Manure and fertilizer contributions to soil mineral nitrogen and the yield of forage maize

摘要: Fifteen field trials were conducted to evaluate soil mineral N measurement as a means for quantifying the total supply forage maize and so form basis fertilizer recommendations on crop-specific basis. In every trial, 4 rates of cattle manure (nominally 0, 80, 160, 240 kg per ha) ammonium nitrate (0, 50, 100, 150 factorially combined. Soil measurements made before application, at time drilling, 7-10 weeks after drilling harvest. Measurements control treatments which received no or showed extensive net mineralisation (mean 140 in followed by decrease due crop uptake, probably immobilisation, approximately same amount This was reason why only one trial significant dry-matter yield response nitrate. Results indicated that , be useful recommendations, should taken drilling. Only if this is less than expected offtake applied. A mean around 64% applied could accounted harvest maize, although reduced 24% single where recorded.