Agronomy and Horticulture, Department of

 

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

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First Advisor

Humberto Blanco

Committee Members

Rhae A. Drijber, Cody F. Creech

Date of this Version

8-2026

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of the requirements for the degree of Master of Science

Major: Agronomy

Under the supervision of Professor Humberto Blanco

Lincoln, Nebraska, August 2026

Comments

Copyright 2026, Samundra Sigdel. Used by permission

Abstract

Improving water retention and other hydraulic properties is key to managing soil water and sustaining crop production under fluctuating and extreme weather events. We assessed how wood biochar (836 g C kg-1) applied at 0, 6.25, 12.5, 25, and 50 Mg ha-1 affected: i) soil hydraulic properties after 5 years and ii) corn and soybean yield, and biomass production of cereal rye cover crop (CC) and CC mix (cereal rye, radish, and winter pea) in sandy, sloping, and semi-arid soils in the central U.S. Great Plains over 6 years. Biochar affected field saturated hydraulic conductivity (Ksat) and water retention, while it had no effect on other hydraulic properties. Biochar reduced Ksat from 226 to 52 mm h-1 in the sandy soil, suggesting that biochar might reduce rapid water drainage in sandy soils. The highest rate (50 Mg biochar ha-1) improved water retention in this order: Sloping > Sandy > Semi-arid soil, while lower rates had no effect. The highest rate increased water retention at 0 to -300 kPa matric potentials in the sloping soil, and at 0 to -1 kPa in the sandy and semi-arid soils in the 0-7.5 cm depth. Further, it increased available water by 46% in the sandy soil and by 80% in the sloping soil, and it had no effect in the semi-arid soil. Corn and soybean yield showed little to no response to biochar application. The highest biochar rate increased CC biomass production by 0.15-0.52 Mg ha-1 in the sandy and sloping soils in some years. Crop and CC did not establish in the semi-arid soil due to limited precipitation. Overall, a high wood biochar rate (50 Mg ha-1) improved some hydraulic properties after 5 years in the sandy, sloping, and semi-arid soils and increased CC biomass in some years in the sandy and sloping soils.

Advisor: Humberto Blanco

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