Manure versus Inorganic N Fertilization: An Assessment of Amendment Impacts on Soil Health and Crop Quality

Authors: MINER, GRACE - Colorado State University; Delgado, Jorge; IPPOLITO, JAMES - Colorado State University; Stewart, Catherine; Manter, Daniel; Del Grosso, Stephen - Steve; Floyd, Bradley; D Adamo, Robert

Submitted to: Soil and Water Conservation Society Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2019
Publication Date: 7/28/2019
Citation: Miner, G., Delgado, J.A., Ippolito, J.A., Stewart, C.E., Manter, D.K., Del Grosso, S.J., Floyd, B.A., D Adamo, R.E. 2019. Manure versus Inorganic N Fertilization: An Assessment of Amendment Impacts on Soil Health and Crop Quality. Soil and Water Conservation Society Proceedings.

Interpretive Summary: n/a

Technical Abstract: Extensive research has focused on developing chemical, physical, and biological soil indicators to evaluate management impacts on soil health. While improvements in soil health can promote crop yield (i.e., via increased nutrient cycling, water capture and storage), published literature statements suggest that soil health also influences crop quality (i.e., protein and mineral concentrations), and there is a potential confounding of the terms ‘yield’ and ‘quality’. However, studies explicitly examining the connections between changes in soil health and crop quality are scarce, and potential associations require additional study and clarification. We evaluated these linkages in a continuous corn experiment containing a zero nitrogen (N) treatment, an inorganic N treatment (179 kg N ha-1), and a N-based manure treatment. These three treatments vary in input amount and type, potentially affecting soil health indicators, yields, and crop quality in differing ways. Manure is an important source of N, carbon, and other nutrients, which can positively influence soil chemical, biological, and physical properties. However, manure poses environmental and management challenges, and it is important to understand the benefits and tradeoffs of manure versus inorganic N fertilization on soil health and crop quality. We assessed select chemical, physical, and biological soil health indicators after 6 cropping years (0-15 cm depth), and also utilized the Soil Management Assessment Framework indexing tool to quantitatively assess changes in soil health. Additionally, we measured plant protein, macronutrient, and micronutrient concentrations in each plant fraction at harvest. Changes in soil health, yields, and crop quality under the different management practices will be discussed, as well as the connections and interactions between soil health and crop quality.