At the LandWISE MicroFarm, we are scoping the use of plant growth regulators to lift yields of peas for processing.
In our region, peas are produced for the global market, and the global price sets the local price. You’ll struggle to find a farmer that says the pay-out is generous. We could focus on increasing the price by $5 a tonne or even $50 a tonne. But that will make us uncompetitive.
So how can we make it a profitable crop?
We could cut costs, though there is little left to remove. Peas don’t usually get fertiliser or slug bait, insecticides or disease sprays. Most get little or no cultivation. They do get herbicide treatment, but many chemicals are relatively cheap.
What’s left?
“Yield is king!” say LandWISE farmers.
The yields of many crops have increased enormously over the last twenty years. Pea yields have not, and are highly variable and unpredictable. Even in good looking crops, yield can be disappointing.
As with any one pass harvest fresh vegetable crop, top yields need good plant, pod and seed numbers, all ready for harvest at the same time. Sometimes parts of a paddock are behind, sometimes parts of plants are left behind.
If part of a paddock matures differently, it is often because the plants emerged at different times. The cause may be soil moisture or temperature differences. Maybe it is compaction related.
If some plants mature at different rates it may be sowing or soil conditions causing uneven emergence.
If some pods mature at different times, maybe flowering was prolonged. If we condense flowering, all the plant’s resources go into peas that get harvested.
Farmers have noted drought-stressed crops can out-yield more vigorous ones. The stressed plants seem to have flowering curtailed, while vigorous ones continue flowering and have late pods and peas that will not be mature at harvest.
The MicroFarm group is looking at plant growth regulators to condense flowering and therefore the harvestable proportion of the crop.
Plant growth regulators control things such as shoot and root growth, internode length, flowering, fruit set and ripening. They are widely used in horticulture and have been used to manipulate flowering times.
We are applying a few options that have shown to have effect elsewhere. It is a first look to see if this is something worth researching further.
Our Discussion Group members’ experience has been brought together to formulate our “grand plan”.
Five different PGR products are being applied to the crop at different growth stages. The PGR’s include gibberellic acid, anti-gibberellin (Cycocel 750, Regalis), cytokinin (Exilis) and anti-ethylene (ReTain). These are potentially potent materials: one of our treatments is 8 grams per hectare.
The treatments are being applied in 3m x 10m strips, but are not being replicated in this initial scoping study. We do however have two sowings so we will get a couple of chances to compare. We will observe effects and yields. If we see evidence of a benefit, we will do a more detailed study.
Gibberellic acid was applied when peas were 10-15cm high. A rapid lengthening and yellowing of treated plants was quickly seen. The yellowing has reduced in time, but the plants are still double the height of their untreated neighbours.
But it is flowering we are interested in and that is still just around the corner. We have noted two flowers in one treated plant, and none elsewhere in the paddock.
The next set of treatments was applied about 10 days before anticipated flowering date. We are watching things closely.
Many thanks to the people involved in formulating the plan, and now implementing it: Plant Growth Regulators were supplied by BASF Crop Protection, Agronica and Fruitfed Supplies. Treatments were applied by Peracto. Plant & Food are monitoring the effects.
A report of results of the season’s PGR trials is posted on the MicroFarm website.
John is a researcher in the Vegetable Centre of the Tasmanian Institute of Agriculture. John has long experience working with farmers to develop systems to care for soil, save time and energy, and grow good crops.
Chris has also addressed previous LandWISE events. He recently returned to SnapFresh Foods to grow salad crops in South Auckland. He will discuss the implications of reverting from controlled traffic farming back to random trafficking. He has seen very significant soil changes, and increases in machinery and energy requirements, water ponding and costs.
LandWISE has been granted funding to develop fertiliser application calibration procedures suitable for farmers applying nutrients with their own equipment. The two year Ministry for Primary Industries’ 
The project will address the two broad types of ground based spreading equipment:
