Soil Nitrogen Dynamics and Maize Production in Municipal Solid Waste Amended Soil

Abstract

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 NO3–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 NO3–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.