An ASAE/CSAE Meeting Presentation Paper Number: 418 A Comparison Of Penetration Resistance Of Organic And Soils Athanasios Alexandrou The Ohio State University A.T.I., Wooster, Ohio, alexandrou.2@osu.edu Deborah Stinner The Ohio State University, OARDC, Wooster, Ohio, stinner.2@osu.edu Mohammad Reza Mosaddeghi Department of Soil Science, College of Agriculture, Bu-Ali Sina University, Hamadan 6174, Iran mosaddeghi@basu.ac.ir Written for presentation at the 4 ASAE/CSAE Annual International Meeting Sponsored by ASAE/CSAE Fairmont Chateau Laurier, The Westin, Government Centre Ottawa, Ontario, Canada 1-4 August 4 Abstract. An organic farming system will control the weeds with mechanical means. This normally translates into a number of extra passages with a tractor that may result in an increase in the soil strength. This study examines the penetration resistance of soils under conventional farming systems with transitional organic farming systems. A soil penetrometer was used, able to penetrate at a depth of 4 cm taking readings every cm. Results show that the penetration resistance does not depend on the farming system. The additional weed control operations that normally will take place in an organic farming system (in relation to a conventional farming system) do not increase the penetration resistance of the soils. Keywords. Penetration resistance, transitional organic farming system, conventional farming system The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect the official position of ASAE or CSAE, and its printing and distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not subject to the formal peer review process, therefore, they are not to be presented as refereed publications. Citation of this work should state that it is from an ASAE/CSAE meeting paper. EXAMPLE: Author's Last Name, Initials. 4. Title of Presentation. ASAE/CSAE Meeting Paper No. 418. St. Joseph, Mich.: ASAE. For information about securing permission to reprint or reproduce a technical presentation, please contact ASAE at hq@asae.org or 269-429-3 (29 Niles Road, St. Joseph, MI 498-969 USA).
Introduction The soil cone penetrometer is recommended as a measuring device to provide a standard uniform method of characterizing the penetration resistance of soils. It consists of a 3-degree circular stainless steel cone with a driving shaft. It also includes a means of force application and data recording (ASAE Standard S313.3). It is currently the most commonly used instrument for assessing soil strength. Scientists have used the soil cone penetrometer to relate resistance to penetration to physical properties of soil (Elbanna and Whitney 1987; Voothees 1987). Those efforts have not been always successful. The problems in the use of a penetrometer are due to the varying soil conditions (even in adjacent locations) and stones in the field. The variability of in situ penetration resistance hinders the evaluation of penetration resistance in studies where evaluation of soil tillage techniques is the main objective (Stelluti et al 1998). Differences in soil penetrometer resistance due to different cultivation techniques were usually examined by separate univariate analyses for each depth measurement (Dickson and Ritchie 1996; Evans et al 1996). Stelluti et al (1998) used a principal component analysis (a multivariate technique) to investigate relationships between penetration resistance and several variables. They assembled measurements of penetration resistance along the whole soil profile into a few significant intervals. This technique has the disadvantage that during the grouping process, it discards a number of data. An organic farming system will control the weeds with mechanical means. This normally translates into a number of extra passages with a tractor and a field cultivator (as many as the farmer considers necessary), that may result in an increase in the soil strength. This study examines the penetration resistance of conventionally cultivated soils with transitional organic soils. Materials and methods Data were obtained in -3 in the field crops organic transition experiment in West Badger farm at the Ohio State University in Wooster, Ohio. This experiment is designed to study ecological changes in land undergoing transition from conventional to organic management of agronomic crops and the economics of transition. The soil is a Wooster silt loam (Soil Conservation Service, 1981). A long-term transition experiment that compares a conventional (corn-soybean) and an organic corn-soybean-small grain-hay farming systems was established in spring in a field that had been in continuous corn for 1 years. The conventional system is managed according to conventional best management practices. The organic system is managed using both practical knowledge from long-time organic farmers in Ohio and new scientific knowledge of soil organic matter dynamics in relation to nutrient cycling and crop production. All phases of the rotations are present each year in a randomized split-block production design with six replicates (Figure 1). Individual plots are 18.29 m (6 ft) by 18.29 m (6 ft). Relationships among indicators of soil quality, nutrient efficiency and carbon sequestration, crop production and quality, weed ecology and profitability among other factors are investigated. For the purposes of the soil penetration resistance experiment only the plots with corn and soybeans for both transitional and conventional farming systems were considered. Tables 1 and 2 and show the farming operations which took place in the year 3. Farming operations were carried out using a Ford 36 tractor. 2
Field Crops Organic Transition Experiment N Farming System 1 Farming System 2 Corn (C c ) Corn (T C ) Oats (T o ) Soybean(C B ) Soybean (T B ) Hay (T H ) Rep 1 Rep 2 Rep 3 431 1-1 1-2 1-3 C B T C T O 1-4 1-1-6 C C T H T B 2-1 2-2 2-3 3-1 3-2 C B T B T H T B T O 2-4 2-2-6 3-4 3- C C T C T O T H T C 3-3 C C 3-6 C B 4-1 T H Rep 4 Rep Rep 6 4-2 4-3 -1-2 -3 6-1 6-2 T B C B C B T H T O C C T B 6-3 T H 7 4-4 T C 4- T O 4-6 C C -4 C C - -6 6-4 6-6-6 T B T C C B T C T O 7 2 84 Figure 1. Experimental layout. Table 1. Field farming operations for the transitional corn and soybeans (3). Date Operation Type/Equipment Crop /6/3 Manure Spreader Rear Box Spreader Organic Corn /6/3 Plow Mold Board Organic Corn /23/3 Disc Field Organic Beans /23/3 Disc Field Organic Corn /27/3 Disc Field Organic Corn /27/3 Disc Field Organic Beans /3/3 Field Cultivate Field Cultivator Organic Corn /3/3 Field Cultivate Field Cultivator Organic Beans 6/2/3 Field Finish Field Finisher Organic Corn 6/2/3 Planter No-till Corn Organic Corn 6/2/3 Planter No-till corn/beans Organic Corn 6/2/3 Cultivate Danish Tine with rolling baskets Organic Corn 6/26/3 Cultivate Danish Tine with rolling baskets Organic Beans 7/3/3 Cultivate Sweep Cultivator Organic Beans /22/3 Combine Combine Organic Beans 12/18/3 Combine Combine Organic Corn 12/18/3 Mower Brushhog Organic Corn 3
Table 2. Field farming operations for the conventional corn and soybeans (3). Date Operation Type/Equipment Crop 4/3/3 Plow Chisel Beans /27/3 Field Cultivate Field Cultivator Corn 6/2/3 Field Finish Field Finisher Corn 6/2/3 Field Finish Field Finisher Corn Soil penetration resistance was measured randomly at 3 different points per experimental plot and sampling date. The soil penetrometer, Spectrum Field Scout soil compaction meter, was able to penetrate at a depth of 4 cm taking readings every cm. Data were logged and then downloaded into computer for further analysis. SAS statistical analysis package (version 9.1) was used for statistical analysis. Measurements were taken on the following dates April 3, 1; June 13-14, 1; September 17-18, 1; March 19, 2; November 26, 2; August, 3. Due to soil strength the penetrometer was not always able to penetrate to its full length in September 17-18, 1 and June 13-14, 1. For statistical analysis purposes readings only up to cm were used for those dates. Various statistical approaches have been used to statistically analyze soil penetration resistance data. In this study we used Proc "mixed" for repeated measures designs at the SAS software. Initially we found the best fit to our data for various covariance structures. In the case of our data the best fit was the unstructured covariance structure. Then statistical analysis was performed to find the interaction between depth, farming systems and crop. Results and Discussion Figure 2 show the results of the averaged values of penetration resistance for April 3, 1. For both conventional and transitional soils, penetration resistance over depth follows a similar pattern. At depths 2 cm ( inches) and 4 cm (18 inches), penetration resistance for conventional soils is greater although the difference is not statistically significant at.1% probability level. 4
Depth (cm) 1 2 3 3 4 4 Resistance (kpa) 3 Figure 2. Means of penetration resistance for conventional and transitional farming systems for measurements taken on April 3, 1. Figure 3 illustrates the penetration resistance of both soils on June 13-14, 1. Due to soil strength the penetrometer was not always able to penetrate to its full length. For this reason data up to cm were used for the statistical analysis. Resistance in both soils follows a similar pattern in both conventional and transitional soils.
Resistance (kpa) 3 Depth (cm) 1 2 Figure 3. Means of penetration resistance for conventional and transitional farming systems for measurements taken on June 13-14, 1. Figure 4 shows the penetration resistance of conventional and transitional soils on September 17-18, 1. Again soil strength did not allow the penetrometer to penetrate to its full length. Resistance was higher for conventional soils at shallow depths. At soil surface ( cm) the difference between the resistance for conventional and transitional soils was statistically different at 1% probability level. For depths larger than 1 cm soil resistance was similar for both soils. 6
Resistance (kpa) 3 3 4 4 Depth (cm) 1 2 Figure 4. Means of penetration resistance for conventional and transitional farming systems for measurements taken on September 17-18, 1. Figure shows the penetration resistance of conventional and transitional soils on March 19, 2. Resistance for both soils follows a similar pattern with no statistically significant differences. Resistance (kpa) Depth (cm) 1 2 3 3 4 4 Figure. Means of penetration resistance for conventional and transitional farming systems for measurements taken on March 19, 2. 7
Figure 6 shows the penetration resistance of conventional and transitional soils on November 26, 2. Resistance for both soils follows a similar pattern with no statistically significant differences. Resistance (kpa) Depth (cm) 1 2 3 3 4 4 3 3 Figure 6. Means of penetration resistance for conventional and transitional farming systems for measurements taken on November 26, 2. Figure 7 shows the penetration resistance of conventional and transitional soils on August, 3. Resistance for both soils follows a similar pattern with no statistically significant differences. 8
Depth (cm) 1 2 3 3 4 4 Resistance (kpa) 3 3 4 Figure 7. Means of penetration resistance for conventional and transitional farming systems for measurements taken on August, 3. The interaction between depth and farming systems did not indicate any statistically significant differences. The same holds true for the interaction between depth, farming systems and crops. Conclusion This study shows that the penetration resistance of soils under conventional farming systems and organic farming systems is not statistically different. There is no proof that farming system and crop influence the penetration resistance of the examined soils. The extra weed control operations that normally will take place in an organic farming system (in relation to a conventional farming system) do not increase the penetration resistance of the soils. References ASAE Standards, 49th ed. 2. S313.3: Soil cone penetrometer. St. Joseph, Mich.: ASAE. Dickson, J. W. and Ritchie, R. M. 1996. Zero and reduced pressure traffic systems in an arable rotation.2.soil and crop responses. Soil Till. Res. 38(1-2): 89-113. Elbanna, E. B. and Witney, B. D. Cone penetration resistance equation as a function of the clay ratio, soil moisture content and specific weight. Journal of Terramechanics: 24(1): 41-6. Evans, S. D., Lindstrom, M. J., Voorhess, W. B., Moncrief, J. F. and Nelson, G. A. 1996. Effect of subsoiling and subsequent tillage on soil bulk density, soil moisture and corn yield. Soil Till. Res. 38(1-2): 3-46. Soil Survey of Wayne County Ohio, 1981. USDA, Soil Conservation Service. 9
Stelluti, M., Maiorana, M., De Giorgio, D. 1998. Multivariate approach to evaluate the penetrometer resistance in different tillage systems. Soil Till. Res. 46: 14-11. Voorhees, W. B. 1987. Assessment of soil susceptibility to compaction using soil and climatic data bases. Soil Till. Res. (1): 29-38.