Research Publication Title

Relationship Between Capillary Rise and Nitrification Potential at Babe + Sage Farm

Major

Environmental Science

Faculty Mentor(s)

Dr. Allison VandeVoort

Keywords

Nitrification, Capillary Forces, Nitrate, Nitrite, Matric Potential

Abstract

Nitrification is the process by which ammonium (NH4+) is converted into nitrite (NO2-) then nitrate (NO3-) by soil bacteria Nitrosomonas and Nitrobacter under aerobic conditions. Nitrification can be beneficial for farmers as it cycles plant-available forms of nitrogen in their soils. It can also be detrimental if occurring at excess since nitrate is very mobile and may leave their fields before plants can obtain it and contribute negatively to surface- and groundwater quality. In relation to the nitrification process, capillary water movement is also vital to crop health. The size and distribution of soil pores controls how water and air can flow within the soil matrix. Water moves through capillary-sized soil micropores against the force of gravity, and is controlled the matric potential of the soil, causing water to move from higher to lower energy areas . The smaller the pore size the greater the capillary rise of water in the soils. In general, water held in capillary pores is the most plant-available water present in soils. Measuring capillary rise allows us to determine the amount of plant available water in the soils and, inversely, the oxygen levels in the soils. Our field site was Babe + Sage Farm, a small local farm in Gordon, GA. Due to high sand content of these soils we predicted low capillary forces creating a very oxygenated environment for nitrification to occur. To test nitrification potential we used the shaken slurry method; we used column analysis to measure the height of capillary rise. Our data supported our hypothesis showing minimal capillary rise in Babe + Sage soils along with strong nitrification potential. We suggested the addition of organic matter to Babe + Sage soils to increase plant-available water by enhancing capillary capabilities, which should also lower the nitrification potential of these soils.

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Relationship Between Capillary Rise and Nitrification Potential at Babe + Sage Farm

Nitrification is the process by which ammonium (NH4+) is converted into nitrite (NO2-) then nitrate (NO3-) by soil bacteria Nitrosomonas and Nitrobacter under aerobic conditions. Nitrification can be beneficial for farmers as it cycles plant-available forms of nitrogen in their soils. It can also be detrimental if occurring at excess since nitrate is very mobile and may leave their fields before plants can obtain it and contribute negatively to surface- and groundwater quality. In relation to the nitrification process, capillary water movement is also vital to crop health. The size and distribution of soil pores controls how water and air can flow within the soil matrix. Water moves through capillary-sized soil micropores against the force of gravity, and is controlled the matric potential of the soil, causing water to move from higher to lower energy areas . The smaller the pore size the greater the capillary rise of water in the soils. In general, water held in capillary pores is the most plant-available water present in soils. Measuring capillary rise allows us to determine the amount of plant available water in the soils and, inversely, the oxygen levels in the soils. Our field site was Babe + Sage Farm, a small local farm in Gordon, GA. Due to high sand content of these soils we predicted low capillary forces creating a very oxygenated environment for nitrification to occur. To test nitrification potential we used the shaken slurry method; we used column analysis to measure the height of capillary rise. Our data supported our hypothesis showing minimal capillary rise in Babe + Sage soils along with strong nitrification potential. We suggested the addition of organic matter to Babe + Sage soils to increase plant-available water by enhancing capillary capabilities, which should also lower the nitrification potential of these soils.