Long-term nitrogen supply from cattle slurry

• Published in: Soil use and management Vol. 21; no. 2; pp. 196 - 204
• Main Authors: Schröder, J.J., Jansen, A.G., Hilhorst, G.J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.06.2005
• Subjects: Decomposition; fertilizer equivalents; manure; modelling; nitrogen; residual effect; silage maize
• ISSN: 0266-0032; 1475-2743
• DOI: 10.1111/j.1475-2743.2005.tb00125.x

. Manures can supply nitrogen (N) beyond the year of application, producing residual effects that are are not fully expressed in short‐term experiments. From 1997 to 2003 we conducted a field experiment on a sandy soil in the Netherlands to quantify the residual N effect. Treatments comprised different time series of cattle slurry applied at rates ranging from 0 to 220 kg total‐N ha−1 yr−1, while compensating for differences in available potassium and phosphorus. Dry matter and N yields of silage maize responded positively (P<0.05) to both current cattle slurry applications and applications in previous years. N yields could be satisfactorily predicted with a simple N model by adopting an annual relative decomposition rate (RDR) of the organic N in cattle slurry of 25–33%. Subsequent model calculations indicated that the relative N fertilizer value (RNFV) of cattle slurry rises from approximately 55–60% when manure is first applied to approximately 80% after 6 and 8 years for RDRs of 33% and 25%, respectively. Given the long manuring history of most agricultural systems, rethinking the fertilizer value of manure seems justified.