Abstract:
An agricultural system for acquiring grain samples from a field includes a combine, a grain sample acquiring apparatus for acquiring a grain sample at a plurality of locations within the field, a location signal generating circuit, and a data recorder which communicates with the location signal generating circuit and records the sample site locations. A method of determining and recording locational variations in characteristics of a crop being harvested includes (a) obtaining a sample of the crop at each of a plurality of locations within the field and uniquely identifying each sample; (b) obtaining a locational description of each sample site; (c) correlating the sample identifications and corresponding locational descriptions into first data pairs; (d) recording the first data pairs in a first data file; (e) analyzing the samples to generate location-specific crop data; (f) correlating the location-specific crop data and the corresponding locational descriptions into second data pairs; and (g) recording the second data pairs in a second data file.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to an agricultural combine harvester, or combine. It relates particularly to a combine including a system for obtaining locationally identified crop samples at a plurality of locations within a field. 
     BACKGROUND OF THE INVENTION 
     Agricultural combine harvesters, or combines, and similar apparatus are used for the harvesting of grain (e.g., wheat, corn, barley) from plants growing upon an agricultural field. Combines combine the grain harvesting operations of reaping, gathering, threshing, and winnowing, or cleaning, which, in earlier years, had been performed by separate apparatus, into a process termed &#34;combining&#34;; hence, the name &#34;combine&#34; harvester. 
     A combine typically includes a frame, a main body supported thereto, and ground support devices such as wheels and/or crawler treads to support the frame on the surface of the field. A combine, or other crop harvesting apparatus, may be configured as an implement towed and steered by a vehicle such as a tractor and having internal devices powered by a power takeoff shaft associated with the tractor, or it may be configured as a vehicle itself powered by an on-board engine, or other suitable prime mover, in which event at least some of the ground support devices are made controllably steerable so that the apparatus may be guided over the field. The present invention applies to both such configurations of crop harvesting apparatus. 
     Traditionally, farmers have had to consider their fields as essentially uniform and homogeneous over their entire areas, as there were no practical means to do otherwise. The advent and progression of site-specific farming, also known as precision farming, however, now makes it possible for a farmer to generate and maintain a Geographic Information System (GIS) database of his fields on his office or laptop computer. The database may be viewed, or printed, as a map having a plurality of selectable layers, wherein each layer represents a data file corresponding to data previously acquired; e.g., regarding soil type, topography, field boundaries and infrastructure, previous years&#39; yield and moisture data, nitrogen content of soil and/or of crop, etc. Each data point within each data file is geo-referenced (i.e., correlated and stored with a corresponding locational description of the location within a field where the data was taken), allowing GIS mapping to be performed. Using this information enables the farmer to discern how best to vary his operations over the field in order to maximize crop production and quality while minimizing expenses. For example, some areas of a field may require more fertilizer, while others require less or none. Similarly, areas of a field can require differing amounts of herbicide, biocide, and/or pH buffering agent. Further, areas of a field may need greater or lesser depths of tilling and/or planting. Other spatially variable parameters are also known. 
     It is known to manually procure a sample of grain after a combine has harvested the grain and emptied its hopper, place the sample in a container, and mark the container with an identification (e.g., field number or description, sample number, date, time, etc.) for later analysis (e.g., of constituents such as protein or gluten). While one could procure and mark a number of such samples, this method does not provide useable knowledge regarding spatial variations within a field since the information regarding the exact locations at which the samples were harvested from the field becomes lost. 
     It is also known to provide for a combine including a system which obtains discrete samples of grain during or immediately after the combining process, prior to the grain being mixed in a storage bin, or grain tank, with other grain processed earlier and elsewhere within the field. Such a system was described by Eisele et al. of Kansas State University, Manhattan, Kans., in &#34;Field Scale Spatial Variability of Wheat Quality&#34;, Paper No. MC97-103 of the American Society of Agricultural Engineers (ASAE), St. Joseph, Mich. This system used sampling sites pre-selected by longitude and latitude coordinates and arranged in a grid pattern. When the combine reached a sampling site, the sampling process was manually triggered by the operator using a button in the combine&#39;s cab. This system, however, did not generate and store sampling site locational data on the combine during the harvesting of the grain. 
     It is also known to provide for an agricultural system including a combine which measures and records geo-referenced grain yield and moisture data using on-board sensors and portable memory devices (e.g., diskettes, PCMCIA cards, zip-disks) or a wireless data link to a remote computer memory device. Such systems are commercially available from, for example, Case Corporation, assignee of the present invention, which produces such products as part of its Advanced Farming Systems, or AFS™, product line. Such systems have heretofore not, however, addressed a need in precision farming to take grain samples in a field for off-line analysis and to then correlate the analysis to the field. 
     It would be advantageous to provide for a combine to include a grain sampling system for the acquiring of samples of grain throughout a field and for identifying the location within the field from which each sample was obtained, so that spatial variations of characteristics of the grain within the field may become known. 
     It would also be advantageous to provide for such a grain sampling system to identify each sample with a unique identification, such as a bar-coded identification, for facilitating off-line sample analysis and entry of sample data into a GIS. 
     It would also be advantageous to provide for such a grain sampling system to correct the locational identifications for offsets due to combine throughput time. 
     SUMMARY OF THE INVENTION 
     The invention relates to an agricultural system for acquiring crop samples from a field of land. The system includes an agricultural combine harvester, or combine, for combining of crop materials and for moving across the field at controllably adjustable ground speeds. The combine supports a crop sample acquiring apparatus for acquiring a sample of combined crop at each of a plurality of locations within the field, a sample source location signal generating circuit, and a data recorder. The data recorder communicates with the location signal generating circuit, and records the location within the field at which each sample was acquired. 
     The invention also relates to an agricultural grain sampling system for use with a combine. The combine combines crop materials bearing grain and is movable across a field of land at controllably adjustable ground speeds. The system includes a grain sample acquiring apparatus for acquiring a sample of combined grain at each of a plurality of locations within the field, a sample source location signal generating circuit supported by the combine, and a data recorder in communication with that circuit. The data recorder records the location within the field at which each sample was acquired. 
     The invention also relates to a method of determining and recording locational variations in characteristics of a crop being harvested from a field of land. The steps include (a) obtaining a sample of the crop using a crop sample acquiring apparatus at each of a plurality of locations within the field and associating a unique identification with each sample; (b) obtaining a locational description of each sample source location using a location signal generating circuit; (c) correlating the unique sample identifications and corresponding locational descriptions into first data pairs; (d) recording the first data pairs in a first data file; (e) analyzing the samples to generate location-specific crop data; (f) correlating the location-specific crop data and the corresponding locational descriptions into second data pairs; and (g) recording the second data pairs in a second data file. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     A full understanding of the invention may be gained from the Drawings taken in conjunction with the Detailed Description below, wherein like reference numerals refer to like parts. 
     FIG. 1 is a partially broken-away perspective view of an agricultural combine harvester, or combine, equipped with a grain sampling system. 
     FIG. 2 is a fragmentary side sectional elevation of the combine. 
     FIG. 3 is a fragmentary sectional elevation of a grain sample acquiring apparatus taken at line 3--3 in FIG. 2. 
     FIG. 4 is a fragmentary plan view of the grain sample acquiring apparatus taken at line 4--4 in FIG. 3. 
     FIG. 5 is a fragmentary sectional elevation of the grain sample acquiring apparatus taken at line 5--5 in FIG. 3. 
     FIG. 6 is a schematic representation of the grain sampling system. 
     FIG. 7 is a block diagram of the grain sampling system. 
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     FIG. 1 shows an agricultural work vehicle, depicted as a self-propelled combine 102. However, the concepts discussed herein are to be construed as applying equally well to a combine which is not self-propelled and configured as an implement to be connected to, pulled by, guided (i.e., steered), and powered by an agricultural vehicle such as a tractor. They are also to be construed as applying equally well to work vehicles for harvesting crops other than grains; e.g., forage choppers, sugar cane harvesters, harvesters of small vegetables, harvesters of specialty seeds, etc. 
     Combine 102 is depicted as a mobile agricultural work vehicle including a frame 104, to which are installed a main body 106, an operator&#39;s station 108, a grain tank 110, an engine (not shown), and ground support devices including drive wheels 112 and steerable wheels 114. However, the ground support devices could also be endless crawler tracks. 
     Combine 102 includes a header 116 configured to cut, snap, or otherwise sever plant stalks near the soil surface and convey the resulting crop material to a central region of header 116, where a feed conveyor, or feeder 118, conveys it into main body 106. A thresher 120 is located within main body 106 and is disposed to receive the crop materials from feeder 118. Thresher 120 separates kernels of grain from larger pieces of other crop materials, referred to herein as trash. The grain kernels are then conveyed to a winnowing, or cleaning, section 122, where smaller bits of trash, debris, dust, etc. are removed by mechanical agitation and a stream of air. Although combine 102 is depicted as an axial-flow combine (i.e., having a thresher with a generally longitudinally disposed axis of rotation), the concepts described herein may also be used on other types of combines including those having threshers with transversely disposed axes of rotation. 
     Combine 102 also includes a grain sampling system 202, described below and including a housing 246 and a grain sample acquiring apparatus 210, and an antenna 264 for wirelessly receiving locational data from, for example, the GPS satellite network. 
     FIG. 2 shows more clearly the grain threshing and cleaning apparatus. Thresher 120 includes a stationary rotor cage 126 of generally cylindrical configuration, within which rotates a generally coaxial and cylindrical rotor 124. A sufficiently large rotor cage gap 128 exists between the inside diameter of rotor cage 126 and the outside diameter of rotor 124 for installation of an intermediate member, shown as a concave 130, which is radially spaced apart from rotor 124 by a controllably adjustable concave gap 134. Motion of rotor 124 within rotor cage 126 and concave 130 causes grain kernels to lose their attachment to the other crop material, or trash, upon which they had grown. Grain kernels, and small bits of debris, fall through apertures 132 within the wall of concave 130 to a grain trough 136 located at a bottom portion of rotor cage 126. 
     A grain augur 138 conveys grain within grain trough 136 rearwardly to cleaning section 122. Mechanical agitation of one or more sieves 123, combined with a generally upwardly and rearwardly directed flow of air from a cleaning air fan 125, causes the generally lighter-weight trash to be blown off of sieves 123 and out of an opening in the rear of combine 102, while the generally heavier grain falls through the openings of the sieves into a cleaned grain trough 140. A cleaned grain augur 142 is located within cleaned grain trough 140 and conveys the cleaned grain to an elevator conveyor (not shown) for filling grain tank 110 (shown in FIG. 1). 
     FIGS. 2, 3, 4, and 5 show a grain sample acquiring apparatus 210 secured to an underside of cleaned grain trough 140. The grain sample acquiring apparatus 210 can alternatively be located on the underside of the auger located in the grain filling tank 110. In one embodiment, portions of grain sampling apparatus 210 are generally similar in configuration to an apparatus developed by Mark D. Shrock et al. of Kansas State University, and described by Edwin L. Eisele et al. in Field Scale Spatial Variability of Wheat Quality, ASAE Paper No. MC97-103. 
     In an alternative embodiment a grain sample acquiring apparatus 210(a) is installed to grain trough 136 (rather than to cleaned grain trough 140 as described above for grain sample acquiring apparatus 210). Crop material throughput time for sampling is then reduced as the grain sample is taken before the sample passes through cleaning section 122. However, the samples may then include objectionably large amounts of trash. In other alternative embodiments (not shown), a grain sample acquiring apparatus is installed to combine 102 at another location where grain is flowing; e.g., at an elevator conveyor transporting cleaned grain into grain tank 110, or at a bypass unit supporting a grain characteristic sensor and mounted upon the elevator conveyor. For example, a grain bypass unit is available from Ag Leader of Iowa that attaches to the side of the grain elevator that transports grain from the cleaned grain trough to the grain hopper. A moisture sensor (or other grain sensors) are attached to the bypass unit and measure grain characteristics at this location. The bypass unit provides a clean sample of grain, thereby avoiding the problems of weed seeds and other foreign matter contaminating the sensor. The present grain sampling apparatus can be configured to extract this clean grain from the bypass unit. 
     In general, it is preferable to obtain samples of cleaned grain and to offset, or correct, known and quantifiable errors in the locational identification caused by combine 102 throughput time in the manner described above. It is also preferable to locate grain sample acquiring apparatus 210 near a combine sensor, in that grain sampling system 202 is then also useful for validating and calibrating the sensor in a real time, harvesting environment. 
     In FIG. 3, grain sample acquiring apparatus 210 includes a sample receiver 212 and a linear actuator 222 connected thereto. Sample receiver 212 is in the form of an open-topped container (e.g., a box) affixed to (e.g., by welding) a plate 218. Plate 218 has a plate opening 224 approximately centered over the open top of sample receiver 212 whereby sample receiver 212 remains substantially open-topped after being affixed to plate 218. Linear actuator 222 is affixed to a lower surface of cleaned grain trough 140 (e.g., by a pin 223 engaging a clevis fork 221 extending downwardly from the underside of trough 140), and plate 218 is slidingly retained to the lower surface of cleaned grain trough 140 (e.g., by flanges 219 shown in FIG. 5), being thereby slidingly movable with respect to cleaned grain trough 140 by linear actuator 222. 
     A trough opening 220 through the underside of cleaned grain trough 140 is covered by plate 218 when plate 218 (and thereby sample receiver 212) are located in a first position by linear actuator 222, and no grain therefore leaves trough 140 via trough opening 220. When linear actuator 222 is activated (e.g., by a &#34;Sample&#34; command signal from a control apparatus as described below), it relocates plate 218 to a second position in which plate opening 224 aligns with trough opening 220 so that grain can fall into sample receiver 212. After a suitable time delay for sample receiver 212 to at least partially fill, linear actuator 222 is deactivated and a return spring (not shown) returns plate 218 and sample receiver 212 to their first positions. Alternatively, linear actuator 222 may be a double-acting actuator (e.g., a pneumatic or hydraulic cylinder pressurized on both sides of its piston) to power plate 218 in either direction between its first and second positions. 
     Sample receiver 212 includes an outlet port 214 for delivery of the grain sample to a grain sample transfer tank 208, and a vent port 216, both described below. 
     FIG. 6 shows an embodiment of grain sampling system 202. Grain sample acquiring apparatus 210 may be located, as discussed above, beneath a grain pan or trough such as beneath cleaned grain trough 140. A vacuum generator 204 is located within or upon combine 102, in the illustrated instance within housing 246. Vacuum generator 204 may be an air pump, or blower, having a vacuum generator inlet port 228 and a vacuum generator outlet port 226, and is powered by any suitable prime mover; e.g., a hydraulic motor, an electrical motor operating on chassis voltage, or a small engine. Vacuum generator 204 may alternatively be associated with the engine (not shown) of combine 102, and mounted and connected to it by conventional methods well known to those of skill in the art and used for alternators, hydraulic pumps, and similar engine accessories. 
     Briefly referring to FIG. 1, housing 246 is shown secured to a side of main body 106 between one drive wheel 112 and one steerable wheel 114. However, housing 246 may be configured and located (e.g., upon or within main body 106) so as to best accommodate components of grain sampling system 202 and to best fit combine 102. 
     Returning to FIG. 6, a grain sample transfer tank 208 is shown having a lower portion 238 generally configured as a funnel (i.e., with a conical portion 239 and a spout 240). Transfer tank 208 may also include a plenum, such as an upper portion 236. Transfer tank 208 also includes a tank inlet port 234 and a tank outlet port 232. Spout 240 is located and disposed above an opening 247 of a sample container 248, and sample container 248 is located in a rotatable carousel 206 holding a plurality of similar sample containers 248. A valve 242 (e.g., a check valve or a solenoid valve) is associated with spout 240 and is configured to allow downwardly directed flow (e.g., of grain through spout 240) at least when vacuum generator 204 is not running and to prevent upwardly directed flow (e.g., of air through spout 240) at least when generator 204 is running. 
     Inlet port 234 of transfer tank 208 is connected to sample receiver outlet port 214 by a sample vacuum hose 244, and outlet port 232 is connected to vacuum generator inlet port 228 by an air vacuum hose 230. Alternatively, a vacuum generator may be configured to be secured to an open top of a transfer tank in a manner similar to the construction of a vertically disposed shop vacuum cleaner, the vacuum generator air inlet in communication with the tank outlet and without a connecting air vacuum hose. 
     In operation, receipt of a &#34;Sample&#34; command by grain sampling system 202 initiates a series of events. Linear actuator 222, normally held (e.g., by a return spring) in a default or &#34;at-rest&#34; position is energized, positioning sample receiver 212 under cleaned grain trough opening 220 so as to allow cleaned grain to at least partially fill sample receiver 212. Linear actuator 222 is then de-energized, or otherwise returned to its prior, or default, state, returning sample receiver 212 to its prior position and again covering cleaned grain trough opening 220 with the solid portion of sampler plate 218. 
     Sequencing in a control program, or activation of a limit switch by return of sample receiver 212, starts vacuum generator 204 which draws a partial vacuum within transfer tank 208. Valve 242 closes to apply the vacuum to sample receiver 212 via tank inlet port 234, sample vacuum hose 244 and sample receiver outlet port 214. Ambient air enters sample receiver 212 via vent port 216, partially relieving the vacuum with a high-velocity flow of air which entrains the grain sample kernels and carries them to and into transfer tank 208. The sectional area of tank 208 exceeds the sectional area of sample vacuum hose 244, and the velocity of air (and entrained grain) is sharply reduced upon entry into transfer tank 208. The grain kernels, being heavier than the air, fall by gravity into a lower portion of transfer tank 208. Transfer tank inlet port 234 may be oriented tangentially with respect to a generally cylindrical surface of upper portion 236, to allow centrifugal acceleration to assist precipitation of grain kernels as in a cyclonic separator. A filter (not shown) may be provided within tank 208 to separate transfer tank inlet port 234 from transfer tank outlet port 232 and remove from the air stream any particles of grain that resist gravitational separation, in the manner of a vacuum cleaner bag or filter. Ambient air may be routed to vent port 216 by a vent hose 250 from a relatively dust-free area near the top of combine 102 to avoid drawing ambient dust in with the grain sample. 
     Control program sequencing then de-energizes vacuum generator 204 and allows valve 242 to open. The grain sample then pours through spout 240 into container 248 of carousel 206. Another sequencing of the control program indexes carousel 206 by one container 248 circular pitch to align the adjacent (empty) container 248 for receiving a grain sample from another location within the field. By keeping track of the number of container&#39;s 248 which have been filled, the system can generate a &#34;sampling complete&#34; indication which can be displayed to the operator when all of the containers 248 have been filled, and sampling can then be disabled until the operator changes the carousel. 
     At any time during this process after the &#34;Sample&#34; command has been received, a unique identification may be associated with an individual container and its location-specific grain sample. One way of doing this includes printing (e.g., with an ink-jet printer 245) an alphanumeric indicia upon sample container 248 or upon a label 249 to be placed upon or applied to sample container 248, the indicia being modified (e.g., incremented) for each successive container 248, for subsequent manual entry into a data base upon off-line sample analysis. Label 249 has a pre-applied adhesive. 
     Alternatively, similar information is printed as a bar-code upon container 248 or upon label 249 for automatic (upon scanning) entry into the data base. In another embodiment, a label (e.g., a plastic label) may be inserted into sample container 248 with the grain. In another embodiment, the alphanumeric or bar-coded unique identification may be pre-applied to sample container 248 and the unique identification correlated with a locational description of the sample source in a memory device 268 (shown in FIG. 7). In another embodiment, a pre-applied bar-coded unique identification may be read by a scanner 251 (shown in FIG. 7) and transmitted to a data processing unit, shown as DPU 260 in FIG. 7, for correlation with locational data and storage in memory device 268. 
     The printed information which identifies the sample includes at least one of a unique sample number, or comparable designation, and the unique location within the field from which that sample was obtained. Additional information (e.g., date, time, field name or number, etc.) may also be printed to aid in the proper handling, routing, analysis, data storage, etc. of the sample Other methods of uniquely identifying samples are known to those of skill in the art; e.g., heat-shrinking imprinted loop-shaped labels about the container. All such variations are within the scope of the present invention. 
     In one embodiment, label 249 is imprinted with a bar-coded locational description of the sample source (i.e., the location of the sample in the field) and applied to the sample container. The locational description may be obtained from a Global Positioning System (GPS) receiver 262 (FIG. 7) with Differential GPS (DGPS) accuracy enhancement, receiving signals from a remote source via antenna 264 (FIGS. 1 and 7). 
     FIG. 7 is a block diagram of grain sampling system 202, wherein DPU 260 communicates with devices including memory device 268, a manual &#34;Sample&#34; command device 270, and a grain sampler controller 276. DPU 260 also communicate with a remote GPS/DGPS source (not shown) via GPS/DGPS receiver 262 and antenna 264, with a remote computer 280 having a GIS database via a wireless datalink, with one or more sensors 272 of crop and/or field parameters, and a location correction circuit 274. 
     DPU 260 determines where, or when, a grain sample is acquired by one or more ways of triggering the acquisition. Samples may be obtained in a grid fashion by sending a &#34;Sample&#34; command at specific increments of travel (i.e., every predetermined amount of distance) by combine 102 (e.g., whenever combine 102 travels a distance equal to the width of header 116 for a grid of squares). Alternatively, samples may be obtained on lapse of a period of time (e.g., every 30 seconds). DPU 260, shown communicating with sensor 272 which senses a characteristic of the crop material or soil (e.g., moisture content of the grain), may be programmed by memory device 268 to initiate a &#34;Sample&#34; command upon receiving a sensor signal indicative of a sudden change in the value of the parameter being sensed, or of the value going outside previously established high and/or low limits. In any of these embodiments, manual &#34;Sample&#34; command device 270 (e.g., a momentary-contact switch at operator&#39;s station 108) may also be used by the operator to acquire a grain sample at any location that is determined to be desirable. 
     Strategically preferred locations of grain sampling may be determined in advance using a remote computer 280 having a GIS map of the field, the map containing locationally identified information relevant to the present grain and/or the field (e.g., last year&#39;s yields; this year&#39;s rates of application of seed, fertilizer, herbicide, etc.; this year&#39;s scouting and remote imaging reports; field topography, drainage, soil types and past analyses, infrastructure, etc.). In one embodiment, memory device 268 is portable (e.g., diskette, PCMCIA card, zip disk), contains a data file of strategically preferred grain sample locations mapped as a layer of the GIS map on remote computer 280, and is compatible with DPU 260. In another embodiment, DPU 260 communicates with remote computer 280 via a wireless datalink and memory device 268 thus need not be portable. 
     Grain sampling system 202 may record sampling site locational data and corresponding sample unique identifications, or unique locational data as sample unique identifications, as a separate data file in memory device 268 or remote computer 280. That file, and the off-line analyses when obtained, can then be added to a GIS data base. 
     In another embodiment, when yield and/or moisture content of grain are being measured and recorded substantially in real time during harvesting, a &#34;marker&#34; is stored in the same data file as that used by the yield or moisture monitor. This data then shows up as a marker indicator on the GIS yield or moisture map that is downloaded at a later point in time. Once the samples are analyzed, the information obtained from the lab analyses is added to the GIS data base. The GIS software can then produce a map that graphically displays areas of high and low values for the particular parameters of the grain that were determined by the analysis. 
     In another embodiment, unique sample identifications are bar-coded onto sample containers 248 prior to commencing harvesting. A scanner 251 then reads the bar-coded identification on each container 248 upon its receiving a sample, and transmits the identification through grain sampler controller 276 to DPU 260 for correlation with locational data and storage in memory device 268, as a yield file marker as described above, if desired, for later use in GIS mapping. 
     Combine 102 throughput time for combining of grain is significant, typically up to 30 seconds in normal operation. This gives rise to significant possible inaccuracy of locational data (e.g., a combine moving at 2 miles per hour travels 88 feet in 30 seconds). Both ground speed of combine 102 and rotational speed of rotor 124 within thresher 120 are controllably adjustable by the operator and are measured parameters. Moreover, header 116 reel speed and feeder 118 speed are correlated to ground speed, and throughput time is largely a function of rotor 124 rotational speed for a particular grain and is thereby readily determined. A location correction circuit, or algorithm, can then be used to generate a location correction factor based upon course (a function of the present and last prior locations reported) and distance (a function of ground speed and elapsed time), for any particular rotor speed. 
     While the embodiments illustrated in the Figures and described above are presently preferred, is should be understood that these embodiments are offered only as examples. For further example, a grain conveyor other than the cleaned grain augur (e.g., the elevator) may be used as a sample source. Sample containers may be flexible plastic bags, linked to each other chain-like on a reel. The vacuum generator may be associated with the combustion air intake side of the engine. Also, due to the vacuum system, the grain or crop samples can be taken from any location where there is a flow of crop, which would typically be near or adjacent to a sensor (e.g., a yield or moisture content sensor) attached to the combine. In fact, situating the crop sampling apparatus in such a location is useful in the present invention&#39;s ability to calibrate or validate the sensors in a real-time harvest application. Other variations of construction rather than invention will be obvious to those skilled in the art, but are nonetheless within the scope and spirit of the present invention. The invention is not limited to any particular embodiment, but is intended to encompass various modifications and differences of construction that fall within the scope and spirit of the claims.