Long-term nitrogen fertilizer replacement value of cattle manures applied to cut grassland

Abstract

Manures supply nitrogen (N) to crops beyond the year of application. This N must be taken into account for agronomic and environmental reasons. From 2002 to 2006 we conducted a field experiment on a sandy soil in The Netherlands (52°03″N, 6°18″E) to better quantify this residual N effect. Treatments comprised different time series of mineral fertilizer N or cattle manures of different compositions, all applied at a rate of 300 kg total N ha −1 year −1 , whilst compensating for differences in available potassium and phosphorus. Dry matter and N yields of cut grassland responded positively (P<0.05) to both current manure applications and applications in previous years, whereas mineral fertilizer N affected yields in the year of application only. N yields could be reasonably well predicted with a simple N model, adopting an annual relative decomposition rate of the organic N in manure of 0.10-0.33 year −1 during the year of application and 0.10 year −1 in the following years. Subsequent model calculations indicated that the N fertilizer value (NFRV) of injected undigested cattle slurry rises from an observed 51-53% when slurry is applied for the first time, to approximately 70% after 7-10 yearly applications, whereas it took two to four decades of yearly applications to raise the NFRV of surface applied farm yard manure to a similar level from an initial value of 31%. Manures with a relatively high first year NFRV (e.g. anaerobically digested slurry) had a relatively small residual N effect, whereas manures with a low first year NFRV (e.g. farm yard manure) partly compensated for this by showing larger residual effects. Given the long manuring history of most agricultural systems, rethinking the fertilizer value of manure seems justified. The results also imply that the long term consequences of reduced N application rates may be underestimated if manuring histories are insufficiently taken into account.

Slurry 15NH4-N recovery in herbage and soil: effects of application method and timing

“…In the present study, 15 N labelling of the slurry ammonium fraction made it possible to follow the fate of slurry N in the soil-plant system and simultaneously calculate losses through a mass balance approach. The slurry ammonium N fraction makes up approximately 50% of the slurry total N and is rapidly available for plant uptake, and therefore is considered the most important fraction for plant growth during the year of application (Schröder et al 2007). …”

Results of potato fertilizer demonstrations in Pangalengan and Garut, Indonesia : Wet season 2014/2015 and dry season 2015

“…The P 2 O 5 removed with the harvested product was lowest for the unfertilized treatment in both locations and showed the lowers surplus. The Apparent Phosphate Recovery (APR, %) of the chemical fertilizer was calculated at 56 days after planting and at harvest as the difference of the P 2 O 5 yield of the fertilized crop and the non-fertilized control crop, expressed as a percentage of the total P 2 O 5 input from the chemical fertilizer (Schröder, et al 2007). Table 4.6 shows that APR ranges from 1 to 15%.…”

The Position of Mineral Nitrogen Fertilizer in Efficient Use of Nitrogen and Land: A Review

“…The eventual NFRV depends on the ratio of mineral N and organically bound N, on the extent to which the fertilizer is effectively incorporated into the soil (determining volatilization losses of ammonia-N [21] [24]), on the length of the growing season (determining the extent to which mineralization patterns of organic N lag behind the crop uptake patterns), on the time of application (as heavier soil types can make it impossible to apply some types of organic fertilizers at the start of the growing season without damaging soils or crops), on weather and soil conditions, and on the manuring history. The manuring history determines to which extent farmers should factor-in the accumulated residual effects of applications in preceding years [26]. In addition to these relatively low and variable NFRVs, is it noteworthy to say that the nutrients in organic fertilizers are generally strongly diluted, whereas nutrients in industrially synthesized N fertilizers are up to hundreds times as concentrated as organic fertilizers, making their handling (storage, transport, positioning) relatively easy.…”