Several Australian horticulture industry delegates recently had an insight into Dutch greenhouse horticulture and the latest in fertigation of greenhouse crops at an international conference in the Netherlands.
Tony Bundock, Senior Instructor—Controlled Environment Horticulture, from the National Precision Growing Centre at the Chisholm Institute of TAFE in Victoria, Haifa Australia agronomists Shaul Gilan and Peter Anderson, and NSW grower Greg Jarman, of Corindi, near Coffs Harbour, attended an international conference in the Netherlands, which was coordinated by Haifa in conjunction with horticulture experts at Wageningen University and Research Centre (WUR) in Bleiswijk.
The two-day conference also was attended by delegates from Africa, England, Eastern Europe, Western Europe, Scandinavia, Spain and Turkey.
Presented by University faculty members, the event covered basic plant nutrition, principles of fertilisation in greenhouse crops, nutrient management and future trends in fertilisation.
Delegates also toured a nearby commercial seedling nursery and research facilities investigating greenhouse water treatment systems; artificial lighting solutions, including LED lights; growing systems, including floating pots; and aspects of greenhouse design. Other experiments involved diverse topics, such as algae production, growing system and s for annual flower production and evaluation of trial material from plant breeders.
Delegates also toured the enormous Leo Ammerlaan seedling production facility located near the Wageningen University and Research Centre (WUR) in Bleiswijk. The greenhouse facility, which comprises more than 25 hectares spread over four sites, produces 10 million vegetable seedlings in rockwool containers annually. The family-owned company specialises in capsicums, tomatoes, eggplant and cucumber seedlings. Vegetables represent only 75% of the annual output, with the balance including various flowers such as orchids, roses, bedding plants and pot plants.
At the time of the tour, only cucumbers were in the vegetable nursery. Tomato, eggplant and capsicum already were planted in growers’ greenhouses. While not permitted to photograph the cucumber Water treatment systems using both ultra violet and hydrogen peroxide are being evaluated for water sterilising efficacy.
New greenhouse design is evaluated in structures built to minimise energy use and maximise crop production. In one structure, light is focused by innovative roof design on to photo-voltaic cells suspended above the crop. Extra light energy, not required by the crop, is utilised to produce electricity for heating and other purposes. CO² enrichment is used in some crops and produced as a by-product of burning natural gas for heating. In the low energy greenhouse, this extra CO² is collected and supplied to growers from a nearby industrial area. The aim of this research is to produce crops using the energy that can be supplied by the greenhouse itself, with no additional energy input.
Artificial lighting is used in the production of seedlings and for short periods during winter for some greenhouse vegetable crops. The research is based on a cost comparison of existing conventional grow-lights with newer LED technology. Reports so far indicate no advantage with the LED systems compared with the current, energetically expensive grow lamps.
While not permitted to photograph the cucumber seedlings, Haifa Australia Agronomist Peter Anderson said Australian growers would have been surprised at the advancement of the seedlings.
“In rockwool containers, the more advanced seedlings were already at flowering stage and were connected to small stakes to keep the 30-40 centimetre vines off the ground,’’ Peter said.
“Many eggplant and tomato seedlings are grafted onto disease-resistant rootstock on site.
“Grading of the seedlings for size is carried out using automated camera graders, with seedlings being graded into three sizes to ensure uniformity of growth when planted out in customers’ production facilities.’’
The nursery is provided with artificial light, while all areas of the greenhouses can be enriched with CO² to promote faster and more efficient growth.
Various irrigation systems are used. A flood and drain system, overhead sprinklers and a travelling boom irrigator can all be used on all crops at various stages.
All irrigation is connected to the fertigation system, which applies fertiliser from a conventional two-tank hydroponic set-up. The fertilisers used for the two tanks—in the familiar ‘Tank A’ and ‘Tank B’ arrangement—are supplied by Haifa and contain all of the macro-elements, plus iron required by the growers. Micro elements, such as copper, zinc and molybdenum, are supplied separately.
The strong response to the international conference has prompted plans for another event in April, 2014.
PH&G – May 2013 – Issue 131