Pasture establishment on a podzolised soil in Northland

Summary

Factors affecting rhizobial populations and the nodulation of two clover and two lotus species in a strongly podzolised soil, Wharekohe silt loam, have been examined.

No clover nor lotus rhizobia were detected in this infertile acid, soil in its undisturbed state. After thorough cultivation lotus rhizobia were found in all samples, and clover rhizobia in samples hom areas which had been limed. The clover rhizobia were largely ineffective on subterranean clover.

In small plots of cultivated soil it was found that:

1.	(a) Inoculation was advisable for white clover, and essential for subterranean clover.
2.	(b) Lime was essential for adequate nodulation of white clover, subterranean clover, and Lotus corniculatus, and beneficial for Lotus uliginosus. Lime-pelletted clover seed gave good initial nodulation.
3.	(c) At the level of liming used, a micronutrient deficiency, apparently of boron, was induced, and addition of a micronutrient mixture increased nodulation and greatly improved nodule form and plant growth.

In nearby inoculated field sowings, good nodulation occurred with red and white clover, but with subterranean clover most of the nodules were found to be ineffective.