Waste composts as nitrogen fertilizers for forage leys

Authors

• Tiina Tontti MTT Agrifood Research Finland, Plant Production Research, Lönnrotinkatu 3, FI-50100 Mikkeli, Finland
• Arja Nykänen MTT Agrifood Research Finland, Plant Production Research, Lönnrotinkatu 3, FI-50100 Mikkeli, Finland
• Miia Kuisma MTT Agrifood Research Finland, Plant Production Research, Lönnrotinkatu 3, FI-50100 Mikkeli, Finland

DOI: https://doi.org/10.2137/145960609788066807

Keywords:

compost, biowaste, sewage sludge, yield, N uptake, N recovery, apparent bio-available N, N balance, N use efficiency

Abstract

Two field experiments, conventional grass ley and organic grass-clover ley, were established with barley as a nurse crop in spring 2000 and given either low or high fertilization with mineral fertilizer (Mineral) or composts. The compost types were municipal biowaste (Biowaste), biowaste + sewage sludge (BioSludge) and cattle manure (Manure). Plant yields and nitrogen (N) uptakes were measured for three years and efficiency of N utilization was estimated. In single application of compost, the total N was mainly in organic form and less than 10% was in inorganic form. Along with increasing amount of inorganic N applied in compost, the yield, N uptake and N recovery increased during the application year. The highest compost N recovery in the application year was 12%, found with Biowaste. In the following years the highest N recovery was found where the lowest total N had been applied. Clover performance was improved in the organic grass-clover ley established with BioSludge fertilization, producing total ley yield comparable with Manure compost. High total N application in composts caused high N surplus and low N use efficiency over three years. Generally, moderate compost fertilization is suitable for ley crops when supplemented with mineral N fertilizer or clover N fixation.;