Environmental Engineering Reference
In-Depth Information
8
Response
of Soil Microflora to Pesticides
Mariusz Cycoń and Zofia Piotrowska-Seget
CONTENTS
8.1 Introduction ........................................................................................................................ 233
8.2 Effect of Pesticides on Soil Respiration and Microbial Biomass ................................. 234
8.3 Effect of Pesticides on Soil Enzyme Activities............................................................... 236
8.3.1 Dehydrogenase Activity ....................................................................................... 236
8.3.2 Fluorescein Diacetate Hydrolyzing Activity ..................................................... 237
8.3.3 Phosphatase Activity............................................................................................. 238
8.3.4 Urease Activity....................................................................................................... 239
8.3.5 Other Enzymes....................................................................................................... 240
8.4 Effect of Pesticides on Soil Nitrogen Transformation Rates ........................................ 241
8.5 Effect of Pesticides on Soil Microbial Numbers ............................................................ 242
8.5.1 Heterotrophic Bacteria .......................................................................................... 243
8.5.2 Fungal Populations................................................................................................ 244
8.5.3 Bacteria Involved in the Nitrogen Cycling......................................................... 245
8.6 Effect of Pesticides on Structural and Functional Diversity of Soil Microbial
Communities ...................................................................................................................... 246
8.6.1 PCR-DGGE Profiling ............................................................................................ 247
8.6.2 Phospholipid Fatty Acid Analysis....................................................................... 248
8.6.3 Community Level Physiological Profile ............................................................. 249
8.7 Conclusions......................................................................................................................... 251
References..................................................................................................................................... 251
8.1 Introduction
In modern agriculture, large quantities of pesticides have been used to control pests and
weeds and thus increase food production. However, their wide and extensive application
and a potential risk that they pose to the soil ecosystem raise a number of environmen-
tal concerns. One of the problems that should be addressed is the impact of pesticides
on nontarget soil microorganisms, resulting in the perceptible changes of soil properties
and the alterations of soil equilibrium for shorter or longer periods. It is well recognized
that balance in the soil environment largely depends on the activity of the microorgan-
isms, since they play an essential role in many soil biological processes, including nitrogen
transformation, organic matter decomposition, and nutrient release and their availability,
as well as stabilization of the soil structure (Edwards and Bater 1990).
Pesticides may affect the microorganisms by reducing their numbers, their biochemical
activities, and the diversity of microbial communities (Martínez-Toledo et al. 1998; Chen
233
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