Data/hora: 25/06/2024 08:58:02

Biblioteca(s): 	Embrapa Soja.	
Data corrente: 	05/07/2005	
Data da última atualização: 	18/01/2013	
Autoria: 	BROWN, G. G.; PATRÓN, J. C.; BAROIS, I.; LAVELLE, P.	
Título: 	Tropical earthworm (Pontoscolex corethrurus: Glossoscolecidae; Polypheretima elongata: Megascolecidae) effects on common bean (Phaseolus vulgaris) and maize (Zea mays) production under greenhouse conditions.	
Ano de publicação: 	2004	
Fonte/Imprenta: 	In: HANNA, S. H. S.; MIKHAIL, W. Z. A. (Ed.). Soil zoology for sustainable development in the 21st century. Cairo, 2004. p.313-339.	
Idioma: 	Inglês	
Conteúdo: 	Earthworm (Pontoscolex corethrurus and Polypheretima elongata) effects on common bean (Phaseolus vulgaris) and maize (Zea mays) production were evaluated under greenhouse conditions. P. corethrurus and P. elongata were introduced into pots filled with a sandy loam nutrient-poor Alfisol and bean growth was evaluated at three harvest dates (30,62 and 97 d). P. corethrurus was introduced into a clayey Andosol rich in C and N, taken from a tropical rainforest with predominance of C3-type plants (15N = 6.0%o; 13C = 27.3 %o) and maize was grown with or without 15N-labeled residues (3.68 atom % 15N) surface residues and harvested on three different dates (37, 131 and 183 d). Soil bulk density, NO3 and NH4-N, pH, moisture and plant shoot, root, pod, cob and grain biomass were measured. Changes in earthworm tissue 13C were used to determine C additions to the soil and potential assimilation of root-derived C by earthworms. Few effects of earthworms on soil properties were detected, although previous work had shown positive effects on nutrient contents of worm-worked soils and castings. Increasingly positive effects of both earthworm species on bean production were observed with time: bean plants tended to grow significantly better in the presence of both P. elongata and P. corethrurus, leading to higher plant shoot and root biomass at the final harvest, although neither bean pod bean seed production were significantly above control levels (no earthworms). Earthworms also increaed N-uptake by plants, although no active nodules were found, due to absence of R. phaseoli in the soil. With maize, earthworms induced only a significant reduction in the above-ground biomass with earthworms-and residues at the final harvest. Recovery of the 15N from residues in the plants was high (>40%), indicating a rapid recycling of the residue N into growing plants. Earthworms decreased significantly the residue N and 15N stocks but had no effects on plant 15N uptake. The number of large VAM spores was significantly increased by earthworm presence, although no differences were found in root infection by VAM. The lack of positive effects of earthworms on maize production are liked due to the soil's richness, and lack of significant effects on soil parameters, while with beans positive effects due to earthworms were likely due to the low natural fertility of the soil used and absence of rhizobia. Earthworm biomass decreased significantly over the experimental period in all treatments (50 to about 80 % in beans, 87 % in maize), except pots with maize residues (only 20 %). Thus residues were important both for increasing maize production and maintaining earthworm biomass. Maize-root derived C reached up to 8% of the bulk soil C after 6 months, and about 8% of earthworm tissue C was derived from maize roots. The present experiment confirms the important role of soil fertility, earthworm species, plant part and experiment duration on the resulting plant response due to earthworms. Given the complexity of responses due to different combinations of earthworms, soils and plants, further work is warranted to properly determine the conditions in which plants can most profit from earthworm activities in soils.	
Thesagro: 	Estufa; Feijão; Fertilidade do Solo; Milho; Minhoca.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Soja (CNPSO)	
Exemplares: 	CNPSO - (25274-1) - UPC - SP - -- - 10483 -  - 10483 - DIS