better crops are grown than by horse ploughing. In the old days in the Highlands the crofter was doing in effect what I was suggesting on p. 2 as being sound policy, namely, treating his arable ground intensively. He did a bit of ground well and got a crop. Not only did he get a higher yield in one year, but he was building up his ground, making capital for the future.

The soil cannot get its air if it is waterlogged, so draining is one of the first necessities. If the arable ground is in a glen, some open drains may be necessary to carry off the water which rapidly seeps down from the hill after heavy rain. Water lying in the soil means a stoppage of those processes of change, a coldness and lateness for plant growth, and conditions are such as to encourage the formation of an acid, rubbery, peat-like soil which is most difficult to work even when dry. When I was on North Rona I observed the soil of the lazy-beds which have not been worked for over 200 years. Its good quality is still apparent, compared with that part which was never tilled. The ground was well drained and the soil deep and there was not a rush or a docken in it. In summer time those lazy-beds are covered with wild white clover, testifying to the goodness and health of soil well tilled by a folk long since gone. These fertile lazy-beds or feannagan are their lasting monument.

2. The Soil as a Sponge

LAZY-BEDS IN THE MAKING, SOUTH UIST

This is one of the few places where new lazy-beds are still being made. Feannagan take up a lot of ground, but they are a good form of husbandry on peaty ground where drainage is difficult. Draining tiles are no good in peat, for peat is like a jelly and dries best with open drains at close intervals.

Those East-Coasters who sometimes express the view—on insufficient observation and through lack of understanding—that West-Coasters are lazy, might take a good look at this picture. It needed a lot of hard labour to get the seaware so neatly laid out on the ground, and it needs a big heart to tackle the digging by hand of this area in the short time before the potatoes must be in.

The West Highland climate is reckoned a wet one, and as much of the ground is peaty, a waterlogged condition is commonly found which exercises us principally towards getting it well drained. Quite apart from the actual drains we may dig, cultivation and liming are also aids to good drainage. But there is the other side of the picture as well—how far can our arable ground withstand the spring droughts ? Peat is a wonderful water-holding substance, useless for growing corn and root crops, but found so often alongside our strips of arable land which tend to dry out between March and June. The peat consists of decayed vegetable matter of a sour, acid kind, which for all practical purposes is like a jelly. Much of our Highland arable land, on the other hand, has lost some of its decayed vegetable matter and has become little more than a mixture of particles of rock. Such a soil lets water pass through it quickly, though some deep-rooting plants may get below this sandy layer. If the soil is shallow, overlying rock, no plant but a quick-growing annual weed gets a chance to survive.

These thin, light soils of the West have little buffering power such as we should find in the clay soils of a large part of England. They have the advantage, however, of being easy to work; they are often early and can be worked almost immediately after heavy rain. But they cannot grow a good crop unless their buffering power of holding water and of holding manures is built up and maintained.

We can attain this end by liberal use of farmyard manure, which in addition to supplying manurial elements gives body to a soil. Rotted farmyard manure in the soil forms a substance called humus, which may be looked upon as being the sponge of the soil. It is difficult to get enough of this non-acid humus into the soil, but there are ways and means if we use our ingenuity. There is no doubt that we need to keep more cattle if only for their value as agricultural implements and manure makers. When housing cattle in winter it is worth while getting as much waste vegetable matter into the manure heap as possible. For example, I recently saw a great heap of rushes tipped on to the rocks at the seaward edge of a croft; this was a waste. Rushes are well worth while stacking for bedding with a view to enlarging the manure pile. They do not rot in the heap as easily as straw, though the process can be hastened by mixing occasional layers of seaweed with the manure. Still another means of providing humus is the. short ley, but if the ley is to play its full part it needs careful management and the help of cattle in grazing and dunging it. It is a subject we shall discuss later.

3. A Balanced Soil

The strength of a chain is that of its weakest link, we firmly believe, but to apply this philosophy to the fertility of the soil where it is of immense importance, we must find a different comparison. A barrel has a number of staves of equal height and will hold water to the height of the staves. Let us liken our soil to the barrel and the crop to the quantity of liquid the barrel will hold. The staves of the barrel represent the several conditions which are necessary for plant growth— sufficient water supply, sufficient air, suitable temperature, enough plant food in the form of nutrient salts, plenty of room for the roots and absence of injurious substances. Our barrel has these six main staves, but some of them, such as the sufficiency of nutrient salts, are themselves made up of several strips of the fabric of the barrel.

A well-balanced soil is like the complete barrel; it will hold water to the limit of its capacity because every stave is sound. Such cultivation as we give that soil would be the equivalent of holding the barrel upright so that it would hold to capacity. Now supposing our barrel gets a dunt which breaks off one stave a foot from the top. Its capacity is reduced for it will not hold water above the height of the broken stave. We get no comfort from assuring ourselves that the other staves are perfectly good. And if, again, someone bores a hole in another stave near the bottom of the barrel, the accident to the first stave will lose all significance until the hole is bunged up, because the barrel will not hold water above that point. If one strip of the stave called nutrient salts is missing or short, we are still going to lose the possibility of a full barrel.

Similarly with our soil; it is no good our saying it is well manured and all the rest of it if the soil is short of air as a result of bad drainage. The plant roots breathe a lot of air and the amount they get is closely linked with the quantity of plant nutrients they can then absorb. Sufficiency of air in the soil is the result of good drainage and cultivation.

It is no good draining and cultivating, either, if we then starve the crop of manure. The whole skill of husbandry is in judging the capacity of our barrel and keeping all the staves to their full height. The barrel will hold no more if we add a bit more to one stave, or even five staves. It would be just a waste of time and money.

When I see a man working hard on a piece of ground that is obviously short of lime and phosphates, I feel sorry, because I know he is wasting part of his labour, just as if he was trying to fill the barrel with water by pouring in pailful after pailful, when one stave was broken. We have to judge the condition of the soil as we would that of the barrel, and if such judgment is a bit beyond our powers we can call in the soil expert just as we would get a cooper to repair the barrel. This service is provided by the Colleges of Agriculture.

4. Cultivation and the Unseen Life of the Soil

If a piece of land gets so dirty with twitch that it has to be raked over and the twitch gathered, it may be noticed that if the rubbish is burnt on one big fire which is kept going for a considerable time, the ground underneath loses its blackness and becomes red. And in the following year you will find that bit of ground barren where the fire was. The reason for this is that the soil has been sterilized : all the minute, single-celled animals are killed and, what is more important, all the bacteria or single-celled plants are killed also, all the millions and millions of them which are present in every handful of soil. Without these bacteria the soil] is worthless for growing plants of agricultural value. What then do the bacteria do, and how can we help them, so that, in their turn, they can help us?

When we burnt that twitch we noticed the soil beneath had turned from black to red. The blackness of the soil indicates that it is rich in rotted animal and vegetable matter, shortly and collectively called humus. Humus, as I have explained already, enables the soil to act as a sponge, keeping it open enough to drain, and yet allowing it to hold water in dry times. The burning of the twitch burnt the humus in the soil beneath as well, the humus which was the home of all those little Robin Goodfellows, the soil bacteria.

CUTTING SEAWEED

Seaware is in the news and appears likely to become the raw material of a considerable industry. The crofter may usefully supplement his cash income by gathering the stalks of tangle for this new industry. Happily, it is well recognized that the natural harvest of weed on the beaches is also one of the raw materials of crofting agriculture and a most necessary one, for it provides organic matter to be transformed into humus in the soil.

Our old friends on the shores of Loch Seaforth have no tangle to cut as have their relations on the western side of the Isles or in more seaward places. They are gathering wrack and the condition of the beach indicates that cutting has been regular, for there is no great wealth of weed. We can imagine an outsider viewing this scene and exclaiming "Uneconomic!" It may be, but for myself it was a job I enjoyed in my island years: the smell of the weed was good and there were interesting things to see among the weed. If we can live and enjoy, then life is good.

The most important groups of soil bacteria concerned in breaking down waste animal and vegetable matter so that it can be turned into plant food, need air just as we do in order to live and work. We aerate the soil by draining it and by our annual cultivations which expose it, turn it over and leave it light. The drainage allows the soil to become warmer; the bacteria work better in warmer soil and produce more humus, which makes the soil black; and a black soil absorbs more heat from the sun so that the bacteria can work harder at breaking down the animal and vegetable waste or organic matter, and the warmer black soil grows crops better and ripens them quicker. The man of sense does not forget his unseen helpers in the soil; he keeps his drains open and gives his ground more than a scratch over once a year.

There is one other necessary condition for the bacteria to work well—that the soil should not be too acid. The addition of lime neutralizes the acidity and provides a chemical base, calcium, with which the nitrogenous part of the products of the bacteria can combine to form a plant food such as calcium nitrate.

This is one of the great everlasting processes going on in the soil and is called by the agricultural scientist nitrification. We dig farmyard manure, fish guts, seaweed and plant roots into the soil ; the bacteria attack them all and break them down into humus. Then the humus is still further broken down till the nitrogenous portion becomes ammonia ; whereupon it is seized by yet another group of bacteria which turn the ammonia into nitrous acid. This stage is an extremely short one, for the nitrous acid combines with the calcium base to form a nitrite, after which a final group of bacterial workmen turn it into calcium nitrate, which substance is available to the plant. The whole thing is like the reverse of an assembly line in a factory. The organic matter comes in raw and a succession of specialist bacteria split it and deal with the subsequent products, until it is rendered available again as pure plant food.

5. The Value of Lime

When I think of the fact that man was liming his ground in prehistoric times, I am struck anew by his inborn capacity to observe, and to act rightly on the evidence of his eyes. Lime is an essential plant food and together with phosphorus is the main constituent of bone, but it is not one of those manures which give a spectacular increase of plant growth shortly after application. On heavy land, the most important part lime may play is in making the soil more workable and easier drained. It also has the effect of helping to clean ground of parasites if it is applied in the newly burnt state.

The shortage of lime and phosphates in the soil makes it necessary to send our hoggs down country for wintering. It is an expensive business and wasteful of condition to take flesh and blood all those miles when the greater benefit would follow from bringing lime to the crofts. Our West Highland agriculture is limited in its possibilities by this shortage of lime and phosphates. We cannot manure our ground heavily to take off big crops unless the lime level is right. It is no exaggeration to say that a period of economic prosperity could follow a good liming of all our arable ground. That would be a large undertaking which we are unlikely to see fulfilled in wartime, but many of us are in a position to do more in the way of liming than we do at present.

There seems to be a good deal of misunderstanding as to the value of various forms of lime. Let us try to understand what lime is : the essential constituent is the metal element calcium, but this substance does not occur alone. It is chemically combined with carbon (charcoal and lamp black are examples of carbon) and oxygen (the gas which forms one-fifth of the air we breathe). Limestone, chalk, coral and shell sand are all forms of calcium carbonate. Now if these substances are subjected to great heat, the carbon and some of the oxygen are driven off in the form of carbon dioxide, the gas which forms one twenty-fifth of the air and which makes the fizz in soda-water. The calcium and some oxygen are left. If we call calcium Ca, carbon C and oxygen O, the result of burning limestone may be represented thus:—

We all know that quicklime is unsteady stuff; the steamer will not carry it except in barrels, and if it is left in a sack in a damp place it soon bursts the sack. Calcium oxide cannot stand alone under ordinary atmospheric conditions, but must take up water to form a more steady substance which is slaked lime or calcium hydroxide. Water is a chemical mixture of the two gases hydrogen and oxygen, so the slaking of quicklime means:—

Even slaked lime is not a fully steady substance; for it takes up carbon dioxide from the air and comes back again to what we started with—calcium carbonate:—

Quicklime kills both plant and animal life: the plant can absorb only calcium carbonate as food. If that is so, you might say, why on earth do we go to all the trouble of burning lime if it has to come back again to its original chemical state before it can be used? It may be the same chemically, but in texture it is quite different ; the limestone was hard rock and this new substance is a finer powder than flour. Just as moist sugar dissolves quicker in tea than lump, so does this finely powdered lime dissolve quicker in the acid water of the soil.

6. Forms of Lime

Lime is the name given to three chemical compounds of the metal calcium—quicklime, slaked lime and carbonate of lime. The last named is the form in which lime is assimilated by plants, but it must be in very small particles to be easily dissolved by the soil water which is more or less acid, depending on whether the soil is "sour" or "sweet."

If you find that a piece of limestone weighs 10 lb. before it is put into the kiln, it will weigh less than 6 lb. when it is thoroughly burnt. This same piece left to slake in the air will soon weigh over 7 lb., and by the time it has become calcium carbonate again it will be 10 lb. of fine powder. The limestone could also be ground to a fine powder and the result on the land would be the same, except that if you applied a ton of quick lime to the acre and allowed it to slake and gather weight naturally you would be saving yourself labour and transport, for you would have to apply nearly two tons of ground limestone to get the same result.

It seems to be more economical to get finely powdered calcium carbonate by crushing and grinding limestone than by burning it and allowing it to slake down, for the use of ground limestone in farming has steadily crown commoner. The arable land of our crofts would be put on a new footing if we could completely neutralize the soil acidity and make it sweet. But we find that the amounts needed for such neutralization are usually far beyond practical possibilities. Who could afford, for example, to apply ten tons of quicklime to the acre?

For all practical purposes we can say that a crop needs half a ton of finely-powdered lime to the acre in the year. We should be doing quite well if we put on that amount every year, but we usually lime land at a heavier rate than that, say two tons to the acre, and let it serve for several years.

We cannot expect to get sufficient manufactured lime transported to the crofting areas at the present time, so it is in our own interests to make what use we can of the natural deposits in the West Highlands and Islands. Most of the old kilns are disused now, though if they could be repaired easily, the fuel consumption would not be excessive. I have been told that when the kilns in Strath Kanaird were in use, it was reckoned that a family could cut peats enough in one day to burn enough limestone to dress the croft for the year. Two other natural forms of lime are shell-sand and coral-sand, which are calcium carbonate. Both are good sweeteners of the soil, but as a particle of shell or coral is relatively large compared with ground lime, a much heavier dressing is necessary—preferably ten tons to the acre on land newly reclaimed. This is hard work, but there is this consolation—that dressing will last twenty years or more, until the soil acids have completely dissolved the particles.

A crew of three or four men with a big open boat could soon gather coral-sand enough to dress the arable land of a township with lime, and as many beaches can be reached by motor lorries the task is even easier.

After an initial analysis by Government chemists the shell or coral would be accepted as eligible for the lime subsidy of 50 per cent. of the cost, including carriage to the croft. Before the war, shell-sand from the Outer Isles was being put down on the east side of the Minch at 11s. a ton. Many of us can do it cheaper than that, so with the subsidy the cost in money for liming in the West need not be great.

Lime tends to sink in the soil, so there is little point in ploughing it in. A light working with harrows or cultivator is all that is necessary.

Wherever there are horses and men we should get busy in the dry weather of March and be prepared to plough the ground twice if necessary, and cultivate oftener still. Lea ploughing, of course, cannot be deeply worked or the turf is brought up again. Our aim should be to lay that furrow slice as flat as possible, using a skim coulter to pare off the grassy edge which might show up and grow.

8. The Sub-Soil

When I look at the title of this talk, I can imagine a good many readers exclaiming, "Sub-soil, indeed, it's little enough top soil we have here, and then we're on bed rock." Such conditions are not uncommon, and the best thing we can do then is to build up the depth of what soil there is with organic matter such as seaweed and dung, in order to increase the water-holding capacity of the soil. But the greater part of the arable land in the West has a bottom of peat, glacial silt or shell-sand. A sub-soil of clay is uncommon here.

Many would-be improvers of our land who have been accustomed to southern conditions have had a rude shock when they have delved below the top few inches of West Highland soils. I have heard of several gardens and some enclosures of arable land being ruined by bringing an infertile sub-soil to the surface. The best advice is—don't do it. Our ground is naturally poor and it has taken a long time to get the upper few inches into workable state. What lies below may contain plant foods, but the physical and bacterially dead state of the sub-soil renders it utterly barren.

Why, then, am I wasting time talking about it? The point is that it is well worth while trying to increase the workable depth of the soil and gradually tapping

SPRING WORK AT UIG, LEWIS

The peat and the shell sand meet at Uig, one of the beauty spots of the Hebrides. The effect of shell sand being blown on to the land in constant small quantities is obvious in the greenness of the ground at such places as Ardroil on the shores of Uig Bay. This crofter has an outfit right for the job and the raw materials of fertility are there behind him—shell sand and seaweed. I believe this bit of country could produce as early a crop of potatoes as any place in Scotland. The trouble just now would be freights, which would eat up all the profits. But it should be remembered that reduction in freight charges needs organization in the townships as well as action elsewhere.

the mineral plant foods which are lying down there unused, or breaking up a little more of the peat so that it will act like soil. Unless the sub-soil is shell-sand, we can take it for granted that it is very sour, and we must apply lime if we are going to disturb that sub-soil so that the soil acids may be neutralized and some of the mineral salts liberated.

A sub-soiling plough has a frame much like an ordinary plough, but instead of there being a coulter, share and mouldboard, there is a big tine or prong which goes down the horse-walk after the normal furrow has been turned and breaks up what lies below to a depth varying from 4 to 9 inches. The ordinary plough then follows and the sub-soil is not brought to the top to bury the working soil. This breaking up of the sub-soil —assuming the drainage to have been made good—will allow air to get down into it, which in its turn will allow seepage of lime from above and the percolation of organic matter and soil bacteria which are a necessity for the proper making of soil. Thereafter, plant roots will make their way down and will help both to drain and aerate the sub-soil as well as add to its nutritive store.

I should not have bothered to say much about sub-soiling in the West Highlands were it not that plough pans are very common. A "pan" is a hard stratum in the soil just below the normal ploughing depth, and in itself possibly not more than an inch deep. A plough pan results from constantly ploughing at one depth and is caused by the laying down of iron salts drained from the upper soil. The pan is usually impervious and does much to lessen the efficiency of drainage, as well as preventing plant roots getting down to what they might gather from the sub-soil. If you are working on a garden scale, you can tackle the pan by trenching as deep as you can and then going along the bottom of the trench with a pick to loosen the pan and the sub-soil below, but for anything bigger you would be advised to rig up a plough with a deep tine. Once the pan is broken, an attempt should be made at deeper cultivation, and after an adequate liming, deep rooting crops should be sown.