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.