- Email: [email protected]
The national tillage machinery laboratory
68
THE NATIONAL TILLAGE MACHINERY LABORATORY T h e d e v e l o p m e n t of a n y s c i e n c e is the a c c u m u l a t i o n and s y s t e m a t i c a r r a n g e m e n t of f a c t s a b o u t a s u b ) e c t . The f a c t s m a y c o m e f r o m d e d u c t i v e r e a s o n i n g o r e x p e r i m e n t & t i o n but in the f i n a l a n a l y s i s the g e n e r a l t a w s d e v e l o p e d m u s t b e t e s t e d and a c c e p t e d , At the N a t i o n a l T i l l a g e M a c h i n e r y L a b o r a t o r y , a r e s e a r c h f a c i l i t y of the U. 5. D e p a r t m e n t of A g r i c u l t u r e , the s t a f f is e n g a g e d in d e t e r m i r u n g and s t u d y i n g the l a w s w h i c h g o v e r n the r e a c t i o n of moil to f o r c e s . The p r i m a r y a i m is to l e a r n a b o u t f a c t o r s w h i c h c a n be a p p l i e d to t h e d e s i g n and u s e of t i l t a g e i m p l e m e n t s a n d t r a c t i v e d e v i c e a , much as w h e e l and c r a w l e r t r a c k s . M a n y of t h e s t u d i e s a r e c o o p e r a t i v e w i t h i n d u e t r y and state and f e d e r a l r e s e a r c h g r o u p s .
I.
H I S T O R YAND PURPOSE
T h e N a t i o n a l T i l l a g e M a c h i n e r y L a b o r a t o r y is a p a r t of the A g r i c u l t u r a l E n g i n e e r i n g R e s e a r c h D i v i s i o n of the A g r i c u l t u r a l R e s e a r c h S e r v i c e . It is l o c a t ed at Auburn, A l a b a m a , on the corner of W e s t Sarnford A v e n u e and D o n a h u e Drive. T h e 6.3-acre site on w h i c h the Laboratory is located is within the c a m p u s and w a s donated to the Federal G o v e r n m e n t by A u b u r n University. T h e Laboratory w a s established in 1 935. It w a s set up to undertake research related to tillage practices and m a c h i n e use in cotton production. H o w ever, since m a n y of the tillage m a c h i n e r y p r o b l e m s in cotton production w e r e c o m m o n to other crops, the scope of research w a s broadened to include all types of tillage m a c h i n e r y and practices. Traction and transport research, w h i c h also involves soil physical reactions and requires similar facilities, w a s part of the original p r o g r a m m e . R e s e a r c h is being conducted to provide information needed to develop tractor wheels or other traction devices w h i c h
will p r o v i d e m a x i m u m pull f o r the m i n i m u m v e h i c l e w e i g h t so that soil c o m p a c t i o n c a n be reduced. A unique feature of the Laboratory is the soil bins w h i c h eliminated m a n y of the difficulties that had b e e n encountered in previous tillage research. T h e bins contain a variety of soils which previously could not be used in studies without a great deal of travel. In field studies it w a s often necessary to wait until natural forces produced a soil condition that w a s desired for specific studies. In the bins, w h i c h are large enough to m a k e full scale studies of tillage tools, tires and tracks, the soils can be fitted with special soil handling machinery. In this m a n n e r the soil in the bins can be m a d e m o r e uniform than is found under field conditions. This is highly desirable in determining c o m parative force m e a s u r e m e n t s on different shaped i m p l e m e n t s and the p e r f o r m ance of tractive and transport devices of various designs. Also, different sol1 conditions can be produced and a given soil condition can be closely approximated f r o m time to time. Another very important feature of the bins is that the surface elevation can be controlled f r o m accurately set rails allowing the depth of tillage to be controlled within very close limits. This accuracy has not been a c c o m p l i s h e d in field studies. T h e soil bins with special equipment allow only the i m p l e m e n t being studied to c o m e in contact with the soil so that the studies are not complicated by wheel tracks and other traffic compaction. M o r e accurate instrumentation can be carried on the bin equipment than is usually available on conventional field research equipment. In June of 1960 the C o n g r e s s of the United States appropriated funds for expanded physical facilities. With these funds a n e w office-laboratory building and a building containing two soil bins w e r e constructed.
69
Fig. I
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on an o u t d o o r b i n c o n t a i n i n g a s a n d y s o i l
70
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.:i FLg.] The staff of the L a b o r a t o r y . F r o m left to right ~ W . R . G i l I , I . F . R e e d , J . H . T a y i o r , G . E . V a n d e n Berg, C . A . K e a v e s , A . W . C o o p e r (Director) 2.
STAFF
The staff is presently composed of six agricultral engineers and one soil scientist. They have undergraduate a n d a d v a n c e d d e g r e e s f r o m 13 d i f f e r ent states ranging from Hawaii to New York and from Michigan to Alabama. I n a d d i t i o n to a l l o f t h e p r o f e s s i o n a l s t a f f m e m b e r s h a v i n g a d v a n c e d d e g r e e s , the)' have had many years experience in this specialized field of research. W i t h t h e s u p p o r t i n g p e r s o n n e l , t h e t o t a l L a b o r a t o r y s t a f f i s 14. I t i s e x p e c t e d that, as a result of the expanded programme o u t l i n e d i n S e n a t e D o c u m e n t 59 of t h e 8 6 t h C o n g r e s s , 1 s t S e s s i o n , s t a r t i n g J u l y 1963 t h e s t a f f w i l l b e i n c r e a s e d b y m o r e t h a n 50 p e r c e n t . 3.
RESEARCH P R O G R A M M E
The programme of r e s e a r c h i s i n t h e a r e a of S o i l - m a c h i n e r y relationships W h i l e t h e m a i n p u r p o s e of t h e L a b o r a t o r y i s to c o n d u c t r e s e a r c h w h i c h w i l l c o n t r i b u t e i n f o r m a t i o n t h a t ~ i I p e r n ~ . i t b e t t e r d e s i g n a n d u s e of t i l l a g e t o o l s a n d traction and transport devices for crop production, much of the basic informat i o n o b t a i n e d w i l l a l s o a p p l y to o t h e r s o i l m o v i n g e q u i p m e n t o r o t h e r o f f - t h e - r o a d vehicles.
71 The following is a list of long t e r m research objectives of the Laboratory. C o m p r e h e n s i v e w o r k h a s b e e n u n d e r t a k e n in o n l y a few of the a r e a s , 3.1
3. Z
3.3
3.4
3.5
3.6
3.7
3.8
4..
D e t e r m i n e the c o m p o n e n t s of f o r c e s t i l l a g e t o o l s e x e r t on the s o i l to m e e t t i l l a g e r e q u i r e m e n t s so t h a t the d e s i g n of t o o l s , h i t c h e s , e n g i n e s a n d t r a c t o r s c a n be f a c i l i t a t e d . S t u d y the i n f l u e n c e of v a r i a t i o n s in t i l l a g e t o o l d e s i g n f a c t o r s and the m e t h o d s of u s e , i . e . w o r k i n g d e p t h a n d s p e e d of o p e r a t i o n , on p o w e r r e q u i r e m e n t s and t i l t h w h i c h i s c r e a t e d i n d i f f e r e n t s o i l c o n d i t i o n s . T h e n d e t e r m i n e the m i n i m u m a m o u n t of soil m a n i p u l a t i o n n e c e s s a r y to p r o d u c e the d e s i r e d tilth. D e t e r m i n e new and m o r e e H e c t i v e m e t h o d s of a p p l y i n g f o r c e s to s o i l so t h a t the m i n i m u m a m o u n t of e n e r g y m a y b e a p p l i e d to p r o d u c e soil tilth, handle soil, or s e c u r e t r a c t i o n / t r a n s p o r t . Study the physical factors which influence the susceptibility of the soil to c o m p a c t i o n and the r e s i s t a n c e to p u l v e r i z a t i o n , c u t t i n g , s h e a r i n g , or movement by mechanical forces. Study the i n f l u e n c e of v a r i a t i o n s in t r a c t i v e / t r a n s p o r t d e v i c e d e s i g n f a c t o r s and t h e i r m e t h o d s of u s e , i . e . t i r e g e o m e t r y , m a t e r i a l s , c o n s t r u c t i o n , w h e e l s l i p , t a n d e m w h e e l a r r a n g e m e n t , b a l l a s t , etc. , on th~ t r a c t i v e and t r a n s p o r t c a p a b i l i t i e s in d i f f e r e n t s o i l c o n d i t i o n s . Study the a b r a s i v e c h a r a c t e r i s t i c s of s o i l s and t h e i r iniquence on the w e a r of v a r i o u s m a t e r i a l s w h i c h m a y b e u s e d in the c o n s t r u c t i o n of tillage tools, t i r e s , or t r a c k s . D e v e l o p m e t h o d s to d e t e r m i n e b a s i c m e a s u r e s w h i c h c h a r a C t e r i z e the s t r e n g t h , r e a c t i o n s , and c o n d i t i o n s o£ s o i l s to be u s e d in c o n j u c t i o u w i t h s o i l - i m p l e m e n t r e l a t i o n s h i p s and in d e s c r i b i n g s o i l tilth. D e v e l o p a t h e o r y of s o i l - m a c h i n e m e c h a n i c s w h i c h w i l l p e r m i t the p r e d i c t i o n of the soil r e a c t i o n to t i l l a g e t o o l s of g i v e n d e s i g n s o r the t r a c t i v e / t r a n s p o r t c a p a c i t y of a d e v i c e f r o m a k n o w l e d g e of the r e q u i s ite soil a n d m a c h i n e p a r a m e t e r s .
COOPERATIVE WORK
In i t s r e s e a r c h p r o g r a m m e , the L a b o r a t o r y c o o p e r a t e s w i t h and a s s i s t s o t h e r a g e n c i e s i n t e r e s t e d in t i l l a g e and t r a c t i o n o r o t h e r w i s e c o n c e r n e d w i t h the s o i l . T h e r e is b o t h f o r m a l and i n f o r m a l c o o p e r a t i o n w i t h S t a t e A g r i c u l t u r a l Experiment Stations, other Federal Research Agencies, private industry, o t h e r p r i v a t e and g o v e r n m e n t g r o u p s , and r e s e a r c h e s t a b l i s h m e n t s in f o r e i g n countries. F r o m the b e g i n n i n g of the L a b o r a t o r y , s t u d i e s h a v e b e e n c a r r i e d out in c o o p e r a t i o n w i t h the A g r i c u l t u r a l E n g i n e e r i n g and A g r o n o m y and S o i l s D e p a r t m e n t s of A u b u r n U n i v e r s i t y . C o o p e r a t i v e w o r k h a s b e e n done on a n u m b e r of e x p e r i m e n t S t a t i o n f a r m s in A l a b a m a , O e o r g i a , M i s s i s s i p p i , T e x a s , I o w a , and O r e g o n . The L a b o r a t o r y has c o o p e r a t e d w i t h m a n y c o m p a n i e s in p r i v a t e i n d u s t r y c o n c e r n e d w i t h the d e v e l o p m e n t a n d m a n u f a c t u r e of t i l l a g e and t r a c t i o n e q u i p m e n t . C o o p e r a t i v e s t u d i e s have b e e n m a d e w i t h m a n u f a c t u r e r s of s u c h e q u i p m e n t as p l o w s , r o t a r y t i l l e r s , c o u l t e r s , s u b - s o i l e r s , d i s k - h a r r o w b l a d e s , c u l t i v a t o r s w e e p s , p l a n t e r s , t r a c t i o n t i r e s , and c r a w l e r t r a c t o r t r a c k s . In
7Z
m a n y of these studies fundamental data are obtained that are included in t e c h rdcal papers published in professional journals. In practically all studies, the cooperating companies obtain data that enable t h e m to better serve the public. Cooperation with private industry is limited to the development of basic information that is useful over extensive areas and beneficial to the entire industry concerned. C o m p a n i e s often furnish equipment for the basic studies and s o m e t i m e s special instrumentation. Engineers f r o m the companies w o r k with the staff of the Laboratory in planning and carrying out studies. In addition to an active cooperative p r o g r a m m e , the Laboratory staff con/ers, discusses, and, w h e n possible, advises individuals and groups on m a t t e r s r e l a t i n g to p r o b l e m s in t i l l a g e , t r a c t i o n a n d t r a n s p o r t . GRADUATE STUDY THESIS PROBLEMS The facilities and staff of the Laboratory are available for use and to help guide graduate and advanced graduate students in thesis p r o b l e m s related to tillage and tract/on. Cooperative a g r e e m e n t s m a y be m a d e with any college o r u n i v e r s i t y to e n a b l e t h e s t u d e n t to do p a r t o r a l l of h i s r e s e a r c h w o r k a t the Laboratory.
5.
6.
FULL SCALE SOIL BINS A N D EQUIPMENT
6.1
The Soil Bins
The Laboratory maintains 9 outdoor and 2 indoor soil bins which contain surface soils selected for making full scale studies of soil-implement relationships. E a c h outdoor bin is 250 feet long, 20 feet wide, and either 2 or 5 feet deep. The bins are separated by concrete walls, and a concrete apron is provided at the end of each bin for assembling equipment to be used in the studies. The indoor bins are 190 feet long, 20 feet wide, and 5 feet deep. T h e y are housed in a sheet metal building 70 feet wide and 200 feet long. T h e s a m e cars operate on the outdoor and indoor bins. A steel rail is m o u n t e d on top of each separating wall of the outdoor bins. T h e indoor bins have a pair of rails for each bin. Specially designed cars used to operate tillage tools, tires, and tracks run on these rails. D u r i n g a study, only the tillage tool or traction device being investigated c o m e s in contact w i t h the soil. C o v e r cars are available to cover any one of the outdoor bins to prevent weather conditions f r o m changing the physical condition of the soil until a test can be completed. The cars protect the soil f r o m rain or retard d r y i n g by the s u n .
6.2
The Soils
T h e s o i l s i n the b i n s w e r e s e l e c t e d to g i v e a b r o a d v a r i a t i o n i n the soil characteristics. T h e y range in texture f r o m high sand contents to high c l a y c o n t e n t s . T h e s o i l s h a v e p h y s i c a l p r o p e r t i e s r e p r e s e n t i n g a w i d e r a n g e of soil properties found throughout the United States. A report is available from the Laboratory which provides information on m o s t of the physical characteristics of t h e b i n s o i l s , a s w e l l a s t h e m i n e r a l o g i c a l a n a l y s e s . T h e s o i l s a r e agricultural types with a characteristic aggregation of particles similar to that found in the field. This basic tilth or structure has b e e n f o u n d to b e v e r y s t a b l e a n d h a s s u r v i v e d s e v e r a l y e a r s of c o n t i n u o u s t i l l a g e without the application of fertilizers or the growing of crops.
73
6.3
Equipment to Measure Soil Forces on Tillage Tools
.% p o w e r car furnishes p o w e r for pulling the tillage tools during investigations. It can be operated at speeds varying f r o m O. Z to lO miles per hour. A n i m p l e m e n t carrier equipped with a d y n a m o m e t e r is operated with the p o w e r car. T h e electrical resistance strain gage d y n a m o m e t e r is constructed to m e a s u r e the draft force, the side force, and the vertical force w h i c h the soil applies to the tillage tool and the three m o m e n t s associated with the three forces. T h e d y n a m o m e t e r will m e a s u r e d r a w b a r loads to ZO, 000 pounds. A generator on the tool carrier f r a m e w h i c h is driven f r o m the rail generates an electrical signal proportional to the speed at w h i c h the tool is operated. W h e n it is desirable to vary the angle of operation of the tool, as in disk studies, an electrical signal is generated proportional to the disk angle. Adaptations can he m a d e to m e a s u r e a varying width or depth of cut w h e n de sirable. All of the electrical signals which represent forces, speeds, or angles are recorded on an 8-charmel recording oscillograph. Any two variables can also be plotted with respect to one another on an X-Y recorder. The electtrical signals can also be transmitted to an analog computer which permits securing and plotting instantaneous values of power or other parameters. Various dynamometer arrangements can be made to measure the force on the whole tool or component parts of one tool or combination of tools.
6.4
Equipment for Studying Actions of Tires and Tracks
A special car is available for studying the performance of traction devices and the effect of traction devices on soil reactions, such as soil compaction. /vieasurements are made on a single tire or other traction device. The five basic measurements w h i c h a r e m a d e a r e (1) d y n a m i c l o a d o n t h e t i r e t h r o u g h o u t t h e o p e r a t i o n , (Z) t h e t o r q u e r e q u i r e d to t ~ r n t h e t i r e , (3) t h e a m o u n t of p u l l t h a t t h e t i r e d e v e l o p s , (4) t h e a m o u n t t h a t t h e t i r e s l i p s d u r i n g t h e o p e r a t i o n , a n d (5) f o r w a r d s p e e d . T h e p r e s e n t e q u i p m e n t w i l l a c c o m m o d a t e tires 68 i n c h e s i n o v e r - a l l d i a m e t e r a n d c a r r y i n g a m a x i m u m l o a d o f 5 , 0 0 0 p o u n d s . The basic data are measured by means of electrical analog signals which are recorded on an 8-channel recording oscillograph. Any combination of signals can be transrn/tted to the analog computer and the signal integrated, multiplied, divided, added, or subtracted. These calculated signals can then be put back on the oscillograph or recorded on an X-Y plotter. In all studies one parerneter is changed slowly and continuously throughout the study and the resulting values of other parameters are recorded. In the case of tires, the slip is usually v a r i e d f r o m 0 to n e a r 100% a n d t h e r e s u l t i n g t o r q u e i n p u t , p u l l , a n d w e i g h t transfer recorded. Studies are normally made in a range of soils and soil conditions which approximate the anticipated service conditions and on concrete.
6.5
Soil Preparation Equipment
The soil properties which are controlled in studies are the degree of compaction, m o i s t u r e c o n t e n t , a n d d e g r e e of p u l v e r i z a t i o n . Several pieces of equipment are available for preparing the soil. A self-propelled car, which r u n s o n t h e b i n r a i l s , o p e r a t e s a l e v e l l i n g b l a d e u s e d to c o n t r o l t h e l e v e l o f the soil surface. This unit also operates a cross-watering unit which is used to add moisture to a soil w h e n desired. It m a y be fitted with a gang of V - s h a p e d packers to pack the soil subsurface or a flat roller to pack the surface. A special rotary tiller can be used to pulverize the soil and leave it in a loose condition. Since the tillage tools or traction devices are run lengthwise in the
74 p l o t s , a c r o s s t i l l e r i s u s e d to s t i r t h e s o i l a c r o s s longitudinal streaks.
the p l o t s to h e l p r e m o v e
7.
SMALL BIN FACILITIES A s m a l l s o i l b i n l o c a t e d i n d o o r s i s u s e d to e x p e d i t e c e r t a i n s o i l - i m p l e m e n t r e l a t i o n s h i p s t u d i e s . O n e b i n i s 18 i n c h e s w i d e , 12 i n c h e s d e e p , a n d 60 i n c h e s l o n g . A n o t h e r b i n , w h i c h i s 12 i n c h e s w i d e , c a n b e e q u i p p e d w i t h a g l a s s s i d e f o r o b s e r v i n g s o i l m o v e m e n t r e s u l t i n g f r o m t h e o p e r a t i o n of t i l l age tools. A r o u n d s o i l b i n u n d e r c o n s t r u c t i o n i s 2 f e e t w i d e , 18 f e e t i n o u t s i d e d i a m e t e r , a n d 12 i n c h e s d e e p . It w i l l b e d r i v e n w i t h a h y d r a u l i c m o t o r so that speeds can be p r o g r a m m e d . T h e round bin will be equipped with a rotary tiller to prepare the soil, a £1at roller to c o m p r e s s the soil, and a dynam o m e t e r tool carrier which will m e a s u r e forces in three directions and the associated m o m e n t s . In all of the small bin facilities, the soil m o v e s and the tool r e m a i n s stationary. This allows better observations of the soil reaction to the tool. In the bins, studies are m a d e on small tools and wheels and scaled m o d e l equipment. Both natural and artificial soils are used in the studies carried out in the small bins. It is anticipated that these facilities will be used for w e a r studies on metals, plastics, and other materials. Friction and adhesion m e a s u r e m e n t s b e t w e e n soils and materials are m e a s u r e d with the se facilities.
8.
LABORATORY FACILITIES
Laboratories and equipment are available for studying soil physical and mechanical properties. In tillage and traction studies, soil strength m e a s u r e m e n t s are qu~te important. S o m e of the equipment used to m e a s u r e strength are shear machines, tension apparatus, and b e a m testers. Soil reactions to p r o g r a m m e d mechanical forces can be m e a s u r e d , as well as soil p a r a m e t e r s which m a y be used to characterize the soil. In this connection, a growth c h a m b e r is planned for the environmental control laboratory. In this unit the temperature, hurn/dity, and light intensity will be c or~rolled. T h e abrasive resistance of metals, plastics, and other materials can be studied, as well as the ability of materials to resist soil sticking. Impact and fatigue test equipment for determining the strength of disks is available. The laboratories contain equipment for m e a s u r i n g g e o m e t r y of tillage tools. A rather complete m a c h i n e shop is available for building and adapting equipment and special instrumentation for the various studies.
9.
FIELD FACILITIES A 1 0 0 - a c r e f a r m containing clay soils and a 3 7 0 - a c r e f a r m containing sandy soils w h i c h belong to the Agricultural Engineering D e p a r t m e n t o£ A u b u r n
University are available for field studies. Other experiment station f a r m s of cooperating states are also available. At times, m e a s u r e m e n t s , such as soil force reactions to tools and w e a r resistance of materials, are m a d e on private farms.
75 10.
PUBLICATIONS
A list of technical publications resulting from the research work at the Laboratory is available. The publications are an important contribution to scientific literature on tillage and traction equipment and related phases of soil science. In many cases they report the results of cooperative studies with private industry, in which the cooperating companies have obtained data that help them provide better equipment.
THE NATIONAL TILLAGE MACHINERY LABORATORY T h e d e v e l o p m e n t of a n y s c i e n c e is the a c c u m u l a t i o n and s y s t e m a t i c a r r a n g e m e n t of f a c t s a b o u t a s u b ) e c t . The f a c t s m a y c o m e f r o m d e d u c t i v e r e a s o n i n g o r e x p e r i m e n t & t i o n but in the f i n a l a n a l y s i s the g e n e r a l t a w s d e v e l o p e d m u s t b e t e s t e d and a c c e p t e d , At the N a t i o n a l T i l l a g e M a c h i n e r y L a b o r a t o r y , a r e s e a r c h f a c i l i t y of the U. 5. D e p a r t m e n t of A g r i c u l t u r e , the s t a f f is e n g a g e d in d e t e r m i r u n g and s t u d y i n g the l a w s w h i c h g o v e r n the r e a c t i o n of moil to f o r c e s . The p r i m a r y a i m is to l e a r n a b o u t f a c t o r s w h i c h c a n be a p p l i e d to t h e d e s i g n and u s e of t i l t a g e i m p l e m e n t s a n d t r a c t i v e d e v i c e a , much as w h e e l and c r a w l e r t r a c k s . M a n y of t h e s t u d i e s a r e c o o p e r a t i v e w i t h i n d u e t r y and state and f e d e r a l r e s e a r c h g r o u p s .
I.
H I S T O R YAND PURPOSE
T h e N a t i o n a l T i l l a g e M a c h i n e r y L a b o r a t o r y is a p a r t of the A g r i c u l t u r a l E n g i n e e r i n g R e s e a r c h D i v i s i o n of the A g r i c u l t u r a l R e s e a r c h S e r v i c e . It is l o c a t ed at Auburn, A l a b a m a , on the corner of W e s t Sarnford A v e n u e and D o n a h u e Drive. T h e 6.3-acre site on w h i c h the Laboratory is located is within the c a m p u s and w a s donated to the Federal G o v e r n m e n t by A u b u r n University. T h e Laboratory w a s established in 1 935. It w a s set up to undertake research related to tillage practices and m a c h i n e use in cotton production. H o w ever, since m a n y of the tillage m a c h i n e r y p r o b l e m s in cotton production w e r e c o m m o n to other crops, the scope of research w a s broadened to include all types of tillage m a c h i n e r y and practices. Traction and transport research, w h i c h also involves soil physical reactions and requires similar facilities, w a s part of the original p r o g r a m m e . R e s e a r c h is being conducted to provide information needed to develop tractor wheels or other traction devices w h i c h
will p r o v i d e m a x i m u m pull f o r the m i n i m u m v e h i c l e w e i g h t so that soil c o m p a c t i o n c a n be reduced. A unique feature of the Laboratory is the soil bins w h i c h eliminated m a n y of the difficulties that had b e e n encountered in previous tillage research. T h e bins contain a variety of soils which previously could not be used in studies without a great deal of travel. In field studies it w a s often necessary to wait until natural forces produced a soil condition that w a s desired for specific studies. In the bins, w h i c h are large enough to m a k e full scale studies of tillage tools, tires and tracks, the soils can be fitted with special soil handling machinery. In this m a n n e r the soil in the bins can be m a d e m o r e uniform than is found under field conditions. This is highly desirable in determining c o m parative force m e a s u r e m e n t s on different shaped i m p l e m e n t s and the p e r f o r m ance of tractive and transport devices of various designs. Also, different sol1 conditions can be produced and a given soil condition can be closely approximated f r o m time to time. Another very important feature of the bins is that the surface elevation can be controlled f r o m accurately set rails allowing the depth of tillage to be controlled within very close limits. This accuracy has not been a c c o m p l i s h e d in field studies. T h e soil bins with special equipment allow only the i m p l e m e n t being studied to c o m e in contact with the soil so that the studies are not complicated by wheel tracks and other traffic compaction. M o r e accurate instrumentation can be carried on the bin equipment than is usually available on conventional field research equipment. In June of 1960 the C o n g r e s s of the United States appropriated funds for expanded physical facilities. With these funds a n e w office-laboratory building and a building containing two soil bins w e r e constructed.
69
Fig. I
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on an o u t d o o r b i n c o n t a i n i n g a s a n d y s o i l
70
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.:i FLg.] The staff of the L a b o r a t o r y . F r o m left to right ~ W . R . G i l I , I . F . R e e d , J . H . T a y i o r , G . E . V a n d e n Berg, C . A . K e a v e s , A . W . C o o p e r (Director) 2.
STAFF
The staff is presently composed of six agricultral engineers and one soil scientist. They have undergraduate a n d a d v a n c e d d e g r e e s f r o m 13 d i f f e r ent states ranging from Hawaii to New York and from Michigan to Alabama. I n a d d i t i o n to a l l o f t h e p r o f e s s i o n a l s t a f f m e m b e r s h a v i n g a d v a n c e d d e g r e e s , the)' have had many years experience in this specialized field of research. W i t h t h e s u p p o r t i n g p e r s o n n e l , t h e t o t a l L a b o r a t o r y s t a f f i s 14. I t i s e x p e c t e d that, as a result of the expanded programme o u t l i n e d i n S e n a t e D o c u m e n t 59 of t h e 8 6 t h C o n g r e s s , 1 s t S e s s i o n , s t a r t i n g J u l y 1963 t h e s t a f f w i l l b e i n c r e a s e d b y m o r e t h a n 50 p e r c e n t . 3.
RESEARCH P R O G R A M M E
The programme of r e s e a r c h i s i n t h e a r e a of S o i l - m a c h i n e r y relationships W h i l e t h e m a i n p u r p o s e of t h e L a b o r a t o r y i s to c o n d u c t r e s e a r c h w h i c h w i l l c o n t r i b u t e i n f o r m a t i o n t h a t ~ i I p e r n ~ . i t b e t t e r d e s i g n a n d u s e of t i l l a g e t o o l s a n d traction and transport devices for crop production, much of the basic informat i o n o b t a i n e d w i l l a l s o a p p l y to o t h e r s o i l m o v i n g e q u i p m e n t o r o t h e r o f f - t h e - r o a d vehicles.
71 The following is a list of long t e r m research objectives of the Laboratory. C o m p r e h e n s i v e w o r k h a s b e e n u n d e r t a k e n in o n l y a few of the a r e a s , 3.1
3. Z
3.3
3.4
3.5
3.6
3.7
3.8
4..
D e t e r m i n e the c o m p o n e n t s of f o r c e s t i l l a g e t o o l s e x e r t on the s o i l to m e e t t i l l a g e r e q u i r e m e n t s so t h a t the d e s i g n of t o o l s , h i t c h e s , e n g i n e s a n d t r a c t o r s c a n be f a c i l i t a t e d . S t u d y the i n f l u e n c e of v a r i a t i o n s in t i l l a g e t o o l d e s i g n f a c t o r s and the m e t h o d s of u s e , i . e . w o r k i n g d e p t h a n d s p e e d of o p e r a t i o n , on p o w e r r e q u i r e m e n t s and t i l t h w h i c h i s c r e a t e d i n d i f f e r e n t s o i l c o n d i t i o n s . T h e n d e t e r m i n e the m i n i m u m a m o u n t of soil m a n i p u l a t i o n n e c e s s a r y to p r o d u c e the d e s i r e d tilth. D e t e r m i n e new and m o r e e H e c t i v e m e t h o d s of a p p l y i n g f o r c e s to s o i l so t h a t the m i n i m u m a m o u n t of e n e r g y m a y b e a p p l i e d to p r o d u c e soil tilth, handle soil, or s e c u r e t r a c t i o n / t r a n s p o r t . Study the physical factors which influence the susceptibility of the soil to c o m p a c t i o n and the r e s i s t a n c e to p u l v e r i z a t i o n , c u t t i n g , s h e a r i n g , or movement by mechanical forces. Study the i n f l u e n c e of v a r i a t i o n s in t r a c t i v e / t r a n s p o r t d e v i c e d e s i g n f a c t o r s and t h e i r m e t h o d s of u s e , i . e . t i r e g e o m e t r y , m a t e r i a l s , c o n s t r u c t i o n , w h e e l s l i p , t a n d e m w h e e l a r r a n g e m e n t , b a l l a s t , etc. , on th~ t r a c t i v e and t r a n s p o r t c a p a b i l i t i e s in d i f f e r e n t s o i l c o n d i t i o n s . Study the a b r a s i v e c h a r a c t e r i s t i c s of s o i l s and t h e i r iniquence on the w e a r of v a r i o u s m a t e r i a l s w h i c h m a y b e u s e d in the c o n s t r u c t i o n of tillage tools, t i r e s , or t r a c k s . D e v e l o p m e t h o d s to d e t e r m i n e b a s i c m e a s u r e s w h i c h c h a r a C t e r i z e the s t r e n g t h , r e a c t i o n s , and c o n d i t i o n s o£ s o i l s to be u s e d in c o n j u c t i o u w i t h s o i l - i m p l e m e n t r e l a t i o n s h i p s and in d e s c r i b i n g s o i l tilth. D e v e l o p a t h e o r y of s o i l - m a c h i n e m e c h a n i c s w h i c h w i l l p e r m i t the p r e d i c t i o n of the soil r e a c t i o n to t i l l a g e t o o l s of g i v e n d e s i g n s o r the t r a c t i v e / t r a n s p o r t c a p a c i t y of a d e v i c e f r o m a k n o w l e d g e of the r e q u i s ite soil a n d m a c h i n e p a r a m e t e r s .
COOPERATIVE WORK
In i t s r e s e a r c h p r o g r a m m e , the L a b o r a t o r y c o o p e r a t e s w i t h and a s s i s t s o t h e r a g e n c i e s i n t e r e s t e d in t i l l a g e and t r a c t i o n o r o t h e r w i s e c o n c e r n e d w i t h the s o i l . T h e r e is b o t h f o r m a l and i n f o r m a l c o o p e r a t i o n w i t h S t a t e A g r i c u l t u r a l Experiment Stations, other Federal Research Agencies, private industry, o t h e r p r i v a t e and g o v e r n m e n t g r o u p s , and r e s e a r c h e s t a b l i s h m e n t s in f o r e i g n countries. F r o m the b e g i n n i n g of the L a b o r a t o r y , s t u d i e s h a v e b e e n c a r r i e d out in c o o p e r a t i o n w i t h the A g r i c u l t u r a l E n g i n e e r i n g and A g r o n o m y and S o i l s D e p a r t m e n t s of A u b u r n U n i v e r s i t y . C o o p e r a t i v e w o r k h a s b e e n done on a n u m b e r of e x p e r i m e n t S t a t i o n f a r m s in A l a b a m a , O e o r g i a , M i s s i s s i p p i , T e x a s , I o w a , and O r e g o n . The L a b o r a t o r y has c o o p e r a t e d w i t h m a n y c o m p a n i e s in p r i v a t e i n d u s t r y c o n c e r n e d w i t h the d e v e l o p m e n t a n d m a n u f a c t u r e of t i l l a g e and t r a c t i o n e q u i p m e n t . C o o p e r a t i v e s t u d i e s have b e e n m a d e w i t h m a n u f a c t u r e r s of s u c h e q u i p m e n t as p l o w s , r o t a r y t i l l e r s , c o u l t e r s , s u b - s o i l e r s , d i s k - h a r r o w b l a d e s , c u l t i v a t o r s w e e p s , p l a n t e r s , t r a c t i o n t i r e s , and c r a w l e r t r a c t o r t r a c k s . In
7Z
m a n y of these studies fundamental data are obtained that are included in t e c h rdcal papers published in professional journals. In practically all studies, the cooperating companies obtain data that enable t h e m to better serve the public. Cooperation with private industry is limited to the development of basic information that is useful over extensive areas and beneficial to the entire industry concerned. C o m p a n i e s often furnish equipment for the basic studies and s o m e t i m e s special instrumentation. Engineers f r o m the companies w o r k with the staff of the Laboratory in planning and carrying out studies. In addition to an active cooperative p r o g r a m m e , the Laboratory staff con/ers, discusses, and, w h e n possible, advises individuals and groups on m a t t e r s r e l a t i n g to p r o b l e m s in t i l l a g e , t r a c t i o n a n d t r a n s p o r t . GRADUATE STUDY THESIS PROBLEMS The facilities and staff of the Laboratory are available for use and to help guide graduate and advanced graduate students in thesis p r o b l e m s related to tillage and tract/on. Cooperative a g r e e m e n t s m a y be m a d e with any college o r u n i v e r s i t y to e n a b l e t h e s t u d e n t to do p a r t o r a l l of h i s r e s e a r c h w o r k a t the Laboratory.
5.
6.
FULL SCALE SOIL BINS A N D EQUIPMENT
6.1
The Soil Bins
The Laboratory maintains 9 outdoor and 2 indoor soil bins which contain surface soils selected for making full scale studies of soil-implement relationships. E a c h outdoor bin is 250 feet long, 20 feet wide, and either 2 or 5 feet deep. The bins are separated by concrete walls, and a concrete apron is provided at the end of each bin for assembling equipment to be used in the studies. The indoor bins are 190 feet long, 20 feet wide, and 5 feet deep. T h e y are housed in a sheet metal building 70 feet wide and 200 feet long. T h e s a m e cars operate on the outdoor and indoor bins. A steel rail is m o u n t e d on top of each separating wall of the outdoor bins. T h e indoor bins have a pair of rails for each bin. Specially designed cars used to operate tillage tools, tires, and tracks run on these rails. D u r i n g a study, only the tillage tool or traction device being investigated c o m e s in contact w i t h the soil. C o v e r cars are available to cover any one of the outdoor bins to prevent weather conditions f r o m changing the physical condition of the soil until a test can be completed. The cars protect the soil f r o m rain or retard d r y i n g by the s u n .
6.2
The Soils
T h e s o i l s i n the b i n s w e r e s e l e c t e d to g i v e a b r o a d v a r i a t i o n i n the soil characteristics. T h e y range in texture f r o m high sand contents to high c l a y c o n t e n t s . T h e s o i l s h a v e p h y s i c a l p r o p e r t i e s r e p r e s e n t i n g a w i d e r a n g e of soil properties found throughout the United States. A report is available from the Laboratory which provides information on m o s t of the physical characteristics of t h e b i n s o i l s , a s w e l l a s t h e m i n e r a l o g i c a l a n a l y s e s . T h e s o i l s a r e agricultural types with a characteristic aggregation of particles similar to that found in the field. This basic tilth or structure has b e e n f o u n d to b e v e r y s t a b l e a n d h a s s u r v i v e d s e v e r a l y e a r s of c o n t i n u o u s t i l l a g e without the application of fertilizers or the growing of crops.
73
6.3
Equipment to Measure Soil Forces on Tillage Tools
.% p o w e r car furnishes p o w e r for pulling the tillage tools during investigations. It can be operated at speeds varying f r o m O. Z to lO miles per hour. A n i m p l e m e n t carrier equipped with a d y n a m o m e t e r is operated with the p o w e r car. T h e electrical resistance strain gage d y n a m o m e t e r is constructed to m e a s u r e the draft force, the side force, and the vertical force w h i c h the soil applies to the tillage tool and the three m o m e n t s associated with the three forces. T h e d y n a m o m e t e r will m e a s u r e d r a w b a r loads to ZO, 000 pounds. A generator on the tool carrier f r a m e w h i c h is driven f r o m the rail generates an electrical signal proportional to the speed at w h i c h the tool is operated. W h e n it is desirable to vary the angle of operation of the tool, as in disk studies, an electrical signal is generated proportional to the disk angle. Adaptations can he m a d e to m e a s u r e a varying width or depth of cut w h e n de sirable. All of the electrical signals which represent forces, speeds, or angles are recorded on an 8-charmel recording oscillograph. Any two variables can also be plotted with respect to one another on an X-Y recorder. The electtrical signals can also be transmitted to an analog computer which permits securing and plotting instantaneous values of power or other parameters. Various dynamometer arrangements can be made to measure the force on the whole tool or component parts of one tool or combination of tools.
6.4
Equipment for Studying Actions of Tires and Tracks
A special car is available for studying the performance of traction devices and the effect of traction devices on soil reactions, such as soil compaction. /vieasurements are made on a single tire or other traction device. The five basic measurements w h i c h a r e m a d e a r e (1) d y n a m i c l o a d o n t h e t i r e t h r o u g h o u t t h e o p e r a t i o n , (Z) t h e t o r q u e r e q u i r e d to t ~ r n t h e t i r e , (3) t h e a m o u n t of p u l l t h a t t h e t i r e d e v e l o p s , (4) t h e a m o u n t t h a t t h e t i r e s l i p s d u r i n g t h e o p e r a t i o n , a n d (5) f o r w a r d s p e e d . T h e p r e s e n t e q u i p m e n t w i l l a c c o m m o d a t e tires 68 i n c h e s i n o v e r - a l l d i a m e t e r a n d c a r r y i n g a m a x i m u m l o a d o f 5 , 0 0 0 p o u n d s . The basic data are measured by means of electrical analog signals which are recorded on an 8-channel recording oscillograph. Any combination of signals can be transrn/tted to the analog computer and the signal integrated, multiplied, divided, added, or subtracted. These calculated signals can then be put back on the oscillograph or recorded on an X-Y plotter. In all studies one parerneter is changed slowly and continuously throughout the study and the resulting values of other parameters are recorded. In the case of tires, the slip is usually v a r i e d f r o m 0 to n e a r 100% a n d t h e r e s u l t i n g t o r q u e i n p u t , p u l l , a n d w e i g h t transfer recorded. Studies are normally made in a range of soils and soil conditions which approximate the anticipated service conditions and on concrete.
6.5
Soil Preparation Equipment
The soil properties which are controlled in studies are the degree of compaction, m o i s t u r e c o n t e n t , a n d d e g r e e of p u l v e r i z a t i o n . Several pieces of equipment are available for preparing the soil. A self-propelled car, which r u n s o n t h e b i n r a i l s , o p e r a t e s a l e v e l l i n g b l a d e u s e d to c o n t r o l t h e l e v e l o f the soil surface. This unit also operates a cross-watering unit which is used to add moisture to a soil w h e n desired. It m a y be fitted with a gang of V - s h a p e d packers to pack the soil subsurface or a flat roller to pack the surface. A special rotary tiller can be used to pulverize the soil and leave it in a loose condition. Since the tillage tools or traction devices are run lengthwise in the
74 p l o t s , a c r o s s t i l l e r i s u s e d to s t i r t h e s o i l a c r o s s longitudinal streaks.
the p l o t s to h e l p r e m o v e
7.
SMALL BIN FACILITIES A s m a l l s o i l b i n l o c a t e d i n d o o r s i s u s e d to e x p e d i t e c e r t a i n s o i l - i m p l e m e n t r e l a t i o n s h i p s t u d i e s . O n e b i n i s 18 i n c h e s w i d e , 12 i n c h e s d e e p , a n d 60 i n c h e s l o n g . A n o t h e r b i n , w h i c h i s 12 i n c h e s w i d e , c a n b e e q u i p p e d w i t h a g l a s s s i d e f o r o b s e r v i n g s o i l m o v e m e n t r e s u l t i n g f r o m t h e o p e r a t i o n of t i l l age tools. A r o u n d s o i l b i n u n d e r c o n s t r u c t i o n i s 2 f e e t w i d e , 18 f e e t i n o u t s i d e d i a m e t e r , a n d 12 i n c h e s d e e p . It w i l l b e d r i v e n w i t h a h y d r a u l i c m o t o r so that speeds can be p r o g r a m m e d . T h e round bin will be equipped with a rotary tiller to prepare the soil, a £1at roller to c o m p r e s s the soil, and a dynam o m e t e r tool carrier which will m e a s u r e forces in three directions and the associated m o m e n t s . In all of the small bin facilities, the soil m o v e s and the tool r e m a i n s stationary. This allows better observations of the soil reaction to the tool. In the bins, studies are m a d e on small tools and wheels and scaled m o d e l equipment. Both natural and artificial soils are used in the studies carried out in the small bins. It is anticipated that these facilities will be used for w e a r studies on metals, plastics, and other materials. Friction and adhesion m e a s u r e m e n t s b e t w e e n soils and materials are m e a s u r e d with the se facilities.
8.
LABORATORY FACILITIES
Laboratories and equipment are available for studying soil physical and mechanical properties. In tillage and traction studies, soil strength m e a s u r e m e n t s are qu~te important. S o m e of the equipment used to m e a s u r e strength are shear machines, tension apparatus, and b e a m testers. Soil reactions to p r o g r a m m e d mechanical forces can be m e a s u r e d , as well as soil p a r a m e t e r s which m a y be used to characterize the soil. In this connection, a growth c h a m b e r is planned for the environmental control laboratory. In this unit the temperature, hurn/dity, and light intensity will be c or~rolled. T h e abrasive resistance of metals, plastics, and other materials can be studied, as well as the ability of materials to resist soil sticking. Impact and fatigue test equipment for determining the strength of disks is available. The laboratories contain equipment for m e a s u r i n g g e o m e t r y of tillage tools. A rather complete m a c h i n e shop is available for building and adapting equipment and special instrumentation for the various studies.
9.
FIELD FACILITIES A 1 0 0 - a c r e f a r m containing clay soils and a 3 7 0 - a c r e f a r m containing sandy soils w h i c h belong to the Agricultural Engineering D e p a r t m e n t o£ A u b u r n
University are available for field studies. Other experiment station f a r m s of cooperating states are also available. At times, m e a s u r e m e n t s , such as soil force reactions to tools and w e a r resistance of materials, are m a d e on private farms.
75 10.
PUBLICATIONS
A list of technical publications resulting from the research work at the Laboratory is available. The publications are an important contribution to scientific literature on tillage and traction equipment and related phases of soil science. In many cases they report the results of cooperative studies with private industry, in which the cooperating companies have obtained data that help them provide better equipment.