ROTATION OF CROPS.

New Zealand Herald, Volume LXV, Issue 20114, 27 November 1928, Page 15

ROTATION OF CROPS.

A DESIRABLE PRACTICE. Tii those times when an intensive programme of cropping is carriod out by the majority of gardeners, little thought is given to the matter of crop rotation. For tlio benefit of tho uninitiated it might Tie as well to explain the meaning of this term. Rotation of crops is the growing of a different kind each year on a particular pieco of ground so that a crop or one belonging to tho same family, or of u similar nature, is not grown on tho same ground more than once in four years or three years at tho very least. Gardening is becoming more and more a science and, therefore, must be practised methodically. Rotation of crops is in accordance with this idea and it should need no further recommendation.

Mention might be made of the illeffects which result from undiscriminate cropping, to serve as a warning to those who aro not favourably inclined toward rotation. Disease organisms may remain in the soil and retain their vitality for several years in cases where crops havo been affected by any fungus pest. It would be folly to plant the same crop in tho same ground tho next year for this would bo inviting trouble. Neither would it bo desirable to plant any other crop which is known to be liable to attack by the same pest. It has been proved that certain crops use up more of certain foods than do others. For instance, cabbages use mostly nitrogen to make thoir growth, and if they were grown in the same ground time after time the supplies of nitrogen would become exhausted while tho soil might still be comparatively rich in its phosphatic and potassic content. By changing the crops, however, the supplies of each of the plant foods aro used up moro evenly and no ono particular food is exhausted moro quickly than tho others. This idea is quiet distinct from manuring and enriching the soil by means of fertilisers, which aro mainly for the purpose of augmenting the supplies already in the soil. When any crop is grown on the same ground repeatedly the soil becomes " sick." To avoid this and similar results the only thing to do is to rotate the crops. Gardeners may find it hard or easy to practise crop rotation, according to tho amount of spaco available and the number of different crops that are cultivated. The greater tho number of crops and the sma'ler the ground under cultivation the harder it is to plan a good rotation. By drawing up a plan of the garden and dividing the whole area into a certain number of plots it is much easier to arrange a suitable rotation. All that is necessary will be to move the crops on one plot each year. Crops which require the soil to be deeply worked should follow others for which the ground was well loosened, and cropis which do not utilise all the manure or fertiliser that was provided for them should bo followed by others for which that kind of manure is suitable. This, of course, can be done only in certain instances and where it is not possible it must be left to tho judgment of the gardener to decide on the order of rotation. ROUTINE GARDEN WORK. requirements of crops. The first consideration with any good gardener is the requirements of his crops. Unless one intends to carry tho work out wholeheartedly it is not worth while attempting any gardening at all. One should take reasonable care at least in performing the various operations connected with gardening. By a Utile extra care and trouble many ' gardeners " who at present have disappointing results would meet with more success. It is at certain stages in their development that the plants require most particular attention. The seedling stage is one of these, it being essential to prevent overcrowding while the plants are small.

In some cases it is necessary to look after the crop right through its development until maturity is reached. To go In the other extreme, some crops require practically no looking after at all. Moisture is a requirement of every crop during the summer. When the dry weather is more advanced and the moisture that has been conserved in the soil has been practically exhausted it is essential that tho moisture requirements of the crops are met by artificial means. In cases where it is imperative for crops to make rapid growth it will be necessary to do a little watering even now for the soil is almost certain to bo getting on the dry side. The requirements of crops extend in the direction of the food supply also and any that may be assisted by means of liquid manuring should be so helped on the lines described a few weeks ago. It is better to stimulate crops now than to wait until the middle of summer, for the heat is then too great for most of the crops to make their most rapid growth. The heat, however, suits crops such as marrow, pumpkins, etc., and these make <rood growth during the whole of the hot season. The asparagus bed may be in need of a I ttle attention at this time as it will now be at tho peak of its production. Stimulants are required in order that the supplies of food in tho bed will not be exhausted in producing tho numerous shoots which constitute the crop. An asparagus bed is expected to last several seasons provided it is replenished each

vpar. . Nitrate of soda is the most, suitable for use as n liquid manure for asparagus, and an ordinary snluion of Aoz. per gallon mav he given once a work at first, and twice a week later on. The young shoots should lie protected from tho ravages ot slugs and snails. The shoots are usually eaten "lien they are about 2in. high. Any of the common remedies that have been mentioned in theso columns will serve to protect them. A word or two on tho manner in which asparagus shoots should ho gathered may prove helpful to those who are new to asparagus culture. To avoid waste the shoots should he cut half an inch below the ground. Tho knife, which should bo moderately sharp, should be used in a slanting position in order to minimise tho risk of damaging other shoots which have not yet appeared above the surface of the soil. Newlv-planled bods should not be cropped at nil unless the number and sizo of the shoots sent up indicate that the crowns are fairly strong. On no account should any cutting be taken off a new bed which was planted with one-year-old crowns. Wherp two-year-old crowns were used and a cutting is being taken, at, least half of tho shoots should bo left, and it will be to the grower's benefit to see that a fair proportion of the thicker and stronger shoots are retained. fn no case should an established bed even be cropped very closely or the vield (he following year will be considerably below the average. Gardeners who study the needs of their crops will attend to the staking of any as soon us it requires support Tomatoes, beans, and peas will require to be staked about this time. Plain stakes will be quite suitable for the tomatoes and runner beans, but in the of p6&B ' twiggy, branches should be provided.