ACCURATELY fertilising almond trees is an ongoing science and something third generation Mildura grower Neale Bennett constantly tweaks in an effort to “find the edge’’ and maximise his return on input investment.
Neale, who is also chairman and a long-term board member of the Almond Board of Australia, operates a 16 hectare almond property and contracting business with his wife, Debbie, at Merbein near Mildura, supplying Almondco at Renmark.
About 50 per cent of their orchard comprises the Non Pareil variety and two pollinator lines, Carmel and Price, each account for 25pc, with the trees ranging in age from 10-24 years.
Since converting to drip irrigation, the orchard nutrition program has generally included 200-250 kilograms/ha of nitrogen, 50kg/ha of phosphorus and 300kg/ha of potassium, although Neale said the program remained pretty fluid depending upon testing.
The property’s soils, featuring sandy loam and areas of limestone rock, are tested in June-July, leaf testing is carried out in January and hull testing is conducted after harvest, which runs from February-April.
Neale said he now concentrated on applying only high quality fertiliser products.
“Like many growers, we could see the options to do it cheaper, but were the fertilisers working properly? They didn’t dissolve and we were forever cleaning out tanks,’’ Neale said.
“It costs you if you have to re-do it.’’
Haifa’s Multi-K potassium nitrate is applied throughout the program and despite the property’s calcareous soils, calcium is not highly available and so Haifa Cal is also applied.
Once ground temperatures rise, Haifa MAP is applied, while Neale has returned to using ammonium nitrate again and he also carries out foliar applications of nitrogen, potassium, calcium and micro nutrients.
The fertigation has moved to applications of smaller amounts more often – a spoon-feeding approach.
“Every time we water, we put something in. It can be daily in the growing season,’’ Neale said.
“But it’s a holistic process and you want a daily, balanced diet for the trees. You constantly ask: are you getting the results and, if not, why?
“Hull testing showed that we were low on boron. We were using a cheaper product and we went to a more efficient product that was more costly and it helped.
“We’ve also used (Haifa) Poly-Feed to correct a slight nutrition problem – and it came into balance.’’
Neale has recently been working closely with local Haifa Market Development Agronomist Jon Corona, looking at early application of Haifa MAP for better responses earlier in spring, as well as Electro Conductivity (EC) levels coming out from the drippers.
“The EC meter reading was showing very saline levels, so we cut down the amount of fertiliser going into the nutrient tank,’’ Neale said.
“We were putting batches of 200kg into the 2500-litre tank because we thought that was needed to get the program out, but we then went to 75-100kg in the nutrient tank and we noticed the growth was more responsive and the trees looked a lot healthier.
“The trees were fully leaved and they responded better than normal. They said thanks for not giving me saline water.
“This is something I have learned. No-one has said: ‘if it’s too salty, trees won’t take it up’.’’
Neale said Jon had commented that different fertilisers would adjust EC differently.
With continuous addition of water and nutrients and with wetting and drying cycles in the soil, accumulation of salts on the soil surface can be problematic and can cause EC spikes when rewetting.
“This is good technical advice that Haifa offers. Haifa wants to support growers, back up its products and help attain the most return for the grower.
“Haifa has also supplied me a mixing chart, which has been a bonus, and has continued to offer on-going support throughout the growing season.’’
“It (the advice) affected the way I applied fertiliser on my trees for the rest of the growing season and since, because I want it in the form that trees can utilise and take up, otherwise you are blowing money again.
“The nutrition, and particularly application, has been a strong focus because you have a set budget there for fertiliser and you think it’s going alright, but you need to have a look at it. If the budget increases, then it’s understanding why, but it also may be able to be cut back.’’
Neale said the nutrition program was continually related back to what the trees needed, with an eye not only on production, but also extension growth and future growth.
“You want to try and get 0.5-metres to 1m of extension growth a year to keep the trees productive.’’
He said back in the 90s, yields of 2.5 tonnes/ha were considered the limit, but with the use of water soluble fertilisers and fertigation, yields of 3-4t/ha were now targeted.
- Copy supplied by Haifa
