Land application of poultry lagoon effluent

Abstract

This research studied the effects of three poultry lagoon effluent application rates on two Sol 'I types and two vegetation systems. The purpose of this research was to determine the environmental impacts from the land application of effluent from lagoons used to treat caged laying hen manure. Informed decisions can be made about the safe and practical rates of effluent application when the environmental impacts are known. Eighteen small plots were installed at the Texas A&M University Farm near College Station, TX (clay soil) and near Overton, TX (loamy soil) where 912 mm and 1,058 mm were received over the study period, respectively. Surface water runoff was collected in steel containers buried flush with the ground at the down slope end of the plots. The plots were installed in existing Coastal bermudagrass fields. TAM90 ryegrass was overseeded in half of the plots in the fall. Poultry lagoon effluent was applied at 0, 538, and 1076 kg total N/ha/yr. Total N, P, K, Ca, Mc,, and Na concentrations were examined in the vegetation. Electrical conductivity, pH, extractable P, K, Ca, Mg, and N03-concentrations were examined in the soil. Electrical conductivity, pH, total N, P, K, Ca, Mc,, and Na concentrations were examined in the surface runoff. An analysis of variance and the Student-Newman-Keuls (SNK) test with an alpha of 0.1were used to statistically evaluate the data. Increasing effluent application significantly increased the yield of vegetation between 70% and 300%. Nitrocren concentrations in the vegetation increased. Total uptake of the other nutrients increased proportionally to the increase in yield. Soil nitrate and potassium concentrations increased with increased effluent application. At the Overton site, nitrate and potassium penetrated down to at least 914 mm. An application of 538 kg N/ha/yr had little impact on the environmental factors examined when compared to 0 kg N/ha/yr. Application of 1076 kg N/ha/yr had little statistical effect on dry matter yield, but electrical conductivity, N03- concentrations, and K concentrations increased in the soil. In the surface water runoff, electrical conductivity increased and the total mass runoff of P and K increased.