Three-year-old Bartlett trees after pruning. The trees are filled with one- and two-year-old fruiting wood and some spurs. Summer pruning, Ethrel (ethephon) sprays, regulated deficit irrigation, and delayed heading of the leaders have created fruiting woo
In Australia, 85 percent of the pears are grown in the Goulburn Valley irrigation area, 100 miles north of Melbourne in the state of Victoria. Bartlett pears have been grown in the valley for more than 120 years, and the average Bartlett tree is more than 60 years old.
In the past, three local canneries used to process about 100,000 metric tons of Bartlett pears a year. After the canneries consolidated, the volume processed dropped to about 36,000 tons a year. Total production of Bartlett pears in 2008 was estimated at 61,000 tons, so the domestic fresh fruit market had to absorb the difference.
Production of Bartlett pears is expected to continue to decrease, because:
- Many orchards with old large trees are costly to maintain and are not being replanted.
- Yield and quality of fruit are substandard.
- Returns from the cannery to the orchardists have not kept up with cost of production.
- Competition from cheaper imported fruit products has increased.
With seedling rootstock, and 330 trees per hectare (133 trees per acre), it often took 17 years before the large, low-density trees reached maximum annual yields of 40 tons per hectare. (One ton per hectare is equivalent to one bin per acre.)
Today, early fruit production and new marketing strategies are essential for profitable orchards. In order to maximize production of a high-density pear orchard, new methods of growing, training, and pruning pear trees must be adopted. A trellis is needed to support the early crops on young trees, and production of 50 tons per hectare at maturity. To grow Bartlett pears for the fresh-fruit market, orchardists need to change their mindset.
In trials at the Tatura Research Institute in the 1970s, Bartlett trees on Pyrus calleryana D6 with 2,222 trees per hectare (900 trees per acre) on a Tatura trellis, produced 60 tons per hectare of fruit in the fourth year. But orchardists believed that they did not need to change, because pear trees were long-lived, and Bartlett pears grown on large trees for the cannery were still profitable.
However, the cost of production has increased, and the global market economy of today is highly competitive and forcing orchardists to grow fruit more efficiently.
P. calleryana is propagated from seed, and this rootstock has been used almost exclusively for more than 50 years. This rootstock is vigorous, grows well in wet or dry soil, tolerates a wide range of soil types, and is compatible with all pear varieties grown in Australia.
Although orchardists are reluctant to plant pear trees at high densities without a size-controlling rootstock, experiments have continued in the Goulburn Valley with high-density plantings onP. calleryana A recent experiment in the orchard of Roger and Matthew Lenne showed that young Bartlett trees could be coaxed into allocating more of their photosynthates to fruit than to wood. The Open Tatura system with two leaders (limbs) was used at 2,222 trees per hectare (900 trees per acre) and a tree spacing of 1.00 by 4.50 meters (3.25 by 15 feet).
Trees were about 2 meters (6.5 feet) tall when planted and had two leaders of equal size. Feathers were stubbed back to ensure that the leaders remained dominant and new shoots were all of the same age. Two leaders can also originate from an unheaded feathered tree by keeping the two bottom feathers and heading the tree above the feathers after planting. However, this would delay production by one year, compared with a nursery tree that has two fully grown leaders.
With integrated tree managementincluding drip irrigation, cross-pollination, and good nutritionfive-year-old Bartlett trees produced 83 tons of fruit per hectare from the first three harvests (see "Bartlett yields on Open Tatura" chart on facing page). The 1.14-hectare (three acre) planting could consistently produce the equivalent of 50 tons per hectare annually without the use of ladders or harvesting aids.
The trees were as efficient in converting light energy into fruit (expressed as yield per tree size) as were Bartlett and Beurre Bosc on size-controlling rootstocks in the United States, and also as young Packham’s Triumph trees on P. calleryana on Open Tatura in Australia. The five-year-old Bartlett trees on Open Tatura produced fruit 250 times more efficiently than a typical 5.50 x 5.50 meter (18 by 18 foot) planting of Bartlett onP. calleryana of the same age in a nearby orchard. The high yield efficiency of the Open Tatura resulted from high light interception and a high allocation of photosynthates to the production of fruit.
The establishment costs for the Open Tatura planting amounted to Australian $34,759 per hectare (U.S.$13,360 per acre), with the trees and training system accounting for most of the costs (see "Costs for Bartlett pears on Open Tatura" chart on facing page). When this experiment started in 2003, the average cost of a nursery tree was Au.$7.63 (U.S.$7.25). Total capital and operational costs by the fifth year amounted to Au.$61,072 per hectare (U.S.$58,625).
This experiment covered only the first five years of the orchard. Although the profitability of a high-density pear planting cannot be based only on the performance of the trees in the first five years, production levels and projected costs beyond the fifth year have been estimated to year 10 in order to come up with a reasonable and fair economic prediction (see "Three marketing strategies" chart on preceding page).
We applied the capital costs in 2003 and operating costs from 2003 to 2008 to a replanted orchard or to a new site in an existing orchard. We did not include the cost of land, irrigation pump, filtration and mains, or management fees.
We assumed the following:
- Annual gross yield after year 5 was 50 tons per hectare.
- Gross returns on size-picked fruit were Au.$600 per ton (U.S.$230 per bin) for the fresh-fruit market, which equates to returns received for the fruit in year 5 (2008).
- Returns for fruit for processing were Au.$350 per ton (U.S.$333 per ton).
- The value of the Australian dollar in 2008 was used to estimate costs and returns for year 6 onwards. No allowance was made for inflation.
The profitability of three marketing strategies was compared. Fruit was size-picked for the fresh-fruit market, not graded by the orchardist, and was sold in bin lots to different packing houses.
The marketing strategies were as follows:
1.Half of the crop was size-picked to be sold as fresh fruit. The other half was strip-picked about ten days later for processing (indicated as 1212).
2.The fruit was given enough time to grow so that two-thirds of the crop could be size-picked, to be sold as fresh fruit. The rest was strip-picked about ten days later for processing (indicated as 23 13).
Fruit was thinned and size-picked twice to be sold as fresh fruit (indicated 1 0). Fruitlets that were small, marked, and misshapen were removed 50 days after full bloom at a cost of $60 per ton.
The economics of the three marketing strategies are summarized in the table "Economic summary"on this page.
With positive cash flow of only Au.$5,613 per hectare (U.S.$2,160 per acre) starting in year 10 (data not shown), Bartlett pears grown on Open Tatura for processing only were not considered profitable.
This experiment dealt with horticultural practices of a high-density planting with high vigor, as well as an economic evaluation of Bartlett pears produced in Australia. We showed that Bartlett trees on seedling rootstock, and grown on Open Tatura, could be brought into full production by year six. However, orchardists should be aware that, without specific tree management practices and marketing strategies to ensure that returns exceed the price of processing fruit, early positive cash flow is not guaranteed.
Our tree management strategies have shown that Bartlett pear trees on P. calleryana on Open Tatura at 2,222 trees per hectare, can be tamed and made productive at an early age and grown profitably, despite published statements that P. calleryana is not suitable for high-density plantings and that the main reason pears are slow to come into production is because of a lack of size-controlling rootstocks. We still believe that a new size-controlling rootstock is needed. However, close planting, drip irrigation, regulated deficit irrigation, tree training, summer pruning, cross-pollination, and early cropping ensure that pear trees on P. calleryana can be made productive early.Horticulture Australia Limited and the Canned Fruits Industry Council of Australia provided funding for this research.Bas van den Ende is a fruit production consultant based in Shepparton, Australia.