Growth of corn in varying mixtures of paper mill sludge and soil

To evaluate different levels of paper mill sludge as a soil amendment for the production of corn (Zea mays L.), sludge was added to 15-cm pots of soil in a greenhouse experiment. Mixtures were made from paper mill sludge (0 to 560 Mg ha(-1) wet weight) mixed with field soil (Hadley fine sandy loam with coarse, mixed, mesic, Fluventic, Dystrochrept deposits). Nitrogen (N) was added as ammonium nitrate at 0 or 200 kg N ha(-1). Eight corn seeds of 'Pioneer Max 21' were seeded into each pot immediately after mixing the paper mill sludge and soil or at 21 days after mixing the media. Seven days after sowing, seedlings were counted in each pot to assess germination (emergence). Delaying of sowing of seeds for 21 days increased the number of seeds that germinated. Corn plants were harvested after 35 days of growth. Plant biomass declined as amounts of sludge increased. Adding N and delaying sowing for 21 days produced the greatest amount of dry mass. Tissue (leaf) total N decreased with increasing amounts of sludge.Addition of N to the mixtures increased the average total N in corn leaves. However, leaf total N still decreased with increasing amounts of sludge added even if N at 200 kg ha(-1) was added to the media. Sowing immediately after setup showed the highest leaf total N if no sludge was added to the mixture. Sowing immediately after setup of the experiment and adding paper mill sludge at 560 Mg ha(-1) produced the lowest total N in corn leaves. Generally, the phosphorus (P) concentration in plants increased as the amount of paper sludge increased. but the increase was less with N added than in treatments without N added. At 21 days, carbon: nitrogen, pH, and salinity of the media declined relative to the initial values. Total N in the media was higher after a 21-day delay than immediately after setup. Organic matter content increased with increasing amounts of paper sludge. Results indicated that addition of paper sludge to soil increased media organic matter and P contents. Germination was hindered when seeds were sown immediately after setup of the experiment, but delaying seeding for 21 days eliminated the germination problem. Nitrogen deficiency was problematic, and more than 200 kg ha(-1) of supplemental N is recommended to overcome immobilization of N.