Effects of Organic Fertilizer and Spatial Analysis of Phosphate at Babe + Sage Farm Soils
Abstract
Eutrophication is a major issue in the world today. The source of nutrients, such as nitrates and phosphates, contributing to eutrophication, is primarily agricultural runoff. Phosphate is often the key limiting nutrient in freshwater ecosystems. By measuring the level of phosphate across terrestrial locations, it is possible to study how this nutrient moves through and over the soil. The location for this study is Babe + Sage Farm in Gordon, GA. Babe + Sage is a small sustainable farm that has been using organic fertilizers for years. Recently, the soil was amended with fish based fertilizers consisting of ground fish waste, containing no oils. Results from previous testing by this research group indicated a high level of phosphate in the soil, most likely originating from the fertilizer. The purpose of this study is to understand how high levels of phosphate in soil affect the surrounding environment, including the managed forest next to the farm, Slash Creek, and Lake Oetter, a large pond less than 1500 feet away. Phosphate primarily affects surface waters in two ways: through desorption of sediment and sediment runoff. In desorption, the phosphate that was sorbed to the soil particles is released, usually as a result of oversaturation of phosphate in the soil. In sediment runoff, the sorbed phosphate travels with soil particles as they move through the environment. Our study investigated phosphate desorption from Babe + Sage soils across solutions with different environmentally relevant ionic strength and pH levels. A pH of 4.6 was used to approximate the pH of natural rainwater in middle Georgia. These data provide information as to how phosphate originating from agriculture is moved after a rain event. The phosphate from this field should be actively desorbing, providing incentive for testing the water of Lake Oetter for phosphates and evidence of eutrophication.
Effects of Organic Fertilizer and Spatial Analysis of Phosphate at Babe + Sage Farm Soils
Eutrophication is a major issue in the world today. The source of nutrients, such as nitrates and phosphates, contributing to eutrophication, is primarily agricultural runoff. Phosphate is often the key limiting nutrient in freshwater ecosystems. By measuring the level of phosphate across terrestrial locations, it is possible to study how this nutrient moves through and over the soil. The location for this study is Babe + Sage Farm in Gordon, GA. Babe + Sage is a small sustainable farm that has been using organic fertilizers for years. Recently, the soil was amended with fish based fertilizers consisting of ground fish waste, containing no oils. Results from previous testing by this research group indicated a high level of phosphate in the soil, most likely originating from the fertilizer. The purpose of this study is to understand how high levels of phosphate in soil affect the surrounding environment, including the managed forest next to the farm, Slash Creek, and Lake Oetter, a large pond less than 1500 feet away. Phosphate primarily affects surface waters in two ways: through desorption of sediment and sediment runoff. In desorption, the phosphate that was sorbed to the soil particles is released, usually as a result of oversaturation of phosphate in the soil. In sediment runoff, the sorbed phosphate travels with soil particles as they move through the environment. Our study investigated phosphate desorption from Babe + Sage soils across solutions with different environmentally relevant ionic strength and pH levels. A pH of 4.6 was used to approximate the pH of natural rainwater in middle Georgia. These data provide information as to how phosphate originating from agriculture is moved after a rain event. The phosphate from this field should be actively desorbing, providing incentive for testing the water of Lake Oetter for phosphates and evidence of eutrophication.