FUNGAL SUCCESSION AND DECAY OF HERBICIDE-TREATED WHEAT-STRAW

The effects of alachlor and haloxyfop on wheat straw decay and fungal succession were studied in laboratory trials. Wheat straw segments wer e immersed in (100 and 1 000 mg/L) herbicides, buried in soil and incu bated at 28 +/- 1 degrees C for 8 weeks. Both herbicides significantly stimulated the mass loss and N-mineralization of wheat straw. CO2 evo lution was not significantly affected while C-mineralization was inhib ited. The pattern of succession of fungi was slightly affected in herb icide-treated wheat straw. However, the frequency of occurrence of Rhi zopus stolonifer was lowered throughout all experimental periods. In a pure culture experiment, both alachlor and haloxyfop at 100, 500 and 1 000 mg/L reduced the radial growth of Alternaria alternata, Aspergil lus niger, A. flavus, Penicillium funiculosum, R. stolonifer and Trich oderma harzianum.