Land-use effects on anion-associated cation leaching in response to above-normal precipitation

Fertilizers and liming agents are generally used to achieve optimal economic yields. However, several negative effects of long-term annual fertilization of nitrogen (N) in particular have been observed, such as reduced cation exchange capacity and decreased base saturation, which may stimulate accelerated leaching loss of other nutrients. Equilibrium-tension lysimeters installed at a depth of 1.4 m were used to evaluate leaching of soil-solution ionic constituents from a tallgrass prairie restoration and optimally and deficiently N-fertilized, no-tillage (NT) and chisel-plowed (CP) maize (Zea mays L.) agroecosystems on Plano silt loam soil (fine-silty, mixed, superactive, mesic Typic Argiudoll). This study was conducted in south-central Wisconsin, USA during a 1-year period of above-normal precipitation between January 2000 and January 2001. The loss of soluble constituents added to agroecosystems to maintain adequate soil fertility and pH, such as N, phosphorus, potassium, calcium, and magnesium, was generally numerically smaller from the natural prairie 25 years after conversion from cultivated agriculture than from optimally and deficiently N-fertilized, NT and CP maize agroecosystems, though the differences were not significant. Tillage and fertilizer N-rate generally did not significantly affect drainage, ionic concentrations, or their leaching losses in the maize agroecosystems, though all parameters evaluated tended to be numerically smaller in the deficiently than optimally N-fertilized maize agroecosystems. Nitrate-N leaching losses were generally significantly positively correlated with leaching losses of K, Ca, Mg, and Na in the maize agroecosystems, but not for the prairie, indicating that nitrate-N leaching plays a significant role in the concomitant loss of cations to maintain soil-solution charge balance in N-fertilized maize agroecosystems in a temperate environment.