Irrigating cherries in warm climates can be efficient

Irrigation and orchard floor management can combine to make cherry growing a sustainable business in warm climates.

This has been demonstrated by Barmera grower Joe Gropler, whose irrigation strategy involves a beneficial relationship between cherry trees and lucerne grown for hay production in the inter-row.

To some it may seem that a tree crop is being grown out of place but the cherries don’t mind as they are exposed to minimal bird and rain damage and less disease pressure compared with those grown in more conventional hilly, cooler, climes. Importantly the value generated from each unit of water is boosted through early ripening and the rewards of having the earliest Australian-grown cherries on the market.

It is not the commodity that is a business risk but uncertainty over water availability and prices. Water restrictions in the past seven years have slowly but surely killed about 1000 of the family’s 14,000 cherry trees grown on 20 hectares. Other trees have dead limbs requiring surgery.

“This has been a big cost as the trees are 12 to 14 years old and it takes eight years to get into full production,” he said. “As the tree deaths are random, the replacement trees will be on the same watering regime as the mature trees around them, which means more water cost than normal for young plantings.”

The fact that he is replacing trees after this experience underlines his belief in a mixed enterprise and use of a crop like cherries to take advantage of efficient irrigation techniques in a warm climate.

In addition to 20 hectares of cherries the business includes 20 hectares of winegrapes and hay production for sale and use in a feedlot on the property where prize South Devon cattle are fattened and return useful organic matter to the orchard.

There is use of advanced moisture monitoring in the orchard and vineyard, with an under-tree sprinkler system for the cherries and drip for the vines. The reason for low level sprinklers is to provide a larger wetted area in faster time than drip to suit the cherry tree root structure and meet water demands on hot days.

Of 15 megalitres/hectare/year applied in the orchard, 13 are for the cherries effectively and two are for the lucerne. According to the South Australian Research and Development Institute, the business’s irrigation practices are on par with industry standards for irrigating cherries and grapevines. As for the combination of cherries and lucerne, it has been determined that this requires much less water than would be needed if the two crops were grown separately as monocultures. This synergy is explained by lower evaporation from the soil surface and an enhanced microclimate created by the increased leaf area (assisted by reduction in excessive sunlight which increases water demand).

Joe adds that other contributors to water use efficiency are a bioactive soil that holds moisture and a cooler orchard floor.Further advantages of lucerne include its deeper roots and use of moisture below the tree root zone, a suitable environment for beneficial insects including bees needed for pollination, penetration of hard pans by deep roots, improvement of drainage, lucerne’s competition with weeds and its contribution of organic nitrogen.

Caption: Joe Gropler has shown that cherries are a viable option and can be water use efficient.

Citation

Land & Water Australia. 2010. Irrigating cherries in warm climates can be efficient . [Online] (Updated November 29th, 2010)
Available at: http://lwa.gov.au/node/3793 [Accessed Thursday 1st of March 2012 07:28:25 AM ].