Lay strong foundations for the new season ahead – Farmers Guardian

At the time of writing, main crop planting is yet to start, but growers have capitalised on a dry February to start preparing seedbeds ahead of planting later this month and into April.

Overwinter ridging

Some tried overwinter ridging, for example forming ridges in the autumn and allowing frosts and winter weather to break down clods rather than relying on cultivations.

This has worked really well, producing some very fine seedbeds on ground recently prepared for earlier-planted salad potatoes. Seedbeds could almost be too fine, so tailor cultivations to soil conditions field by field, and potentially leave out a pass where appropriate.

All fields have been tested for phosphate and potash, and although prices are high, do not cut corners. Potatoes are relatively poor nutrient scavengers, so good base nutrition – preferably in the ridge or worked into seedbeds – drives early development.

The same applies to nitrogen, where typically 70-80 per cent of total nitrogen is applied before planting. Depending on the season, this will then be topped up with foliar nutrition in the summer.

Minimising early weed competition is also vital, but fortunately we have a good armoury of residual pre-emergence herbicides, reducing the reliance on post-emergence products, which are more limited.

Aclonifen has proven particularly useful, even in recent dry springs and will feature heavily in pre-emergence programmes, supported by other actives according to site, soil type and weed pressure. On black fen soils, for example, metribuzin is useful.

This region features varied potato growing, from first and second earlies under fleece to general purpose chipping, bagging and processing crops.
Maincrop planting is yet to commence at the time of writing, however, earlies are in and have received a robust pre-emergence herbicide based on metribuzin, aclonifen, pendimethalin, or clomazone.

Crucial

A good pre-emergence application is crucial given there is only one shot at weed control in crops under fleece. Unlike open ground potatoes, there is no option to go back with a contact herbicide before crop emergence.

The pre-emergence programme on maincrop potatoes will involve similar actives, although metribuzin cannot be used on certain varieties. The main contact herbicides are either carfentrazone-ethyl orglyphosate, depending on the weeds present.

There were some big fluctuations in temperature during February, highlighting the importance of planting potatoes into warm soil to get crops away quickly and reduce the risk of issues such as rhizoctonia – made worse when seed tubers sit in cold ground for longer.

Fertiliser efficiency is another big consideration, and although prices have fallen recently, many growers bought at higher levels so need to maximise every application.

Applying more nitrogen in seedbeds (typically 75 per cent) rather than top dressing is one way of doing this, ensuring nitrogen is close to developing roots, and reducing the risk of surface losses. Base applications can be topped up with foliar methylated urea at tuber initiation, with total amounts varied according to crop requirements and soil N-Min tests.