ESTABLISHMENT AND MANAGEMENT OF 'GRASSLANDS MAKU' LOTUS IN ACID, LOW FERTILITY TUSSOCK GRASSLANDS

Abstract

'Grasslands Maku' lotus (Lotus pedunculatus Cav.) is a legume with high potential for the development of acid (pH < 5.2), phosphate-deficient soils which represent approximately half of the area of the tussock grasslands of New Zealand. Experiments at a number of sites have shown Maku lotus to produce about three times the yields from clovers under similar levels of superphosphate topdressing. The superiority of lotus is attributed to its greater P efficiency on acid soils high in exchangeable Al. Maku can be established with low topdressing (100 kg superphosphate/ha) . Because of its responsiveness to additional P (and given more reafistic seed prices), it lends itself to low-cost development with low fertilizer input followed by intensification of the programme by topdressing as the development generates capital. Good establishment can be obtained from oversowing at 2 to 3 kg seed/ha and allowing time for increased density via rhizome spread. Rhizome development can be enhanced by deferring grazing in the establishment year until April following spring oversowing. While lime (0.5 t/ha) increases establishment, the economics of liming as a means of economizing in seed is doubtful. When the lotus was allowed to regrow to 15 cm, grazing with sheep to 2.5 cm compared with grazing by cattle to 7.5 cm did not affect yields. Evidence under farm conditions suggests lotus will persist on acid soils under close and continuous grazing.