Purpose: Fertilisation may cause an accumulation of phosphorus in soil, which may increase risk of P transfer to waters both in colloidal and dissolved forms. This study evaluated the effect of agronomic management on the potential risk of P losses from soil to water bodies in a long-term experimental platform (NW Italy) subjected for 15 years to different maize-based crops and mineral or organic fertilisation based on nitrogen crop requirements. Materials and methods: The field experiment is based on maize for grain and maize for silage cropping systems fertilised with nitrogen-phosphorus-potassium and phosphorus-potassium or with manure and slurry. Soil and P losses were estimated using a simple dispersion test and the amount of suspended solids, total P, colloidal and soluble P determined. Suspended solids were also characterised for their Fe, Al, Ca, C and N contents. Results and discussion: Fertilisation management, mineral or organic, strongly modified the processes which drive soil P buildup and its mobilisation rather than the cropping system type. Manure and slurry application for 15 years has led to a larger P soil surplus compared to mineral fertilisation. However, the contrasting effect of added organic material and P on aggregation/dispersion processes resulted in minor losses of dispersed solids and colloidal P than those expected from the P increase and high Olsen P. Potentially mobilised P was mostly found in suspended solids (>92%); however, a consistent amount of dissolved P was present in the manured soils, indicating that in soils which have reached excessive P levels and are close to P saturation, mobilisation of dissolved P becomes relevant. The amount of dissolved P was well related with Olsen P (r2 = 0. 92, on average), whilst, surprisingly, particulate P was not related, indicating that particulate P losses cannot be estimated only considering the soil P status. Mineral or organic fertilisation caused also a preferential selection of the suspended solids which showed a different composition, highlighting that the type of fertilisation may affect not only the amount but also the type of P and suspended solids which are mobilised. Conclusions: These findings show that fertilisation, mineral and organic, rather than cropping system strongly affects the amount and the type of suspended solids and P which are mobilised. This may have important implications on understanding the factors and mechanisms that control P transfer and its release from particles into waters.
Titolo: | Effect of agronomic management on risk of suspended solids and phosphorus losses from soil to waters | |
Autori Riconosciuti: | ||
Autori: | T. Borda; L. Celi; L. Zavattaro; D. Sacco; E. Barberis | |
Data di pubblicazione: | 2011 | |
Abstract: | Purpose: Fertilisation may cause an accumulation of phosphorus in soil, which may increase risk of P transfer to waters both in colloidal and dissolved forms. This study evaluated the effect of agronomic management on the potential risk of P losses from soil to water bodies in a long-term experimental platform (NW Italy) subjected for 15 years to different maize-based crops and mineral or organic fertilisation based on nitrogen crop requirements. Materials and methods: The field experiment is based on maize for grain and maize for silage cropping systems fertilised with nitrogen-phosphorus-potassium and phosphorus-potassium or with manure and slurry. Soil and P losses were estimated using a simple dispersion test and the amount of suspended solids, total P, colloidal and soluble P determined. Suspended solids were also characterised for their Fe, Al, Ca, C and N contents. Results and discussion: Fertilisation management, mineral or organic, strongly modified the processes which drive soil P buildup and its mobilisation rather than the cropping system type. Manure and slurry application for 15 years has led to a larger P soil surplus compared to mineral fertilisation. However, the contrasting effect of added organic material and P on aggregation/dispersion processes resulted in minor losses of dispersed solids and colloidal P than those expected from the P increase and high Olsen P. Potentially mobilised P was mostly found in suspended solids (>92%); however, a consistent amount of dissolved P was present in the manured soils, indicating that in soils which have reached excessive P levels and are close to P saturation, mobilisation of dissolved P becomes relevant. The amount of dissolved P was well related with Olsen P (r2 = 0. 92, on average), whilst, surprisingly, particulate P was not related, indicating that particulate P losses cannot be estimated only considering the soil P status. Mineral or organic fertilisation caused also a preferential selection of the suspended solids which showed a different composition, highlighting that the type of fertilisation may affect not only the amount but also the type of P and suspended solids which are mobilised. Conclusions: These findings show that fertilisation, mineral and organic, rather than cropping system strongly affects the amount and the type of suspended solids and P which are mobilised. This may have important implications on understanding the factors and mechanisms that control P transfer and its release from particles into waters. | |
Volume: | 11 | |
Pagina iniziale: | 440 | |
Pagina finale: | 451 | |
Digital Object Identifier (DOI): | 10.1007/s11368-010-0327-y | |
Rivista: | JOURNAL OF SOILS AND SEDIMENTS | |
Appare nelle tipologie: | 03A-Articolo su Rivista |
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