That most weeds produce a far greater abundance of seeds than our domestic crops is a characteristic the significance of which seems to have escaped the orthodox botanist. Or, if the botanist has followed up the clue to its logical explanation, the resultant revelations have not been acted upon by the agriculturist. For clearly no plant is so profuse in its seeding or persistent in its growth unless it has an essential and very important part in the pattern of nature. If practically all the plants which seed themselves by the million and are apparently impossible to eradicate without poison sprays, are, in the eyes of man 'weeds', that is surely the fault of man, who has failed to discover the useful purpose with which I am convinced each weed has been endowed.
Man's task is not to destroy out of hand everything in nature which he has so far failed to employ for his own immediate profit. Man has no reasonable grounds for assuming that because a plant appears to be an obstacle to his immediate purpose, it is necessarily a thing to be despised and destroyed. It is more than likely that man's immediate purpose is misguided, not that the plant is misplaced.
It is surely unintelligent in the extreme to kill or destroy any animal or plant whose service in the universe we have failed to appreciate. We should rather apply such intelligence as we have in seeking the place and purpose of each living thing in the design of nature. I have found this one of the most satisfying exercises of the human mind, heart and hands. And I am unashamed in advocating the use of the heart in such human endeavour. Far too many of man's pursuits are restricted to brain and brawn; and when any emotion is allowed to creep in, it is only at the lowest level, stimulating the lowest instincts, with no reference to the finest attributes usually associated with with the influence of the heart.
In the study of plants as in the study of animals I have tried to make such principles operate; and the result has been a considerable simplification of some hitherto unfathomable farm problems. And in this context comes my discovery of the value of farm weeds, and the development of a system of utilizing, in ways which prevent them from becoming a nuisance, plants which before were an unmitigated pest in my cropping rotation.
The best way to deal with a nuisance is to turn it to good use, especially if it is not easy or economical to get rid of it. As a student of herbs for animal health and soil fertility, I am sure this is the right approach to weeds. Consequently, for some years I have used much of my land and time in experiments on the utilization and control of the common weeds of the farm.
Such experiments meant first encouraging the weeds to grow in sufficient numbers to different stages of maturity, then using them, and later controlling them in various ways. In spite of some rude comments from my neighbours, I have been able to learn that practically every weed which we regard as a pest, can be managed in such a way as to make use of it at certain stages of the rotation and to eliminate it at others.
COUCH is about the only exception. For, though it has valuable medicinal properties, being a tonic to kidneys, bladder and reproductive system, with anti-sterility powers, it doesn't readily share a field with other crops. It prefers a virtual monopoly of the soil, and therefore if ever it is to be used it will probably only be as a separate permanent crop and not in conjunction with other domestic crops; and that may quite well be a possibility, for I believe the most persistent things in nature are persistent for a good purpose if only we can find it. But our task at present is to be rid of it, and the only really effective way to do that is to have a summer fallow—a practice which lost favour during and since the war. But if couch has no other purpose than to make us take a summer fallow now and then, it has a value. I still believe the biblical sabbath year is an essential of good husbandry.
CREEPING THISTLES, the next most troublesome weed, can be used and at the same time eliminated in a silage crop. A lucerne mixture is the best for this purpose. Thistles are a good source of protein and also have a beneficial effect on the breeding capacity of animals. A district officer of the Agricultural Committee told me that the highest protein silage he had seen was made from a mixture predominantly of thistles. A lucerne mixture sown on a thistly field will eliminate the thistles in three years of cutting for silage two or three times a year. But the thistles should be allowed to grow nearly to maturity each time before they're cut, for the destruction to be complete. Thistles in grassland can also be cleared by allowing them fully to grow and mowing in July. Most of us encourage our grassland thistles by cutting them too soon and so encouraging the root development.
NETTLES are one of the richest known sources of protein in nature, and for this reason of all weeds the nettle offers probably the best possibilities for development as a commercial crop. Comfrey, the greatest yielder of protein, is already accepted as a farm crop, thanks to the recent researches of Mr. Lawrence D. Hills and the Henry Doubleday Research Association. Nettle hay is well known as a food for goats, and I have made excellent silage for cows from a mixture of nettles and comfrey. As with thistles, nettles may also be destroyed when and where necessary by repeated cutting at maturity—not during the earlier growing stages which, as with thistles, strengthens the root system.
COMFREY is a subject in itself. It is now being used increasingly for pig and poultry feeding and as silage for cattle, being perhaps the heaviest yielding 'weed' in existence when properly cultivated. My present farm is infested with the Russian variety which was used extensively here, during the 1890's, to feed a large stud of horses. I am developing it now for cattle silage and compost material.
DOCKS are valuable as deep-rooting suppliers of minerals and trace elements, but in very limited numbers: for docks so quickly get out of hand. Again, they can be eliminated by cutting at maturity—just before they go to seed. And, believe it or not, even the disc harrow can destroy both docks and thistles if it is used thoroughly enough. The discs must be used alone and not in conjunction with the plough. I have destroyed a complete carpet of thistles by repeated discing until the young thistles were reduced each time almost to pulp. Docks can similarly be destroyed by cutting up the growing crown, while it still grows, leaving the root to decay in the ground. It is when the dock is brought to the surface by ploughing and then cut into pieces with the disc harrow that it is multiplied.
Of course, the safest and surest way with docks is the sheer hard labour of pulling or digging—a costly job these days.
PERSICARIA or RED-SHANK is another weed that makes good silage—and mowing once before it seeds will get rid of it. I have used and eliminated persicaria in two ways: by sowing oats and vetches and cutting the mixture of oats, vetches and persicaria for silage, just before the persicaria seeds; and by using the persicaria as a green manure on an unsown field—i.e. allowing it to grow to a leafy stage then discing it in as a green manure— repeating the operation three times between April and September. The same treatment is effective with FAT HEN.
CHARLOCK, though it is a nuisance in a corn crop, makes good silage for milk cows—especially mixed with lucerne or vetches; and it can easily be controlled by taking a silage crop. I have even rid a field of charlock, which swamped out a crop of kale, by cutting it and carting it to the cows in place of kale. In autumn, before they have tasted the real kale, they will eat it wilted—though they won't readily come back to it after kale.
Weeds, like CHICKWEED and GROUNDSEL, have provided me with thousands of tons of green manure for discing in between crops, and being annuals they rarely become a nuisance.
The tendency to destroy all weeds indiscriminately, especially by means of poison sprays, is a policy of despair now that the buckrake and green crop loader have made silage-making—a sure method of controlling weeds—so easy. Good husbandry surely demands a more intelligent study of the utilization and control of these sources of fertility and health.
I am continuing on my present farm experiments on weed utilization and control begun at Goosegreen—and I may say that I start with a wonderful array of well-established crops of many varieties!
On my present farm I have had some grand opportunities to demonstrate the process which uses weeds for the purpose of organic top-soil fertility building and at the same time cleaning a very dirty field.
I have in fact made a virtue out of the fact that my farm was in a very weedy state as well as low in fertility when I took it over; and I am using the weeds to build fertility, and in the same process clean each field.
When a dirty field is to be re-seeded, or cropped in any way, my procedure before cropping is to give it a weed-mulch fallow which builds fertility by using the weeds in the process of eliminating them.
If it is friable enough to work up enough soil with the disc harrows or rotary hoe only, I churn up the whole field with either or both. On some occasions I have preceded the disc harrows with a cultivator. But if the ground is hard and all the weeds cannot effectively be cut without the plough then the whole field will have to be ploughed just once; but not more than five inches deep—just enough to cut all weed roots and turn them over. Then all subsequent cultivations, throughout a full summer fallow, are done with the disc harrow or rotavator.
Instead of repeated ploughing to prevent any further weed growth from developing, I allow the weeds to grow up to the flowering stage, when they have produced their maximum bulk; then I use them as a green manure, discing them thoroughly into the top soil. The contribution which a disced-in weed crop makes to soil fertility is beyond all chemical analysis.
After the first weeds are disced in, the field is left untouched again for about a month or six weeks, The weeds again grow up to produce a further substantial green-manure crop, which is again disced in before any seed is set. These operations are repeated several times, allowing the weeds to grow: sometimes to their full maturity, to provide, when they are disced in, a large tonnage of bulky organic matter to improve the friability and water-holding capacity of the top soil; sometimes discing in when the growth is lush and green and at a high level of protein content, to add large quantities of nitrogen to the soil. Either way the weeds are always disced in before they go to seed. This results in the destruction of all weeds in the top few inches of soil—for what is missed in one discing is caught in the next and each time that the field rests, and growth is allowed, more un-germinated weed seeds germinate and grow and are disced into the soil before they can establish, unless seed is brought from outside by birds and wind.
But the field is never ploughed again before being sown. This would only bring up dormant weed seeds and put the now clean humus-rich topsoil down to the level where anaerobic conditions operate, making it quite useless to the crop that is to be sown.
But left unturned, with the destroyed weeds incorporated with the top soil, the soil begins to emulate the hedgerow conditions. The decaying weeds release organic acids in the process of decay, and the acids in turn dissolve the essential minerals which are nearly always present in every type of soil—but not always available or soluble until the acids of decaying organic matter make them so.
The action of aerobic nitrifying bacteria gathers nitrogen from the air to supplement the nitrogen directly supplied by the crop of green weeds. Thus, instead of dissolving the weeds in a deadly spray the consequences of which we cannot measure in destruction of ultimate fertility and human life, we have used the weeds to gain vast quantities of organic manure, and, in the process, left the field virtually weed-free.
If it is felt that the field needs further cleaning, the first crop sown is a silage crop, which can be followed with a further short repeat of the weed-mulch fallow in the month or two after it is mown for silage in its green state.
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