USRE18132E - Ments - Google Patents

Description

l July 2l, 1931.

IETHOD FOR TREATING SOILS T0 PROIOTE PLANT @Rm Mar/s HSM/ner INVENTOR.

Reissued July 21, 1931 UNITED STATES PATENT OFFICE CHARLES H. SPENCER, OF GLENDALE, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, T0 SUB-SOIL AERATION COMPANY METHOD FOR TREATING SOILS TO PROMOTE PLANT GROWTH Original No. 1,677,153, dated July 17, 1928, Serial Nc. 87,673, led February 11, 1926. Application for 4 reissue led .Tuly`17, 1930.

cause of poor plant growth is the .lack of a propel' degree of porosit of the soil in which the plants are rooted. uch lack of porosity prevents the proper infiltration of both air and water necessary to the plants growth, and causes the retention of foul gases in the soil. Many theories and beliefs are extant as to the benefits of ample supplies of pure air in the soil adjacent the roots, and likewise as to the advantages and reasons for keeping the soil in a porous or well broken condition, but the fact is admitted, by practically all horticulturists and agriculturists, that healthy plant growth can be had only when the soil is in such condition that the infiltration of fresh atmospheric air, and of water is possible.

In addition to the above it is generally conceded by all those skilled in the art, that the existence of fresh air, adjacent the roots of plants, is necessary to the plants growth, although it is not definitely known whether the air is most beneficial to the roots directly, or whether it aids the activities of the nitrifying bacteria of the soil, but it is a well recognized fact that closely compact soil, or even. suitably porous soil, covered by standing water is not conducive to healthy plant growth.

Deep plowing and frequent cultivating are the only known practical methods for breaking up the soil and subjecting it to the beneficial action of new and fresh air.

Crops and trees set out in virgin soil invariably flourish for a time and later become decadent because constant action of rain water and irrigating water, washing down through the porous upper layers of soil, settle the finer and more soluble particles of earth into a closely compact strata, generally known as hard pan. Hard pan is practically impervious to atmospheric air and to water. Long lived growths, such as trees, are difficult of proper cultivation without injury t0 the roots. In groves, the only known Serial No. 468,719.

method of treatment is to subsoil to a depth below the surface. This lets in a limited amount of air and water, but subsoiling cannot be carried on close to the tree or its roots and is therefore of limited benefit.

Hard pan, or relatively impervious stratas, may form even as a result of one or two heavy rains or surface irrigations, and there is no known method for breaking up such formations while the plants are growing. Deep seated hard pans, in the case of trees, choke the roots, and where the roots go to considerable depths for water, they penetrate the low hard pans into a soil which is deficient in air and which is charged with foul gases.

Even where very deep plowing is resorted to annually, the fact remains that before the Y plants are matured, the soil becomes so compact near the surface as to prevent proper and natural infiltration of air and water t0 the soil in which they are rooted.

It is therefore one of the primary objects of the invention to provide improved methods and means for breaking the ground, and particularly the deeper hard pans, at any desired time, and particularly after planting, or in the case of orchards, to break the soil and hard pans without injury to the trees and their roots.

, Another, and perhaps equally important object of the invention, is to provide improved methods and means for forcing `foul air out of the ground, and for causing new air to reach the roots.

Another object of the invention is to provide for breaking, and rendering pervious, the deep lying hard pans which cannot be reached by ordinary plowing.

As a means for aerating soil, it has been proposed to lay pipes under ground, with openings therein,` and to blow air into these pipes, so that it may escape through the openings and percolate through the ground t0 expel the foul gases, and to provide new oxygen and nitrogen for the soil. Such method is impractical in that the air soon finds channels through the ground which offer least resistance to its escape, and these channels are finally enlarged by the escaping air until all the air introduced readily escapes by way of such channels without being compelled to spread throughout the ground. In fact, by far the great majority of technical persons Will state with conviction, that air forced into 5 the grounfataanyfpermanent point'will find evenhraily,-or create, a line oleast'resistance of escape, and cannot be compelled tospread through theground. "Another 'object of the. invention is to provide for breaking the ound, from an appreciable depth upwar ,-to, and including the surface, so that stan ing water or subse- Iquent rainsr andzirrigata'ons will readilysink into the ground. From observations of my 15 methods, as well as observations of natures Jdethods, I have concluded that ground maintained in alsuitable condition of porosity will beloonsbantlyreaerated by such rain or irrigatiorn Thlsis due to the fact that the great i 4&0 density of water permits of its going into the interstices of the earth and 'replacing the foul vfgases. Subsequently, when the water is '.e'vapoated or taken lin by the plants, the "veids createdlarelled'with atm heric air vgf-"foreeddownwardly into the'voids y atmospheriepressure i x:Another object of the invention is'toV pro- Ivide for'quiteevenly -aerating large areas with minimum expenditure.

Still otherobjeets and advantages of my invention will appear hereinafter.

1vllyin'velition resides in the provision of a 'method,^rather' than any specific device,rfor "breaking and aerating ground, but in order 85 to carry out this method,l certain apparatus is required, although it will be apparent, here- "inariter, that'there Vare' numerous 4forms of limwn apparatus and devices which` may be `employed to carry out my invention. How- 4b 'ever-,to more clearly explain my invention I have 'illustrated one form of apparatus, 'and -Ysome devices for carrying out the method.

It is to be understood that I do not limit ll1rylselfto any particular device, except within'th'escope of the appended claims.

'Inthe A'said drawings: "FigJI isa diagrammatic view of4 an apparatus suitable for carryingout myimproved In methods.

HFigJ2is aviewin vertical section of aVmod- .'icatron of a part thereof.

Fig. 3 is a view *incross'sectiom illustrating eine of the'steps inV my method.

"Fig 1 4 is a view in section, illustrating another-*subsequentstep rwhich 4may be ernpieyed i im further carrying ein; the complete methodgwhichis aboutt'o'be described.

In carrying dutmy' invention, I'employ a U0 fluid in'gaseusfom, ,suchas air, or of course, an-nertgaisg'fr '-heneeiall active' gases other thanair may' be enfiploye'cl.7

f 'For' mstbenelllzial results, and particularlyit carry out all'tlre foregoing objects of the I6 nveiitifn', thegas is"intmduced,'with proper head or pressure, at points below the surface; preferably below the first impervious layer, or at least below the first few inches of soil. l have found that migratory dust and the hu- 'mus generally render the top of the ground less pervious than the immediate underlying layers, and usually there is a hard pan well below the. more porous overlying earth. Therefore, the air is to be injected, at a point to which, or below which water and/or air should percolate. In the case of a distinct hard pan or impervious layer, the air is preferably Vintroduced below such impervious layer. In the case of crops, or in the case of lawns, where the roots are closely inter- 80 laced, and form a mat or sod of earth and roots, the air should be 'introduced at least Y' below such sod.

The apparatus shown in Fig. 1, comprises an air compressor 10, mounted on a truck 11,.-'85 yand driven by an internall combustion engine 12. The compressor 10 discharges to a tank 14, and in this instance the tank is fitted with the pressure gauge 15. From the tank there extendsa long flexible conduit, or commonago yair hose, 16. In conformance with a salient feature of the invention, I provide a spud 17 adapted to be inserted yor driven into the ground. The spud illustrated in Fig.' lis 'provided with a pointed end 17', and a bore i155 18 closed at the upper end,- as at 18'. At the lower end, said spud is provided with a plurality of apertures 19 which open out laterally. "The hose is 'conneete'd to thespudby a coupling 20.` VA valve 21 is 'placed between ijQ00 vthe'hose and the spud to regulate or shut oil the supply of air.

;In carrying out'my improved methdwith the apparatus described, the spud is driven Y into the ground to a suitable depth, prefer- @i05- ably'more than one' foot, and usually about 'three feet." -By drivingthe 'spud the vsoll l-is packed'around' the same and acts as a seal to revent air from escaping around they spud.

' ostsoils requiring treatment' liy-'myfmthod (im `are ,characterized by a relatively impervious layer or hard pan 22, usually-deeper than the plow'has been able to reach. In thecase of a tree 23, it is not possible to plow close to it Without injury vto the roots, and therefore,

'particularly in the case of irrigated groves,

v'The een@lesseris.` 'eperatea preferably, g; r

continuously, and air flows through the tank and hose to the spud. The apertures in the Spud should be of slightly reduced total area as compared to the area of flow through the smallest part of the hose or the valve, so that the air issues from the apertures at appreciable velocity. When the air is first turned on it is preferable to open the valve slowly, as the tank may contain air at an excessive pressure. W hen the valve is being opened, the surface of the ground should be watched to see that the air is not admitted at. sufficient pressure to cause a breaking or buckling of the ground.

Finally the pressure in the tank drops until the air is going into the ground as rapidly as it is being delivered to the tank, and the entire pneumatic system reaches a state of constant pressure. Some of the pressure of the air is of course required for moving the air through the hose, while another pressure difference is required for accelerating the air through `the orifices of the spud. When the air is fiowing continuously into the ground, the pressure in the cavities immediately surrounding the oriices is only slightly` greater than atmospheric pressure.

If the pressure around the orifices is very great, the ground adjacent the nozzle will be caused to bulge visibly and objectionable crevices may form to allow the air to escape Without properly permeating the ground.

'By admitting the air slowly until the valve is wide open and the ground is taking the air properly, such premature breaking of the ground is obviated. In the case of a spud one and one-half inches in external diameter, I have been able to introduce 350 cubic feet of free air per minute in such manner that the air travels great distances under ground without escaping unduly at any given point. In sandy soils, for example, I find that the pressure with a spud of the size just mentioned, is only about three pounds per square inch greater when the spudA is in the ground than when it is discharging freely to the open air. This indicates the small pressure difference required to put the air into the ground in soil of this kind. The above mentioned amount of air was injected with the lower end of the s ud about three feet below the surface.

owever; the pressure carried in the tank is always well in excess of three pounds per square inch, in order to overcome the resistance of the holes, and to give velocity to the air escaping from the orifices. In actual operation I have carried from 2() pounds to as high as 80 pounds pressure in the tank, with no pressure regulator between. Obviously, should the soil at any time offer great resistance, the entire pressure of 80 pounds, in the latter instance, would be available to overcome this resistance. Contrary to general opinion, this pressure does not act to blow the soil up from around the spud. Whenever any high resistance is crea-ted by the soil, the pressure merely acts to overcome that resistanceI and open up crevices adjacent the spud, to allow the air to permeate the ground.

In all instances, I have found it advisable to always carry a tank pressure in excess of that represented by the weight of the soil to that depth, so that the excess pressure will be brought to bear against any temporary resistance.

As the air issues from the orifices at appreciable velocity it keeps the earth from closing the apertures and forms small cavities or crevices, such as shown, around the spud, and the air enters the interstitial spaces of all the exposed earth. The air travels laterally underground, even when there is no hard pan, apparently more rapidly than it travels vertically. A hole (not shown) may be dug near the spud and filled with water to a slight depth, or the walls of the hole may be sprinkled with water. A similar hole may be prepared at a greater distance. Bubbles appear in the water as the air and stale gases are driven from the ground into the hole, and the hole in closer proximity does not show much greater escape of air or gas than does the hole which is remote from the spud. Holes prepared thirty feet away from the point of injection show escape of airand gas after a very short period of injection. Immediately the air is turned off at the nozzle, such escape is seen to cease. If the surface of the ground is sprinkled at varying distances from the nozzle, it will be seen that some air, or the gases expelled by the air below, escapes upwardly through the ground adjacent the spud, but a similar escape will be noted several feet away, as well.

By running the compressor continuously, air may be injected for a long period of time. When it is calculated that a sufficient amount of air has been injected, the spud is moved to a new location. If, for instance, the spud is moved ten feet away each time t-o a new location, this means that each injection should provide air to aerate one hundred square feet of soil three feet deep. Since the air or gas content of soil seldom exceeds one third of its total volume, it will be seen that one hundred cubic feet of air per minute will suffice. I

Since the air is injected well below the surface, it is introduced to the ground below the gases which occupy the interstices adjacent the surface. Therefore, the first escape noted represents foul gases, rather than air, and when it is obvious that air is escaping and the ground adjacent the spud is saturated with fresh air, the spud should be moved to a new location.

In the case of a quite impervious layer, air injected below this layer, or hard pan, will travel great distances and remain thereunder, until another step in my method is employed ftobrea'k the hard pan. The same is true n the'case of lawns. Much of the lawn surface, particularly when wet, will hold the air down, but limited areas at various points will allow the gases to be driven out by the new air.

While the compressor is running and the '-air is entering the ground at a maintained pressure, and before moving the spud, the ound ma be broken or internally plowed by the fol owing procedure The valve at the spud isfclosed. The ressure in the hose and tank is just that su cient to inject the air properly into the ground, but as soon as the valve is closed, the pressure in the tank and hose increases. Shortly, in the space of a few seconds, the valve is opened quickly. Kir at a high pressure rushes rapidly into the cavities and crevices around the spud and iii'ls them with high pressure air more vrapidly than this air can expand and disseminate vthrough the adjacent soil. The previous injection of air has driven lighter Vparticles upwardly, so that the upper stratas are' quite well aled against' sudden upward escape''f air. The inteistices are filled with fresh air at, or above, atmospheric pressure. The high pressure air travels laterally and exerts a pressure upon the overlying earth. Since the weight of the ground above is less than one pound per square inch per foot deep, this excess pressure will cause the overlying ground to rise, and the surface V4will bulge visibly. This of course causes enlargement of the cavities and possible elongation of the crevices. The valve is closed vagain and the lair pressure again built vup, preferably to an evenhgher pressure than before. Sudden release 'o this pressure fills the' increased crevices and cavities and causes'a farther reaching bulging of the earth.` When this is repeated a few times, according to the nature of the soil, the ground is greatly loosened, broken and provided with `myriads of cavities.

In the case of sudden injection of high pressure air below hard pan, the results are even more noticeable and the hard par. is broken by' myriadsof elefts. After the ground is so broken, -it is of course wasteful of air to attempt to inject air for the further permeation of the soil, it being preferable to break the ground only after it has been aerated.

Obviously, ground so treated is filled with fresh air, the foul gases are driven oii', and the ground is highly receptive to water, even below the previously impervious layer. The beneitsrof such treatment in plant growth can be readily appreciated. Grass, alfalfa, and similar crops show almost immediate and surprising results. Trees treated, particularly close to the roots, show renewed and vigorous growth in a few weeks. Surface irrigated lands,I which shed the major portion of irrigation water, will be found tol absorb water at-asurprising rate `after being aerated by nygpmcess. `Even clods vor lumps ofearth 'area may be covered eliiciently. By 'observing thediference between'the pressure required to force air through a given spud'to the open air, and the pressure required to force air out of the spud while it is embedded in the ground, the pressurere'quired to cause the air to permeate the ground is determined.

In designlngA compressor outfits and spuds,`

the areas of flow to the spuds andhose should be proportioned accordingly, allowing for a slight excess pressure to force the air through the khose and to lgive Vreasonable velocity to the'air escaping fromtheforifices lof the spuds, and to allow for overcoming any temporaryv resistance.

In the modied form of'spud, the end is Y open, as at 40. Thisspud may be driven into some grounds readily, by allowingthe vairto esca e freely from'the end-thereof, while-'the spu is being forced by hand into theground. The air blast blowsa 7hole-ah'eadrof the'spud. When the hole is down the'required depth, the airis turned off and the loose earth around the Spudv is tamped vdown by foot pressure,-'only. Then the airis turned on slowly atfirstuntil the pressure comes down to that at which it has been found advisable to operate.

In'considering the possibilities of injecting air into the ground, 'itshould be 'realized-"that the particles of'earth Vcohere vto each other. Even 'should air immediatelyv adjacentv the spud exert an upward pressure inV excess aof the super-imposed weight of the earthabove it, the pressure will not necearily raise the ground immediately above it. This is Vbecause, whena given area of ground Yisrraised it tends to `adhere to more ren otek portions which hold it down. With a spudof the type just described, having an open end of of an inch diameter, 350 cubic feed of air r minute, or more, may be injected without itsblowing the soil away from around the Spud. 'perating 'under such conditions, it is frequently observed that by sprinkling the ground,'bub blesof water will form on'thesurface and will remain for long intervals 'without bursting. This fact indicates that the pressure of'airl in the ground immediately under the surface, under the operating conditions just mentioned, is not high.

Since the surface is 'somewhat rsealeid by dust, humus andthe like, it is not improbable that injected 'air will descend well below the Spud-as readily, and perhaps more readily, than it will travel upwardly. Thisfact is also due to the unlimited depths -of voids which exist in the ground below the spud.

lWhen-` the soilis broken and-loosenedby my method, it absorbs water rapidly. The plants and nitrifying bacteria in the soil will eventually use up the new air injected. However, water percolating down through the well broken soil will displace the subsequently formed foul gases and will ll the voids. When this water is taken by the plants,wor is evaporated, new atmospheric air will rush in to take its lace, and thus nature will carry on continuedp aeration as long as I, by my method, keep the ground in proper condition.

When subsequent rains and irrigation again pack the soil and cause it to be formed into a hard an, it is again necessary to employ the a ove described methods. Obviously, I can internally plow and aerate ground which is filled with roots, and I can even treat ground in which tender plants have just sprouted, without injury to same.

Earth at a depth where water cannot penetrate, due to compact layers of hard pan, is of course quite dry. This mass of earth is composed of myriads of grains lying upon each other with interstitial spaces between. Air has so little resistance in traveling through a small orifice that it will disseminate through the interstitial spaces almost as freely as if the particles of earth were not there. In other words, since the earth near the. surface is far from beingsolid, it contains air or gases. If a room full of air is filled with dry earth, 25 per cent of the air originally in the room will remain. Air jets of reasonable velocity will direct air through the interstices as readily in one direction as in another. As far as atmospheric pressure differences are concerned, it will be understood that the atmospheric pressure difference represented by a difference of elevation of six feet, for example is negligible. Air injected into the exact center of the earth filled room, if injected downwardly, will travel downwardly more readily than upwardly. After the air injection is discontinued, then of course the air will tend to equalize throughout the room. On this theory, I believe it will be most efficient to inject the air downwardly, or laterally into the earth. No matter how deep the air may go, it will eventually equalize with the atmospheric air, but downward or lateral injection provides for saturating the ground more quickly and provides for storing greater quantities of fresh air in the ground in a given time.

I now prefer that the volume 0f air introduced into each hole, in terms of cubic feet of free air, be at least one quarter that of the square of the distance in feet between the holes multiplied by the average depth of each hole in feet.

It will be apparent now that myl method provides air in all the interstitial spaces of the ground, whereas subsoiling, plowing,

harrowing, and the like, do not provide air to all the interstices, but only to the surfaces of the resultant lumps of earth.

Having thus described my invention I to said hole to cause its dissemination through the adjacent soil to open up lateral crevices, and subsequently admitting successive limited charges of high pressure air to said hole to cause visible swelling of the surface of the ground.

3. The method for internally disrupting soil; which method consists in providing a source of high pressure air, providing a hole in the ground, admitting air from said source to said hole in successive defined injections; each successive injection admitting the air at a higher volumetric rate.

4. The method of treating large areas of soil to promote plant growth; said method consisting in providing a plurality of spaced holes in the ground, introducing a volume of air to one of said holes at a slow rate to permit of its dissemination through the ground without visible movement on the part of the surface of said ground, subsequently introducing air to said hole for short defined periods at a considerably higher volumetric rate to cause visible movement on the part of the surface of the ground adjacent the hole, and repeating the above mentioned steps in the order named, in another hole; the said volume of air introduced to each hole, in terms of cubic feet of free air, being at least one quarter that of the square of the distance in feet between said holes multiplied by the average depth of each hole in feet.

5. The method of breaking soil for the infiltration of air, water and the like; which method consists in providing a hole in the ground to a given depth, providing a volume of high pressure gas, the pressure of said gas being several times that represented by t-he weight of the soil per square inch to the depth of the hole, slowly admitting some of the gas to said hole at such rate that the gas enters the ground before building up a pressure in said hole in excess of that represented by the weight of the ground per square inch to the depth of the hole, and subsequently allowing the high pressure gas to escape to the hole at a considerably increased rate.

loo

lewe 6. The method of treatingv soils; which .method Consists f ntrodlein atmsphervic ai to'the ground at a. p ointlelow` the V'surface therepf iinvtili t l* ad'laeent groungis 5 changea With :11r,*aaml tferelft'e'r releasing i h'gh pressure air into the charged 't'o' eluse' a breakin'g'up' of the S011.

nfThe vmethod 'bi treatingA soils; which consists of introducing, atnispherie air t0 10 thel'ground at alypoint blowlthesurfgce there# of ata moderate "ressure until the adjacent' ground is charge with air, and thereafter l'aing high pressure alix: int() 'the' Vcharged grnd t `:rra,te's'uei-egr1t te canse a, breaking 15 up ofthesil." In testmonxwhereo bewut? @mx my sgngtrl e @HAARLEM-SEWER;

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