Learning about drought


Experience of Australian farmers demonstrates the need to prepare a response plan in advance.


By Judie Steeves W


hen southern Australian farmers experienced severe drought conditions between 2003 and 2009, they had to scramble frantically to get


water–one way or another.


Instead of following growers here in a scramble after drought hits, Pacific Agri-food Research Centre research scientist Denise Neilsen travelled around the globe last fall to take lessons that could be applied here–before drought occurs.


“If we can be prepared beforehand with a region-wide drought plan and the adoption of conservative irrigating practices, we’ll be way ahead,” she notes. As well, Neilsen says it’s important that we retain a buffer in our allocation of water, because that buffer will be needed in low water years in the Okanagan. However, there have already been a number of changes made to irrigation practices here with installation of more-efficient irrigation systems such as drip and micro- jet.


New, high-density plantings of dwarf trees made it possible for growers to install such irrigation systems, which wouldn’t work with the standard, old, spreading trees, Neilsen explained.


Today, most growers in southern Australia also use drip irrigation and irrigation scheduling to reduce the amount of water used.


One very influential grower, Kym Green of the Adelaide Hills area, found he improved soil health and water holding capacity through building up the soil’s organic matter from two per cent to 6.2 per cent. By the 2008 to 2009 crop year, water allocations in some regions of southern Australia were reduced to 18 per cent and growers had to take drastic steps to survive.


18


Down Under


Bush cherries growing in the Australian island state of Tasmania.


That included: reducing their planted area, sacrificing less valuable crops; minimizing crop water demand by reducing canopy size and 'survival pruning’ with leaf removal; maximizing irrigation efficiency with drip irrigation; purchasing water; and even purchasing vineyards for their licenses, reported Neilsen. A variety of soil moisture measuring devices came into use, from completely computerized systems such as Enviroscan to tensiometers, to an automated moisture tension measuring system called gdot which has a large display system that is visible from a drive-by tractor.. Fertigation is used by many growers, and some reduced irrigation after harvest to both control growth and reduce water use.


Every cherry orchard includes at least one, and often several, Summerland cherry varieties developed at PARC on a range of rootstocks from Colt to Gi.6, she said.


Denise Nielsen


While the Australian drought was caused by severe weather, it was exacerbated by water supply policy and by the loss of a major reservoir, which was off-line for


repairs when the drought began.


As a result of the drought, farmers there have adopted conservative water management practices, and Neilsen says that adopting such irrigation techniques before a drought would leave valley farmers in a better position when the next drought occurs here.


Nielsen also says the province’s new Water Act should include a protected allocation for agriculture and no designation of different amounts of water for different agricultural commodities.


Within the Okanagan Basin, there’s still time to protect agricultural water supply in order to minimize the impact on growers, if future climatic variability is taken into account during the current Water Act Modernization discussions, she said.


British Columbia FRUIT GROWER • Summer 2012


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