Progress 11/15/02 to 11/14/06
Outputs
To build the basic understanding of short and long-term ecological changes in land that is in transition from conventional to organic production, a field crop transition experiment was established using a randomized split-block design at the Ohio Agricultural Research and Development Center in Wooster, Ohio. In this study, we report the major physical, chemical and biological changes in soils as influenced by different crop rotations and management practices for six years, in organic and conventional farming systems. Results suggested, higher soil organic matter soil carbon (SOMSC) in the upper soil layers (15cm and 30cm) than lower layers (>45cm). Compared to baseline SOMSC of 25024.5kg/ha, organic systems showed significant increase in SOMSC up to 33075 kg/ha compared to 31185 kg/ha in conventional systems. Total N increased from 3015kg/ha (baseline) to 3454 kg/ha in organic compared with 3293 kg/ha in conventional systems. Similarly, P values drastically increased
from 122.8 kg/ha to 181.4 kg/ha in transitional organic compared to 73.6kg/ha in conventional systems. In conjunction with SOMSC, particulate organic matter (POM) fractions, microbial biomass nitrogen and total nitrogen in the soil showed increasing trends in organic compared to conventional plots. At the end of sixth year rotation, soil pH, showed significant changes, the organic tending to be neutral (from baseline 6.13 to 6.67 pH) compared to conventional systems (6.13 to 6.23). All the basic cations (Ca, Mg, K and Na), showed significant increase in organic compared to conventional plots. Further, principal component analysis (PCA) was used to examine associated correlations and variance between different soil parameters and climate characteristics. In case of organic systems, the first and second principal components could explain 49% and 28 % of the sampled variance. The loadings were all fairly large and highly positive for bulk density, soil organic matter soil carbon,
particulate organic matter, mineral associated organic matter, base cations K, Ca, Mg, along with precipitation parameters. Negative loadings were found for most of the temperature parameters along with microbial biomass nitrogen. In contrast, the second and third components were dominated by climatic parameters (annual precipitation range, annual mean temperature, maximum and minimum temperature along with the precipitation in the wettest quarter). The first two principal components could together explain 77% of the sampled variance in the transitional organic datasets. For conventional systems, although the trends in PCA loadings were similar to transitional organic, the intensities were different. Conventional systems showed relatively high positive loadings for nitrate compared to organic systems. In contrast, the loadings for cation exchange capacity were comparatively high for transitional organic compared to conventional systems. In overall, these results demonstrate the
potential of organic management practices in improving soil quality and nutrient balance, even in short term rotations.
Impacts
Our findings suggest that organic farming can be a viable management system for carbon sequestration in spite of all the tillage involved and have important implications to yields as well as overall patterns of carbon and nitrogen cycling.
Publications
- No publications reported this period
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Progress 01/01/05 to 12/31/05
Outputs
In this study, we report changes in soil carbon and nitrogen pools in Ohios Field Crop Transition Experiment (FCTE). Results suggested higher total soil organic matter soil carbon (SOMSC) in the upper soil layers (15cm and 30cm) than lower layers (45cm) in both the transitional organic corn-soybean-oats-hay (TO) and conventional corn-soybean (C) systems. Compared to baseline SOMSC of 25024.5kg/ha, TO showed significant increase in SOMSC up to 33075 kg/ha compared to 31185 kg/ha in C. Total N increased from 3015kg/ha (baseline) to 3454 kg/ha in TO compared with 3293 kg/ha in C. In conjunction with SOMSC, particulate organic matter (POM), microbial biomass nitrogen and total nitrogen in the soil showed increasing trends in TO compared to C. Principal component analysis (PCA) was used to examine correlations and variance between different soil parameters and climate characteristics. In TO, the first and second principal components could explain 49% and 28 % of the
sampled variance. The loadings were all fairly large and highly positive for bulk density, SOMSC, POM, mineral associated organic matter, along with precipitation parameters. Negative loadings were found for most of the temperature parameters along with microbial biomass nitrogen. In contrast, the second and third components were dominated by climatic parameters (annual precipitation range, annual mean temperature, maximum and minimum temperature along with the precipitation in the wettest quarter). The first two principal components could together explain 77% of the sampled variance in TO. For C, although the trends in PCA loadings were similar to TO the intensities were different. C showed relatively high positive loadings for nitrate compared to TO.
Impacts
Our findings thus far are suggesting that organic farming can be a viable management system for carbon sequestration in spite of all the tillage involved and have important implications to yields as well as overall patterns of carbon and nitrogen cycling.
Publications
- No publications reported this period
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Progress 01/01/04 to 12/31/04
Outputs
To build the basic understanding of short and long-term ecological changes in land that is in transition from conventional to organic production, a field crop transition experiment was established using a randomized split-block design at the Ohio Agricultural Research and Development Center in Wooster, Ohio. In this study, we report the major physical, chemical and biological changes in soils as influenced by different crop rotations and management practices for short term (four years), in organic and conventional farming systems. Results suggested, higher soil organic matter soil carbon (SOMSC) in the upper soil layers (15cm and 30cm) than lower layers (>45cm). Compared to baseline SOMSC of 25024.5kg/ha, transitional organic systems showed significant increase in SOMSC up to 33075 kg/ha compared to 31185 kg/ha in conventional systems. Total N increased from 3015kg/ha (baseline) to 3454 kg/ha in transitional organic compared with 3293 kg/ha in conventional systems.
Similarly, P values drastically increased from 122.8 kg/ha to 181.4 kg/ha in transitional organic compared to 73.6kg/ha in conventional systems. In conjunction with SOMSC, particulate organic matter (POM) fractions, microbial biomass nitrogen and total nitrogen in the soil showed increasing trends in organic compared to conventional plots. At the end of third year rotation, soil pH, showed significant changes, the transitional organic tending to be neutral (from baseline 6.13 to 6.67 pH) compared to conventional systems (6.13 to 6.23). All the basic cations (Ca, Mg, K and Na), showed significant increase in transitional organic compared to conventional plots. Further, principal component analysis (PCA) has been used to examine associated correlations and variance between different soil parameters and climate characteristics. In case of transitional organic systems, the first and second principal components could explain 49% and 28 % of the sampled variance. The loadings were all
fairly large and highly positive for bulk density, soil organic matter soil carbon, particulate organic matter, mineral associated organic matter, base cations K, Ca, Mg, along with precipitation parameters. Negative loadings were found for most of the temperature parameters along with microbial biomass nitrogen. In contrast, the second and third components were dominated by climatic parameters (annual precipitation range, annual mean temperature, maximum and minimum temperature along with the precipitation in the wettest quarter). The first two principal components could together explain 77% of the sampled variance in the transitional organic datasets. For conventional systems, although the trends in PCA loadings were similar to transitional organic, the intensities were different. Conventional systems showed relatively high positive loadings for nitrate compared to organic systems. In contrast, the loadings for cation exchange capacity were comparatively high for transitional
organic compared to conventional systems. In overall, these results demonstrate the potential of organic management practices in improving soil quality and nutrient balance, even in short term rotations.
Impacts
Our findings thus far are suggesting that organic farming can be a viable management system for carbon sequestration and have important implications to yields as well as overall patterns of carbon and nitrogen cycling.
Publications
- No publications reported this period
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Progress 01/01/03 to 12/31/03
Outputs
To build basic understanding of short and long-term ecological changes in land that is transitioned from conventional to organic production a Field Crop Transitional Experiment was established in spring 2000. Two cropping systems are compared: a conventional corn-soybean (C) and organic corn-soybean-small grain-hay (TO). All phases of the rotations are present each year. Relationships among indicators of soil quality, nutrient cycling efficiency and carbon sequestration, crop production and quality, were studied over a period of three years. Results from this ongoing experiment suggested that, by the end of the first rotation cycle for the organic system and second rotation cycle for conventional systems, Soil Organic Matter soil carbon (SOM-SC) increased significantly in organic systems compared to conventional systems. In conjunction with SOM-SC, Particulate Organic Matter (POM) fractions, microbial biomass nitrogen and total nitrogen in the soil showed increasing
trends in organic plots compared to conventional plots. Changes in SOM-SC correlated well with the total nutrient availability (total nitrogen). Soil microbial biomass has been found to exert source-sink function for extractable organic nitrogen on some of the field plots. Increased SOM-SC levels observed in the organic plots has been attributed to increased amounts of carbon entering the soil compared to that lost to the atmosphere by oxidation, suggesting possible carbon sequestration potential over long term periods. Consequently, the positive effects of organic farming on SOM-SC and nitrogen has been mainly ascribed to the application of the greater amounts of organic fertilizer and the increased share of fodder plants and green manure in the crop rotation. Higher levels of available C and enhanced physical environmental condition found in organic farming plots have been related to higher total microbial biomass and soil respiration compared to conventional plots. In particular,
the increase in microbial biomass N fraction in organic farming plots appears related to higher amounts of organic residues in the organic system. Ammonia and nitrate concentrations were found to be significantly higher in conventional than in the organic system, especially in conventional corn plots. The late spring soil nitrate test showed sufficient levels of N available in both organic and conventional treatments. The latter finding is important in that it indicates that the organic system is producing adequate N levels through the release from organic matter and biological fixation by legumes. Increase in POM suggests the improved soil quality in organic farming plots, as it is associated with increase in soil respiration and microbial biomass-C and N. The increase in the microbial biomass nitrogen suggests that organic farming has as positive effect on active soil nitrogen. Further, increased POM and microbial biomass nitrogen in the organic plots compared to conventional plots
suggests the possible potential increase in nitrogen mineralization and nitrogen availability to plants in the organic system over the long term.
Impacts
Our findings thus far are suggesting that organic farming can be a viable management system for carbon sequestration and have important implications to yields as well as overall patterns of carbon and nitrogen cycling.
Publications
- Stinner, D. H., K. V. Prasad, B. R. Stinner, D. McCartney. 2003. Soil Organic Carbon and Nutrient Dynamics in Transitional Organic and Conventional Farming Systems. Results from a Field Crop Transition Experiment. Organic Agriculture Symposium. 2003 Annual Meetings ASA-CSSA-SSSA, Denver, CO. 11/4/03, 11/5/03.
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