Management influences on sheep behaviour, dung distribution and soil phosphate

Abstract

The behaviour of Merino wether hoggets grazing an existing management experiment at Tara Hills High Country Research Station was studied during summer 1981/1982. The experiment compared three stocking rates and three management systems (continuous, two paddock intermittent grazing, six paddock rotational). The daytime distribution and activity of the hoggets, dung distribution, and Olsen-P levels of topsoils were recorded on ten altitudinal strata within each of the nine treatment areas. Dung frequency was more closely correlated to grazing distribution than to either resting or total animal distribution. This is contrary to the generally accepted belief that dung accumulation is associated with resting behaviour. Increasing stocking rate led to a more even grazing and dung distribution. Subdivision by itself did not improve the evenness of distribution although it may have enhanced the stocking rate influence. There was little correlation between dung frequency and soil Olsen- P levels, especially outside the night camp areas. This indicates the importance of factors such as plant uptake and herbage consumption in the phosphate nutrient cycle. Olsen-P levels were consistently higher in the high stocking rate paddocks relative to the low stocking rate. Levels in the medium stocking rate fluctuated between these two. The implications of these findings in regard to the effects of intensification of farming in the high country on nutrient cycling and fertiliser requirements are discussed.