Executive Summary:

The DPI Table Grape Irrigation Benchmarking Project was initiated during the season 2001/02. It was established primarily as a tool for identifying “best irrigation management practices” with the goal of improving irrigators' performance and efficiency.

This annual report contains nine years of growers' data, from Victoria and New South Wales, covering seasons 2002/03 to 2010/11. Examples of the main information gathered for each site were the amount of water used, the variety, the irrigation system and scheduling method used, the pumping and water costs, and the crop yield and gross return.

While the number of growers in the study has remained around 13 to 14 over the years, in season 2010/11 the number of sites (65) and associated area (132.9 ha) have increased by 26 and 72.6 ha respectively when compared to season 2002/03. It should be noted that this is not a representative sample of growers and care must be adopted when attempting to extrapolate the results to the broader irrigation community.

The grape varieties planted at the different sites were Autumn Royal, Calmeria, Cardinal, Crimson Seedless, Flame Seedless, Ohanez, Menindee Seedless, Rally Seedless, Red Emperor, Red Globe, Thompson Seedless and Zante Currant.

The extreme rainfall events experienced by many table grape growers in the 2010-2011 irrigation season led to many sites in this study being water logged or prone to high disease pressure, both of which led to lower quality and yields.

The average yield of all varieties for drip irrigated sites in 2011 (5.7 t/ha) was less than half that of 2010, and 21.8 t/ha lower compared to the average of 2009. In the case of low level irrigated sites, the average yield in 2011(5.4 t/ha) was 8.6 t/ha and 18.5 t/ha lower than the averages of 2010 and 2009 respectively.

For the first time since 2005 there were more participants using capacitance probes (27) than reported experience (18) as their scheduling method. There was virtually no difference in the average water applied for each of the scheduling methods reported in 2011 Irrespective of the irrigation scheduling method used, the seasonal averages in 2011 were among the lowest of the nine seasons studied.

The median values for water applied for drip (4.01 Ml/ha) and low level (4.27 Ml/ha) irrigated sites were very similar in the 2011 season. In 2011 75% of the low level sites used 4.57 Ml/ha or less while 4.61 Ml/ha was the median for the drip irrigated sites. The medians for the previous two years for low level irrigated sites were 9.21 Ml/ha in 2010 and 8.31 Ml/Ha in 2009 and 6.59 Ml/ha and 7.39 Ml/ha for drip irrigated sites in the same years.

The season 20010/11 resulted in 13.8% of sites scoring within the target 85-90% application efficiency range with a further 33.8% scoring over 90%. This result indicates that there are still many sites that could improve their timing and amount of irrigation.

The average application efficiencies for sites with drip irrigation were more consistent over the nine years and were also higher than those for low level irrigation. In 2011, the application efficiency for low level irrigation was 21% less than the average for drip irrigation, and 1% below its own nine-year average of 86%. The nine-year averages show that drip irrigated sites had an application efficiency average of 86% while the low level irrigated sites only averaged 74%.

The crop production per megalitre results for both drip (0.55 t/Ml) and low level (0.39t/Ml) irrigated sites were the lowest on record. Despite the drop in water applied for each of the irrigation systems (see Figure 5) the reduced yields (see Figure 4) had a greater influence on these results. The results from previous years ranged from 1.4 t/Ml (2007) to 4.85 t/Ml (2003) for drip irrigated sites and 1.8 t/Ml (2006) to 3.47 t/Ml (2004) for low level irrigated sites. In 2011 the range was greater for drip irrigated sites (0 to 6.9 t/Ml) than for the low level irrigated sites (0 to 4.58 t/Ml).

The results for 2011 shows that both drip (1.4 t/Ml) and low level (1.3t/Ml) irrigated sites average crop production per Megalitre were the lowest on record. Both were well under their long term average with drip 1.1 t/Ml less. The different varieties grown each had an average crop production per Megalitre of water in 2011 lower than in 2010 and all were under their long term average except for low level irrigated Flame Seedless.

The median value for gross return per megalitre for 2011

($1107/Ml) was lowest on record, with the previous lowest being $3067/Ml in 2005 compared to the highest of $6753/Ml in 2009. The range of values in 2011 was very large being $0/Ml to $21653/Ml which is the second highest value on record. For only the second time since the start of the project low level irrigated sites ($3976/Ml) showed a higher gross return per megalitre than their drip irrigated counterparts ($3078/Ml). Both the low level (-$560/Ml) and drip (-$1935/Ml) had lower averages in 2011 than their long term averages. Drip irrigated sites have a higher long term average than the low level sites.

The gross return and cost performance indicators should be treated only as technical information, as they were determined using a partial system approach. A sound economic analysis was beyond the scope of the study, since it would have involved a whole system approach and more complex analysis, e.g. marginal analysis.

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