February 1999 // Volume 37 // Number 1 // Research in Brief // 1RIB3

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Identifying Effective and Efficient Methods To Educate Farmers about Soil Sampling

This study compares three educational methods, (a) a slide set, (b) a pamphlet, and (c) a combination of slide set and pamphlet in identifying the most effective and efficient method of the three for educating 99 farmers about soil sampling. Both immediate and delayed post-tests were used in assessing attitudes about soil sampling, gains in immediate and long term knowledge, and preferences for educational methods. Farmers' attitudes did not adversely impact learning. However, farmers did lack prerequisite skills to correctly perform soil sampling. All three Extension methods were found to be effective with the pamphlet being the most efficient.

Robert N. King
Agriculture Program Leader
Cornell Cooperative Extension, Monroe County
Rochester, New York
Internet address: rking@monroecc.edu


As budgets become tighter and resources dwindle, identifying effective and efficient instruction becomes increasingly important (Houghton, Arrington, & Bradshaw, 1994). To identify effective and efficient instruction, answers to specific questions must be resolved about the methods and media that should be used. Effectiveness involves a criterion measure that attempts to assess the achievement of predetermined objectives. Effectiveness usually concentrates on improving or achieving an outcome with a given level of resources. Efficiency usually involves a quantitative assessment of the resources used in obtaining a given outcome and focuses on reducing resources (inputs) for a given outcome (output) (Levin, 1983).

A key component to identify effectiveness and efficiency of instruction is determining the best pacing method for providing instruction. Pacing is a concerted effort that encourages learners to progress through instruction in either a group (group-paced) or individual (self-paced) process (Shale 1987). Pacing methods are the time-dependent methods used by a learner to work through information. Generally, self-paced methods are as effective as group-paced methods for adult learners. Moreover, self-paced methods are more flexible since they encourage open entry and exit policies that allow learners to adjust and accommodate other commitments (Watson, 1990).

Purpose and Objectives

The purpose of this study was to identify effective and efficient pacing methods to educate Pennsylvania farmers about soil sampling. Specific objectives were to: (a) determine the attitudes of farmers concerning soil testing and sampling; (b) determine if there was a change in immediate and long term level of knowledge of subjects after exposure to either a slide set, a pamphlet, or a slide set and pamphlet; (c) identify the costs of using these methods and media; and (d) determine attitudes and preferences of subjects concerning methods and media to learn about soil sampling.

Research Procedures

A quasi-experimental, non-equivalent, control-group design that used immediate and delayed post-tests compared three treatments: (1) a slide set (X1, group-paced); (2) a pamphlet (X2, self-paced); and (3) a slide set and pamphlet (X3, group- and self-paced). The population (N=99) consisted of farmers in south central Pennsylvania who attended county Extension meetings and were on county Extension mailing lists.

Three intact groups were chosen based on similarities of seven key variables: age, educational level, farm income, employment status, crop types, type of farm, and acreage. Subject selection was also based on the availability of groups and mailing lists. All subjects were self-selected and treatments were not randomly assigned. The instrumentation was based on previous survey and quasi-experimental research. Attitudes toward soil testing and sampling were measured by Likert-type scales and was based on previous research conducted by King, Rollins, and Yoder (1994). Attitudes and preferences concerning information sources were measured by Likert-type scales, and was adapted from previous research conducted by Smith, McGhan, and Miller (1989).

The knowledge section used multiple choice questions and was developed by the researcher and an Extension specialist from the Agronomy Department at The Pennsylvania State University. Sixteen questions assessed a subject's knowledge of soil sampling. Instrumentation was reviewed for content and face validity by researchers and faculty at the university. Using the Kuder Richardson 21, a post-hoc reliability score of .75 was achieved for 96 subjects on 10 multiple choice questions.


All subjects were male farmers with at least a high school education. Farmers in the slide and pamphlet group had less farming experience and tended to be younger than farmers in either the slide or pamphlet groups (see Table 1). Farmers in all three intact groups were similar with respect to the type of animal operations, crops grown, and acreage owned or rented. For all three intact groups, the majority (80%) of farmers relied on the farm as their primary place of employment.

Table 1
Variable by Treatment Group
f Median Mean SD SE
   Slide and Pamphlet 19 38.0 38.58 10.41 1.96
   Slide 39 48.0 47.26 14.26 2.28
   Pamphlet 38 43.5 48.84 11.03 1.79
Years farming
   Slide and Pamphlet 18 14.5 15.56 8.35 1.96
   Slide 36 25.0 27.75 14.05 2.34
   Pamphlet 38 25.0 26.90 10.98 1.98
Acres Owned
   Slide and Pamphlet 14 100.0 135.82 144.46 35.03
   Slide 33 90.0 134.48 169.69 28.68
   Pamphlet 38 141.5 185.4 131.78 21.90
Acres Rented
   Slide and Pamphlet 14 89.0 145.70 220.70 53.37
   Slide 27 33.0 118.30 157.50 26.25
   Pamphlet 30 75.0 112.76 140.16 22.74

Attitudes and Background of Farmers

All farmers indicated some knowledge and positive attitudes about soil sampling and testing. Before receiving the treatment (instruction), farmers in each intact group indicated confidence in taking a soil sample. After the instruction, farmers in all three intact groups indicated that their level of confidence in collecting a soil sample had not changed (Table 2). The majority of farmers (50-60%) in all three intact groups possessed soil probes and had performed soil sampling within the last year. Over 80% of the farmers in all three intact groups who did not own a soil probe indicated they would take soil samples if a probe or auger was made available.

Table 2 Variable by Treatment Group
f Median Mean SD SE
How confident are you with taking a soil sample?
   Slide and Pamphlet 21 4 3.71 0.96 0.21
   Slide 36 4 3.70 0.82 0.14
   Pamphlet n/a n/a n/a n/a n/a
How confident are you with taking a soil sample?
   Slide and Pamphlet 20 4 4.15 0.37 0.08
   Slide 36 4 3.91 0.81 0.13
   Pamphlet 39 4 3.92 0.96 0.15
Delayed Post-test
How confident are you with taking a soil sample?
   Slide and Pamphlet 11 4 4.27 0.79 0.24
   Slide 28 4 3.96 0.74 0.14
   Pamphlet 24 4 4.00 0.98 0.20
How confident are you with the results of a soil test?
   Slide and Pamphlet 21 5 4.60 1.50 0.33
   Slide 37 4 3.94 0.78 0.13
   Pamphlet 38 4 4.24 0.54 0.09
Scale: 1 = Not at all confident
3 = Skeptical
5 = Very Confident

Gains in Immediate and Delayed Level of Knowledge

Only the two intact groups receiving group-paced instruction were given pre-tests. Both groups' pre-test scores were approximately 50% less (8 out of 16 correct) than each of the groups' immediate or delayed post-test scores (12 out of 16 correct). Pre-test scores indicated that these farmers lacked prerequisite skills and knowledge to correctly perform soil sampling (see Table 3).

Table 3 Summary of Test Scores
f Mean SD
Slide and Pamphlet
   Pre-test 19 8.31* 2.85
   Post-test 19 13.52 1.61
   Delayed post-test 11 13.91 1.81
   Pre-test 34 8.82* 2.31
   Post-test 32 13.75 2.54
   Delayed post-test 28 12.32 3.09
   Pre-test n/a n/a n/a
   Post-test 36 11.81 2.89
   Delayed post-test 24 12.33 2.68
*T-test: groups did not significantly different at p .05 (F=.49; df 1/51)
**One-way ANOVA: groups not significantly different at p .05 (F=2.87; df 5/144)
Barlett's test yielded a X2 of 2.148 (p .057) indicating homogeneity among variances

After exposure to the instructional method, all three intact groups greatly improved their post-test and delayed post-test scores about soil sampling. The results of a one-way ANOVA on the immediate and delayed post-test scores for all intact groups did not show significant differences between groups (F=2.87; df 5/144; p< .05). The majority of farmers in all three intact groups retained facts and concepts for at least a two week period after exposure to instruction.

Costs of Methods and Media

The costs of instruction were based on actual and estimated costs established by the Pennsylvania Department of Education. Treatment X1 (slide) cost $1,557 and treatment X2 (pamphlet) cost $1,213 to develop, design, and implement. Treatment X3 (slide and pamphlet) was estimated to cost $2,560 to develop, design, and implement. The costs to design, develop, and implement the instruction associated with these three treatments indicated that the pamphlet version was the least costly to produce.

Preferences for Methods and Media

Based on group means, all three intact groups indicated that their educational program: (a) was attractive; (b) was not too difficult; (c) made them want to learn; (d) was interesting; (e) was convenient to use; (f) provided a good way to learn, (g) did not take too much time; (h) related well to their farm; and (i) used good examples. However, farmers preferred group-paced instruction rather than self-paced instruction to learn about soil sampling. All three intact groups indicated that an Extension meeting, a workshop with a pamphlet, and the one-on-one with an agent were their top three choices for learning about soil sampling. Farmers in all three intact groups also indicated that such information should be available at: (a) an Extension office; (b) a fertilizer dealer; or (c) a telephone number to call so information can be mailed. Overall, the three educational programs were relevant, appropriate, easy to understand, and maintained a subject's interest.


Even though farmers had confidence in their ability to collect a good soil sample before receiving instruction, they still lacked the necessary skills and knowledge to do it correctly.

The Extension methods (slide set and/or pamphlet) used in this study are effective for providing facts and concepts concerning soil sampling. Learning and retention of facts and concepts in both immediate and delayed knowledge were similar for all methods. Consequently, the pamphlet (self-paced) is the most efficient method.

An instructional solution exists to improve a farmer's ability to correctly perform soil sampling. This study confirms other research suggesting that errors associated with soil test results are primarily due to "poor" soil sampling procedures (Walsh & Beaton, 1973; Ferguson, 1994; Wanzel, 1995). This study also confirms that a large amount of variance in learner achievement is due to a deficient prerequisite background (Bloom, 1971, 1976).


Despite farmers indicating confidence in their abilities to perform soil sampling, soil tests should include a detailed explanation of soil sampling procedures. Extension educators should consider placing more emphasis on basic knowledge and skills to ensure appropriate learning of both old, current, and new subject matter.

The subject matter need not be "new" or "novel" to maintain interest or prompt learning. Extension educators should consider the relevance of any subject matter when deciding whether or not to include it in an educational program.

Farmers indicated a preference for Extension meetings, workshops with a pamphlet, and one-on-one instruction. Therefore, Extension programs using pamphlets and meetings should be continued. Ultimately, the choice of methods should be based on cost, relevance of the subject matter, and the needs of the learner. This information should continue to be provided by local Extension offices, fertilizer dealers, and/or by a telephone number to call so information can be mailed. According to Bowen (1986) and Ubadigbo & Gamon (1988), agribusiness is likely to support such an educational program.


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