A survey of 170 randomly selected, irrigated, dairy farms in northern Victoria
and 9 in southern New South Wales was conducted to examine and benchmark the
key factors influencing water-use efficiency. Water-use efficiency was defined
as the amount of milk (kg milk fat plus protein) produced from pasture per
megalitre of water (irrigation plus effective rainfall). Information on
water-use, milk production, supplementary feeding, farm size and type, pasture
management, and irrigation layout and management was collected for each farm
by personal interview for the 1994–95 and 1995–96 seasons. The
farms were ranked in the order of water-use efficiency with the average farm
compared with the highest and lowest 10% of farms.
The range in water-use efficiency was 25–115 kg milk fat plus
protein/ML, with the highest 10% averaging 94 kg/ML and the
lowest 10% averaging 35 kg/ML. The large range in water-use
efficiency indicated potential for substantial improvement on many farms. The
high water-use efficiency farms, when compared with the low group: (i)
produced a similar amount of milk from less water (387
v. 572 ML) (P<0.05), less land
(48 v. 83 ha) (P< 0.05) and a
similar number of cows (152 v. 143 cows); (ii) had
higher estimated pasture consumption per hectare (11.5
v. 5.5 t DM/ha) (P<0.01)
and per megalitre (1.0 v. 0.5 t DM/ML)
(P<0.01); (iii) had higher stocking rates (3.2
v. 1.8 cows/ha) (P<0.01);
(iv) used higher rates of nitrogen fertiliser (59 v. 18
kg N/ha.year) (P<0.05) and tended to use more
phosphorus fertiliser (64 v. 34 kg P/ha.year)
(P<0.10); (v) used similar levels of supplementary
feed (872 v. 729 kg concentrates/cow); (vi) had
higher milk production per cow (396 v. 277 kg fat plus
protein) (P<0.05); and (vii) directed a higher
proportion of the estimated energy consumed by cows into milk production (53
v. 46%) (P<0.05).
The survey data confirmed that irrigated dairy farm systems are complex and
variable. For example, the amount of feed brought in from outside the milking
area varied from 0 to 74% of the estimated total energy used by a
milking herd. There was a large range in the level of supplement input amongst
the farms in the high water-use efficiency group, and in the low water-use
efficiency group. This indicates that the management of the farming system has
a greater impact on the efficiency of water-use on irrigated dairy farms, than
the type of system.
The data from the survey provide information for individual farms, a measure
of the water-use efficiency of the industry, and an indication of the quality
of regional land and water resources.
Genetic Variation of Morphological Traits and Transpiration in an Apple Core Collection under Well-Watered Conditions: Towards the Identification of Morphotypes with High Water Use Efficiency
