Effects of nitrogen fertilizer and pesticide management on floodwater ecology in a wetland ricefield. II. Dynamics of microcrustaceans and dipteran larvae.
Abstract
Algal, zooplankton, and mollusc populations were monitored over a crop cycle in the floodwater of a tropical ricefield subject to various N-management and pesticide regimes. This paper gives the results on dynamics of microcrustanceans and dipteran larvae. Dominant groups developed in the succession mosquito + chironomid larvae to ostracods to copepods + cladocerans. Populations of ostracods and mosquito+chironomid larvae expanded rapidly after broadcast N applications. Deep placement of N avoided the proliferation of ostracods and dipteran larvae. With the exception of chironomid larvae early in the crop cycle, aquatic invertebrates were generally less abundant in treatments where Azolla sp. was incorporated. When considered at the crop cycle level, aquatic invertebrate populations were not significantly affected by applications of butachlor and carbofuran.
Citation
Simpson, I.C.; Roger, P.A.; Oficial, R.; Grant, I.F. Effects of nitrogen fertilizer and pesticide management on floodwater ecology in a wetland ricefield. II. Dynamics of microcrustaceans and dipteran larvae. Biology and Fertility of Soils (1994) 17 (2) 138-146. [DOI: 10.1007/BF00337746]