Fate of P from organic and inorganic fertilizers assessed by complementary approaches

Abstract

Long-term field experiments (LTFEs) can provide an extensive overview on the effectiveness of phosphorus (P) management. In order to have a detailed insight into the availability and distribution of the P in soil as affected by organic and inorganic fertilizers (no P, triple-superphosphate (TSP), compost and compost + TSP), soil samples collected at a LTFE established in 1998 in Northern Germany at different sampling dates and soil depths were subjected to P characterization including the double-lactate method (P-dl) as standard soil test, the degree of P sorption (DPS), the sequential P fractionation and isotopic exchange kinetics. While the type of fertilizer had rarely an effect on the soil P pools, higher amounts of P applied resulted in increased values of P-dl, labile P fractions and P that was isotopically exchangeable within 1 min (p < 0.05). The DPS values varied from on average 40.2% (no P) to 47.2% (compost + TSP) with small variations during the experimental time. In contrast, significant shifts from less available to readily available P pools were measured between the sampling in autumn 2017 and spring 2019. The differences in the P budgets between the treatments corresponded to the differences of the total P stocks in 0–90 cm, yet with an estimated upward or downward movement of P between the soil depths as consequences of long-term deficit or surplus of fertilizer P. The use of complementary methods in this study contributed to a better understanding of the potential availability of P in soil in a long term perspective.

The Potential of Microgranular Fertilizers to Reduce Nutrient Surpluses When Growing Maize (Zea mays) in Regions with High Livestock Farming Intensity

“…The fertilizer treatment with the highest P input (DAP) resulted in similar yields as that of the variant with the lowest P influx (the control treatment (slurry only), without any additional fertilizer) (Table 1). Previous studies have similarly shown that differences in P inputs and fertilizer types do not automatically result in different levels of P forms available to plants within the soil P pool and thus yields, depending on the crop [29,30]. Furthermore, the soil of the study site was already moderately rich in P, which may have led to the fertilizer having a smaller effect.…”

Long‐term changes in soil phosphorus in response to fertilizer application and negative phosphorus balance under grass rotation in mineral soils in Nordic conditions

“…1 kg per year can be explained by leaching (Räty et al., 2020). Although major Pi leaching into the subsoil is unlikely since Pi is adsorbed by Al and Fe hydroxides (Kaila, 1963b), there is evidence of some transport of low‐molecular‐weight Po compounds and translocation of Po into the subsoil via root systems (Dott & Sharpley, 2015; Hu et al., 2022), while transport of eroded material has traditionally been considered the major route of P loss in fertilizer application experiments (Sibbesen, 1986). Additionally, uncertainties in sequential extraction, containing various steps is seen in SEM in Ruukki.…”