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Fig. 4. Species-treatment biplot of the relationships between weed species abundance(emerged seedling count in 2004) in the soil seed bank and treatments from principal componentanalysis. Species codes are given in Table 1. Rare species (counts < 2) omitted.Fertilizer regime and crop establishment method were given linear scores. For establishment,TPR = 1, DSRm = 2, DSRh = 3; fertilizer regimes coded in relation to total added nutrient,kg ha –1 . Axis 1 (horizontal) correlations with fertilizer regime and crop establishment methodwere –0.13 and 0.31 and correspondingly for axis 2 (vertical), –22 and –0.15. The directionindicated by the vector for crop establishment method indicates DSR; thus, Monochoriavaginalis is associated with TPR and Ischaemum rugosum associated with DSR.rugosum and, to a lesser extent, Fimbrystilis spp. and Eclipta prostrata, with directseededplots. Close species associations in the biplot may be a consequence of theaveraging effect of yearly variation in the abundance of individual weed species duein part to factors influencing seedling recruitment, as discussed above, and commonoccurrence in both TPR and DSR plots.The implications for sustainable weed managementin DSR in the BarindWhere farmers have limited control over field water regimes, as on shallow slopingland affording a toposequence, a diverse weed flora will result.Site position on the toposequence and soil nutrient status (Pane et al 2000),coupled with patterns of seasonal variation in rainfall, have a marked effect on therecruitment of individual weed species and hence the composition of the weed floracompeting with the emerging crop.Attempting to simply attribute this composition to a particular method of cropestablishment, for example, TPR or DSR, however, lacks precision and relevance (as76 Mortimer et al