SOIL AND ITS PREPARATION

Evening Star, Issue 17637, 16 April 1921, Page 11

SOIL AND ITS PREPARATION

The following lecture was recently given by Mr F. H. Hollingsworth at the weekly meeting of the Dunedin Gardening Club:

I have been asked to speak to you on soil and its preparation for next seasons crop, and as many of the crops will now bo finished and ready lor lilting it behoves all now to plan for next season's crops. The first thing to remember is rotation, avoiding aa far as possible planting too same crop twice, with the exception of onions, which may be grown on the same ground for years. I’ have some beds that have been in onions for the last five years, and I think they were better this season than before. . , Cabbage, cauliflower, turnips, Brussels sprouts, curly greens, and all the brassica family should be shifted on to ground that has previously been in peas. Beans, potatoes, parsnips, carrots, etc., otherwise, you will soon be troubled with club root, which is easy to get but difficult to get rid of. Now, to grow any crops well and satisfactorily the soil, of course, and its preparation is the starting-point. Fertile soils are mainly composed of varying proportions 01 san I, clay, chalk, and humus or dead aniinl and vegetable matter. Sand consists of trains of quartz and other minerals and rocks. Clay consists of extremely fine partides of sand and other inert materials cemented together with a portion ot sticky substance like putty in its nature. Chalk and limestone are different forms ot ulio (same substance —carbonate of lime. It 1001 b of chalk bo burnt in a knn 56 h ot quicklime are obtained, and 441 b of ear borne acid "as are given off. The 561 bot quicklime are capable of absorbing carbonic acid from' the air. Chalk or lime is an absolute essential for the fertility of the soil, ns firstly it provides the plant food, inro sand and pure clay are quite useless for the nourishment of the plant without the inns. Secondly, it serves to counteract sonnies'., and is, necessary for the preparation 01 available plant foods in the soil. .Lime or chalk is the chief basis of fertility m too soil. _ Humus is the name given for the organic matter in the soil, and it represents the dead and decaying residue of roots, _ leaves of former crops, and of previous dressings ot dung and other organic manures, Hiimm; consolidates a light soil and makes a l>ca\ y soil porous; hence the value of a good dressing of farmyard manure, whilst it serves m lock up and preserve the potash and ammonia in the soil. Its slow decay produces carbonic acid pas. which corrodes rock fragments and mineral particles, sotting free potash and phosphates. Humus imparls a dark color to the coil, and every practical man is in favor of a soil possessed ot a rich dark color. Such soil is possessed ot great reserves of fertility. Peat represents a soil composed almost entirely from the residue of previous vegetation, generally found in marshes and swampv places, St. Kilda soil being^of this nature.' It is nearly always deficient in lime and is freouentlv sour from the acids produced by the decaying vegetable matter. Generally speaking, peat lands require to bo drained and limed to bring them into a state of fertility. ' Lime is always sinking, so if you dig it in you put it too low to be of much use to the crepe, and vonr expense will be most y wasted. Another mistake many people make about lime: they seem to think that if they haro a piece of very wet- irroimd all they have to do is to* lime it and it will bo dry. Lime on very wet land only makes it writer. Drain your land first, then apply the lime, and you will soon see tho benefit. A simple test to find out if vour ground requires lime is to take a handtol of soil and place it in a basin. Add sufficient water to cover it; when the air hubbies have ceased to come out of the soil add about half an ounce of spirits of salts. If the soil contains sufficient chalk or lime ft very distinct pfferveseenco will be produced; if no gas is scon bubbling iro. or only one or two little streams of bubbles, then be quite certain your soil requires lime. Lime helps considerably in_ the crowing of vegetables, some crops being especially benefited by it. If apnlicd from two tons ner acre, or. say. six bags to g-aere, lima belns tp break up many plant foods in the soil, and makes them so that plants can u«e them. Lime, however, should not be applied nor mixed with manure, and the best, way is to dig up your garden rourii, and in a couple of months scatter the lime on the surface, and let, it lay till you go to work up you? ground for the crop?. It should then he lightly laked in boloW the surface. Next to the soil itself in importance _is drainage. Everv gardener knows that soils vary considerably with regard to temperature. Tlio chief cause of coldness in the soil is wetness. A wet soil requires far more Sun beat to warm it than a soil that is fairtv dry and porous; hence good drainage is the first essential to_ even warmth. Humus, hy making the soil dark in color, makes it, more ready to absorb the heat of the sun, just the same as a black coat, is far hotter than a. light, one on a blazing dav. I sunnose the earne reason operates with the ladies’ dresses, am! that is the reason why they don the light £a,shion| in summer.

Tire first thine, then, to attend to is drainage, and there is nothin? so good for this as pipe drains. They should bo laid 2ft Bin derm if possible, and each lino of drains should he at least 3Bffe apart, and have a slight, fall to the outlet. Any side drains should bo put in at an angle to the main ones. The next thing w the preparation of tire ground, either bv ploughing, digging., or trenching. For largo gardens ploughing would likely be the cheapest, but it should bo suheoiled to allow of a deeper rooting surface for votir crops. With regard to the soil m_ your garden, suppose you have a place particularly suited for growing sweet, peas, and you would like to continue growing them there, you will, or must by some means renew the soil; for it would not be wise to continue growing them in the same soil. You may, however, still grow them in the place if yon trench tout ground. All you will require to do is to take out a trench, say, _ 3ft wide and two snades deep, and wheel it away to the far side of the garden. Then break up the bottom of the trench, fill it in with grass, weeds, and rubbish; then mark off a second 3ft and dig it into your first trench, adding wmo good rotten manure. Cany this on till the whole piece is finished, lour last trench von will fill in with the soil taken from your first trench and by his means vou will have removed the whole of that poHion of your garden. I fmd tbs bottom of llio trenches a splendid place to bury weeds and rubbish, also the stalks of caband cauliflowers, and any other refuse which soon becomes offensive and untidy if left lying about. , I am not in favor of long-handlc-shovel digging. I believe in a good spade, put well down, and the soil properly turned over keeping a good trench in front 6f you, I am often amused at people digging. They

start out with a nice clean trench, but before they have gone far they have either a. trench three times the proper size or none at all, with a small mountain in one place and a valley not far from it, possibly thinking anything will do. You know the old proverb: “If a thing is worth doing at all it is worth doing well." So if you spend a little more time over your digging you will have less work later on. On the question of manuring, many people say; “I’m using only artificial manure for my garden, as this stable manure brings so many weeds, and I’m always weeding.” No doubt stable manure does bring you plenty of weeds, but often the way you"use it is the reason. If you got it some time before you used it find had it stacked and left to rot down propedy, you would not .be troubled with eo many weeds. I know, generally, people get a load of manure for say Saturday. It is just new and green, and the weed seeds have not had time to germinate. Then it is wheeled straight on to the garden and dug in, and in ft week or two you have a splendid crop of weeds. Had tho manure been slacked and turned once or twice during a period of four weeks most of the weeds would have been killed before, going into tho ground. With all the weed trouble, I am still a believer in the old-fashioned, wen-rotted farmyard manure. No doubt von will get crops to grow well with artificial manure; but if you always keep on with it, and use the same sort, vou will find in time that you will fail to grow anything. Rear in mind that artificial manure does not improve your land to any extent, because it adds no humus ’o the soil. Ennnvard manure returns to the soil that which has been taken from it. You can assist artificial manure by green ‘manuring—that is. by sowing different crops, such as peas, vetches, mustard, oats, or barley and then diguing them into the ground whilst they are quite soft and green. This will supply a certain amount of for plants to'feed on: but I believe the nest results will undoubtedly be gained from a ir o od dressing of farmyard manure. In ih'bt land it retains the, moisture; in heavy land it helps to open and free it, dud also lets in the influence of sun and wind.