Title: EFFECTS OF NITROGEN AND THREE SOIL TYPES ON MAIZE (ZEA MAYS L.) GRAIN YIELD IN NORTHEAST CHINA
Abstract: The study aimed to understand the effects of nitrogen (N) and soil types on maize (Zea mays L.).Grain yield (GY) is essential for identifying optimal N fertilizer management practices and agricultural policies.In this study, we report results from an on-farm experiment carried out from 2009 to 2012 with five N levels and three soil types in Northeast China.Results revealed that the GY was affected significantly by soil types, with loam soil having an average GY of 10225 kg ha -1 , followed by clay soil (9218 kg ha -1 ) and sandy soil (6434 kg ha -1 ).The optimal N rates required to achieve maximum GY were on average 182, 173, and 160 kg ha -1 , and the corresponding maximum GYs were 10872, 9999, and 7266 kg ha -1 for loam, clay, and sandy soils, respectively.The optimum N treatment (168 kg N ha -1 ) reduced residual nitrate N content and N losses by 97 and 451 kg N ha -1 , respectively, and improved N recovery efficiency (REN) by 17%.In conclusion, within-field soil management zones based on soil textural classes could be used to guide soil sampling and establish soil-specific N fertilizer recommendations to achieve high GY with high REN in Northeast China.