Programa e Resumos - I Congresso Ibérico de Ciência do Solo 2004

I Congresso Ibérico da Ciência do Solo – 15 a 18 de Junho de 2004, Bragança, Portugal
Municipal Waste Compost´s phytotoxicity on lettuce’s germination and
biomass.
Raúl del Río González 1 , Diana Hernández 2 , José Manuel Fernández 2 , Hector Matias Fritis 2
& Alfredo Polo Sánchez 2
1 Centro de Ciencias Medioambientales (CCMA), C.S.I.C. c/Serrano 115 dpdo., 28006 Madrid,
Spain. Tel: (+34) 91.411.53.01 – Fax: (+34) 91.411.53.01 – E-mail: raul@ccma.csic.es &
rlglez@terra.es
2 Centro de Ciencias Medioambientales (CCMA), C.S.I.C. c/Serrano 115 dpdo., 28006 Madrid,
Spain. Tel: (+34) 91.411.53.01 – Fax: (+34) 91.411.53.01 – E-mail: apolo@ccma.csic.es
Resumo
Comunicação: Painel
Municipal Waste Compost (MWC) can produce contamination and phytotoxicity on
soils and our goal will be to describe in which way or ways this phytotoxicity, at
different MWC concentrations, is being affected to the soil´s properties. This
phytotoxicity is tested on the lettuce’s germination and final biomass.
The experiment was carried out in spring, inside a greenhouse based on standard ISO
11.269-2 and using a clay soil as the matrix for Compost. The culture chosen was
Lactuca sativa (lettuce). The dose of Compost used were 0 (control), 20, 150, 300, 450,
600, 750 and 900 The essay lasted 28 days, during which, the number of seeds
germinated, germination´s rate (GR) was measured. After this period, the final number
of plants (G), the aerial (Bpl), root (Br) and total (Bt) biomass of the plant were
measured as well as the soil’s electrical conductivity (EC) and soil’s pH.
MWC´s phytotoxic effects on G can be observed in doses up to 150 m3·Ha-1. Bt has a
quite similar behavior. Both have a LOEC (lowest observed effect concentration) at
150. With this dose we have more than 60% reduction compared with control and 20.
And more than 90% reduction with 600 m3·Ha-1. There are no significant differences
between Br & Bpl in that phytotoxic effect. The increase of EC and pH is significantly
correlated with the decrease of G & Bt. And only those two parameters can explain and
absorb the most part of the phytotoxicity in a model. All the treatments have the same
GR, almost 100 % of the seeds germinated do so after 14 days.
As a result, MWC shows phytotoxicity on the lettuce plant with concentrations
superior to the ones used in field. It can also be said that only EC and pH are a strong
explanation of this phytotoxicity. The phytotocity affect has an equal effect in the
Germination and the Biomass but have no effect on the rate of germination.
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