FRUIT-GROWING.

Otago Witness, Issue 3111, 29 October 1913, Page 12

FRUIT-GROWING.

By J. C. Blackmore, ex-Governmcnt Pomologist.

TILLAGE v. ORCHARDS IN GRASS SOD.

About 20 years ago the New Zealand Government began to impart information on fruit-growing by the appointment of pomologists—one for each island. On commencing their duties they found that the almost universal opinion of the New ZoaInad fruit-grower and farmer was that the orchard did just about as well without tillage of its sod as it did with tillage, and if such was the case, what was the use of cultivation ? However, although the advice offered in respect of the tillage of orchards was to some extent at first unwillingly received, it ultimately was the means of causing many owners of orchards that wore in grass sod to consider the merits and demerits of the grass sod orchard versus the tillage system, and not a few have been won over to a rational method of orchard tillage, much to their pecuniary advantage. The following paper bearing on the subject of orchard tillage dca!6 with the question in a very able manner. It is by one of America’s foremost authorities, Dr M. P. Hedrick, horticulturist, Geneva Experimental Station, New York. It was recently read before the Fifth Convention of the Fruit-growers’ Association of Adams County, Pennsylvania.

Dr Hedrick, in introducing the subject that commercial fruit-growing was a comparatively new development in America, sold the first settlers of the New World brought seeds and fruit from the Old (World, for it was impossible with the sailing vessels to bring grafts of the trees themselves. All the old orchards came from seeds. The first great impetus to American fruit-growing came just after the revolutionary w-ar, when a great number of men in different parts of the country became interested in introducing new fruits into the States. They shipped to the Old World the trees, flowers, and plants found in that country, and brought back varieties of the different European fruits. Horticulture had its beginning at that time. Steam navigation gave another impetus. Before that time trees and fruit could be carried over the ocean only with the greatest difficulty. With the advent of steam navigation these difficulties were removed, and many varieties were introduced into America. At the same time codlin moth, apple scab, woolly aphis, and other posts, which before that time could not be carried across the ocean, were introduced. The third and chief impetus came after the Civil war. It came with the better transport facilities whereby fruits could be transported from place to place. Until that time fruit had been carried from the producer to the consumer only by horses, but now railroads and steamboats came into use. Later developments have been the use of refrigerator cars, cold storage, and means of evaporating and canning fruit. In the old days the fruits were wholly an adjunct to the farm, the trees were planted near the house, and along lanes and fences, and in sod, and the orchards were depastured. The trees received comparatively little care. There was little money to be made from fruit-growing; but with the development of commercial fruit interests, it was found necessary to change, and men began to cultivate their orchards. It was found that the trees responded to good care. Fifteen or twenty years ago practically all the experimental stations wore united in the belief that orchards were improved by cultivation and tillage. There wore some exceptions, where orchards wore planted on hillsides or wet land. Some of these exceptions were so icmarkable that much attention was called to them. One or two of our agricultural papers, in particular, began to cite these exceptional eases as best of all. This led to a controversy as to the merits of sod and tillage. Our experimental station at Geneva felt that it was necessary to try the two methods side by side. I want (o give you an account of some of these experiments. My subject implies a controversy. This disputed question is: Will an apple orchard thrive and fruit bettor under tillage or in sod, with the grass used as a mulch? The Geneva Experimental Station is conducting two experiments to settle this question. Tins paper is largely a report on one of these trials of the two methods of orchard management, the other not having been carried out far enough to warrant a report. In a controversy of any kind terms must bo defined, and to properly understand the experiment the conditions under which it is undertaken must be considered, and I hasten to the task. It is necessary to define tillage. The definition is sharp and clear. To till is to plough, cultivate, or hoc the sod. Tillage is a humble word, with its flavour of soil and its suggeetivencss of sweating toil; but it is an old word, and should be an honoured one. It has rendered mankind untold and unsellable service. It is pract ; sed wherever there is agriculture in the world, and nearly all the plants which minister to the needs of human kind have to bo improved by tillage To plough, cultivate, or hoe the soil, to turn and stir the soil, and so improve the crop or so improve the soil these simple operations were the beginnings of agriculture and the beginnings of civilisation, and they have been the chief task of all civilised people. Tillage is so universal and so essential a part of agriculture that those who oppose it for any domesticated plant should p look well to its origin, to its history, and its present place in agriculture before charging it with evil. There are two words to define in the compound word “sod-mulch. ’ Sod is soil mode compact and held together by the matted roots of living grass. “Mulch ’ is an organic material, placed about trees to prevent evaporation and furnish humus. The sod-mulch advocates divide into several sects in the manner of making use of sod and mulch. One sec* keeps sheep on the sod, and others pigs, and still another says

that the grass is not sufficient and must be supplemented with straw or manure. We can understand the experiment to bo discussed better if wc take a glance at the philosophy of tillage and that of sodmulch. The objects of tillage are so well set forth by one of the leading living authorities on the subject. Professor King, that I give them without the change of a single word.

He says: “ (1) To secure a thorough surface uniformity of the field, so that an equally vigorous growth may take place over the entire area, (2) To develop and maintain a, large effective depth of soil, so that there shall be ample living room, and extensive feeding surface, and large storage capacity for moisture and available plantfood materials. (3) To increase the humus of the soil through an extensive corporation of organic materials, so that there may be strong growth of micro-organisms and the maintenance of a high content of watersoluble plant-food material. (4) To improve the tilth and maintain the best structural condition in the soil, so that the roots of the crops and the soil organisms may spread readily and widely, to place themselves in the closest contact with the largest amount of food materials. (5) To control the amount, to regulate the movement, and to determine the availability of the watersoluble plant-food materials present in the soil, so that the growth may be more rapid, normal, and continuous till the end of the season, to convert the entire root zone of the soil into a commodious sanitary living ami feeding-place perfectly adapted to the needs of the roots of the crop, and to the soil organisms, adequately drained, perfectly ventilated, and sufficiently warm. (8) To reduce the waste of plant-food materials through the destruction of woods and the prevention of their growth by thorough prevention of surface washing and drifting by high winds.” It is impossible by any other means than by tilling to obtain for the apple the conditions enumerated above, soil, the conditions enumerated above, soil uniformity, depth, or a commodious living room, and increase of humus, improved physical conditions of the soil, conservation and regulation of moisture, greater availability of plant food, a sanitary place, clean, drained, ventilated and sufficiently warm, and the destruction of weeds. Are not these objects worth striving for with any cultivated plant? I am fortunate, too, in being able to give the philosophy of the sod-mulch, and in the words of Mr Grant Hitchmgs, whom wc all know as one of the chief advocates of it. Mr Hitchings says this system gives one practically the whole spring and summer to grow and market other crops, while the orchard is growing of its own accord a supply of vegetable matter for humus that all the authorities agree is so necessary for proper soil maintenance. This means that you can do a business without extra help, growing strawberries, green peas, early potatoes, etc., and have the money for the fruit in the autumn to swell your bank account instead of paying it out for fertilisers and cultivation. Other advantages are that you can drive through the orchard to spray better on sod than on cultivated soil, as the latter sometimes gets muddy, and also gets washed badly on rolling ground. You can allow your apples to mature fully on the trees, as if they should fall on the grassy mulch nine-tenths of them would be marketable. By making repeated gatherings the yield would bo largely increased, and the quality improved. With the mulch method you accumulate humus in your soil. With clean cultivation you burn it out or exhaust it.

We are now ready for direct evidence as to the relative values of tillage and sod mulch for the apple. How does the system of management pan out In a commercial orchard? The orchard in which the Geneva Station for five years tried the methods is located on the farm of Mr W D. Auchter', at South Greece. The orchard consists of 10 acres in sod. The soil is a medium heavy clay loam, rich, and containing enough gravel to make it porous. It. was selected as typical of the average orchard soil of Now York. The experiment being carried on is a broader one than a simple trial of tillage and sod mulch. The experimenters hope to add something to what is now known about the food and drink of trees, how trees take them in, make use of them, and with what effects, what influences soil temperature and soil ventilation have on the development and function of tree roots, and, amongst still other problems, what the relationship between grass and the apple may be. ft should be said, too, that the experiment is to run 10 years at the least, and that tlie results now given cover but half the minimum period, and are therefore in some respects inconclusive and superficial. For instance, the discussion centres round the yield of fruit. While, of course, the crop is the ultimate criterion of orchard treatment, yet the effect upon the tree, as indicated by the leaf, root, and wood development, is quite as important an index of the value of tree treatment as the crop of fruit. The care of two plots in the orchard has been as follows: —The tilled plot is ploughed in the spring and cultivated six times during the summer, ending the cultivation about August 1, at which time a cover crop of barley, oats, or clover is sown On the sod mulch plots the grass is cut once or twice during the season, and allowed to lie and decay as a mulch. The grass crop has usually been large, but last year it was enormous, being thick and tall, standing to the top of the forewhccl of a buggy, and no one could say that it ever was sufficient for a good mulch. In all other of care the treatment has been the same in the two plots. The ultimate criterion of the relative merits of the management to which an orchard is subjected is the crops of fruit obtained. It. is important, however, that trees should grow well, and for the measure of vigour there are several characteristics of the trees available, as the leaf areas on the trees, the length of new wood formed, the number of the now shoots, and the colour of leaf and wood,- the properties of the fruit, ns size, colour, time of maturity. keeping qualities, and flavour must be noted.

Wo come now to a discussion of those criteria. The effects of the two managements on yield of fruit aro shown by the following figures:

Average yield per acre in the plots or the five years: Sod, 72.9 bushels; tillage, 109 barrel's; difference in favour of tillage

per acre, 36.1 barrels. These figures scarcely need comment. For an average of five years the tillage plot shows an increase of a. little over one-fourth over the sod-mulched plot. The figures first given show that each succeeding year the difference becomes greater, indicating the continuous loss of vigour of the sod-mulched trees. One of the chief advantages of the sod-mulched method, as put forth by Its promulgators, is that it is a much less expensive method of caring for an orchard. The average expenses per acre of the two methods of management for five years was 17doI 92c for sod, and for tillage 24d0l 62c—in favour of the sod. It is true that the output has been greater for the tilled plot, but the income has been greater. The cost of production has been materially less for the tilled trees, and that is the main point of the whole discussion. A cheap and easy way of growing apples is not necessarily the most remunerative way. Leaving the yield of fruit for a brief consideration of the effects of the two treatments on tree characters, we can mention first the leaf area was not strong; but the merest glance through the orchard '' oulcT show that there were more and larger leaves on the tilled plot than on the sod-mulched plot. The experienced orchardist knows that sparsity of foliage imd smallness of leaf can indicate but one thing—illhealth. So, too, there was something amiss with the colour of the leaves. It did not need a, trained eye to detect the difference m colour of foliage in the two plots. The dark and rich green of the tilled plots could be noticed a half-mile from the orchard, indicating an abundance of food and moisture, and the heyday of health; while from the same distance it could be seen that the foliage of the sod-mulched trees was pale and sickly; of all signs of superiority of the two trees the colour of the trees spoke eloquently, and more than one man of the hundreds who visited the orchard was heard to say as his eye lighted on the contrasts in colours of the sick and the well trees, “That satisfies me.” The in colour in the leaves of the sodmulched trees was due to a lack of chlorophyl or leaf green. Chlorophyl is essential to assimilation of plant food, and when it is lacking, the trees become starved and stunted. The leaves on the sod-mulched trees assumed their autumnal tints a week or 10 days earlier than those on the tilled trees, and the foliage dropped that much earlier, thus seriously cutting short the growing season of the grass trees and thereby impairing their vitality. The new wood produced by the grass trees tells a similar tale of injury. It was not half that produced on the tilled trees. The twigs were not plump and well filled out. there were fewer new shoots, and the wood of the mulched trees lacked the clear, bright, brown, rich tiiA, of Jiealth, so that in midwinter one could pick out mulched trees and tilled trees by the colour of the wood. As to colour, there is no question but -that the fruit from the sod-mulchcd plot is much more highly coloured than that from the tilled plot. This difference varies with the seasons. Mulched fruit ripens from a week to 10 days earlier than tilled fruit.' If the variety and season arc such that the tilled fruit can remain on the trees some days after the mulched fruit must be picked, the difference in colour is much less. The light colour of the tilled fruit is readily and clearly explained. The colouring matter of the skin of the apple, like that in the leaves, consists of chlorophyl or leaf green. The colour of the ripening fruit is duo to the changing of the chlorophyl of the skin into the coloured substance of autumnal tints. Therefore, since the sod fruit ripens earlier, it colours earlier, and in most seasons better. The abnormal high colour of the sod fruit in this orchard is one of the most marked signs of the deleterious effect of the sod on the trees. Every man of experience has observed that when a tree is starved, stunted, girdled, or injured its foliage and its fruit take on high colour. Radiant colour in fruit or leaf is often the hectic flush of a diseased patient. Bright colour of the fruit of the §od-mulchcd trees may be purchased at the expense of the vigour and the health of the tree. The later ripening period of the fruit of the tilled would be different with some varieties and in some localities, but in general, under the conditions existing in New York, late ripening is an advantage. Fruit from both plots for the five years Has been kept in cool storage to test its relative keeping qualities. The work has born in charge of Mr G. H. Powcil, cool storage export of the United States Department of Agriculture, who writes me in brief:

“There appears to have been little practical difference in the keeping quality between fruit from sod land and fruit picked a few days later from the tilled land. There is but little difference in the quality of the fruit, when specimens can be had at the same degree of maturity, but the tissues of the sod-mulched fruit begin to break down so quickly after harvesting that at any time after this period flic tilled fruit is bettor in qualitv. Tin's has been true in the whole of the five seasons, a fact affirmed by repeated testimony by those in charge of the experiment, and attested bv many who have seen the fruit at the Geneva Station and at horticultural meetings. The more pleasing colour of the sodmulched fruit loads many to think that it is of higher quality, but it only rcouircs a taste to convince one to the contrary. “In considering the cause of the difference noted between the two systems of management we can do little more than state the hypothesis which seems to account for the results. The experiment is not by any means concluded, «n<l definite reasons cannot l)c advanced until all the proof is available. Yet, it seems to me I am warranted in offering the following hypothesis: “f 1) Plant food is more available in the tilled plot than in the mulched plot; there is an abundance of the nlant food necessary for the welfare of the tree, and tho production of crops in both ploW is certain. for the trees in the tilled plot showed in all respects good feeding, and also such trees In the -sod-mulched plots as had any considerable proportion of their roofs in soil where there were no grass roots. More* over, two of the chief elements of plant food, potash and phosphoric acid, were added to a part of the trees in each plot for three successive seasons, but without appreciable result in either case. It is evi> dent that there is plenty of food in the sod land, but for some reason it, is not available to the apple trees. The trees arc starving in a land of plenty. “(2) Tho sod-muleh does not conserve moisture as well os tillage. The chlof study in the orchard for tho summer. 1907, wae the water content of the soil in the two plots. One hundred and twenty-eight

samples of soil were taken at different times during the summer, under conditions safeguarded in every way possible, to determine accurately the amount of moisture in the soil. The analyses showed approximately that the water content in the tilled soil during the past summer was twice as great as in the sod plot, thereby substantiating what had long been known, that tillage is a better means of conserving moisture than mulching. Trees must have water. If an apple tree bears 10 barrels of fruit there are about eight and a-half barrels of water in the tree’s outlet. In a full-grown apple tree it is estimated that the total leaf area is about one million square inches. Mr F. C. Standish, of the Geneva Station, has counted the etomato, or pores, on a square inch of the apple leaf, and finds that a fair average is about 150,000 per square inch, or, for the leaf area of the whole tree, 150,000,000.000 spores. Now, to supply the demands of its 10 barrels of apple children with their 150,000,000.000 spores, while these are constantly giving moisture, is enough to drive a tree to drink, and the apple tree becomes a hard drinker when in the heat and drought of summer the apple tree is compelled to share its scant supply of water with the thirsty hoards of hangers-on found in an orchard sod. The trees must suffer still further, as a diminished water supply entails a cutting-off of the food supply. Plant food enters the tree as a solution, and an apple tree suffering from lack of water suffers, as a necessary consequence, from a lack of food. A thirsty plant is a hungry plant. “(3) The sod-mulching soil is loss well aerated. In the experiments we arc carrying on, I have not attempted to secure evidence on this point. It is obvious that cod interferes with the air supply in the ground beneath it, and it is not hard to believe that such interference would hinder the proper development and prevent the proper work of roots. The muffler of mulch, wlrch forms a part of the system of orchard management, would, of course, intensify the deleterious effects of the sod in the above respect. “(4) The soil temperature is lower in the sod-mulched plots than in the tilled plots. It is possible that the harmful action of grass may bo accounted for in part by the influence of the sod on the temperature of the soil. During the summer of 1907 the soil temperature was taken in the tilled and mulched plots twice a day for 41 days at the depths of 6in and 12in, under as nearly as possible comparable conditions. At both depths the difference was in favour of the tilled plot. At 6in the difference was slight, being only one-third of a degree; but for the greater depth of 12:n the average in favour of the tilled plot was l|deg. It is not an assumption to say that the higher temperature is most favourable to the growth of the apple tree, for plant physiologists, soil physicians, and bacteriologists agree that an increase in soil temperatures is favourable to plant growth. As one of them puts it, the soil is the great factory that has its production vastly increased as the temperature rises. “(5) There are probable differences in the biological or germ-like activities taking place in the soil. This is a matter which I am not qualified to speak of with certainty; but I know that the men who arc studying the sod find that there are various kinds of micro-organisms inhabiting the soil, which have much to do with the proper functioning of the roots that grow therein. The soil is teeming with countless millions of living organisms, which bring about necessary changes of one kind and another in the soil. Without them the higher vegetation would not grow. Now, the activities of these benelieial organisms are dependent upon soil conditions, and Mr King tolls us in tho quotation given above that tillage induces a strong growth of soil organisms; that it improves tilth so that soil organisms spread readily and widely; and that it converts the root zone into commodious and sanitary living-places for these soil organisms.

“ (6) The grass may have a toxic or poisonous effect upon apple trees. At the fiftieth annual mooting of the Western New York Horticultural Society the writer gave an account of a scries of plot experiments which seemed to show that grass roots in some way poisoned poach trees. The United States Department of Agriculture has published a number of observations and experiments to show that different plants growing in the same soil may poison each other. I am also able to give the results of a most excellent series of experiments, planted and carried out by the Woburn Experimental Farm in England. These experiments were planned to show the effects of growing trees in grass, the latter to bo used as a mulch. The following gives the results of the experiments in question;—As to the general effects of grass produced on apple trees, the results of the last few years have brought forth nothing which can in any way modify our previous conclusions as to the intensely deleterious nature of the effects. We can only repeat that no ordinary form of ill-treatment,, including even the combination of bud-planting, growth of weeds, and total neglect, is not so harmful as grow’ng grass around them. The evidence which we shall bring forward will, wo believe, bo sufficient to dispose of the views that the grass effrets are duo to the interference l with either the food supply, the water supply, and air of the trees, and that it must in all probability bo attributed to the action of some product, direct or indirect, of grass-growing, which exorcises an actively poisonous effect upon the root of the tree. I do not put forth the statement that grass poisons the apple as one having been proved, but I say it may bo so “ In conclusion, you arc warned that particular cases do not warrant general conclusions. The Auditor experiments arc in many respects a particular caSc, and the apnle-grower must bear in mind that under other conditions —his own perhaps—the trees mav have behaved very differently. The orchard was selected as being typical of Western New York conditions, and the results obtained may therefore be regarded as expressly applicable to this region, but there are peculiarities of soil and location which may change them. It is n simple matter for an orchardist to plough up a part of an orchard in grass and cultivate it for a few years, or an easy matter for one who has tilled an orchard to lay a part of it down in grass, cutting the grass and using it as a mulch, and in a few years ho will sec what happens. .We want more experimenters amongst fruit growers, and these are good experiments to try. When a man becomes dissatisfied with the crops of apples he is getting, the opportunity of giving another warning cannot he lost. The sod-mulch method is heralded as (he cheap and easy method. If they begin • to apply

it to tillage they are likely to look for a cheap and easy way of planting —the Stringfellow way, for instance, a cheap and easy way of spraying. Some will not embarrass themselves with the trouble of taking care of the trees at all, and in the end will wind up as an ordinary no-account fruitgrower. I do not mean to say that all’-will, but some of them will. “In chemistry, physics, astronomy, and all of the exact sciences, the workers constitute a jury of keen, trained men, before whom new doctrines can be tried. The jury is always sitting, and false doctrine is quickly weeded out. Agriculture has no such jury. Its workers ara scattered; many are apathetic; they differ in training and in degree of intelligence, and speak many languages. They can therefore be no suitable jury to try new doctrine, and there are no recognised authorities to approve or disprove them. It comes about, therefore, that false and erroneous doctrines often grow unheeded and choke out the true and the useful. Agriculture needs now and ever to be defended against false doctrine. I am venturing to play the part of a defender to-day. and I have gone far in the defence of tillage and in condemnation of sod-mulched orchards. It is because there is need.”

Bush rls. Bushels (in sod). (tillage-) 1904 .. . 591,9 1995 233 278.9 1906 .. . 210.3 531.1 1907 .. 275.3 424.3 1908 .. 722.5