McCain Foods Green Beans
Planting
Dwarf green beans for McCain Foods were planted in all treatments on the 28th of December. All treatments were planted in beans, Conventional and Hybrid treatments ex. peas, and the Regen treatment ex. cover crop/fallow. All treatments were disc ripped and rolled one month before planting and regrowth sprayed out four days before planting.
We applied different rates of starter fertiliser to each treatment. In the Hybrid and Regen treatments we added a biological seed treatment. All treatments had the same bean variety planted at the same rate. We are grateful to our good friends at Nicolle Contracting for their patience when planting the trial.
As always, we are measuring lots of thing over the growing season. For the beans, we have been particularly interested in canopy cover, soil nitrogen availability, pest and disease pressure, yield and of course, gross margins.
Canopy Cover
We measure canopy cover percentage weekly using the Canopeo app. There was little difference in the treatments until early Feb when the Regen treatment took off, and canopy size increased at a faster rate. This treatment is visibly taller and ground cover is greater than the other two treatments.
The Hybrid treatment has lagged, probably due to some early slug damage. When the pea vine was disced, some residue remained on the surface, a perfect spot for slugs to hang out. We applied slug bait to all treatments to reduce further damage.
Disease Presence
The main disease issue we are worried about in beans is sclerotinia. We have so far applied one protectant fungicide to each treatment to protect against sclerotinia, as well as botrytis (different products depending on treatment).
Earlier in February we noted that there was young leaves wilting, most prominently in the Conventional and Hybrid treatments, however was apparent to a lesser degree in the Regen. A thorough inspection by Ben Prebble (McCain Foods) and Shelley Bath (Horticentre) concluded that we were starting to see signs of fusarium. Diagnosis was through the presence of brown/purple, woody lower stems. Phosphorus acid application is planned to treat the fusarium as soon as we have an appropriate spray window.
Pest Presence
A common pest insect in beans is looper caterpillar. Standard McCain Foods practice is to apply an insecticide to knock out caterpillars, when a fungicide is being applied. There are two active ingredients that can be used, neither of which are friendly to beneficial insects/natural enemies. Early in the month we saw some suspected signs of caterpillar chewing, however there are no threshold values to use to trigger spray applications. The Conventional treatment had an insecticide applied (Karate Zeon), however we held off in the other two treatments, as there were no clear signs of damage.
A leaf damage survey was completed following this, which understandably found more damage in the Regen & Hybrid than in Conventional, however still not visually a huge amount of damage. A few caterpillars have been found. We have been recommended a biological alternative, BioBit (Bacillus thuringiensis), which will kill caterpillars but not any eggs. We will likely need more than 1 application, to control the next hatched caterpillars. BioBit will be applied in the next spray window.
Nitrogen Management
We have been closely following nitrate nitrogen levels in the soil. The chart below shows nitrate-N in the top 30 cm from when the Conventional and Hybrid cover crops were sprayed out, through to mid Feb.
Nitrate-N in the Regen treatment has been increasing steadily since the cover crop was mulched in early October. The levels in the Hybrid treatment have been higher than the Conventional since harvest. This is likely due to most of the residue being baled and removed in the Conventional, vs retained and incorporated in the Hybrid.
A typical bean program includes a side dressing of fertiliser which includes nitrogen. A leaf test in early Feb found that nutrient levels were good in all treatments. In discussion with Mark Redshaw (Yara), we decided that because the canopy in the Conventional and Hybrid was less developed than the Regen, these treatments would receive a late application of nitrogen despite tests saying levels were satisfactory. The intent was to give these treatments a boost ahead of harvest.
The Conventional treatment had 200kg/ha of Nitrabor applied, the Hybrid a half rate of 100kg/ha. The Regen is to receive a foliar nutrient application of Croplift to maintain canopy health and this will also be applied to the Hybrid.
Application was completed via Airborne Solutions drone, to apply accurately over plots.
Next Steps
We are approx. 2 – 3 weeks away from harvest, with a target harvest date of 6th of March. Hand harvests will be completed to determine yield, followed by machine harvest.
