Potato growers are being urged to prepare for next season by testing soil from land going into potato production for nematodes and nutrients.
With the open autumn allowing good progress with cereal establishment and fieldwork, there is a perfect opportunity to start forward planning ahead of the new season’s crop.
According to Spud Agronomy potato specialist John Sarup, the more questions that are asked now, the better prepared growers will be in the spring.
“These tests should be routine to ensure we are getting value for money from our inputs and there is a even stronger case on rented land,” he says.
High potato cyst nematode (PCN) populations can have significant yield effects and it was estimated the soil-borne pest cost the UK potato industry £40m in 2011.
Forward planning – potatoes
Soil sampling rates need to be as high as possible, advises Scottish Agronomy potato expert Eric Andersen, to ensure population estimates are as accurate as possible.
He also says growers should be identifying which of the two major species – Globodera pallida and Globodera rostochiensis – are present, as it will affect decision-making in the spring.
“There are varieties that have resistance or partial resistance to pallida or rostochiensis, so variety selection will be influenced by which species is present,” he explains.
Mr Andersen says chemical control using nematicides must be included in any PCN control strategy, even where soil egg counts are found to be low – less than 10 eggs/g soil.
“Low egg counts from samples can often lead to the highest multiplication rates, or not be representative of the whole field if sampling isn’t robust enough.
“Therefore, I would plan to incorporate a nematicide at planting where the soil hasn’t been fumigated with metam sodium,” he adds.
The incidence of free-living nematodes (FLN) should also be investigated, with the problem on the increase.
The three major species of FLN favour irrigated, light soils where they can move freely, and any testing should be carried out soon after there has been some rainfall.
“Growers should have a handle on numbers, as FLNs can spread tobacco rattle virus (TRV), which causes spraing (tainting) in the tuber and where varieties are susceptible, treatment will be required,” explains Mr Sarup.
Soil analysis for nutrients will also be important for decision-making, and testing for pH, phosphate, potash and magnesium will be vital to ensure fertiliser inputs are optimised.
Mr Sarup points out that on rented land, many potato growers are leaving behind nutrients that aren’t being fully used by the crop, which is uneconomical.
“I think potato growers also need to start thinking about the minor nutrients and how they interact with the major ones depending on pH, and draw up a soil nutrition plan.”
In addition to soil nutrition, Mr Andersen also reminds growers to consider soil’s structural condition ahead of the new season, which will dictate cultivation practices.
“Using electromagnetic scanning to identify soil texture and depth can be used to set depth control for bed preparation, minimising compaction and unnecessary clod creation,” he explains.