Soil nitrogen dynamics and maize production in municipal solid waste amended soil

Municipal solid waste compost (MSWC) can enhance soil organic matter and crop nutrient supply. High C:N ratio composts can temporarily deplete plant-available soil N reserves, requiring supplemental N fertilization to ensure optimum crop growth. The objective of our research was to measure seasonal soil NO(3)-N dynamics to serve as an indication of N mineralization, immobilization, and leaching as affected by MSWC and N fertilizer rates. The MSWC (C:N 40:1) was applied in one year only to a Galestown sand (sandy, siliceous, mesic Psammentic Hapludults) at rates of 0, 63, 126, and 189 Mg ha(-1). Maize (Zea mays L.) was planted and N fertilizer rates of 0, 168, 336, 504, and 672 kg ha(-1) were applied as split-plot treatments. First-year maize total dry matter production plateaued at the 250 kg ha(-1) N rate, averaged across MSWC rates. Soil NO(3)-N decreased inversely proportional to MSWC rates, due to MSWC immobilization of soil and fertilizer N. Cereal rye (Secale cereale L.) winter cover crop total dry matter yield and total crop N increased linearly with increasing MSWC rates. Second-year maize total dry matter, total plant N, maize grain yield, and grain N increased linearly with increased MSWC rates applied the first year. During the second growing season, there was an increasing supply of plant-available N, due to mineralization of organic N in the MSWC with increasing MSWC rate; however, the supply of mineralized N was inadequate to meet crop growth requirements for maximum maize yield.