| Abstract: | The effects of seven herbicides, alone or combined with a commercial compound fertiliser, on nitrogen and phosphorus transformations in soil, were investigated in the laboratory. No significant effect was observed without the fertiliser. When the fertiliser (N:P:K ratio 20:14:14) was applied (2 gkg?1 of soil), asulam markedly reduced nitrification, while increasing the mineralisation of nitrogen; chloridazon, glyphosate, isoproturon and paraquat all prevented the reduction in available phosphate that occurred in the control soil in the first 2 weeks. The rates of degradation of dalapon and isoproturon were greatly reduced in fertilised soil. The importance of these results is discussed in the context of the requirements of registration authorities. |
