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| Titel |
Soil fertilization with composted solid waste: short term effects on lettuce production and mineral N availability |
| VerfasserIn |
Nunzio Fiorentino, Massimo Fagnano |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054929
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| Zusammenfassung |
| Composting of the solid waste organic fraction would be a possible solution to the
long-standing rubbish problem, limiting the amount of waste going to final disposal.
Furthermore is well recognized the key-role of composted organic matter in increasing soil
fertility, porosity, structural stability, moisture and nutrient availability, biological activity and
root aeration. The positive effects of compost addiction on soil organic matter (SOM)
humification have also been proved in different agricultural systems; it could be particularly
useful in Mediterranean areas, where the degradation of SOM is accelerated by the
alternance of dry-warm and humid-temperate seasons and by the high intensity and
frequency of soil tillage in horticultural soils. Nevertheless the effects of compost
addiction on N availability for crops are contrasting in relation to the pedo-climatic
conditions.
The present work focuses on the effects of compost fertilization on soil N kinetics and on
lettuce N uptake and yield. An open-field experiment was carried out in a farm
in Caivano municipality (40Ë 56’N, 14Ë 19’E), 12 km far from Naples City, to
compare the following treatments: not fertilized control (NF), mineral fertilization
(MF), compost fertilization with 10 (CF10), 30 (CF30) and 60 (CF60) Mg ha-1
of compost from solid urban wastes. Two cultivars of iceberg lettuce (L. sativa
var. capitata L.) were used, ‘Audran’ in the 1st growth cycle and ‘Sagess’ in the
2nd one, suitable to summer and winter cropping periods respectively. Compost
fertilization was performed only before the 1st cycle, while mineral fertilization with
84 kg ha-1 of N (ammonium nitrate) was carried out at transplant of both lettuce
cycles.
The experimental design was a randomized block with 3 replicates and all the data were
subjected to ANOVA, using the MSTAT-C software (Crop and Soil Science Department,
Michigan State University, Version 2.0). Mean separation was made by using LSD
test.
MF, CF30 and CF60 gained the highest total yield in both the growth cycles. On the
average lettuce yield was lower in the winter cycle as a consequence of lower SOM
mineralization and of nitrate leaching from the root layer during the rainy season. Obviously
yield reduction in the winter cycle was pronounced in not fertilized plots (-40%), while it was
slighter for CF60 (-16%). This difference was probably due to the mineral N release from
compost between the two growth seasons, getting to the highest nitrate content in topsoil
layer (0-20 cm) at the 2nd lettuce transplanting (65 mg kg-1 and 25 mg kg-1 for CF60 and
NF respectively).
The nitrate content of lettuce leaves, on a fresh weight basis, was much lower than 466/01
European Directive threshold (493 mg kg-1 on the average vs 4500 mg kg-1) in both
growing cycles, confirming the low nitrate accumulation rate in the Mediterranean area. N
budget, calculated as the difference between N supplies and N uptake in the two growth
seasons, showed a significantly higher value in CF60 (153 kg N ha-1) and a strong N deficit
in NF and CF10, whereas a balanced budget (not different from 0 kg ha-1) was measured in
MF and CF30.
The results achieved in the present study demonstrated the compost ability to sustain
lettuce N requirements in coarse textured soils, and highlighted the need to balance the
compost doses according to N requirement of cropping systems thus reducing N surplus
and nitrate pollution hazard. A better understanding of N mineralization patterns
of composted manures in different soils could be the best way to reach this goal. |
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