Microsite effects on abundance of sown species on uncultivable slopes

Abstract

Hill country has a vast array of microsites that may influence the success and uniformity of establishment of oversown pasture species and their persistence. In spring 2014, studies were conducted at Woodville (southern Hawke's Bay; summer-wet) and Cheviot (North Canterbury; summer-dry) to determine the effect of gentle (14-21o) and steep (32-40o) slopes on the presence and contribution to sward dry matter (DM) of oversown species in rotationally grazed swards aged 30 or 36 months. Gentle slopes had greater soil water content (29 versus 25%) and Olsen P (34 versus 26 μg/ ml) than nearby steep slopes. Perennial ryegrass (94 versus 80%) and phalaris (6 versus 2%) were present in a greater proportion of plots on gentle than on steep slopes, respectively, whereas subterranean clover had a greater presence on steep than on gentle slopes (6 versus 1%). Perennial ryegrass comprised a higher percentage of DM in swards on gentle than on steep slopes (27 versus 11%). The percentage of DM contributed by other individual species did not differ significantly between slope classes. The persistence of most sown species was unaffected by slope; microsite variation was not a major influence on species persistence. Keywords: hill country, microsites, pasture species, plant-microsite matches