The influence of earthworms on the mobility of microelements in soil and their availability for plants

• Published in: Eurasian soil science 2008-12, Vol.41 (12), p.1306-1313
• Main Authors: Bityutskii, N. P., Kaidun, P. I.
• Format: Article
• Language: English
• Subjects: Analysis; Bioavailability; Calcium carbonate; Earth and Environmental Science; Earth Sciences; Ethylenediaminetetraacetic acid; Geotechnical Engineering & Applied Earth Sciences; Hydroponics; Manganese; Physiological aspects; Plant biology; Soil Biology; Soil sciences; Worms
• ISSN: 1064-2293; 1556-195X
• DOI: 10.1134/S1064229308120089

The influence of earthworms ( Aporrectodea caliginosa, Lumbricus rubellus, L. terrestris , and Eisenia fetida ) on the mobility of microelements and their availability for plants was studied. The contents of water-soluble Fe and Mn compounds extracted from the coprolites were 5–10 times higher than that in the soil (enriched in calcium carbonate and dried) consumed by the earthworms. This digestion-induced effect became higher with the age of the coprolites (up to 9 days) and took place under their alkalization. In the excreta (surface + enteric) of earthworms, the Fe concentration exceeded those of Mn and Zn by many times. Iron and manganese were mostly concentrated (>80% and >60%, respectively) in the organic part of the excrements. In the tests with hydroponics, the excreta were found to be a source of iron compounds available for plants that were similar to Fe 2 (SO 4 ) 3 or Fe-citrate by their physiological effect in the case when the Fe concentration in the excretions was above 0.7 μM. However, the single application of excreta of different earthworm species into the CaCO 3 enriched soil did not significantly affect the plant (cucumber) nutrition. The analysis of the transport of microelements with xylem sap showed that this fact appeared to be due to the absence of an Fe deficit in the cucumber plants because of their high capability for the absorption of weakly soluble iron compounds.