THE GARDEN

Star (Christchurch), Issue 19119, 11 July 1930, Page 11

THE GARDEN

NOTES FOR THE AMATEUR.

v ■■ ■ - = By

D. COMBRIDGE.

Rotation in Crcpping. Rotation in cropping is to most, rather a mysterious affair and appears at first thought to belong to the scientist or botanist, but in practice it is most simple and it makes garden work more interesting. Briefly, rotation is a systematic arrangement of the cropping of the ground in order that its manurial content may be conserved over a longer period for the benefit of more than one crop. There is an old saying, “Potatoes where potatoes -were never, onions where onions were ever,” and as regards these two vegetables the rule is pretty correct. The wisdom of rotation need hardly be questioned as the absence of it so soon shows itself in the soil becoming potato sick, or cabbage sick, as the case may be. The periods over which rotation may be worked vary from three years to eight years, according to the 'size of the garden and the planning of the gardener. No doubt where an eightyear interval elapses before the same crop is grown on the ground it stands to reason that the crop will be as good as it is possible to get it subject to seasonal conditions. Further, the incidence of blights and diseases is undoubtedly favoured by frequent cropping on the same ground of the same or allied plants, whilst the reverse is true where rotation is practised. The spores of a fungus disease dropped in the soil from one crop perish for want of a host if a new and.totally different crop is occupying the ground. The added vigour given a class of plant when it follows its correct rotation assists it to withstand green fly and other insect pests. All plants give off and deposit in the soil substances that are injurious to plants of the same natural order or family, whilst these same substances are most beneficial for other crops. An outstanding example is celery. This leaves a substance behind that is most beneficial to the onion. This may be further remarked upon in connection with deep-rooting crops such as parsnips. These draw their substance from the lower strata of the soil, whilst they enrich the top spit to the benefit of shallower rooting plants, such as lettuce, partly because of the shade the leaves give to the ground during summer, preventing evaporation, and partly because, there are no surface roots using up the food in the top soil layer. Again, different plants require their foods in varying proportions. Therefore proper rotation is more economical °n manure and the work of manuring. This brings up the value of our trenching and the fact that its accomplishment may be done in stages as time, manure and energy direct. If one-fifth of the garden is properly trenched each year the crop, or crops, that go on to trenched ground may be placed in newly trenched ground each

year, and a five-year rotation worked, during the whole of which period the p soil will be getting thoroughly improved as well as being systematically ’ s cropped. The question of what method . of rotation to follow, whether three, five or eight years, depends not only .. on the size of the garden but on the e quality of the soil, as it may not be fit to grow some things at all to begin r with, but it can be improved. It is e also governed by the products required, L that is, some things may be disliked or s not found profitable to grow owing to ». proximity to a market garden or pog tato district as the case may be. A further consideration is the manure at ( command. This governs the scheme n or limits it because, if only two loads “ of stable manure per annum can be procured it must be apportioned to do k , the greatest amount of good each sca--3 SOnf A very simple method and one that e canont fog anyone is to divide the vegetables up into three classes: (1) e Fibrous rooted, (2) tap-rooted. (3), tus berous-rooted. Then by dividing the \ ground up into three portions each secD tion of ground grows one class of vegel_ table, at a three-yearly interval. Class 1 includes the largest list, such as spinnach, lettuce, peas, cabbage. Class 2 is r much smaller, embracing the beets, 2 parsnips, carrot and salsify, while class 3 s is smaller still, containing potatoes and I artichokes. This opens up the difficulty a of giving us too large a plot for roots and not enough for the fibrous class, j and it further causes perplexity in t knowing in what class onion, turnip t and radish come, and what crop should t they follow. This brings us to dividt in S pur plants up into their respective • families or natural orders, which is - done for us in our standard plant die- ; tionaries. i The rule is never to grow plants of ; the same family on the same piece of : ground. Spinach must not follow beet. ; ii*i spite of the fact that beet is a i deeper rooting crop. Neither should . celery follow carrot or parsnip, nor tur- • nips follow the cabbage family. The effect of growing tomatoes on - land that has grown potatoes is to inJ vite trouble from fungus diseases, to : say nothing of a diminished crop. It ■ is necessary to work to an arranged ■ plan and therefore the various portions ; of ground devoted to each vegetable should be clearly marked out, and every crop moved on a block each year. ■ The following is a list of what may have preceded this season’s intentions • and what may follow. Readers could copy it out in column formation as a ■ guide in planning. It suggests at first • reading a three-year rotation, but such is not the intention; the five or eightyear rotation may be easily built up , from it:—Cabbage family, followed by : beans, followed by leeks; celery, foli lowed bv beet, followed by peas; pota-

toes, followed by turnips or cabbage family-, followed by carrots; peas, followed by Brussels sprouts, followed by lettuce; onions, followed by spinach, or lettuce, followed by carrots; leeks, followed by perpetual or spinach beet, followed by peas or beans; early potatoes, followed by celery, followed by peas; celery, followed by onion, followed by the cabbage family ; peas or beans, followed by potatoes, followed by the cabbage family; parsnips followed by beans or peas, followed by leeks; turnips, followed by celery, followed by peas. From the above a comprehensive system may be worked cut, remembering always that the guiding principle is the family that each vegetable falls into. All the Leguminosae deposit nitrogen in the soil in a manner that is readily available to growing plants and therefore crops that produce foliage for const jtion are the best to succeed them. bage is the most notable successor to peas. Celery again leaves in the soil food that is most useful for the growth of peas. Celery needs potash salts and not much nitrogen. Onions also do well in soil that has grown celery. The question of apportioning an area of ground that falls due for a crop, of which only a little is needed, will always arise. The remedy is to fallow that piece; it will do it a lot of good to give it a spell every fifth or eighth year. Opportunity may thus be had to green manure it, which is m profitable. ANSWERS TO CORRESPONDENTS. “New Brighton.”—The best method is to procure some more good soil as you did at first, sieve it to free it from stones which would spoil the mower, and spread it evenly over the ' surface of the lawn to the thickness of one. inch. The lawn would be benefited by a cutting prior to putting on the soil, and the rejuvenated roots will push up new grass through the soil in due course next September. Some, well dried fowl manure could be mixed with the soil at the rate of one barrowful to every cubic yard of soil; that is to say one and a half barrowfuls of dry poultry manure to every load of soil. Artificial fertiliser is good, but can be very easily overdone. Blood and bone is the best, no doubt, and it may be scattered over the lawn at the rate of two ounces to every square yard before the soil goes on, but if it is used, do not use the fowl manure. Sheep manure from the Addington yards could be obtained, but with cart age may prove too expensive. The perpetual use of artificial manure, however, on a lawn year after year will ultimately impoverish it, so that topdressing with soil must come into the picture, at regular intervals.