality. When harvested, these leaves present no abnormal difficulties in the process of curing. ’ , In a wet season the crop nearly always grows rank and coarse and fails to ripen at' the proper time, often continuing to grow throughout the harvesting period without ripening at all, and, when harvested, only , a very small percentage of bright leaf is obtained from each curing batch. By topping lightly and leaving the full number of ' leaves on each plant the reverse effect to that of heavy topping is obtained, and the effects of the wet season are largely counteracted. The young, newly-formed leaves remaining. at , the top of the plant draw so heavily on the food supply that the flow to the lower fully-grown leaves is, to all intents and' purposes, cut off, thus reducing the tendency to rank

growth and allowing the leaves to ripen in the usual way. Suckering . About 10 days after topping, suckers or laterals appear in the axils of the leaves, due to an attempt by the plants to reproduce themselves. These suckers should be removed at least once a week. In normal circumstances these growths should not be allowed to remain on the plant for any time after they have obtained two inches in length, as from this size onward they begin, to draw so heavily on the plant’s food supply that in a very short time the main leaves are starved and become thin and papery, with immature ripening setting in. ■ 1 \ When suckers make an appearance early in the plant’s growth, particularly around the .base of the plant, it is an : infallible sign that the plants have been raised from inferior seed.

U. A. YELDHAM,

Tobacco

Instructor, Motueka.