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© 2007 Plant Management Network. Crop Management Practices in Indiana Soybean Production Systems Shawn P. Conley, Assistant Professor, and Judith B. Santini, Research Statistical Analyst, Department of Agronomy, Purdue University, West Lafayette, IN 47907 Corresponding author: Shawn P. Conley. conleysp@purdue.edu Conley, S. P., and Santini, J. B. 2007. Crop management practices in Indiana soybean production systems. Online. Crop Management doi:10.1094/CM-2007-0104-01-RS. Abstract To meet the current and future needs of todays soybean producer it is vital that agricultural researchers and extension specialists clearly understand the production concerns of our clientele. The objective of this research was to characterize the current management practices of Indiana soybean (Glycine max (L.) Merr.) growers, to identify specific educational needs, and to provide a framework for directing applied soybean research efforts. This assessment was conducted through a direct-mail survey. The results of this survey define distinct similarities and differences among growers of different farm operation size. Large acreage growers (≥ 1000 acres) were more likely to plant soybeans in rows spaced 11 to 20 inches, reduce seeding rates, plant earlier, and have higher yields. Large acreage growers were also more likely to own a yield monitor, conduct on-farm research, use a computer, and routinely use the internet. Our research also identified different research and educational needs based on farm operation size. By specifically targeting these needs, agricultural researchers and extension specialists may improve the economic and environmental sustainability each clientele group. Introduction Since the introduction of glyphosate-tolerant soybean in 1996, management of soybean production systems have dramatically changed (8). Today growers are faced daily with new crop and pest management technologies, new agronomic traits, and an ever-changing pest complex. These new pests the soybean aphid (Aphis glycines) (7) and the soybean rust fungus (Phakopsora pachyrhizi) (7,9) may combine to form a potentially devastating pest complex, both of which require management with pesticides. To maintain commercial viability, soybean growers in the US must continue to adopt new pest and crop management tools and technologies (5). The objective of this research project was to identify current agronomic production practices and concerns of Indiana soybean producers to aid Purdue Extension and research faculty in developing extension programs and educational materials that meet current and future clientele needs, and to provide a framework for directing applied soybean research efforts. Methodology and Statistical Analysis A seven-page direct-mail survey was sent to 5000 Indiana soybean growers in August of 2005. Purdue University consulted with the Indiana Agricultural Statistics Service to develop and distribute the survey to growers representing various size farming operations and geographic regions within Indiana. Indiana Agricultural Statistics Service generated the mailing list, distributed the surveys, conducted follow-up phone calls to non-respondents, and entered all of the responses into a database. Once the information was entered into the database all of the personal information of respondents was deleted. The database was then transferred to Purdue University for statistical analysis. A chi-square test was conducted on response frequency counts using SAS PROC FREQ (SAS Institute Inc., Cary, NC). A significant chi-square indicates that the distribution of responses is different among the rows or columns of a table of frequency counts. Results are generally presented as percents to provide a uniform frame of reference. For continuous measures, farm size was the treatment and the experimental design was completely randomized. Analysis of variance was conducted and least-squares means were compared by t-tests where the F test was significant (P ≤ 0.05). Survey Response Rate A total of 1330 growers returned this survey; however only 1310 growers indicated the size of the farm operation. This response rate of 27% was similar to the response rates reported by others (1,2,4). The survey was divided into three sections: crop management, pest management, and marketing. Responses to each question were characterized by farm operation size and crop reporting district. In this manuscript we focus on analysis and discussion of the responses to the agronomic production questions with respect to differences in total farm operation size. The farm size responses are broken down into the following acreage categories: 0 to 99 acres, 100 to 249 acres, 250 to 499 acres, 500 to 999 acres, and 1000+ acres, with 206, 320, 263, 262, and 259 respondents, respectively. Data tables were ranked by overall response rate. Row Spacing, Seeding Rate, Seeding Depth, and Inoculants Soybean row spacing differed as farm operation size increased (Table 1). As farm size increased, row spacing of 11 to 20 inches increased and row spacing ≥ 21 inches decreased. Farm operation size also impacted the average soybean seeding rate (Table 2). As farm size increased, the soybean seeding rate in the 150,000 to 225,000 seeds/acre range also increased, while seeding rates < 150,000 and > 225,000 seeds/acre decreased. However, these results may be confounded by the differences in row spacing among grower operation size. Table 1. Impact of farm operation size on soybean row spacing.
x Chi-square = 59.941; df = 8; P ≤ 0.0001; n = 1173. Table 2. Impact of farm operation size on soybean seeding rate.
x Chi-square = 83.413; df = 28; P ≤ 0.0001; n = 1134. Independent of farm size the mean soybean seeding rates were 197,167, 178,031, and 153,515 plants/acre, respectively, for rows spaced ≤ 10, 11, to 20, and ≥ 21 inches. Results were similar to Purdue University seeding rate recommendations of 200,000 seeds/acre at ≤ 10-inch row spacing, and greater than the 11- to 20-inch row spacing recommendation of 161,000 seeds/acre (9.4% greater) and the ≥ 21 inch row spacing recommendation of 127,000 seeds/acre (17.1% greater). This suggests that a significant number of growers may be able to decrease input costs by simply lowering their seeding rates in rows spaced greater than 10 inches. Farm size did not affect the depth at which soybeans are planted. Twelve, 46, and 42% of respondents plant their soybeans at ≤ 0.75, 0.76 to 1.49, and ≥ 1.50 inches, respectively. Farm size also did not affect the decision to use a soybean inoculant in 2005. Independent of farm size 17.8% of respondents indicated that they used a soybean inoculant. Of those respondents that used an inoculant, 44.6% indicated a yield response and 41.1% reported increased early season vigor as the primary reason for using an inoculant. Of those respondents that did not use an inoculant, 52.2% cited no yield advantage, 24% cited cost, and 18.1% cited extra labor as the primary reason for not using an inoculant. Planting Date Changes As farm size increased, respondents were more likely to have an earlier start date for planting soybean (Table 3). When compared to 10 years ago, 27.8, 32.2, 7.0, 3.4, 2.4, and 27.3% of respondents indicated that they plant their soybean crop one week earlier, two weeks earlier, three or more weeks earlier, later by one week, other change, or no change in planting date, respectively. Independent of farm size, 27.3% of respondents began planting soybean prior to 1 May in 2005. Table 3. Impact of farm size on soybean planting start date.
x Chi-square = 152.039; df = 32; P ≤ 0.001; n = 1208. Farm size did not affect how growers ranked yield increase and technology advances as factors that have influenced planting date (Table 4). However, farm size did affect how growers ranked the importance of improved soybean varieties, weather changes, spreading out the work load, and industry re-plant programs as factors that have influenced planting date. The importance of spreading out the workload and improved soybean varieties increased as farm size increased, whereas the importance of weather pattern changes decreased as farm size increased. Industry re-plant programs were the least important factor influencing planting date. Independent of farm size, a perceived yield increase, improved soybean varieties, and weather pattern changes ranked as the most important factors that have influenced planting date. Table 4. Rank of the importance of the following factors that influenced planting date.
x Ranking based on a scale of 1 to 5, where 1 = very important and 5 = not important. y *, **, *** significant at P ≤ 0.05, 0.01, and 0.001, respectively. Variety Selection Independent of farm size, 18.5, 44.3, 25.3, and 11.9% of respondents purchased their soybean seed in July to October, November to December, January to February, and March to June, respectively. As farm size increased the number of varieties planted also increased (P ≤ 0.0001); however, 54.5% of growers with 1000+ acres planted 4 or less varieties in 2005. Independent of farm size 28.2, 24.9, 29.1, and 17.7% of respondents planted 1, 2, 3-4, or ≥ 5 varieties of soybean in 2005. Farm size did not affect how respondents ranked the importance of disease resistance, seed dealer recommendations, or grain quality traits when selecting a soybean variety (Table 5). However, farm size did affect how growers ranked the importance of yield potential, presence or absence of a glyphosate tolerant trait, seed price, and personal relationship with a seed company when selecting a soybean variety. Independent of operation size, yield potential, presence or absence of the glyphosate-tolerant trait, and disease resistance were the main factors considered when selecting a soybean variety. Grain quality traits were ranked the least important factor growers considered when selecting a soybean variety. The lack of interest related to grain quality traits may be attributed to the lack of current price premiums for these traits. Table 5. Rank of the importance of the following factors in selecting a soybean variety.
x Ranking based on a scale of 1 to 5, where 1 = very important and 5 = not important. y *, **, *** significant at P ≤ 0.05, 0.01, and 0.001, respectively. Tillage, Cropping Systems, and Fertility In 2004, 36% of US soybean acreage was tilled prior to planting (3). In our survey, the decision to till prior to planting was not affected by farm size. Growers cited soil amelioration (aeration, stubble incorporation, etc.), weed control, and increased yield (37.8, 22.5, and 21.2% respectively), as the primary reasons for tillage prior to planting soybean. Independent of farm size, 53.4% of respondents indicated that they primarily utilized a strict corn-soybean rotation, whereas 8.6% of respondents utilized some other form of a corn-soybean rotation in their production system. Only 1.4 and 1.7% of growers indicated that their primary crop rotation was either continuous corn or continuous soybean, respectively. The remaining 34.9% of respondents incorporated another crop, usually wheat or forage, into their primary rotation. Farm operation size impacted the frequency of soil testing and the frequency of phosphorus and potassium application (data not shown). Independent of farm size, 8.5, 22.0, 33.1, 32.5, and 3.9% of respondents indicated that they soil tested every year, every two years, every three years, every four or more years, or never, respectively. Furthermore, independent of farm size 52.2, 38.7, 3.3, 2.3, and 3.5% of respondents indicated that they applied phosphorus and potassium every year, every two years, every three years, every four or more years, or never, respectively. Farm size did not impact the application method of phosphorus and potassium. Ninety-four percent of growers surface broadcast phosphorus and potassium, whereas 3% of growers deep-banded phosphorus and potassium. The remaining 3% of respondent applied phosphorus and potassium in another manner. Independent of farm size, 89% of respondents have never applied a foliar micro/macro nutrient to their soybean crop. Of those respondents that have applied a foliar nutrient 23.9, 23.0, 25.5, 8.4, and 19.2% applied phosphorus, potassium, manganese, boron, and others, respectively. Technology Usage and Method of Information Delivery Farm operation size greatly impacted technology usage among respondents (Table 6). As farm operation size increased, technology usage also increased. The greatest disparity of technology usage among operation sizes was the use of yield monitors. Large growers are more likely to use a yield monitor than smaller growers. Growers of all sizes conducted some form of on-farm research. The adoption and use of yield monitors by larger operations, however, does simplify yield measurements in these on-farm trials. It is also important to note that less than 50% of all respondents routinely use email. This may explain why most respondents prefer to receive alerts by postcard over email and phone. Table 6. Percentage of growers that utilize various technologies in their farming operation.
x Ranking based on a scale of 1 to 5, where 1 = very important and 5 = not important. y *, **, *** significant at P ≤ 0.05, 0.01, and 0.001, respectively. Farm operation size also impacted the ranking of various methods of information delivery (Table 7). Independent of farm size, print material ranked as the preferred method for receiving information. Field days, county-based meetings, and industry meetings ranked higher than state/regional based meetings or web-based information delivery. The low importance of web-based information delivery is likely due in part to the lack of routine internet use by our clientele and the low use rate of computers. Table 7. Rank the importance of the following methods of soybean information delivery.
x Ranking based on a scale of 1 to 5, where 1 = very important and 5 = not important. y *, **, *** significant at P ≤ 0.05, 0.01, and 0.001, respectively. As extension budgets remain stagnant, extension educators and faculty are strongly urged to decrease the number of local meetings and focus on state/regional meetings and to develop and deliver information via the web. This survey indicates that these methods are the least desirable methods of information delivery for our grower clientele. To maintain strong contact and support with this clientele group we must continue to deliver at least some of our programs locally, encourage more growers to utilize computers, and develop web-based materials that are simple, informative, and effective. Factors that Affect Soybean Net Return and Yield Farm size did not affect grower perception regarding the relative importance of weather, weeds, soil fertility and pH, and agronomics issues as factors that limit soybean net return (Table 8). However, farm size did affect grower perception regarding the importance of marketing, varieties, insects, and diseases and as factors that limit soybean net return. Independent of farm size, weather was ranked as the most important factor that limits soybean net return. Weeds, marketing, and soil fertility and pH ranked as the top management factors that limit soybean net return. Weeds were also ranked as the number one pest problem in Indiana soybean production systems (unpublished data). The rank differences in marketing are related to the additional marketing and selling options available to large acreage versus small acreage operations (unpublished data). Table 8. Rank the importance of the following factors that limit soybean net return.
x Ranking based on a scale of 1-5, where 1 = very important and 5 = not important. y *, **, *** significant at P ≤ 0.05, 0.01, and 0.001, respectively. As farm size increased grain yield also increased (Table 9). Fifty one percent of growers that manage 1000 or more acres reported soybean yields between 50 and 59 bu/acre; whereas only 27.7% of growers with less than 100 acres yielded between 50 and 59 bu/acre. Conley et al. (5) reported that large acreage growers were likely to scout their soybean field more regularly, apply a foliar fungicide to soybean, apply their own pesticides, and possess a more thorough understanding of the pest complex that they must manage. This suggests that large acreage growers may manage their soybean crop better than smaller acreage growers. Table 9. Farm size impact on grain yield.
x Chi-square = 86.431; df = 12; P ≤ 0.001; n = 1216. Crop row spacing also impacted yield (P ≤ 0.0001). Independent of farm size, yield was greater in rows spaced 11 to 20 inches when compared to ≤ 10- and ≥ 21-inch row spacings. Yield was 51.4, 49.7, and 48.7 bu/acre, respectively. These yield results are likely confounded by the disparity in yield among farm operation sizes and the preferred row spacing of the different farm sizes. These pooled yield results however, may partially explain the perception among growers that row spacing yield differences do not exist. The results of this survey define distinct similarities and differences among growers of different operation size. Large acreage growers (≥ 1000 acres) were more likely to plant soybeans in rows spaced 11 to 20 inches, reduce seeding rates, plant earlier, and have higher yields. Large acreage growers were also more likely to own a yield monitor, conduct on-farm research, use a computer, and routinely use the internet. Independent of farm size growers select varieties based on yield potential, presence or absence of the glyphosate trait, and disease resistance characteristics. Growers also prefer print materials, field days, and local meetings over large district meetings. All growers rank web-based materials as the least desirable method of information delivery. Our results suggest clear differences in the specific research and educational needs among growers of different operational size. It is critical that these needs are defined and the appropriate information delivered to improve the production systems and economic viability of these distinct grower groups. Acknowledgments The authors would like to thank the Indiana Soybean Board for funding this research and the Indiana Agricultural Statistics Service for their cooperation in developing, distributing, and tabulating the results of this survey. (Purdue ARP Manuscript Number 2006-18029.) Literature Cited 1. Aref, S., and Pike, D. R. 1998. Midwest farmers perceptions of crop pest infestation. Agron. J. 90:819-825. 2. Bourgeois, L., Morrison, I. N., and Kelner, D. 1997. Field and producer survey of ACCase resistant wild oat in Manitoba. Can. J. Plant Sci. 77:709-715. 4. Czapar, G. G., Currey, M. P., and Wax, L. M. 1997. Grower acceptance of economic thresholds for weed management in Illinois. Weed Technol. 11:828-831. 5. Heatherly, R. G., and Elmore, R. W. 2004. Managing inputs for peak production. Pages 451-525 in: Soybeans: Improvement, Production, and Uses. ASA, CSSA, SSSA, Inc., Madison, Wisconsin. 6. Krupke, C. H., Obermeyer, J. L., and Bledsoe, L. W. 2005. Soybean aphid. Perdue Ext. Publ. No. E-217-W, Purdue Univ., West Lafayette, IN. 7. Kuchler, F., Duffy, M., Shrum, R. D., and Dowler, W. M. 1984. Potential economic consequences of the entry of an exotic fungal pest: The case of soybean rust. Phytopathology 74:916-920. 8. Marra, M. C., Piggot, N. E., and Carlson, G. A. 2004. The net benefits, including convenience, of Roundup Ready soybean: Results from a national survey. Tech. Bull. 2004-3. Center for Integrated Pest Manag., Nat. Sci. Found., Washington, DC. 9. Pivonia, S., and Yang X. B. 2004. Assessment of the potential year-round establishment of soybean rust throughout the world. Plant Dis. 88:523-529. |
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