03755naa a2200193 a 450000100080000000500110000800800410001910000160006024501700007626000090024652028780025570000160313370000180314970000150316770000240318270000150320670000190322177303210324013149572008-09-25       2008    bl uuuu     u00u1 u    #d1 aLAZCANO, C.  aNutritional and non-nutritional effects of vermicompost on the growth and yield, of sweet maize (Zea mays L.)brole of plant genotype and effects on soil properties.  c2008  aVermicompost has shown to improve germination and enhance growth in some plant species at low doses because it contains plant growth promoting substances produced by microorganisms. Nevertheless, published data show a certain inconsistency, and it is speculated that plant growth promotion might depend on many other factors, like plant genotype. The objective of this study was to evaluate the nutritional and non nutritional effects of rabbit manure vermicompost on the growth, nutrition (N, P, K leaf content) and yield (fruit production, fruit quality) of four maize varieties in a field assay. The effects of the vermicompost were compared to the effects of rabbit manure and mineral fertilization. The changes exerted by these treatments on soil biological properties (enzyme activities, soil respiration, microbial biomass, bacterial and fungal growth) were also evaluated. The doses of the fertilizers were adjusted to a normal NPK mineral fertilization for an expected final grain production of 4 Tm/Ha and the nutrient content was balanced among the treatments. An extra dose, for an expected grain production of 6 Tm/ Ha, was included to separate the nutritional and non-nutritional effects on plant growth and yield. Experimental units consisted of 10 m2 plots with the combination of variety x type of fertilizer x dose. Twenty-six seeds were planted in each plot and plots were distributed following a randomized design. The type of fertilizer used did not influence the germination, early growth, flowering and final growth of the maize plants. Since these parameters were under strong genetic control, they were only influenced by the doses of fertilizer. Neither did the type of fertilizer affect the final yield (tons of grain per hectare) of the plants. No effects were observed, either, in the quality of the marketable cobs due to the type of fertilizer, and the parameters analyzed proved to be influenced primarily by plant genotype and secondarily by the dose of fertilizer. Both vermicompost and manure modified some of the soil parameters, increasing the availability of an essential plant nutrient like PO4 through the enhancement of the activity of the enzyme alkaline phosphatase. Protease activity was also enhanced in the organic treatments, where there was significantly higher fungal biomass and bacterial growth. The maize plants reacted to the quantity of nutrients supplied but not to their quality, and the changes exerted by the organic fertilizers in soil biological properties were not enough to produce a significant increase in plant growth and yield. Nevertheless, both the manure and the vermicompost performed similarly to the mineral fertilizer even at the extra dose, and therefore, the use of this type of organic fertilizers is well worth considering in the context of more environmentally-friendly practices in agriculture.1 aREVILLA, P.1 aMALVAR, R. A.1 aORDÁS, B.1 aGÓMEZ-BRANDÓN, M.1 aMONROY, F.1 aDOMÍNGUEZ, J.  tIn: INTERNATIONAL COLLOQUIUM ON SOIL ZOOLOGY, 15; INTERNATIONAL COLLOQUIUM ON APTERYGOTA, 12., 2008, Curitiba. Biodiversity, conservation and sustainabele management of soil animal: abstracts. Colombo: Embrapa Florestas. Editors: George Gardner Brown; Klaus Dieter Sautter; Renato Marques; Amarildo Pasini. 1 CD-ROM.