Stimulating interest in and adoption of precision agriculture methods on small farm operations

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1 Stimulating interest in and adoption of precision agriculture methods on small farm operations C.W. Yohn 1, T.J. Basden 2, E.B. Rayburn 2, E.M. Pena-Yewtukhiw 3 and J.T. Fullen 4 1 West Virginia University Extension Service, 1948 Wiltshire Road, Suite 3, Kearneysville, WV 25430, USA; Craig.yohn@mail.wvu.edu 2 West Virginia University Extension Service, P.O. Box 6108, West Virginia University, Morgantown, West Virginia , USA 3 Division of Plant and Soil Sciences, P.O. Box 6108, West Virginia University, Morgantown, West Virginia , USA 4 Allegheny Ag, P.O. Box 172, Union, West Virginia 24983, USA Abstract In 2005, West Virginia University Extension funded a demonstration of precision soil sampling and precision nutrient management. West Virginia University Extension Service partnered with a crop consultant and custom applicator (Fullen Fertilizer) to perform this task. In land owners consigned 272 hectares to an expanded demonstration. These farms were soil sampled using conventional (0.56 hectares per sample) and precision (0.76 hectares per sample) method. WVU Extension paid for the conventionally taken samples. The individual soil data points were used to determine the number of hectares represented by the sample, the soil type and yield potential for alfalfa, mixed grass and corn from soil survey. Results showed that precision sampling and application required more lime than recommended by conventional sampling. Precision management required more phosphorous and less potash on fewer hectares than recommended by conventional management. Where higher recommendations for fertilizer and lime were called for using precision sampling it is assumed that crop yields would be higher since the crop needs were not being fully met using conventional sampling techniques. Extension education through presentations, a field day and farmer to farmer talks resulted in 625 additional hectares being sampled. Over 647 hectares received precision application of lime, phosphorous and potash. This occurred on five of the twelve co-operators and eight new land owners. Producers have used this information to change management practices including using mineral feeders and hay placement to guide cattle to specific field areas to redistribute nutrients, and delineate areas for variable nutrient application using conventional equipment. Acquisition of precision tools has increased in the area. Private consultants are partnering to help farmers interpret collected data. Keywords: extension, demonstration, technology Introduction Precision agriculture has its roots in the mid to late 1990 s with adoption by farmers and custom applicators being slow. This slow adoption has brought into question the economic benefit of sitespecific management of cropland. A review of 108 refereed journals, non-refereed monographs and popular press found that 63% indicated positive net returns for a given precision agriculture technology, while 11% indicated negative returns. Mixed results were indicated in 26% of the studies (Lambert and Lowenberg-DeBoer, 2000). Previous to this study acreage was sampled yearly for annual crops and once every two to three years for perennial forage crops. These soil samples were acquired by taking random samples EFITA conference

2 across each field, combining and mixing these samples, and sending a representative sub sample to commercial testing laboratories or to the West Virginia University Soil Testing Laboratory. A case study conducted by West Virginia University Extension Agent Brian Wickline and Tim Fullen of Fullen Fertilizer showed an economic advantage to zone sampling techniques and the precision application of lime, phosphorous and potash over conventional recommendations and application using a composite sample and whole field application of nutrients on one farm. This case study stimulated a small WVU grant to duplicate the trial in several other areas of the state. One of those was a beef and hay farm in Jefferson County, located in the karst limestone geology of the Shenandoah Valley approximately 80 kilometres west of Washington, DC. This demonstration duplicated the same procedures followed in the Wickline-Fullen trial and demonstrated an economic advantage when soil type and crop response was taken into account. The small trial conducted on 14 hectares with fields that were less than eight hectares in size in 2006 lead to an expansion of the case study in Jefferson County in the spring of Material and methods Fullen Fertilizer and West Virginia University Extension Service took both precision and conventional samples in the same fields at the same time using the same equipment. Collection and analysis of conventional samples were paid for by West Virginia University and precision sampling, analysis and mapping were paid for by the producer. The producer also covered all costs related to the application of lime and nutrients. West Virginia University Extension Service provided funding for moving the application truck 402 kilometres from its home base in southeast West Virginia. The goal was to recruit at least 16 hectares per farm for a total of 162 hectares sampled and at least 30% of those hectares treated using precision management. A variety of farming enterprises were identified in Jefferson County including dairy, beef, row crop and hay. These farms provided differences in how nutrients had been applied, how often soil tests had been taken and how nutrients may change with the influence of animal manures. The farms were located throughout the county to increase the number of soil types that would be represented. Producers were past co-operators with the Extension Service and had showed to be early adopters of proven technologies. All samples were taken in the spring of 2007 between March 30, and April 5 by Fullen Fertilizer using a 4 4 ATV mounted Simple Simon (Allegheny Ag, Union, WV) sampler. Precision samples were taken in field zones. Each geo-positioned sample was represented with five 3.2 centimetre diameter cores, 10.2 centimetres deep, one in the centre and four on the circumference of an approximately 12 meter radius circle. Position data was collected using a Raven GPS (Raven International, Sioux Falls, SD) connected to an IPaq personal digital assistant(pda) (Hewlett- Packard, Palo Alto, California) which was installed with Farm Works Farm Site Mate(Farm Works Software, Hamilton Indiana). Conventional samples were pulled in a random pattern. If the initial field was larger than 16 hectares, the field was subdivided into smaller management units based on topography and field characteristics. Samples were collected for each farm and partially air dried. A comparison was conducted to evaluate the amount of soil collected with precision versus conventional sampling methods. The samples were then sent to Waters Agricultural Laboratory in Camilla, Georgia. A Melich 1 analysis was done for water and buffered ph, phosphorous, potassium, calcium, magnesium, and sulphur. Fertilizer recommendations were based on recommendations from Virginia Tech. Mapping interpolation was accomplished by Fullen Fertilizer using AGIS developed by Delta Data Systems. Each producer received a copy of the soil sample results, printed maps showing nutrient levels, ph and application 456 EFITA conference 09

3 maps for lime, diammonium phosphate and muriate of potash. Each producer was given a copy of ViewPoint a software product from Delta Data Systems that allows the producer to view maps and evaluate hectares that require treatment. Results were shared with producers and explained by Fullen Fertilizer. Precision application was accomplished with a Trimble Ag 132 (Trimble Navigation Limited, Sunnyvale, California), a Rockwell Vision System (Rockwell Automation, Milwaukee, Wisconsin) and a Dickey-john Land Manager 2 (Dickey-john, Auburn, Illinois). Interpolation of soil type was accomplished using shape files from AGIS(Delta Data Systems, Picayune, Mississippi), SAMB Orthophotos (2003) from the West Virginia GIS Technical Centre, Soils from the NRCS Soil Data Mart in ArcGIS 9.0 (ESRI, Redlands, California). Results were shared through an October field day with seventeen farmers, certified crop advisors and nutrient management consultants in attendance. Two presentations were made to grower groups in Virginia by the author with over 100 producers in attendance. The results were shared in a December newsletter with a circulation of 1,300 area producers in a three county area. Results and discussion Approximately 271 hectares on twelve farms across the county were sampled both precision and conventionally (35 fields). Most of the farms were located in the eastern portion of the county. Large fields were subdivided into smaller management units to more accurately determine nutrient needs. The maximum unit size was 14 hectares; the minimum was 2 hectares with an average of 7.8 hectares. In all, three fields and one farm were further divided because of size or management units. Two fields were 26 hectares and were each divided into three management units. Another 35 hectare field was divided into three units and a small 17.4 hectare farm was divided into 5 fields because of fencing that would limit equipment movement. In these same fields, 344 precision samples were taken. Each sample represented an average of 0.75 hectares with a maximum area of 1.5 hectares and a minimum of 0.35 hectares. These samples represented 21 different soil types having the following range in yield potentials: Corn 6.9 to 11.3 metric tons per hectare Mixed Grass\Legume Hay 3.4 to 8.5 metric tons per hectare; and Alfalfa 4.8 to 12.1 metric tons per hectare. All soil test results, hectares represented by the sample, soil type represented by the sample and yield potential of the soil were tabulated into one database. To determine the economic variables of precision and conventional fertility management costs were gathered for nutrients and the services (Table 1). Precision sampling costs also included mapping and software provided to the producer to view the maps. Printed copies of the maps, analysis and recommendations were also provided. All spreading cost is based only on the hectares requiring application. The differences in costs for lime spreading are explained by pricing procedures in this region. Most conventional applicators charge by the ton applied rather than a flat fee for spreading on a per hectare basis and a separate charge for lime. Summarizing by nutrient applied, the following can be said. Lime An additional 78.8 metric tons would have been applied to an additional 22.7 hectares with precision recommendations versus conventional recommendations. On nine (75%) of the twelve farms more lime would have been applied. Six (50%) of those farms would have had more hectares treated while the remaining six farms would have been split evenly between treating less or the same hectares as was recommended with the conventional sampling. EFITA conference

4 Table 1. Summary of costs used in economic analysis (US Dollars). Item Conventional Precision Soil sampling and analysis through $ 7.41 per hectare $ per hectare commercial lab Lime spreading $ per metric ton $ per hectare Fertilizer spreading $ per hectare $ per hectare Diammonium phosphate (DAP) $ 857 per metric ton $ 857 per metric ton Muriate of potash $ 540 per metric ton $ 540 per metric ton Lime Included in lime cost $ per ton Diammonium phosphate (DAP) An additional 12.1 metric tons would have been applied to 41.7 fewer hectares with precision recommendations nearly doubling the rate per hectare treated over conventional sampling. Ten of the farms (83%) required more material. Nine (75%) of the farms would have had the material applied to less hectares while three (25%) required it on the same hectares as was recommended with conventional sampling. Muriate of potash Cooperators would have applied 4.3 metric tons less material to 81 less hectares using the precision recommendations over the recommendations from conventional sampling. Eight (67%) of the farms required less material and on ten of the farms (83%) the material would have been applied to less hectares. The other two (17%) required material on more hectares. Crops grown The fields on six of the farms sampled were crop fields, five of the farms had forage, either pastures or hayfields sampled and one had a crop field and alfalfa field sampled. Of the hectares sampled, 157 hectares (58%) were cropland and 114 (42%) hectares were in forages. Using the same analysis as used previously for nutrients to evaluate the differences between cropland and forage land. Cropland An additional 51.5 metric tons of lime would have been applied to an additional 17 hectares with precision recommendations versus conventional recommendations. In the case of diammonium phosphate (DAP), 17 less hectares would have been treated with 2.9 metric tons more material. When applying potash 75.3 less hectares would have been treated and the cooperators would have saved 5.1 metric tons of material. On all six farms (100%) more lime was required. Two (33%) of the farms required the material on less hectares while four (67%) required it on more. Two (33%) required less phosphorous, four required More (67%), but four of the farms (66%) required the material on fewer hectares while one required the material on the same hectares as was recommended by the conventional sampling method. The potash application showed that 83% of the area required less material while 67% would have had the material applied to less hectares than would have been applied using the recommendations from conventional sampling. 458 EFITA conference 09

5 Forage land An additional 28 metric tons of lime would have been applied to 9.3 hectares with precision recommendations versus conventional recommendations. In the case of diammonium phosphate (DAP), 17 less hectares would have been treated with 8.9 metric tons more material. The application of potash would have required that 15 less hectares were treated with 1 more metric ton of material. Three (60%) of the five farms required more lime and two (40%) required less that recommended through conventional sampling. Three (60%) of the farms required the material on less hectares while two (60%) required it on more. All five farms (100%) required more phosphorous, three (60%) of the farms required the material on less hectares while two (60%) required it on the same hectares as recommended with conventional sampling. The potash application was the same for the amount of material and area as 80% required less material on less hectares than would have been applied using the recommendations from conventional sampling. The other farm required more material on more hectares than the conventional sampling method would have recommended. Economic evaluation Variations in application levels and hectares covered affect the costs of precision sampling and application. In more than one case no lime was recommended from the conventional samples taken, but lime application was recommended from the precision sampling. Costs for each farm are more a reflection of nutrients needed and the variation in the fields than the additional cost of the precision technology. Table 2 demonstrates the difference in hectares treated between the two methods. The cost per hectare was quite variable as well. Only one farm would have realized a savings by using precision over conventional sampling and application. This dairy farm with a 14.6 hectare field would have saved $ per hectare by using precision soil testing and application. The other eleven farms had an added expense by using this precision technology. The cost per hectare ranged from $ per hectare to $ per hectare. The average cost among all twelve farms was $ per hectare. The high cost of diammonium phosphate (DAP) greatly influenced costs. Many more metric tons (59) were recommended through precision sampling. Management practices changed\technology adopted The largest impact of precision sampling has been field variation and how this has affected land owners. The mapping showing this variability has lead to producers sampling more fields and talking to neighbors about the technology. Precision sampling and application of nutrients is not available locally. Of the original twelve producers, five have had more hectares sampled and had at least lime applied at a variable rate. An additional nine producers have also requested and used this technology through the fall of 2007 and spring of Four of those new producers were influenced by Extension publications and presentations. The remaining five were encouraged by producers who have previously participated in the program. Three of the producers have drawn on Table 2. Comparison of treated hectares by sampling method. Conventional Precision Hectares sampled Percent treated with lime 67% 77% Percent treated with phosphorous 94% 81% Percent treated with potash 60% 35% EFITA conference

6 the expertise provided by Fullen Fertilizer to purchase and learn how to use a light bar, purchase and learn how to use a yield monitor and work with a custom planter and harvester coordinate and overlay yields and variable rate planting with fertility. Fullen Fertilizer also investigated additional field problems by mapping compaction using a penetrometer. This was done on no less than three fields with producers taking tillage action at the traffic pan zone. Several farmers used the maps in nontraditional ways to distribute nutrients. The original pilot farm used the maps to direct cattle to areas requiring nutrients through the strategic placement of mineral feeders and moving hay feeding to nutrient deficient areas. This same producer directed the custom application of poultry litter to nutrient deficit areas in a hayfield. This particular area had been identified years before by a custom harvester to the producer s father. Only after precision sampling did the area show as requiring 113 kilograms of muriate of potash per hectare. Another producer used the results to divide the 26.3 hectare field into the three smaller management units. While this was not a normal precision application, the division into three management units was an improvement over managing the field as one unit. A third producer actually physically flagged 16 hectares to direct the local custom applicator to treat these deficit areas more than once to improve fertility in those areas. Research interesting areas are emerging. The data collected were used by Dr. Rayburn and Dr. Pena-Yewtukhiw to develop economic thresholds to warrant precision sampling and application, evaluate thresholds for nutrient levels in the soil that warranted precision sampling and the number of samples that need to be taken based on the variability found over the 271 hectares. Their research is an outgrowth of the original study and will result in more than one scholarly product. Conclusions Twelve farms participated in a trial to evaluate the precision soil sampling and application of nutrients versus conventional sampling and nutrient application. Nearly 271 hectares were represented and included hectares in crops, pasture and hay land. Precision sampling recommendations required the application of more lime on more hectares, more phosphorous on fewer hectares and less potash on fewer hectares than recommended through conventional sampling. Only one farm would have realized a savings by using precision sampling and application over conventional sampling and application. That farm would have realized a $ per hectare savings. The other eleven farms had an expense by using this precision technology. The cost per hectare ranged from $ per hectare to $ per hectare. The average cost among all twelve farms was $ per hectare. This was mostly due to the additional lime and diammonium phosphate (DAP) applied based on precision recommendations. Through Extension publications and presentations, farmer to farmer encouragement and expansion of hectares sampled and treated on five of the twelve original farms, over 810 hectares (a 298% increase from the original hectares) have been sampled on a total of twenty-one farms. Ten of the twenty-one farms precision applied lime and two farms precision applied phosphorous and one precision applied both phosphorous and potash. Producers have utilized the information generated to distribute nutrients in nontraditional ways, have expanded the use of other precision agriculture tools on the farm and utilized the expertise offered by Fullen Fertilizer to expand precision agriculture technology beyond soil fertility. More hectares will be sampled precision followed by precision application of nutrients as this technology is being embraced by more producers. The knowledge gained through precision sampling and nutrient application accelerated interest among new farmers and those that participated in the original study. The commercial Certified Crop Advisor who pulled the original samples has done all the additional 460 EFITA conference 09

7 sampling. He is also mentoring a young agriculturalist to pull the precision samples and learn how to create maps. A custom farming operation has used information from soil sampling to expand services he offers including variable population rate corn planting and yield monitoring. The lead author has written a USDA Conservation Innovation Grant totaling nearly $ 400,000 to expand the purchase of services, equipment and software by farmers and custom fertilizer applicators to encourage the expansion of precision technology as a result of this study and the enthusiasm by other farmers. Future challenges include evaluating the yield response that uniform fertility across the field may bring which will improve adoption of this technology and improved stewardship of the land. References AGIS. Delta Data systems, Inc. ArcGIS 9.0. ESRI Corporation, Redlands, California Lambert, D and Lowenberg-DeBoer, J Precision agriculture Profitability Review. Site-specific Management Centre School of Agriculture Purdue University Frames/newsoilsX.pdf. NRCS Soil Data Mart Jefferson County West Virginia aspx?county=wv037. West Virginia GIS Technical Centre ftp://ftp.wvgis.wvu.edu/pub/clearinghouse/samb03/utm83/ utm83zone17n. EFITA conference

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