Assessing the impact of an organic cover cropping system on plant and soil potassium behavior

Open Access
Author:
Bao, Nancy Yunan
Area of Honors:
Environmental Resource Management
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Jason Philip Kaye, Thesis Supervisor
  • Robert David Shannon, Honors Advisor
Keywords:
  • soil
  • potassium
  • cover crops
  • biogeochemistry
Abstract:
As one of the essential macronutrients supplied by the soil, potassium is critical in plant metabolism and defense mechanisms against abiotic and biotic stresses. In conventional and sustainable agricultural production, potassium is a crucial component in fertilization to ensure optimal crop growth and development. Crop quality is dependent on a myriad of factors corresponding to water and nutrient uptake which are linked to potassium regulated pathways. To better understand controls on soil exchangeable potassium, the main source taken up by plants, this study investigates the effects of different monoculture cover crop treatments across different growing seasons on potassium acquisition in cover crops of an organic cropping system. We are conducting an exploratory data analysis of potassium concentrations in the aboveground biomass of seven cover crop species: oat, radish, pea, red clover, crimson clover, cereal rye, canola. The data were collected from an ongoing study conducted in an organic cropping system which follows a soy-wheat-corn rotation with cover crops planted after wheat and before corn. Our goal is to understand the potential impacts that specific cover crops have on K uptake by plants. We found that the aboveground biomass %K of radish and clover were consistently higher than that of other monoculture cover crops measured in the fall and spring, respectively. While soil exchangeable K differed significantly across time, it did not vary between different monoculture treatments within a season. Our findings suggest there is not a drawdown effect of soil test K from cover crop uptake. These analyses provide further insight to how different cover crop treatments and soil conditions may alter plant potassium acquisition for fine tuning nutrient management plans and improving cover and cash crop quality and yields.