Efecto de los lodos residuales de la planta tratadora de aguas en Aguascalientes (México) sobre los artrópodos del suelo de dos agroecosistemas

  1. Flores Pardavé, Lizbeth
Supervised by:
  1. Ana Jesús Hernández Sánchez Director
  2. Francisco Flores Tena Co-director

Defence university: Universidad de Alcalá

Fecha de defensa: 08 July 2009

Committee:
  1. Jesús Pastor Piñeiro Chair
  2. Miguel Ángel Rodríguez Fernández Secretary
  3. M. Isabel Sastre Conde Committee member
  4. Carmen Lobo Bedmar Committee member
  5. Vicente Manuel Ortuño Hernández Committee member

Type: Thesis

Abstract

Actually the societies has increased production of organic wastes, in the end of the last century has begun to attach importance to scientific research that may enable the use of such wastes in agriculture in Latin America with the purpose of to evaluate their effects. This work was carried out in Aguascalientes state (Mexico), where large volumes of wastewater are treated in a purifyng plant obtaining large quantities of resultant byproduct sewage sludge (biosolids). Among all the possible uses of this byproduct the application to agricultural soils is the alternative widespread in most countries of the world. The effects of biosolids on soils and crop production is the most frequent subject of study, but we do not have knowledge about the effects on soil fauna. Therefore, our investigation focuses on assessing the effect of biosolids on soil arthropods of two common forage agroecosystems in the Mexican highlands (alfalfa and corn). And this has been tried: - Characterize the biosolids produced for the more important wastewater treatment plant of Aguascalientes state, their composition related with fertility and toxicity due to its application to soils of agroecosystems. - To estimate the abundance and diversity of soil arthropods by experimental field that include different rates of application of biosolids in two soil of these agroecosystems. - A comparative study of the relationship between soil arthropod fauna and forage production with habitual management in Mexcican agroecosystems and with the recent practice of biosolids addition. - To know deeply relations arthropod food webs in soil with application of sewage sludge as well as the relations of these organisms with heavy metals entering the waste ground. - Identify functional groups of soil arthropods in agroecosystems amended with biosólidos. - Provide scientific knowledge about the soil arthropods in Mexico, especially any of the groups would be more abundant in the systems studied. The major difficulties to execute these goals have been linked to both the taxonomic diversity of soil organisms as each species requires different protocols for their taxonomy, and the absence of comparable data with those obtained by us, both for the type of soil and climate where biosolids are applied. However, the volume of samples of arthropods collected in the scenarios where this investigation was carried out through three tests in fields, with different time duration (two consecutives years after biosolids application and other two tests six months after biosolids addition) and other bioassay under controlled conditions (three months) for each of the agroecosystems (alfalfa and corn), they have allowed us to complete all objectives. The results are summarized below. The analysis of samples of sewage sludge could be applied to soils on forage agroecositemas at the Mexican Altiplano because not exceed levels prescribed by Mexican legislation. Taxonomic groups of soil arthropods most abundant in soils have been springtails, mites, beetles, flies, hemiptera, hymenoptera and spiders. Biosolids increased the abundance of springtails and mites, especially when using high doses of biosolids applied to soil, as the abundance and diversity of the community of heterotrophs decreases with the application of high doses. The springtails seems to be the protagonist group in these systems, although their seasonal dynamics are involved both climatic factors such as predator-prey relationships (mites-springtails), and the volume of biosolids applied. This research provides not only quantitative data on the arthropods of agricultural soils of Mexico, it helps to show the importance of this biological component in the flows of N and P in agroecosystems added with the organic waste in question.