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| Titel |
Effect of compost supplies on soil bulk density and aggregate stability. Results from a six years trial in two experimental fields in Northern Italy |
| VerfasserIn |
C. Calzolari, F. Ungaro, P. Salvador, D. Torri |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026424
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| Zusammenfassung |
| Results of a long term trial (2002-2007) on the effect of different organic amendments on
topsoil structural properties at the end of the 6th year are presented.
Two soils located in two experimental farms of the Emilia-Romagna region (Northern Italy),
namely a silty clay loam Haplic Calcisol under sorghum (Sorghum bicolor, L.) continuous
cropping, and a silty Calcaric Cambisols under peach (Persica vulgaris, Mill.), have been
treated with a different amount of organic amendments. Four different treatments were tested
plus control: manure (10 Mg ha-1 y-1), low input compost (5 and 10 Mg ha-1 y-1), high
input compost (10 and 40 Mg ha-1 y-1), and no-tillage. In all the plots soil samples were
collected three times every year: at the beginning of the growing season, at full crop
coverage and after harvest. At each time, samples were collected in three replicates
and soil bulk density and aggregate stability were measured. At the end of the 6
years trial 930 bulk density and 405 aggregate stability measurements were made
available.
The influence of organic amendments on soil physical properties is different according to the
considered soil property and to the different soils. Soil bulk density (BD) shows clear
and statistically significant differences among the tested theses, all with a marked
seasonality and distinct temporal trends. The overall trends observed in the two soils are
coherent with the amount of organic matter distributed in the different theses and with
the field operations (tillage mainly), but with a short term effect. More important,
over the period of observation and within each year, the treatments exhibit cyclical
variations due to climate seasonality. Among the treatments, that with distribution of
manure exhibits the weakest seasonal variations and a substantially stable general
trend, with BD values slightly lower than those observed for the control. Different
effects are also observed on soil aggregates stability, but also in this case a temporal
trend is not clearly detectable, suggesting that the amendments have no cumulative
effect at least during the 6 years of observations, and the responses are different in
the two trials: slightly positive for the low compost supply in the silty clay loam
Haplic Calcisol and negative for both low and high compost supply in the silty
Calcaric Cambisols. The dominant issue is the seasonal variability of aggregate
resistance which is well shown at the site where more data are available. Data also
hints an ambiguous behavior of the compost: increasing the amount of applied
compost leads to a slight increase in aggregate stability which is then followed by a
decrease, as if the aggregation capability of the compost is counteracted by a dispersion
effect. |
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