Grass establishment and performance on a high country soil fertilised with nitrogen

Abstract

Slowreleasesulphur-coatedurea(SCU) was drilled with seed of 'Grasslands Nui' ryegrass (Lolium perenne L.), 'Grasslands Roa' tall fescue (Festuca arundinacea Schreb.), 'Grasslands Wana' cocksfoot (Dactylis glomerata L.), 'Grasslands Maru' phalaris (Phalaris aquaticaL.), and 'Massey Basyn' Yorkshire fog (Holcus lanatus L.) in glasshouse and field trials to improve establishment on a low fertility high country soil. In the field trial, SCU (50 kg nitrogen(N)/ha) was also broadcast at sowing and uncoated urea (50 kg N/ha) was broadcast after seedling emergence. In the second year, one half of each field plot was given 125 kg N/ha in five applications and in the third year all field plots received 125 kg N/ha in three applications. Grass establishment was greatly enhanced by 25-75 kg N/ ha. SCU, drilled with the seed at rates above 25 kg N/ha, caused germination injury but surviving seedlings responded well to any additional N. At the highest N rates (100 kg/ha or more) individual grass plants grew vigorously but their patch y cover allowed the resident hawkweed (Hieracium piloseUa L.) to grow vigorously in the intervening spaces. SCU broadcast at sowing or uncoated urea broadcast after emergence were generally less effective than the same rate of drilled SCU. Although Nui and Roa had the most uniform establishment, the second year yields were best overall for Wana and Basyn where N had been applied in both the first and second years. Without N in the second year there was little growth in any plots. Maru seedlings did well initially but appeared to suffer from aluminium toxicity in the second year. Third year yields were highly dependent on the application of N in the second year and to a lesser extent on the first year's application. The cultivarresponse varied, withNui being most affected by lack of N in the second year and Basyn the least. The need to supply N in a manner which minimises germination injury yet maximises uptake by the see~l.ing .is discussed. The option of applying N fertIlIser IS c?mpared with liming, and with using a legume-dommant phase to improve N availability.

Introduction, production, and persistence of five grass species in dry hill country

“…This has led to a dilemma between the desire to continue to include grasses in the sowing mixtures (as this is what is ultimately required), and the experience of low success, leading to the use of low seeding rates to reduce overall costs. Recent experience has shown the need to minimise any competitive, moisture, and nutrient stress through land preparation and management, to improve grass establishment (Pollock 1989). Little research has been undertaken into the introduction of grasses following legume establishment, although there is ample advice that grasses need to be introduced.…”

Dryland legumes: perspectives and problems

“…Any use of N fertiliser to aid legume establishment is a fine balancing act at low application rates (e.g. Pollock 1989). Legumes preferentially use available soil N rather than establish their root nodule bacteria N-fixation system.…”

Establishment response of 12 legumes to nitrogen fertiliser rate and placement when direct drilled intoHieracium‐infested, montane tussock grasslands

“…Drilling N with the seed had a similar effect to basal fertiliser in increasing seedling development but reduced germination/early seedling establishment. However, Pollock (1989) found no germination injury from drilling low rates of slow release sulphur-coated urea (SCU). A practical method of improving seedling growth without impairing germination would be to drill 15-20 kg ha" 1 N as SCU, mixed 62 New Zealand Journal of Agricultural Research, 1998, Vol.…”

“…Pollock (1989) and Woodman et al (1994) improved grass establishment by the application of small amounts of nitrogen (N) fertiliser at sowing. Rates of N at 25 kg N ha~' and above reduced germination when drilled with the seed but the growth of surviving seedlings responded to the N fertiliser.…”