Fertilizer value and nitrogen transfer efficiencies with clover-grass ley biomass based fertilizers

• Published in: Nutrient cycling in agroecosystems Vol. 107; no. 3; pp. 395 - 411
• Main Authors: Benke, Anna Pia, Rieps, Ann-Marleen, Wollmann, Iris, Petrova, Ioana, Zikeli, Sabine, Möller, Kurt
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.04.2017; Springer Nature B.V
• Subjects: Agriculture; ammonium compounds; Animal manures; Biogas; Biomass; Biomedical and Life Sciences; Clover; Composting; Composts; Cropping systems; Efficiency; Farms; Fertilizers; Grasses; green manures; Legumes; Life Sciences; Lolium; Manures; Mathematical models; Mineralization; Nitrogen; Organic fertilizers; Original Article; Phosphorus; phosphorus fertilizers; silage; Specialized farming; temperate zones; Cut and carry; Composts; Animal manures; Biomass silages; Phosphorus; Digestates; Nitrogen
• ISSN: 1385-1314; 1573-0867
• DOI: 10.1007/s10705-017-9844-z

In temperate regions, legume-based green manures are a key element of organic rotations. However, specialized farms lack sufficient mobile organic fertilizers. To gain a better understanding of the N flows and the nitrogen (N) and phosphorus (P) fertilizer value of different clover-grass-based fertilizers (biogas digestate, compost, silage and fresh clover-grass obtained from clover-grass ley biomass), we assessed their fertilizer value. Nitrogen and P offtake by the ryegrass was used to assess the short-term effects. The data were completed using model calculations to assess the field-to-field N-transfer efficiencies and the overall N-transfer efficiencies. The greatest plant N offtake was achieved with digestates (64%) and the lowest from the compost (6%) and solid farmyard manure (14%). The mineralization rate was positively related to the NH 4 + –N/total N ratio ( P  < 0.01, r 2  = 0.82). The model calculations indicate that the overall short-term N-transfer efficiencies are driven by the field-to-field N-transfer efficiency and the field-to-crop transfer efficiency. However, in the long term, model calculations indicate that a high field-to-field N-transfer efficiency is the key strategic approach when aiming to achieve cropping systems with a high overall long-term N-transfer efficiency. Consequently, the results showed that aerobic decomposition (composting) significantly lowered field-to-field as well as field-to-crop N-transfer rates. The relative P use efficiency strongly differed among the fertilizers. In particular, freshly cut clover-grass and solid manure increased P availability and led to an increase of plant P offtake that was higher than the amount of P supplied.