The effects of paraquat spraying, seed placement, and pre-germination on the appearance and survival of white clover, cocksfoot, and ryegrass seedlings from spring oversowing in hill country

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Abstract
Some factors affecting success or failure of oversowing were examined. White clover (Trifolium repens L. ‘Grasslands Huia’), cocksfoot (Dactylis glomerata L. ‘Grasslands Wana’), and ryegrass (Lolium perenne L. ‘Grasslands Nui’) seed was placed at precise locations in a hill country sward and the appearance and survival of seedlings in response to treatments were monitored. Treatments included paraquat spraying (0.8 kg a.i./ha) before oversowing, seed placement on or below the soil surface, and pre-germination of seed. The number of seedlings established was in the order Huia > Nui > Wana, however the number of leaves per seedling was generally in the order Nui > Wana > Huia. Averaged over the three species, seedlings were larger and more abundant for sprayed treatments compared with non-sprayed treatments. Seed placed below the soil surface appeared as seedlings more rapidly than seed on the surface, but subsequent seedling development was similar for both seed placement treatments. Pre-germinated seed appeared more rapidly than seed sown dry, but subsequently showed no advantage in plant establishment. The dynamics of seedling appearance and death are presented and reasons for differences between treatments are discussed.