CHAPTER XI
SOWING AND HARVESTING


THE careful application of the principles ofsoil treatment discussed in the preceding chapters will leave the soil in good conditionfor sowing, either in the fall or spring. Nevertheless, though proper dry-farminginsures a first-class seed-bed, the problem of sowing is one of the most difficultin the successful production of crops without irrigation. This is chiefly due tothe difficulty of choosing, under somewhat rainless conditions, a time for sowingthat will insure rapid and complete germination and the establishmcnt of a root systemcapable of producing good plants. In some respects fewer definite, reliable principlescan be laid down concerning sowing than any other principle of important applicationin the practice of dry-farming. The experience of the last fifteen years has taughtthat the occasional failures to which even good dry-farmers have been subjected havebeen caused almost wholly by uncontrollable unfavorable conditions prevailing atthe time of sowing.


Conditions of germination

Three conditions determine germination: (1) heat,(2) oxygen, and (3) water. Unless these three conditions are all favorable, seedscannot germinate properly. The first requisite for successful seed germination isa proper degree of heat. For every kind of seed there is a temperature below whichgermination does not occur; another, above which it does not occur, and another,the best, at which, providing the other factors are favorable, germination will goon most rapidly. The following table, constructed by Goodale, shows the latest, highest,and best germination temperatures for wheat, barley, and corn. Other seeds germinateapproximately within the same ranges of temperature:--

Germination Temperatures (Degrees Farenheit)
  Lowest Highest Best
Wheat 41 108 84
Barley 41 100 84
Corn 49 115 91


Germination occurs within the considerable rangebetween the highest and lowest temperatures of this table, though the rapidity ofgermination decreases as the temperature recedes from the best. This explains theearly spring and late fall germination when the temperature is comparatively low.If the temperature falls below the lowest required for germination, dry seeds arenot injured, and even a temperature far below the freezing point of water will notaffect seeds unfavorably if they are not too moist. The warmth of the soil, essentialto germination, cannot well be controlled by the farmer; and planting must, therefore,be done in seasons when, from past experience, it is probable that the temperatureis and will remain in the neighborhood of the best degree for germination. More heatis required to raise the temperature of wet soils; therefore, seeds will generallygerminate more slowly in wet than in dry soils, as is illustrated in the rapid germinationoften observed in well-tilled dry-farm soils. Consequently, it is safer at a lowtemperature to sow in dry soils than in wet ones. Dark soils absorb heat more rapidlythan lighter colored ones, and under the same conditions of temperature germinationis therefore more likely to go on rapidly in dark colored soils. Over the dry-farmterritory the soils are generally light colored, which would tend to delay germination.The incorporation of organic matter with the soil, which tends to darken the soil,has a slight though important bearing on germination as well as on the general fertilityof the soil, and should be made an important dry-farm practice. Meanwhile, the temperatureof the soil depends almost wholly upon the prevailing temperature conditions in thedistrict and is not to any material degree under the control of the farmer.

A sufficient supply of oxygen in the soil isindispensable to germination. Oxygen, as is well known, forms about one fifth ofthe atmosphere and is the active principle in combustion and in tile changes in theanimal body occasioned by respiration. Oxygen should be present in the soil air inapproximately the proportion in which it is found in the atmosphere. Germinationis hindered by a larger or smaller proportion than is found in the atmosphere. Thesoil must be in such a condition that the air can easily enter or leave the uppersoil layer; that is, the soil must be somewhat loose. In order that the seeds mayhave access to the necessary oxygen, then, sowing should not be done in wet or packedsoils, nor should the sowing implements be such as to press the soil too closelyaround the seeds. Well-fallowed soil is in an ideal condition for admitting oxygen.

If the temperature is right, germination beginsby the forcible absorption of water by the seed from the surrounding soil. The forceof this absorption is very great, ranging from four hundred to five hundred poundsper square inch, and continues until the seed is completely saturated. The greatvigor with which water is thus absorbed from the soil explains how seeds are ableto secure the necessary water from the thin water film surrounding the soil grains.The following table, based upon numerous investigations conducted in Germany andin Utah, shows the maximum percentages of water contained by seeds when the absorptionis complete. These quantities are reached only when water is easily accessible:--

Percentage of Water contained by Seeds at Saturation
  German Utah
Rye 58 --
Wheat 57 52
Oats 58 43
Barley 56 44
Corn 44 57
Beans 95 88
Lucern 78 67


Germination itself does not go on freely untilthis maximum saturation has been reached. Therefore, if the moisture in the soilis low, the absorption of water is made difficult and germination is retarded. Thisshows itself in a decreased percentage of germination. The effect upon germinationof the percentage of water in the soil is well shown by some of the Utah experiments,as follows:--

Effect of Varying Amounts of Water on Percentage of Germination
Percent water in soil 7.5 10 12.5 15 17.5 20 22.5 25
Wheat in sandy loam 0.0 98 94 86 82 82 82 6
Wheat in clay 30 48 84 94 84 82 86 58
Beans in sandy loam 0 0 20 46 66 18 8 9
Beans in clay 0 0 6 20 22 32 30 36
Lucern in Sandy loam 0 18 68 54 54 8 8 9
Lucern in clay 8 8 54 48 50 32 15 14


In a sandy soil a small percentage of water willcause better germination than in a clay soil. While different seeds vary in theirpower to abstract water from soils, yet it seems that for the majority of plants,the best percentage of soil-water for germination purposes is that which is in theneighborhood of the maximum field capacity of soils for water, as explained in ChapterVII. Bogdanoff has estimated that the best amount of water in the soil for germinationpurposes is about twice the maximum percentage of hygroscopic water. This would notbe far from the field-water capacity as described in the preceding chapter.

During the absorption of water, seeds swell considerably,in many cases from two to three times their normal size. This has the very desirableeffect of crowding the seed walls against the soil particles and thus, by establishingmore points of contact, enabling the seed to absorb moisture with greater facility.As seeds begin to absorb water, heat is also produced. In many cases the temperaturesurrounding the seeds is increased one degree on the Centigrade scale by the mereprocess of water absorption. This favors rapid germination. Moreover, the fertilityof the soil has a direct influence upon germination. In fertile soils the germinationis more rapid and more complete than in infertile soils. Especially active in favoringdirect germination are the nitrates. When it is recalled that the constant cultivationand well-kept summer fallow of dry-farming develop large quantities of nitrates inthe soil, it will be understood that the methods of dry-farming as already outlinedaccelerate germination very greatly.

It scareely need be said that the soil of theseed-bed should be fine, mellow, and uniform in physical texture so that the seedscan be planted evenly and in close contact with the soil particles. All the requisiteconditions for germination are best met by the conditions prevailing in a well-keptsummer fallowed soil.


Time to sow

In the consideration of the time to sow, thefirst question to be disposed of by the dry-farmer is that of fall as against springsowing. The small grains occur as fall and spring varieties, and it is vitally importantto determine which season, under dry-farm conditions, is the best for sowing.

The advantages of fall sowing are many. As stated,successful germination is favored by the presence of an abundance of fertility, especiallyof nitrates, in the soil. In summer-fallowed land nitrates are always found in abundancein the fall, ready to stimulate the seed into rapid germination and the young plantsinto vigorous growth. During the late fall and winter months the nitrates disappear,at least in part, anti from the point of view of fertility the spring is not so desirableas the fall for germination. More important, grain sown in the fall under favorableconditions will establish a good root system which is ready for use and in actionin the early spring as soon as the temperature is right and long before the farmercan go out on the ground with his implements. As a result, the crop has the use ofthe early spring moisture, which under the conditions of spring sowing is evaporatedinto the air. Where the natural precipitation is light and the amount of water storedin the soil is not large, the gain resulting from the use of the early spring moisture.often decides the question in favor of fall sowing.

The disadvantages of fall sowing are also many.The uncertainty of the fall rains must first be considered. In ordinary practice,seed sown in the fall does not germinate until a rain comes, unless indeed sowingis done immediately after a rain. The fall rains are uncertain as to quantity. Inmany cases they are so light that they suffice only to start germination and notto complete it and give the plants the proper start. Such incomplete germinationfrequently causes the total loss of the crop. Even if the stand of the fall cropis satisfactory, there is always the danger of winter-killing to be reckoned with.The real cause of winter-killing is not yet clearly understood, though it seems thatrepeated thawing and freezing, drying winter winds, accompanied by dry cold or protractedperiods of intense cold, destroy the vitality of the seed and young root system.Continuous but moderate cold is not ordinarily very injurious. The liability to winter-killingis, therefore, very much greater wherever the winters are open than in places wherethe snow covers the ground the larger part of the winter. It is also to be kept inmind that some varieties are very resistant to winter- killing, while others requirewell-covered winters. Fall sowing is preferable wherever the bulk of the precipitationcomes in winter and spring and where the winters are covered for some time with snowand the summers are dry. Under such conditions it is very important that the cropmake use of the moisture stored in the soil in the early spring. Wherever the precipitationcomes largely in late spring and summer, the arguments in favor of fall sowing arenot so strong, and in such localities spring sowing is often more desirable thanfall sowing. In the Great Plains district, therefore, spring sowing is usually recommended,though fall-sown crops nearly always, even there, yield the larger crops. In theintermountain states, with wet winters and dry summers, fall sowing has almost whollyreplaced spring sowing. In fact, Farrell reports that upon the Nephi (Utah) substationthe average of six years shows about twenty bushels of wheat from fall-sown seedas against about thirteen bushels from spring-sown seed. Under the California climate,with wet winters and a winter temperature high enough for plant growth, fall sowingis also a general practice. Wherever the conditions are favorable, fall sowing shouldbe practiced, for it is in harmony with the best principles of water conservation.Even in districts where the precipitation comes chiefly in the summer, it may befound that fall sowing, after all, is preferable.

The right time to sow in the fall can be fixedonly with great difficulty, for so much depends upon the climatic conditions. Infact the practice varies in accordance with differences in fall precipitation andearly fall frosts. Where numerous fall rains maintain the soil in a fairly moistcondition and the temperature is not too low, the problem is comparatively simple.In such districts, for latitudes represented by the dry-farm sections of the UnitedStates, a good time for fall planting is ordinarily from the first of September tothe middle of October. If sown much earlier in such districts, the growth is likelyto be too rank and subject to dangerous injury by frosts, and as suggested by Farrellthe very large development of the root system in the fall may cause, the followingsummer, a dangerously large growth of foliage; that is, the crop may run to strawat the expense of the grain. If sown much later, the chances are that the crop willnot possess sufficient vitality to withstand the cold of late fall and winter. Inlocalities where the late summer and the early fall are rainless, it is much moredifficult to lay down a definite rule covering the time of fall sowing. The dry-farmersin such places usually sow at any convenient time in the hope that an early rainwill start the process of germination and growth. In other cases planting is delayeduntil the arrival of the first fall rain. This is an certain and usually unsatisfactorypractice, since it often happens that the sowing is delayed until too late in thefall for the best results.

In districts of dry late summer and fall, thegreatest danger in depending upon the fall rains for germination lies in the factthat the precipitation is often so small that it initiates germination without beingsufficient to complete it. This means that when the seed is well started in germination,the moisture gives out. When another slight rain comes a little later, germinationis again started and possibly again stopped. In some seasons this may occur severaltimes, to the permanent injury of the crop. Dry-farmers try to provide against thisdanger by using an unusually large amount of seed, assuming that a certain amountwill fail to come up because of the repeated partial germinations. A number of investigatorshave demonstrated that a seed may start to germinate, then be dried, and again bestarted to germinate several times in succession without wholly destroying the vitalityof the seed.

In these experiments wheat and other seeds wereallowed to germinate and dry seven times in succession. With each partial germinationthe percentage of total germination decreased until at the seventh germination onlya few seeds of wheat, barley, and oats retained their power. This, however, is practicallythe condition in dry-farm districts with rainless summers and falls, where fall seedingis practiced. In such localities little dependence should be placed on the fall rainsand greater reliance placed on a method of soil treatment that will insure good germination.For this purpose the summer fallow has been demonstrated to be the most desirablepractice. If the soil has been treated according to the principles laid down in earlierchapters, the fallowed land will, in the fall, contain a sufficient amount of moistureto produce complete germination though no rains may fall. Under such conditions themain consideration is to plant the seed so deep that it may draw freely upon thestored soil-moisture. This method makes fall germination sure in districts wherethe natural precipitation is not to be depended upon.

When sowing is done in the spring, there arefew factors to consider. Whenever the temperature is right and the soil has driedout sufficiently so that agricultural implements may be used properly, it is usuallysafe to begin sowing. The customs which prevail generally with regard to the timeof spring sowing may be adopted in dry-farm practices also.


Depth of seeding

The depth to which seed should be planted inthe soil is of importance in a system of dry-farming. The reserve materials in seedsare used to produce the first roots and the young plants. No new nutriment beyondthat stored in the soil can be obtained by the plant until the leaves are above theground able to gather Carleton from the atmosphere. The danger of deep planting lies,therefore, in exhausting the reserve materials of the seeds before the plant hasbeen able to push its leaves above the ground. Should this occur, the plant willprobably die in the soil. On the other hand, if the seed is not planted deeply enough,it may happen that the roots cannot be sent down far enough to connect with the soil-waterreservoir below. Then, the root system will not be strong and deep, but will haveto depend for its development upon the surface water, which is always a dangerouspractice in dry-farming. The rule as to the depth of seeding is simply: Plant asdeeply as is safe. The depth to which seeds may be safely placed depends upon thenature of the soil, its fertility, its physical condition, and the water that itcontains. In sandy soils, planting may be deeper than in clay soils, for it requiresless energy for a plant to push roots, stems, and leaves through the loose sandysoil than through the more compact clay soil; in a dry soil planting may be deeperthan in wet soils; likewise, deep planting is safer in a loose soil than in one firmlycompacted; finally, where the moist soil is considerable distance below the surface,deeper planting may be practiced than when the moist soil is near the surface. Countlessexperiments have been conducted on the subject of depth of seeding. In a few cases,ordinary agricultural seeds planted eight inches deep have come up and produced satisfactoryplants. However, the consensus of opinion is that from one to three inches are bestin humid districts, but that, everything considered, four inches is the best depthunder dry-farm conditions. Under a low natural precipitation, where the methods ofdry-farming are practiced, it is always safe to plant deeply, for such a practicewill develop and strengthen the root system, which is one big step toward successfuldry-farming.


Quantity to sow

Numerous dry-farm failures may be charged whollyto ignorance concerning the quantity of seed to sow. In no other practice has thecustom of humid countries been followed more religiously by dry-farmers, and failurehas nearly always resulted. The discussions in this volume have brought out the factthat every plant of whatever character requires a large amount of water for its growth.From the first day of its growth to the day of its maturity, large amounts of waterare taken from the soil through the plant and evaporated into the air through theleaves. When the large quantities of seed employed in humid countries have been sownon dry lands, the result has usually been an excellent stand early in the season,with a crop splendid in appearance up to early summer. .A luxuriant spring crop reduces,however, the water content of the soil so greatly that when the heat of the summerarrives, there is not sufficient water left in the soil to support the final developmentand ripening. A thick stand in early spring is no assurance to the dry-farmer ofa good harvest. On the contrary, it is usually the field with a thin stand in springthat stands up best through the summer and yields most at the time of harvest. Thequantity of seed sown should vary with the soil conditions: the more fertile thesoil is, the more seed may be used; the more water in the soil, the more seed maybe sown; as the fertility or the water content diminishes, the amount of seed shouldlikewise be diminished. Under dry-farm conditions the fertility is good, but themoisture is low. As a general principle, therefore, light seeding should be practicedon dry-farms, though it should be sufficient to yield a crop that will shade theground well. If the sowing is done early, in fall or spring, less seed may be usedthan if the sowing is late, because the early sowing gives a better chance for rootdevelopment, which results, ordinarily, in more vigorous plants that consume moremoisture than the smaller and weaker plants of later sowing. If the winters are mildand well covered with snow, less seed may be used than in districts where severeor open winters cause a certain amount of winter-killing. On a good seed-bed of fallowedsoil less seed may be used than where the soil has not been carefully tilled andis somewhat rough and lumpy and unfavorable for complete germination. The yield ofany crop is not directly proportional to the amount sown, unless all factors contributingto germination are alike. In the case of wheat and other grains, thin seeding alsogives a plant a better chance for stooling, which is Nature's method of adaptingthe plant to the prevailing moisture and fertility conditions. When plants are crowded,stooling cannot occur to any marked degree, and the crop is rendered helpless inattempts to adapt itself to surrounding conditions.

In general the rule may be laid down that a littlemore than one half as much seed should be used in dry-farm districts with an annualrainfall of about fifteen inches than is used in humid districts. That is, as againstthe customary five pecks of wheat used per acre in humid countries about three pecksor even two pecks should be used on dry-farms. Merrill recommends the seeding ofoats at the rate of about three pecks per acre; of barley, about three pecks; ofrye, two pecks; of alfalfa, six pounds; of corn, two kernels to the hill, and othercrops in the same proportion. No invariable rule can be laid down for perfect germination.A small quantity of seed is usually sufficient; but where germination frequentlyfails in part, more seed must be used. If the stand is too thick at the beginningof the growing season, it must be harrowed out. Naturally, the quantity of seed tobe used should be based on the number of kernels as well as on the weight. For instance,since the larger the individual wheat kernels the fewer in a bushel, fewer plantswould be produced from a bushel of large than from a bushel of small seed wheat.The size of the seed in determining the amount for sowing is often important andshould be determined by some simple method, such as counting the seeds required tofill a small bottle.


Method of sowing

There should really be no need of discussingthe method of sowing were it not that even at this day there are farmers in the dry-farmdistrict who sow by broadcasting and insist upon the superiority of this method.The broadcasting of seed has no place in any system of scientific agriculture, leastof all in dry-farming, where success depends upon the degree with which all conditionsare controlled. In all good dry-farm practice seed should be placed in rows, preferablyby means of one of the numerous forms of drill seeders found upon the market. Theadvantages of the drill are almost self-evident. It permits uniform distributionof the seed, which is indispensable for success on soils that receive limited rainfall.The seed may be placed at an even depth, which is very necessary, especially in fallsowing, where the seed depends for proper germination upon the moisture already storedin the soil. The deep seeding often necessary under dry-farm conditions makes thedrill indispensable. Moreover, Hunt has explained that the drill furrows themselveshave definite advantages. During the winter the furrows catch the snow, and becauseof the protection thus rendered, the seed is less likely to be heaved out by repeatedfreezing and thawing. The drill furrow also protects to a certain extent againstthe drying action of winds and in that way, though the furrows are small, they aidmaterially in enabling the young plant to pass through the winter successfully. Therains of fall and spring are accumulated in the furrows and made easily accessibleto plants. Moreover, many of the drills have attachments whereby the soil is pressedaround the seed and the topsoil afterwards stirred to prevent evaporation. This permitsof a much more rapid and complete germination. The drill, the advantages of whichwere taught two hundred years ago by Jethro Tull, is one of the most valuable implementsof modern agriculture. On dry-farms it is indispensable. The dry-farmer should makea careful study of the drills on the market and choose such as comply with the principlesof the successful prosecution of dry-farming. Drill culture is the only method ofsowing that can be permitted if uniform success is desired.


The care of the crop

Excepting the special treatment for soil-moistureconservation, dry-farm crops should receive the treatment usually given crops growingunder humid conditions. The light rains that frequently fall in autumn sometimesform a crust on the top of the soil, which hinders the proper germination and growthof the fall-sown crop. It may be necessary, therefore, for the farmer to go overthe land in the fall with a disk or more preferably with a corrugated roller.

Ordinarily, however, after fall sowing thereis no further need of treatment until the following spring. The spring treatmentis of considerably more importance, for when the warmth of spring and early summerbegins to make itself felt, a crust forms over many kinds of dry-farm soils. Thisis especially true where the soil is of the distinctively arid kind and poor in organicmatter. Such a crust should be broken early in order to give the young plants a chanceto develop freely. This may be accomplished, as above stated, by the use of a disk,corrugated roller, or ordinary smoothing harrow.

When the young grain is well under way, it maybe found to be too thick. If so, the crop may be thinned by going over the fieldwith a good irontooth harrow with the teeth so set as to tear out a portion of theplants. This treatment may enable the remaining plants to mature with the limitedamount of moisture in the soil. Paradoxically, if the crop seems to be too thin inthe spring, harrowing may also be of service. In such a case the teeth should beslanted backwards and the harrowing done simply for the purpose of stirring the soilwithout injury to the plant, to conserve the moisture stored in the soil and to acceleratethe formation of nitrates. -The conserved moisture and added fertility will strengthenthe growth and diminish the water requirements of the plants, and thus yield a largercrop. The iron-tooth harrow is a very useful implement on the dry-farm when the cropsare young. After the plants are up so high that the harrow cannot be used on themno special care need be given them, unless indeed they are cultivated crops likecorn or potatoes which, of course, as explained in previous chapters, should receivecontinual cultivation.


Harvesting

The methods of harvesting crops on dry-farmsare practically those for farms in humid districts. The one great exception may bethe use of the header on the grain farms of the dry-farm sections. The header hasnow become well-nigh general in its use. Instead of cutting and binding the grain,as in the old method, the heads are simply cut off and piled in large stacks whichlater are threshed. The high straw which remains is plowed under in the fall andhelps to supply the soil with organic matter. The maintenance of dry-farms for overa generation without the addition of manures has been made possible by the organicmatter added to the soil in the decay of the high vigorous straw remaining afterthe header. In fact, the changes occurring in the soil in connection with the decayingof the header stubble appear to have actually increased the available fertility.Hundreds of Utah dry wheat farms during the last ten or twelve years have increasedin fertility, or at least in productive power, due undoubtedly to the introductionof the header system of harvesting. This system of harvesting also makes the practiceof fallowing much more effective, for it helps maintain the organic matter whichis drawn upon by the fallow seasons. The header should be used wherever practicable.The fear has been expressed that the high header straw plowed under will make thesoil so loose as to render proper sowing difficult and also, because of the easycirculation of air in the upper soil layers, cause a large loss of soil-moisture.This fear has been found to be groundless, for wherever the header straw has beenplowed under; especially in connection with fallowing, the soil has been benefited.

Rapidity and economy in harvesting are vitalfactors in dry-farming, and new devices are constantly being offered to expeditethe work. Of recent years the combined harvester and thresher has come into generaluse. It is a large header combined with an ordinary threshing machine. The grainis headed and threshed in one operation and the sacks dropped along the path of themachine. The straw is scattered over the field where it belongs.

All in all, the question of sowing, care of crop,and harvesting may be answered by the methods that have been so well developed incountries of abundant rainfall, except as new methods may be required to offset thedeficiency in the rainfall which is the determining condition of dry-farming.