Abstract:
Proc. Aust. Soc. Anim. Prod. (1978) 12: 267 MEASUREMENT OF MICROCLIMATE AROUND GRASS SHELTERS USING A DATA LOGGER A.R. MARJORAM*, B.E. MOTTERSHEAD* and J.J. LYNCH* Rows of phalaris grass shelters have been shown by Lynch and Alexander (1976) to increase the survival of lambs and newly shorn sheep during cold, windy weather. This is thought to be due to a modification of microclimate near the shelters when compared to unsheltered paddocks. A portable, low power data logger has been developed to measure microclimate. At preselected times it sequentially samples a maximum of 32 sensors for temperature, wind speed, rainfall intensity and wind direction in 90seconds. In this preliminary investigation, 14 shielded thermistors and 12 miniature anemometers were used to monitor temperatures and wind speeds at various distances either side of shelter, at ewe (45 cm) and lamb (16 cm) heights. The. phalaris shelter strips ran north-south, were 1 m wide and approximately 1 m high. A westerly wind of 3 to 18 km/h predominated during the 72 h measurement period. Temperatures accurate to ? O.l'C were recorded every half hour and meaned for each distance from shelter over day, 0700-1900 h, and night, 1900-0700 h. The most significant variations occurred on still frosty nights (Figure IA) when it was up to 4'C warmer inside the shelter. Wind speed (WS) at ewe and lamb heights in the lee of the shelter was reduced to 11% and 3% of unsheltered speed (Figure IB) and increased to 58% and 59% 5 m away. The results show that the warmer temperatures measured inside grass shelters and the reduction in wind speed to the lee of shelter help explain the sheltering behaviour of shorn ewes which was reported by Lynch and Alexander (1976). The use of a data without disturbing the from a large number of this on paper tape in a logger to automatically record microclimate environment has the advantages of obtaining data transducers at high sampling rates, and recording computer compatible format. . LYNCH, J.J., and ALEXANDER, G. (1976). Appl. Anim. Ethel. 2: 305, * CSIRO, Division of Animal Production, Armidale, N.S.W. 2350, 267. I