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Short-term Effect of Fertilization and the Long-term Effect of Soil Organic Management History and its Relationship to Above-ground Insect Suppression

Orellana Vintimilla, Diego Patricio
http://rave.ohiolink.edu/etdc/view?acc_num=osu1483699208567652

Abstract Details

2017, Master of Science, Ohio State University, Entomology.
One way farmers manipulate pest pressure in organic farming is through soil fertility management. Effects of soil fertility practices include both, the immediate and short-term changes in plant nutrient availability, as well as more long-term effects on soil community structure and function. Despite evidence suggesting that the application of compost has both, long-term and short-term effects on pest suppression, few attempts had been made to assess the impact of both factors on tomato susceptibility to Spodoptera exigua, beet armyworm (BAW), performance. This study has two specific objectives: 1) investigate the short-term effect of compost fertilization and the long-term effect of soil organic management history on insect performance, plant growth, and plant primary chemistry, and 2) determine how other factors, such as plant variety and phenological stage, might modify expression of this organic soil-mediated insect susceptibility. In chapter 2, I investigated the effects of different levels of compost fertilization and different organic field histories on Spodoptera exigua (BAW) performance, tomato growth, and plant free amino acid levels. I measured both immediate effects of compost application and historical effects of field management on plant growth. I observed that S. exigua larval weight did not vary between soils, and had a weak linear relationship with compost rate. The effects of compost on insect survivorship appeared dependent on soil history. I measured a linear response of plant growth and foliar free amino acids to compost rate. In addition, I measured that some amino acids had positive relationship with insect performance (i.e. glutamine and proline), while others showed a negative relationship (i.e. aspartic acid and the non-protein amino acid GABA). In chapter 3, I considered how two other factors might modify expression of soil-mediated changes in tomato susceptibility to BAW: plant variety and phenology. Here, tomatoes were grown in the greenhouse using soils from the same fields as in chapter 2 and fertilized with either inorganic salts (18-18-21 N-P-K) or dairy-manure compost. Significantly lower insect performance was observed on compost-amended tomatoes, though the difference was mainly significant when applied to the organic soil with a low compost history. Compost produced lower mean S. exigua larval weight than did chemically fertilized plants, consistently on both organic fields. The expression of insect performance did not differ by plant variety or phenology, since no interactions of such factors with soil history and amendment were observed. I measured lower insect performance on tomatoes during the flowering stage. Moreover, I observed that the suppressive effect of compost was extended to the flowering stage. Foliar free amino acids were lower on compost-amended tomatoes, and I also measured a decline in free amino acids from the vegetative to flowering stage. A significant relationship (r2=0.4) was observed between larval weight and total free amino acids. In summary, this study highlighted the importance of soil fertility management as a strategy to reduce insect pest pressures in crops. I measured short-term effects of compost addition, but not long-term effects of soil management, on S. exigua larval success that correlated positively with levels of plant free amino acids.
P. Larry Phelan (Advisor)
Casey Hoy (Committee Member)
Warren Dick (Committee Member)
86 p.
Entomology
Organic farming Soil history Soil-mediated Compost Beet armyworm tomato Susceptibility Plant variety Plant phenology

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Citations

  • Orellana Vintimilla, D. P. (2017). Short-term Effect of Fertilization and the Long-term Effect of Soil Organic Management History and its Relationship to Above-ground Insect Suppression [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483699208567652

    APA Style (7th edition)

  • Orellana Vintimilla, Diego. Short-term Effect of Fertilization and the Long-term Effect of Soil Organic Management History and its Relationship to Above-ground Insect Suppression. 2017. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1483699208567652.

    MLA Style (8th edition)

  • Orellana Vintimilla, Diego. "Short-term Effect of Fertilization and the Long-term Effect of Soil Organic Management History and its Relationship to Above-ground Insect Suppression." Master's thesis, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483699208567652

    Chicago Manual of Style (17th edition)

osu1483699208567652
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This open access ETD is published by The Ohio State University and OhioLINK.