TURNIP GROWING.

Sun (Christchurch), Volume III, Issue 867, 20 November 1916, Page 11

TURNIP GROWING.

MANURING AND CULTIVATION. The manuring of the land for turnips is one of the principal factors which leads to success in the cultivation of the crop (says "Arare" in the "New Zealand Farmer"). In manuring for turnips or other crops there are four points that must be considered, to wit, climatic conditions, the nature of the soil, the position in the rotation, and the cultivation of the land previous to sowing the seed. All of these more or less modify the effect of the manure on the crop. First, the quantity and kind of manure to be used on turnips varies greatly, according to the climate. Tn districts where the rainfall is heavy a greater weight of manure per acre can be profitably applied than is the case where the rainfall is light. Therefore, practically speaking, the heavier the rainfall the greater the weight of manure applied, while the drier and warmer the climate the lighter the manuring adopted. The amount of artificial manure used in different climates ranges from lcwt lo scwt per acre, and the results obtained from practical experiments conducted over a series of years justify this wide range. Therefore in the wetter parts it is not uncommon to apply heavy dressings of artificial manures, and when we take into consideration the nature oi' a good crop of turnips to the New Zealand farmer, the expense of heavy manuring when conditions are favourable, and when the yield of the crop is largely increased, there is wisdom in the practice. On the other hand, it would be the height of folly to apply heavy dressings of manure on light, shingly land with a. correspondingly light rainfall. In this ease the young plants would be forced too much in their early stages, and in all probabiliy the crop would suffer a severe check later on which would have a detrimental effect, not only on the development of the bulbs, but also on the quality of the roots. Referring to the latter, it is worthy of note that there has been evolved in the turnip a shallow, rooty habit, and that the root system is not proportionate to the size of the bulb. Accordingly it is necessary that there should be a sufficiency of plant food within easy reach of the growing plant. Unlike the mangel and other vigorous rooting plants, the turnip does not possess the same power for searching for plant food in the soil as the former. When very heavy dressings of manure are applied to the mangel crop, especially if the mixture contains a large proportion of salt or kainit, instead of applying this all directly with the seed, part of it is sometimes sown separately. This is either broadcasted on the surface beforehand,, or some prefer to allow the manure to run through a coulter each side of the one that is sowing the seed. This is the safer plan, and does not affect the germination of the seed, and the mangels take up the manure from the soil as reepvired. On the other hand, with the turnip crop, unless sown directly under the much of the manure will not reach the. roots of the growing crop. Therefore much of the fertiliser will be wasted as far as the turnip crop is concerned.

The weight and kind of manure must vary according to the position the turnip is placed in the rotation. Phosphates every whore prove the most effecive manures, ■ and of these superphosphate usually gives host results. On heavy land basic slag or basic superphosphates may prove most useful for he full development of the crop. This class of land generally speaking does not call for a heavy dressing of potassie manures, though in some cases their application in a light form may prove profitable, while in the lighter classes of soil, almost without exception, the use of potassie manures in some form or other gives profitable results. But, as the latter is usually applied in the form of kainit, or sulphur of potash, and as these manures are very difficult to proeuro at the present time, it may be necessary to cut them out altogether or apply only a small quantity. It may not be generally known that wood ash makes an excellent substitute for the above-named potassie manures. With this in view, all available wood ashes should be carefully saved for the turnip crop. These should be put through a fairly tine sieve, so that any lumps likely to block the drill will be removed. The ashes can be mixed up with the other manures. Apart from their manorial qualities ashes are useful to mix with super that is inclined to be sticky, as this renders the super more easily drilled. It is claimed by many prominent farmers who use wood ashes extensively that they are not only valuable from a manurial point of view, but that their use materially assists in preventing the crop from being taken by the turnip fly, and also by the grass grub, which has proved so Very destructive to the turnip crop of late years.

The cultivation of the land for turnips must be thorough. It is now a well recognised fact that the more cultivation given for this crop the greater will be the net result. Good cultivation improves the physical condition of the soil, and extends the feeding area for roots. It increases the depth of the soil in which the plants grow by loosening it, so that plants obtain a deeper root. It causes the land to dry and warm up in spring. It makes the conditions of moirture and temperature more uniform throughout the growing season. It assists the soil to save moisture by increasing the water holding capacity of the soil. It checks evaporation by means of the surface mulch. It hastens and augments chemical action in Ihe soil by aiding to set free plant food already in the soil, as it admits free circulation of air through the surface soil, and thus promotes nitrification. In this sense cultivation is manure. Therefore it would lie the height of folly to add large dressings of artificial manure in the vain endeavour to make up for bad or iusufli c.ient cultivation. Good cultivation and manuring must ever go hand in hand. It was quite a common practice among our plains farmers but a few short years ago to simply plough land direct out of lea (perhaps late in the season), and to give the land just sufficient cultivation to work the mere surface to a line enough tilth for the seed. It is needless to say that under such a system the results were often very disappointing. It is, however, gratifying to note that this haphazard method of cultivation for the turnip crop is fast dying out, and is replaced by a more thorough system of cultivation, if possible, the land should be ploughed in early winter, so that if a second ploughing is deemed necessary the latter may bo done as early in spring as possible. This will ensure a better chance of a good germination of the seed and a more vigorous growth afterwards. This is the season when the eggs from the grass grub are in the pupa stage, and are very soft, and therefore easily crushed or destroyed. Frequent stirring of the soil at this season will be the means of do-

stroying millions of these insects, and as the safety of the crop depends to a very great extent upon keeping these pests in check, any method adopted that will tend to check their increase should be taken advantage of.