By Yadunath Bajgai
Besides other soil properties, core samples are used for determination of bulk density, water-holding capacity and hydraulic properties in seven soil series (Blount, Warsaw, Pewamo, Eldean, Spinks, Gilpin and Coshocton) in Ohio. Water holding capacities or water retention capacities in different land use practices such as minimum-till, plough-till, no-till, forest and meadow in Ohio are being evaluated. Generally, soils under forest and meadow are likely to experience less or no anthropogenic disturbance and thus allow formation of better soil structure (aggregates) compared with the soils under plough-till farming. Besides land management, the soil organic matter (SOM) regulates aggregate formation. Less or no soil disturbance allow primary soil particles to integrate with SOM to the form aggregates.
The aggregates such as seen in the figure, mainly provide soil functions of resisting the impacts of disruptive forces of rainfall, windstorm or soil tillage. Further, soil aggregates are often said to help infiltrate water into the soil when irrigation water is applied or during the rainfall which protects against the likelihood of being flooded. Soils with higher SOM content and aggregates have higher ability to reserve soil water which could be useful for plants during the drought. The water retention characteristics of C-FARM soil samples under minimum-till, plough-till, no-till, forest and meadow are assessed in terms of available water capacity, field capacity and permanent-wilting point using pressure plates.