6 had a more diverse Mix treatment than Strip 1 (as indicated in table 1). Effects of this more diverse grass-clover mixture are assumed to be negligible, for the difference between Mix and No-mix was insignificant and the sown species mixture of strip 6 had less time to establish than strip 1.

Total nematodes

The data on total nematode abundance obtained from counting and performing a Q-PCR differed with approximately a factor 10, the question rises whether both data-sets are representing reality. In this study, the data obtained from counting nematodes under the microscope do most likely represent reality better than data obtained from the Q-PCR. This is because less errors could be made in the counting method. The samples were well shaken while 5 mL suspension was taken. Possible explanations for the large difference in nematode numbers between the two quantification methods, are pipetting errors during dilution of samples, or a possible lack of shaking of PCR samples during pipetting. In both scenario’s, less nematodes are possibly transferred into the final Q-PCR tubes than assumed. Although the data cannot represent reality quantitatively, the data within a method can be used as relative values, for the samples are all treated in the same way.

As stated in the results, nematode abundances in the 2 year old grass-clover mixture were shown to be higher than in the one year old mixture. This was significant in both count data and Q-PCR data.

Organic matter content

The field is relatively heterogeneous considering organic matter (OM) content. Expected was to find a relation between OM and fungivorous nematode abundances [15]. However, no correlation exists between Aphelenchoididae or total nematode abundance and organic matter content, according to the results. Possible explanations could be the influence of factors such as Mix/No-mix treatment, water availability or compaction of the soil.

Conclusions

The most important finding is the increase of total nematode abundance in