Final Report for GNC04-029

Transferring Information from Research lab to Farm Field: Evaluation of On-Farm Soil Quality Tests Kits for Grower Use in Sustainable Strawberry Production

Project Type: Graduate Student
Funds awarded in 2004: $9,988.00
Projected End Date: 12/31/2006
Grant Recipient: Iowa State University
Region: North Central
State: Iowa
Graduate Student:
Faculty Advisor:
Gail Nonnecke
ISU Horticulture Department
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Project Information

Summary:

The use of a soil quality test kit at two Iowa fruit and vegetable farms shows that grower attitudes toward the usefulness of the kit can be enhanced by having growers use the kit in their fields and by seeing its effectiveness for themselves. The kits were effective at measuring changes in field soil based on changes in crop management, time of year, and climatic conditions. These results enhanced the grower’s attitude of using soil kits by showing upward and downward trends in soil quality based on soil management decisions made by the growers over the course of a year. Based on the results of a questionnaire mailed to Iowa small fruit growers in 2005 and 2006, awareness of the soil quality test kit and soil quality concepts increased over the period. Interest in using a field test kit to monitor soil conditions to help improve crop productivity remained high. Cooperating strawberry growers felt that the information provided by the soil quality test kit was useful, but they were uncomfortable taking and interpreting the measurements themselves. The growers suggested that the kit would be practical for people with more expertise in the area of soil quality, such as extension personnel or qualified crop consultants.

Introduction:

Physical and chemical analyses of field soil have been proven useful for monitoring nutrient status in strawberry production. However, these analyses can be improved by measuring biological properties in addition to physical and chemical properties. Biological indicators in soil are very sensitive to changes in their environment and can be an early indicator of soil quality trends (Rice et al., 1996). Thus biological properties such as soil respiration and microbial C and N have the potential to be good indicators of soil quality (Kennedy and Papendick, 1995). The soil quality data collected can be quantified and used as a component of an overall soil quality index. The soil quality index can be used by strawberry growers to compare different soil management practices or to monitor changes in soil quality in the same field over time. Several mathematical formulas have been proposed for this purpose (Doran and Parkin, 1996; Gregorich et al., 1994; Karlen et al., 1997; Kennedy and Papendick, 1995; Parr et al., 1992; Seybold et al., 1997; Singh et al., 1992) and we will base our model on these. In order to bring the soil quality concept to a wider audience the USDA-ARS developed the Soil Quality Test Kit to be used as an assessment tool for managing land in a sustainable way while maintaining profitability (Andrews et al., 2002; Ditzler and Tugel, 2002; Wander et al., 2002). The kit was designed to be used by USDA personnel and landowners and incorporates biological indicators of soil quality in the soil quality analysis.

Project Objectives:

This project was initiated to familiarize Iowa fruit growers with a method to improve their ability to monitor soil quality trends in a relatively quick and cost-effective manner and was composed of two parts: Part 1) On-farm research trial with strawberry growers, and Part 2) A controlled, randomized and replicated research experiment carried out at an ISU research station.

The objectives for part one: 1) assist two commercial strawberry growers in the use of a soil quality test kit on their farm, collect and interpret soil quality data, and obtain their perspective on its usefulness, 2) present state and regional fruit growers with information and research results about soil quality testing, 3) conduct soil quality interest survey of Iowa small fruit growers.

The objectives for part two: 1) Examine the influence of four weed management systems in strawberry production on the physical, chemical, and biological indicators of soil quality, 2) Combine physical, chemical, and biological soil properties into a soil quality index for strawberry production, 3) Determine and correlate the impact of weed management systems and a proposed soil quality index on weed and strawberry plant growth and development.

Cooperators

Click linked name(s) to expand
  • Dean Henry
  • Gail Nonnecke
  • Norman Schettler

Research

Materials and methods:

The study consisted of two parts. Part one was conducted at the farms of two Iowa strawberry growers, one in central Iowa and one in western Iowa, and at the Iowa State University (ISU) Horticulture Research Station near Ames, IA. Part two was also carried out at the ISU Horticulture research station.

Part One: Soil quality test kit evaluation at grower farms (Carroll and Nevada, Iowa) and at ISU Horticulture Research Station.
Soil quality test kit data were collected in established commercial crop fields chosen by each grower. All treatments received conventional production practices, including herbicide and synthetic fertilizer applications. Soil quality test kit data were collected from two fields at each farm and consisted of collecting three sub-samples per site. Samples were collected from in-row locations. ISU personnel assisted growers with data collection. The following data were collected according to procedures described in the Soil Quality Test Kit Guide (1999); soil respiration, water infiltration, bulk density, electrical conductivity, pH, earthworm count, and soil physical observations. Soil quality test kit data were collected at the ISU research station in the herbicide treatment plots of a newly established strawberry field (described below). Data were collected in July and October of 2004 and 2005.

Part Two: Effects of four weed management strategies on soil quality at ISU Horticulture Research Station, Ames, IA.
The experiment consisted of four weed management treatments in a randomized complete block experimental design with four replications. The treatments were: 1) killed cover crop of hairy vetch/rye; 2) compost + corn gluten meal + straw mulch treatment; 3) conventional herbicide treatment; and 4) methyl bromide soil fumigation treatment. The experimental plots were 30 x 30 feet (9.1 x 9.1 m). Plots contained seven rows of strawberries spaced 42 inches (1.1 m) apart, center-to-center. The two outside rows of each plot served as guard rows. Dormant crowns of ‘Jewel’ Junebearing strawberries were planted in early May 2004, at a spacing of 18 inches (45.7 cm) between plants in the row. Weed and strawberry data collected included weed species, number, biomass, and percentage weed cover (in three randomly placed 0.25 m2 quadrats/row/plot), percentage matted-row fill, leaf nutrient analysis, plant shoot and root dry weight, total and marketable strawberry yield, berry number, and average berry weight.

Experimental methods at I.S.U Horticulture Research Station plots:
Site Layout
Previously, the site had matted-row ‘Honeoye’ strawberry production from 1998 – 2002. In 2003, the site was fallow plowed until the establishment treatments were applied in September. The soil type is a Clarion loam; a fine-loamy, mixed, superactive, mesic Typic Hapludolls, in a Clarion-Webster-Nicollet association. Experimental plots were separated from the other treatment plots by an alleyway of common Kentucky bluegrass (Poa pratensis) that was at least ten feet (3.1 m) wide on each side. Alleyways were seeded in September, 2003.

The five center strawberry rows provided sufficient matted-row production for soil sampling and plant growth and development data collection. Plants were grown and maintained in matted-row production as described by Pritts and Handley (1998). Plot was to be irrigated to supplement the equivalent of one inch water/week. Insects and diseases were controlled as recommended in the Iowa Commercial Small Fruit and Grape Spray Guide (Gleason et al., 2004).

Soil Sampling
Soil samples were collected from all plots at depths of 0 – 6 inches (0 – 15.2 cm) and 6 – 12 inches (15.2 – 30.5 cm) in September, 2003, to establish baseline reference values that ensuing soil data measurements were compared against. Five soil cores were taken on a NW to SW transect in each plot and combined to make one sample. The soil probe tip was 2.1 cm in diameter. In addition to weed, strawberry yield and plant growth measurements previously mentioned, soil samples were taken for physical, chemical, and biological properties at randomly assigned points within the strawberry row in each treatment plot in April, 2004, September, 2004 and September, 2005. Physical soil properties that were measured include soil texture, soil bulk density, percent aggregate stability (Arshad et al., 1996), water infiltration, water content, water holding capacity (Lowery et al., 1996), water retention characteristics (Klute, 1986), and soil temperature. Chemical soil properties to be measured include total organic C & N (Nelson and Sommers, 1982), pH, electrical conductivity (Smith and Doran, 1996), and mineral N (NH4 & NO3), P, & K (Allan and Killorn, 1996). Soil biological properties to be measured include microbial biomass C (Horwath and Paul, 1994), potentially mineralizable N (Drinkwater et al., 1996), soil respiration (Parkin et al., 1996), microbial biomass C/total organic C ratio, respiration/biomass ratio (Visser and Parkinson, 1992), and earthworm number (Blair et al., 1996).

Experimental treatments: The four treatments were chosen based on the need to model our weed management experiment on both actual strawberry production practices as well as on modifications of standard practices. Also, in order to develop a soil quality index that can be applicable to most strawberry growers, we needed to use standard production practices. The hairy vetch and rye cover crop treatment that was killed with a knife roller is an example of a weed management technique that has shown promise in other areas of the United States and has the potential to reduce the use of herbicides while also improving soil structure and fertility. Corn gluten meal (CGM) has shown promise as a natural preemergence weed control product and provides approximately 10 % N by weight. We believe that the combination of CGM and straw mulch for weed control and compost to improve soil structure and fertility could be another effective non-chemical weed management system. Soil fumigation with methyl bromide has been a standard practice in many parts of the United States for many years. We would like to better understand the impact of soil fumigation on physical, chemical, and biological properties of soils. Management of weeds with herbicides is the most common technique, so it has the potential to be the most useful experimental treatment in terms of applying what we learn in the experiment to on-farm practices.

Treatment 1) Living: A cover crop mixture of hairy vetch (Vicia villosa) at 40 lb/acre, and cereal rye (Secale cereale) at 30 lb/acre, was planted on September 18, 2003 and was killed with a knife roller in late April 2004 (Year one). In fall 2004, a cover crop mixture of cereal rye was sown in the fall between strawberry rows and killed with a roller for use as a mulch in April 2005. In 2005 and 2006, after fruit harvest and renovation, sorghum-sudangrass hybrid (Sorghum bicolor (L.) Moench × Sorghum Sudanese (P.) – Stapf. ‘Greentreat IV’) was be established at the rate of 136 lb/acre (152 kg/ha) between strawberry rows to serve as a living mulch. When living mulch reached a height of approx. 30 inches (76.2 cm) it was cut to a height of approx. 5 inches (12.7 cm) and allowed to re-grow. Cutting of living mulch was repeated until frost.

Treatment 2) Compost + corn gluten meal + straw mulch: Composted, finished hog manure and corn gluten meal to obtain the equivalent of 50 lbs N/acre at planting and 50 lbs N/acre in August of year one. Straw was be applied as a soil mulch within rows to a shallow depth (2 in, 5.2 cm) in year one; Composted, finished hog manure and corn gluten meal to obtain the equivalent of 50 lbs N/acre at renovation and 50 lbs N/acre in August (floral initiation application) of year two.

Treatment 3) Fumigation (and herbicide applications as needed): Spring 2004 – Preplant fumigation with methyl bromide. Postemergence herbicides if needed late in season Poast EC (Sethoxydim 1.lb. a.i./gal @ 1.0 to 2.5 pt. plus 2 pt. of crop oil concentrate in 25 gal. water/acre) when grasses reach a few inches tall. Wick applications of glyphosate throughout season as needed. Spring 2005 – DCPA immediately after after renovation. Formula 40 (2, 4-D triisopropanolamine salt plus 2,4-D dimethylamine salt) @ 1.0 – 1.5 qt. in 25-50 gal of water/acre at renovation. Wick applications of glyphosate throughout season as needed.

Treatment 4) Herbicides alone (no fumigation) Spring 2004 – Preplant, Preemergence Dacthal W-75 (DCPA 75% a.i.) spray in Late April 2004 @ 9lbs/acre (8.4 kg/ha a.i.) (PM-1375). Repeat in June after hoeing or cultivating. Wick applications of glyphosate throughout season as needed. Spring 2005 – DCPA immediately after renovation. Formula 40 (2, 4-D triisopropanolamine salt plus 2,4-D dimethylamine salt) @ 1.0 – 1.5 qt. in 25-50 gal of water/acre at renovation. Wick applications of glyphosate throughout season as needed

Literature Cited

Allan, D.L. and R. Killorn. 1996. Assessing soil nitrogen, phosphorus, and potassium for crop nutrition and environmental risk, p. 187-201. In: J.W. Doran and A.J. Jones (eds.). Methods for assessing soil quality. SSSA Special Publication 49. Soil Sci. Soc. Amer., Madison, WI.
Andrews, S.S., J.P Mitchell, R. Mancinelli, D.L. Karlen, T.K. Hartz, T.K., Horwath, W.R. Pettygrove, G. S. Scow, K.M. Munk, and S. Daniel. 2002. On-Farm Assessment of Soil Quality in California’s Central Valley. Agron J 94:12-23.
Arshad, M.A., B. Lowery, and B. Grossman. 1996. Physical tests for monitoring soil quality, p. 123-141. In: J.W. Doran and A.J. Jones (eds.). Methods for assessing soil quality. SSSA Special Publication 49. Soil Sci. Soc. Amer., Inc. Madison, WI.
Blair, J.M., P.J. Bohlen, and D.W. Freckman. 1996. Soil invertebrates as indicators of soil quality. In: J.W. Doran and A.J. Jones (eds.). Methods for assessing soil quality. SSSA Special Publication 49. Soil Sci. Soc. Amer., Inc. Madison, WI.
Ditzler, C.A. and A.J. Tugel. 2002. Soil quality field tools: Experiences of USDA-NRCS soil quality institute. Agron. J. 94:33-38.
Doran, J.W. and T.B. Parkin. 1996. Quantitative indicators of soil quality: a minimum data set. In: Doran, J.W. and A.J. Jones (eds.) Methods for assessing soil quality. SSSA Special Publication 49. SSSA, Inc. Madison, WI.
Drinkwater, L.E., C.A. Cambardella, J.D. Reeder, and C.W. Rice. 1996. Potentially mineralizable nitrogen as an indicator of biologically active soil nitrogen, p. 217-229. In: J.W. Doran and A.J. Jones (eds.). Methods for assessing soil quality. SSSA Special Publication 49. Soil Sci. Soc. Amer., Inc. Madison, WI.
Gleason, M.L., D.R. Lewis, P.A. Domoto, and G.R. Nonnecke. 2003. Iowa commercial small fruit and grape spray guide. Iowa State Univ. Ext. Bul. PM-1375 (In press).
Gregorich, E.G., M.R. Carter, D.A. Angers, C.M. Monreal, and B.H. Ellert. 1994. Towards a minimum data set to assess soil organic matter quality in soils. Can. J. Soil Sci. 74(4):367-385.
Horwath, W.R. and E.A. Paul. 1994. Microbial biomass, p.753-773. In: R.W. Weaver, et al., (eds) Methods of soil analysis. Part 2. Microbiological and Biochemical properties. Soil Sci. Soc. Amer. Madison, WI.
Karlen, D.L., M.J. Mausbach, J.W. Doran, R.G. Cline, R.F. Harris, and G.E. Schuman. 1997. Soil quality: a concept, definition, and framework for evaluation. Soil Sci. Soc. Am. J. 61(1).
Kennedy, A.C. and R.I. Papendick. 1995. Microbial characteristics of soil quality. J. Soil Water Cons. 50:243-248.
Klute, A. 1986. Water retention: laboratory methods, p. 635-662. In: A. Klute (ed.) Methods of soil analysis. Part 1. 2nd ed. Agron. Monogr. 9. ASA and Soil Sci. Soc. Amer., Madison, WI.
Lowery, B, W. Hickey, M. Arshad, and R. Lal. 1996. Soil water parameters and soil quality, p. 143-155. In: J.W. Doran and A.J. Jones (eds.). Methods for assessing soil quality. SSSA Special Publication 49. Soil Sci. Soc. Amer., Inc. Madison, WI.
Nelson, D.W. and L.E. Sommers. 1982. Total carbon, organic carbon, and organic matter, p. 539-579. In: A.L Page, R.H. Miller and D.R. Keeney (eds.). Methods of soil analysis Part 2. Chemical and Microbiological Methods. 2nd ed. Agronomy Series No. 9. Amer. Soc Agron. and Soil Sci. Soc. Amer., Madison, WI.
Parkin, T.B., J.W. Doran, and E. Franco-Vizcaino. 1996. Field and laboratory tests of soil respiration, p. 231-245.
Parr, J.F., R.I. Papendick, S.B. Hornick, and R.E. Meyer. 1992. Soil quality: attributes and relationship to alternative and sustainable agriculture. Am. J. Altern. Agr. 7:5-11.
Pritts, M. and D. Handley. 1998. Strawberry production guide for the northeast, midwest, and eastern Canada. N.E. Reg. Agr. Eng. Serv., Ithaca, N.Y.
Rice, C.W., T.B. Moorman, and M. Beare. 1996. Role of microbial biomass carbon and nitrogen in soil quality. In: Doran, J.W. and A.J. Jones (eds.) Methods for assessing soil quality. SSSA Special Publication 49. SSSA, Inc. Madison, WI.
Seybold, C.A., M.J. Mausbach, D.L. Karlen, and H.H. Rogers. 1997. Quantification of soil quality. In: B.A. Stewart and R. Lals (eds.). Proceedings from an international symposium on carbon sequestration in soil. Adv. Agron. Lewis Publ.
Singh, K.K., T.S. Colvin, D.C. Erbach, and A.Q. Mughal. 1992. Tilth index: An approach to quantifying soil tilth. Trans. ASAE. 35(6):1777-1785.
Smith, J.L. and J.W. Doran. 1996. Measurement and use of pH and electrical conductivity for soil quality analysis, p.169-185. In: J.W. Doran and A.J. Jones (eds.). Methods for assessing soil quality. SSSA Special Publication 49. Soil Sci. Soc. Amer., Inc. Madison, WI.
USDA-ARS/NCRS. 1999. Soil quality test kit guide.
Visser, S. and D. Parkinson. 1992. Soil biological criteria as indicators of soil quality: Soil microorganisms. Amer. J. Alt. Agr. 7:33-37.
Wander, M.M., G.L. Walter, T.M. Nissen, G.A. Bollero, S.S. Andrews, and D.A.Cavanaugh-Grant. 2002. Soil Quality: Science and Process. Agron. J. 2002 94: 23-32.

Research results and discussion:

Part One: Soil quality test kit evaluation at grower farms (Carroll and Nevada, Iowa) and at ISU Horticulture Research Station.

Objective 1. Assist two commercial strawberry growers in the use of a soil quality test kit on their farm, collect and interpret soil quality data, and obtain their perspective on its usefulness.

Over the course of two years (2004, 2005) each grower was visited on four occasions. Each grower chose the fields where the tests were to be conducted and was instructed on the use of the soil quality test kit and interpretation of results. Each grower was assisted by Iowa State University personnel in the collection of field data. In order to show how the soil quality test kit could be used to measure changes in soil over time the test kit was used to collect data at the same field site in the fall of 2004 and again after one year. To show how the soil quality test kit could be used to compare soils from two different fields at the same time of year data were collected from two different field sites on the same day. After one year data were compiled by the graduate student and each grower was visited and interviewed to compare their initial and final impressions about the usefulness of the test kit.

One site was in Central Iowa and the other site was in West-central Iowa. Each field had three sample sites, north, middle, and south.

Comparisons made over time. Incorporation of large amounts of organic matter in the Central Iowa farm research field in 2005 showed that the middle and north sample sites had reduced bulk density, volumetric water content, and increased water-filled pore space. The south and north sites showed increased soil respiration. At the West-central Iowa farm site, where no amendments had been made since the previous year, bulk density decreased in the east and middle sample sites, soil respiration decreased sharply overall, and infiltration rate was highly variable when Fall 2004 and 2005 measurements are compared.

Comparisons made between soil management.
At the Central Iowa farm, a field recently amended and cultivated was compared with a field that was planted to a perennial crop two years before. Bulk density was lower in the recently tilled field, but other measurements were similar or highly variable. At the West-central Iowa farm a field that had been in strawberries for four years was compared to a field that also had been in strawberries for four years, but that had recently been plowed and cultivated. Observations showed that measurements from the east and middle sample sites had slightly increased bulk density, water holding capacity, soil respiration, and infiltration rate. Samples from the west site showed the opposite trends.

Two or more years of data are required to see trends in soil quality. However, these results show that after one year the soil quality test kit measurements revealed changes taking place in the soil due to soil management. The variability of the data shows the importance of taking multiple samples and also in choosing the location of sampling sites.

After working with the soil quality test kit for one year, the grower cooperators saw the benefits of using such a test kit on their farm. The cooperators stated that in their opinion other growers might need to see a direct economic benefit from using the kit before it would be adopted. Although the kit was designed to use relatively simple and low tech methods for taking measurements, the user must progress through learning the correct practices to collect samples appropriately. Also, the growers mentioned that they did not feel they had the technical background to accurately interpret the results. These observations indicate that the growers believe that the soil quality test kit is a welcome and useful tool, but that most growers would rather have the tests interpreted by someone with more expertise. If growers were to interpret the results, more training would be necessary.

Objective 2. Present state and regional fruit growers with information and research results about soil quality testing.

During the period from July 2004 through August 2006, 14 presentations were given to fruit and vegetable growers that included information about the soil quality concept, research results from our trials with growers, and demonstrations in the use of the soil quality test kit. Presentations were given in Iowa, Missouri, Nevada, and Wisconsin with attendance at these meetings totaling approximately 3,180. Eight publications featuring our soil quality research or survey data and our work with the soil quality test kit were published. Most of the reports are available online to a worldwide audience.

Objective 3. Conduct soil quality interest survey of Iowa small fruit growers.

In order to measure initial grower interest in the soil quality concept a questionnaire was mailed in March 2005 to all members of the Iowa Fruit and Vegetable Growers Association who indicated they grow berry crops. Of the 113 deliverable surveys that were mailed 29 were completed and returned for a 26 % return rate. The postcard-sized survey contained 12 short questions designed to assess the current level of awareness and interest in soil quality and the soil quality test kit among Iowa berry growers. The survey also included questions about grower soil management practices.
Growers were instructed to circle Yes, No, or Don’t Know for the following questions:

1. Have you heard the term “Soil Quality”? Y N DK

2. Have you heard the term “Soil Quality Test Kit”? Y N DK

3. Have you heard of the USDA Soil Quality Institute? Y N DK

4. Do you believe that soil erosion ever reduced your berry crop yield? Y N DK

5. Do you believe that soil compaction ever reduced your berry crop yield? Y N DK

6. Would you say that you have healthy soil in most berry crop fields? Y N DK

7. Do you consider the health of your soil when making berry crop
management decisions, e.g., tillage practices, type of fertilizer used? Y N DK

8. Do you add compost, manure, or other organic materials to your fields? Y N DK

9. Do you believe that organisms in the soil are important for berry yield? Y N DK

10. Do you believe that your fields are producing at their maximum yield? Y N DK

11. Do you believe that berry crop yields could be improved by monitoring the
soil’s health with a field test kit? Y N DK

12. Do you believe that berry growers would be interested in learning about
a soil quality test kit that would help monitor the health of their soil? Y N DK

The results of the initial survey (2005) revealed that although 69 % of these Iowa small fruit growers had heard the term ‘Soil Quality,’ 66 % had not heard of the soil quality test kit and 86 % had not heard of the USDA Soil Quality Institute. Most of the growers believed that they have healthy soils, considered the health of their soil when making crop management decisions, and about one half added compost, manure, or other organic materials to their fields. Most were aware of the importance of soil microorganisms to crop yield (88 %), and also were open to the idea of monitoring the quality of their soil with a soil quality test kit. Overall, the initial survey of 2005 showed that these Iowa berry growers were somewhat aware of the impact that their production practices were having on the quality of their soil, but were not aware that they could monitor the quality of their soil with a test kit. These growers also showed interest in learning how the soil quality test kit could be used to help improve their crop yields.

A second, final survey was mailed to growers in April 2006 to assess changes in grower awareness of the soil quality concept and the soil quality test kit. The second survey was identical to the initial survey used in 2005. Thirty percent of the questionnaires were returned representing an increase of fifteen percent compared with the number of responses returned in 2005. Twenty-one growers who did not return questionnaires in 2005 returned questionnaires in 2006.
In order to assess changes in grower awareness of soil quality issues over time it was necessary to compare responses only from growers who returned questionnaires in both 2005 and 2006. Forty-five percent of growers that returned questionnaires in 2005 returned questionnaires in 2006. This equates to a response rate of 12 % from all 113 growers who received questionnaires in 2005 and 2006. Therefore, the following percentages relate to the 13 growers that returned questionnaires in both years.

1. Have you heard the term “Soil Quality”?

All growers claimed to have heard the term ‘soil quality’ in 2006, which represents an 8.3 % increase compared to 2005.

2. Have you heard the term “Soil Quality Test Kit”?

Sixty-two percent of growers were familiar with the term ‘Soil Quality Test Kit’ in 2006. This represents a 100% increase compared with 2005.

3. Have you heard of the USDA Soil Quality Institute?

In 2005, one grower had heard of the USDA Soil Quality Institute and in 2006 three growers reported that they had heard of the USDA Soil Quality Institute (200 % increase).

4. Do you believe that soil erosion ever reduced your berry crop yield?

Eighty-five percent of growers reported that they believed that soil erosion had not ever reduced their berry crop yield. The number was the same as in 2005, however, two growers changed their switched their position on the 2006 questionnaire.

5. Do you believe that soil compaction ever reduced your berry crop yield?

In 2006, 46 % of growers reported they believed soil compaction had ever decreased berry crop yield compared to 54 % in 2005. This reflects the uncertainty of growers about this issue as seven changed their position from 2005 including a 50 % increase in the number of growers that answered ‘Don’t Know’ in 2006.

6. Would you say that you have healthy soil in most berry crop fields?

Seventy-seven percent of growers in both 2005 and 2006 believe that they have healthy soil in their berry crop fields although two growers changed their reply to ‘Don’t Know’ in 2006, which may indicate growth in uncertainty with the issue of what defines ‘healthy soil.’

7. Do you consider the health of your soil when making berry crop management decisions, e.g., tillage practices, type of fertilizer used?

Compared with 2005, in 2006, there was a 200 % increase in the number of growers who claimed that they do not consider the health of your soil when making berry crop management decisions.

8. Do you add compost, manure, or other organic materials to your fields?

There was no change in the percent of growers that claim to add compost, manure, or other organic materials to their fields. Sixty-two percent of growers replied yes to this question in both years.

9. Do you believe that organisms in the soil are important for berry yield?

Compared to 2005, in 2006 there was a decrease of 9.1 % growers who believed that soil organisms in the soil are important for berry yield and there was a 100 % decrease in the number of growers who believed that organisms in the soil are important for berry yield. However, there was a 100 % increase in the number of growers who replied ‘Don’t Know’ in 2006 which may reflect an increase in uncertainty about the role of microorganisms to crop yield.

10. Do you believe that your fields are producing at their maximum yield?

Compared to 2005, in 2006 there was a 100 % decrease in the number of growers who believed that their fields were producing at their maximum yield as well as a 100 % increase in the number of growers who answered ‘Don’t Know.’ This may reflect a belief by growers that there is potential to improve their crop yields through improved management, but there is uncertainty about what those techniques are. These results suggest that these growers are open to new ideas, such as soil quality monitoring.

11. Do you believe that berry crop yields could be improved by monitoring the soil’s health with a field test kit?

There was no change in the percentage of growers who believed that berry crop yields could be improved by monitoring the soil’s health with a field test kit (69 %).

12. Do you believe that berry growers would be interested in learning about a soil quality test kit that would help monitor the health of their soil?

One grower changed their answer from ‘Yes’ to ‘Don’t Know’ in 2006 which resulted in an 8 % decrease in the percentage of growers who believe that berry growers would be interested in learning about a soil quality test kit that would help monitor the health of their soil.

The results of the survey show that awareness of the soil quality test kit increased during the course of the project for the population of growers that participated in the questionnaire. The results show an increase in those growers no knowing about the role of microorganisms in crop productivity and soil management. The results also show that berry growers believe that their fields are not producing at their optimum levels (question 10) and could be managed in ways that could improve crop yield (question 11), possibly with the use of a soil quality test kit (question 12).

Results and Discussion/Milestones (Continued)

Part two: Effects of four weed management strategies on soil quality at ISU Horticulture Research Station, Ames, IA.

Total yield in 2005 for the fumigation treatment was higher than all other treatments by 108, 74, and 36 percent (living mulch, straw mulch, and herbicide treatments, respectively). Marketable yield, berry number, and berry size were similar among all treatment plots. In 2006, total yield and marketable berry number for the fumigation treatment was greater than all other treatments . Total yield in the fumigation treatment was higher than all other treatments by 41, 11, and 16 percent (living mulch, straw mulch, and herbicide treatments, respectively). Marketable yield in 2006 in the fumigation treatment was higher than all other treatments by 56, 26, and 18 percent (living mulch, straw mulch, and herbicide treatments, respectively). Marketable berry size was similar among all treatments.

In 2004, strawberry leaves from plants in the fumigation and herbicide treatment plots had a higher percentage of zinc, iron, and aluminum than plants found in the straw mulch or killed-cover crop treatment plots. The level of ammonium-nitrogen was found to be ten percent higher in the fumigated and herbicide treatment plots than in the straw mulch and killed-cover crop; nitrate-nitrogen levels were 43 percent higher in the killed-cover crop and straw mulch plots than in the herbicide and fumigation treated plots.

There were no differences in percentage weed cover or dicot (broad leaf) weed biomass (in the strawberry row) among the four weed management treatments in July or August 2004, or in May or August 2005 and 2006. Weed number between rows was negligible in all treatments. In May 2006, monocot (grass-like) weed biomass was greater in the living mulch treatment than all other treatments.

Preliminary analysis indicated that in Oct. 2005, respiration in the top 7.5 cm of soil was higher in the living mulch and straw mulch treatment plots than in the herbicide treatment plots or plots fumigated with methyl bromide. Earthworm counts were not different among treatments in Fall 2004 or 2005.

All weed management systems provided comparable weed control in all three years of 2004 to 2006. However, perennial weeds increased in one of the straw mulch treatment plots (hand-weeded only) in 2006. Fumigated treatment plots produced more total and marketable strawberry yield in 2006 than the other treatment plots, however, the difference in yield between the treatments was smaller than 2005. Soil nutrient analyses, soil respiration, and physical soil quality measurements indicated that living and straw mulch treatment strategies created soil conditions beneficial for microorganisms. Enhanced nutrient cycling provided by microorganisms shows that measuring microbial activity in soil may become a valuable part of efficient soil fertility management.

Participation Summary

Educational & Outreach Activities

Participation Summary

Education/outreach description:

From the period July 2004 through August 2006, information about the soil quality test kit evaluation project and research results were presented or published as follows:

Presentations and Displays

July 2004 – Craig Dilley, graduate student, Horticulture Dept., Iowa State University, presented informational display showcasing the soil quality test kit at the Iowa Fruit and Vegetable Grower Association annual field day at the Iowa State University Horticulture Research Station, Ames, IA (attendance approximately 90).

Jan. 2005 –Craig Dilley, graduate student, Horticulture Dept., Iowa State University, and Dean Henry, grower cooperator, gave a presentation about experiences with the soil quality test kit at the Iowa Fruit and Vegetable Grower Association annual meeting, Marshalltown, IA (attendance approximately 40).

Jan. 2005 – Craig Dilley, graduate student, Horticulture Dept., Iowa State University, presented informational display showcasing the soil quality test kit at the Iowa Fruit and Vegetable Grower Association annual meeting, Marshalltown, IA (attendance approximately 200).

Jan. 2005 – Dr. Gail Nonnecke, Professor, Horticulture Dept., Iowa State University, gave a presentation that included results of soil quality test kit research at the Mid-America Fruit Growers Conference, Excelsior Springs, MO (attendance approximately 35; conference attendance approximately 150).

Jan. 2005 – Dr. Paul Domoto, Iowa State Fruit Extension Specialist, Horticulture Dept., Iowa State University, gave a presentation that included results of related soil quality research at the Iowa Wine Growers Association annual meeting, Des Moines, IA (attendance approximately 200; conference attendance approximately 250). These presentations have been made available to the general public at the following url: http://viticulture.hort.iastate.edu/research/research.html

July 2005 – Craig Dilley, graduate student, Horticulture Dept., Iowa State University, presented Poster ‘Effect of Four Weed Management Systems on Soil Quality in Junebearing Strawberry Production’ at American Society for Horticultural Science Annual meeting in Las Vegas, NV (conference attendance approximately 1100).

Jan. 2005 – Craig Dilley, graduate student, Horticulture Dept., Iowa State University, gave a presentation about results and experiences with the soil quality test kit at the Iowa Fruit and Vegetable Grower Association annual meeting, Marshalltown, IA (attendance approximately 30; conference attendance approximately 200).

Jan. 2006 – Craig Dilley, graduate student, Horticulture Dept., Iowa State University, presented informational display showcasing the soil quality test kit at the Iowa Fruit and Vegetable Grower Association annual meeting, Marshalltown, IA (conference attendance approximately 200).

Jan. 2006 – Craig Dilley, graduate student, Horticulture Dept., Iowa State University, presented informational display showcasing the soil quality test kit at the Iowa Wine Growers Association annual meeting, Des Moines, IA (conference attendance approximately 220).

Jan. 2006 – Dr. Paul Domoto, Iowa State Fruit Extension Specialist, Horticulture Dept., Iowa State University, gave a presentation that included results of related soil quality research at the Iowa Wine Growers Association annual meeting, Marshalltown, IA (attendance approximately 150; conference attendance approximately 250). These presentations have been made available to the general public at the following url: http://viticulture.hort.iastate.edu/research/research.html

Jan. 2006 – Dr. Gail Nonnecke, Professor, Horticulture Dept., Iowa State University, gave a presentation that included results of soil quality test kit research at the Wisconsin Fresh Fruit and Vegetable Conference, Oconomowoc, WI (attendance approximately 110; conference attendance approximately 300).

June 2006 – Craig Dilley, graduate student, Horticulture Dept., Iowa State University, demonstrated the use of the soil quality test kit for the Iowa Fruit & Vegetable Grower’s Association Summer Field day and presented informational display showcasing the soil quality test kit at the Iowa State University Horticulture Research Farm (conference attendance approximately 100).

June 2006 – Craig Dilley, graduate student, Horticulture Dept., Iowa State University, demonstrated the use of the soil quality test kit for the Continuing Education program for Iowa High School Vocational Agriculture Teachers and presented informational display showcasing the soil quality test kit at the Iowa State University Horticulture Research Farm (conference attendance approximately 200).

Aug. 2006 – Craig Dilley, graduate student, Horticulture Dept., Iowa State University, presented informational display showcasing the soil quality test kit for the Iowa Grape Grower’s Association Field day at the Iowa State University Horticulture Research Farm (conference attendance approximately 120).

Publications

Dilley, C. and G. Nonnecke. 2004. Weed Management and Soil Quality in Strawberry Agroecosystems. Annual Fruit and Vegetable Progress Report. Iowa State Univ. Extension FG 601: 52-53.

Dilley, C. and G. Nonnecke. 2004. Use of Soil Quality Test kits by Growers
to Monitor Soil Quality in Strawberry Agroecosystems. Annual Fruit and Vegetable Progress Report. Iowa State Univ. Extension FG 601: 54-55.

Dilley, C. and G. Nonnecke. 2005. Effect of Four Weed Management Systems on Soil Quality in Junebearing Strawberry Production. Annual Progress Reports 2005. Iowa State Univ. Extension ISRF05-36: 29-30. http://www.ag.iastate.edu/farms/05reports/hort/EffectsofFourWeed.pdf

Dilley, C. and G. Nonnecke. 2005. On-Farm Research Trial on Iowa Strawberry Production with USDA/NRCS Soil Quality Test Kit. Annual Progress Reports 2005. Iowa State Univ. Extension ISRF05-36: 31-32.
http://www.ag.iastate.edu/farms/05reports/hort/OnFarmResearch.pdf

Dilley, C. and G. Nonnecke. 2005. Effect of Four Weed Management Systems on Soil Quality in Junebearing Strawberry Production. HortScience 40(4):1058.

Dilley, C. 2006. An Ounce of Prevention is Worth a Pound of Cure: Benefits of Using a Soil Quality Test Kit in Junebearing Strawberry Production. Iowa Fruit & Vegetable Grower’s Association Newsletter, April.

Dilley, C. and G. Nonnecke. 2006. Comparison of Sustainable and Conventional Weed Management
Systems in Junebearing Strawberry Production. Annual Progress Reports-2006. Iowa State Univ. Extension ISRF06-36.

Dilley, C. and G. Nonnecke. 2006. Soil Quality Interest Survey of Iowa Small Fruit Growers. Annual Progress Reports-2006. Iowa State Univ. Extension ISRF06-36.

Project Outcomes

Project outcomes:

The cooperating growers have indicated that their knowledge and awareness of soil quality has increased and that by learning how to conduct soil quality tests, even if they do not conduct all the tests themselves, they are more likely to make informed decisions about soil management practices. The impact of both on-farm research and public talks and informational displays on Iowa berry grower awareness and attitudes toward soil quality and the use of the soil quality test kit to monitor soil on their farms was not quantified but may be reflected in the increased awareness of the soil quality test kit as shown in the results of the questionnaire. It is likely that some growers who became interested in soil quality through exposure to our project, or other sources, will test some of the ideas for themselves. If these growers adopt all or some of the soil quality techniques and the techniques prove to be profitable, not only will the grower benefit, but society will benefit through improved soil, water, and air quality.

Economic Analysis

No Economic Analysis Conducted

Farmer Adoption

The results of the survey confirm the idea that small fruit growers are interested in soil quality and the information provided by the soil quality test kit, especially in regard to improving yield. However, our trials with actual growers suggest that the average grower is likely to believe that the soil quality test kit requires knowledge and skills they do not have.

Although the growers that participated in the study appreciated the information provided by the kit, they commented that they were hindered from using the kit by their lack of expertise. We encouraged the growers to use the kit at any time for their own purposes and one of the two growers did so; he used the pH and EC meters provided with the kit. The use of the pH and EC meters by the grower instead of the other more complicated measurements may indicate that growers are more interested in soil quality measurements that are quick and require little interpretation. It appears logical that if many of the tests in the kit could be replaced by quickly read meters, such as a CO2 meter, the growers would be more inclined to use them. However, not all of the tests can be replaced with meters, so a challenge will remain to motivate growers to take all measurements in the soil quality test kit.

In order to observe the long-term impact of this trial with Iowa small fruit growers, we have obtained funding to continue the research begun in this study. The new study includes two grape growers in addition to the two strawberry growers that took part in this research trial. These experiments are currently being conducted in 2006 and will continue in 2007.

Recommendations:

Areas needing additional study

The results indicate that additional study is needed to better understand the hurdles that deter fruit growers from using a soil quality monitoring strategy such as the soil quality test kit. Once those hurdles have been identified, methods can be tested that will increase the likelihood of fruit growers adopting such kits or other techniques to monitor their soil quality.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.