Effect of spring application of a paper mill soil conditioner on corn yield

Use of paper mill residuals as soil amendment on farmland is believed to have a beneficial impact on crop yields and soil quality. The objective of our study was to evaluate the effect of spring applying Domtar Soil Conditioner (SC) (pulp and paper mill waste water treatment residue) to a sandy soil in eastern Ontario, Canada. The effects of SC on corn (Zea mays L.) yields, N concentrations in plants, and post-harvest levels in soil of NO3, P, K, Mg, organic matter (OM), and pH were investigated. The experimental design was a randomized complete block with five treatments, replicated four times. The treatments included two SC rates (15 and 25 Mg ha(-1) dry matter: SC15 and SC25), 150 kg ha(-1) NHNOs-N (N150), a composite SC and mineral fertilizer treatment (15 Mg ha(-1) dry matter SC and 75 kg ha(-1) NH4NO3-N: SC15N75), and a control. The experiment was repeated annually from 1997 to 2001. Addition of SC the spring before planting increased grain yield by 2360 kg ha(-1) for SC15 and by 2908 kg ha(-1) for SC25 vs. the control. When N was also added (SC15N75), the average increase vs. the control was 3406 kg ha(-1). More total N was measured in the corn plants from the plots amended with SC than the control. The SC amendments temporarily increased soil OM but did not increase NO3-N leaching risk. Annual spring application of SC improved corn yield but had little impact on soil nutrient levels, OM, and pH.