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+3.0Echi_cruMars_creEcli_albLept_chiMono_vagPScir_junMoll_penEchi_colLudw_hys Cype_iriMurd_nudIsch_rugErag_tenPasp_disTyph_triKCype_halEleu_indDigi_cilComm_benpHCype_tenLind_sppHedy_cor Fimb_milCype_rotLudw_octPhyl_nirCyno_dacAxis 1CAlte_sesCype_difEuph_hirAmma_bacBrac_mutAxis 1 Axis 2Port_olepH –0.954 –0.277Hedy_bifC –0.616 –0.661Lind_cruPK–0.028–0.5160.6940.156Axis 2Spha_ind–2.5–2.0 +3.0Fig. 7. Biplot diagram for species and selected soil variables from canonical correspondenceanalysis. Arrows indicate the direction of change of environmentalvariables (pH, P, K, and C) and their relationship with ordination axes. Correlationsbetween measured environmental variables and axis scores are inset. Speciesnames are truncated (see Table 3).Ammannia baccifera was dominant. Both Echinochloa colona and Fimbristylismiliacea showed a broad adaptation to toposequence conditions (Fig. 6), although thelatter was more abundant in mid slope.These communities are likely to have comprised plants of varying age, sincemature individuals may have escaped manual weeding operations earlier in the life ofthe crop or be younger by virtue of recruitment after weeding has ceased. Assumingthat the last weeding was approximately 40–50 days after emergence and bootingwas one month later, then 30 days may have elapsed between the completion of manualweeding and the census. This time period is of sufficient duration for populations ofEchinochloa colona, Fimbristylis miliacea, and Lindernia spp. to develop, and forspecies with strong developmental plasticity to complete the life cycle and contributeseed to future weed infestations.282 Pane et al