Doctor of Philosophy, The Ohio State University, 2024, Environment and Natural Resources
Soil physical properties play a crucial role in agricultural productivity and environmental sustainability. This study investigated the seasonal dynamics of soil physical properties under different tillage and drainage practices in poorly drained soils of Ohio, focusing on their interrelationships with soil structure, crop growth, and climate across various agricultural production stages. Soils were sampled under long-term tillage (no-till, NT vs chisel-till, T) and drainage (drained, D vs non-drained, ND) management. Intact soil cores and undisturbed bulk samples were collected at 3 depths in different seasons. The research examined a. soil hydraulic properties, including saturated hydraulic conductivity (Ksat), unsaturated hydraulic conductivity (Ks) and water diffusivity (Ds) at field capacity, field infiltration, and plant available water capacity (AWC), b. soil structure, including bulk density (BD), pore size distribution (PSD), water stable aggregates (WSA), mean weight diameter (MWD), penetration resistance (PR), and aggregate tensile strength (TS), c. soil physical quality index (SQI) with the selected indicators, and d. crop development and climate factors, including crop height, crop yield, ground coverage, air temperature, daily precipitation, and rainfall intensity.
Specifically, this thesis aims to:
a. Investigate the dynamics of soil hydraulic properties (Ksat, Ks, Ds, field infiltration, AWC) under different tillage and drainage practices.
b. Assess the dynamics of soil structure (WSA, MWD, PSD, PR, TS) under different tillage and drainage practices.
c. Determine the yield-oriented SQI across different seasons of crop production.
In terms of the first objective, results in Chapter 2 showed that NT generally maintained higher Ksat (0.675-0.898 cm/hr vs 0.307-0.572 cm/hr, p=0.001-0.124) in fallowing seasons, especially in surface soils, due to better soil aggregation and ground coverage. However, during growing seasons, NT (0.326-0.774 cm/hr) (open full item for complete abstract)
Committee: Rattan Lal (Advisor); Brian Slater (Advisor); M. Scott Demyan (Committee Member)
Subjects: Agriculture; Environmental Science; Natural Resource Management; Soil Sciences; Sustainability