PGRO says pulse sowing conditions more important than date

Growers are showing renewed interest in sowing pulses this spring, so expert advice on getting crops off to the best start will be well worth heeding.

Be prepared to be patient, especially when establishing peas, urges the PGRO’s Anthony Biddle. That’s his prime tip for newcomers to pulses and those perhaps returning to them after a break of several seasons.

“It’s all too easy to forget that peas and beans can’t tolerate wet or compacted soil,” he warns.

Under good conditions spring beans may be sown any time after St Valentine’s Day (14 February). Peas are best drilled between the end of March and the start of April.

“However, sowing date isn’t nearly as important as soil condition, though peas must be in before May or yields really start to suffer.”

Peas are relatively shallow rooted and need to spread unimpeded to make best use of nutrients and water and to develop sufficient nitrogen-fixing root nodules, says Dr Biddle.

“Beans need to get their roots down early to be able to withstand dry spells.”

Peas can perform well on most soil types if compaction is avoided. “Try not to grow beans on drought-prone land.”

Ideally, ground intended for pulses will have been ploughed in dry weather in the autumn to allow a useful frost mould to develop. But on many farms, that may not have been possible this season, Dr Biddle acknowledges.

Ploughing late or in wet conditions can cause compaction, restrict drainage and prevent soils drying out.

Aim to achieve seed-beds with as few passes as possible. “Over-consolidation often causes root development problems. That’s because heavy rain on soil which can’t drain causes waterlogging. And if that lasts more than 48 hours the plants get foot rot and die.”

Plough pans can also lead to waterlogging. The best way to assess potential problems is to dig a test pit, preferably the year before sowing, to check for consolidated zones and/or lack of structure, says Dr Biddle.

“But a simple penetrometer – DICKEY-John sells one – or even a garden fork, can be used to detect tight soils both before and after cultivations. If you feel tightness it’s even more important not to try to force crops in.”

Most modern drills will sow peas and beans efficiently, he says. “Aim for 3cm of settled soil over the top of the seed. More people are using min-till methods nowadays, and there’s a temptation to sow a bit deeper if you’re doing so. But there’s no real advantage. It tends to give more erratic emergence, and pigeons and crows will always pose trouble anyway.”

Now that the post-emergence herbicide armoury has been severely thinned by withdrawals, it’s more important than ever that pre-emergence residuals are given every chance to work.

So the target, via rolling if necessary, should be reasonably level seed-beds with clods no bigger than a clenched fist, he advises.

“On some light soils you’re likely get away without rolling. On others it’s a balance between getting what you want without over-doing it, probably using ring rolls. You certainly shouldn’t need heavy flat rolls as for grass seed-beds.”

Seed is the most costly pulses input, so correct sowing rates are important, stresses Dr Biddle.

“For most peas the optimum plant stand is 70/sq m, for marrowfats it’s 65. For spring beans you’re looking at 35-40 plants/sq m. You’ll need to allow a little extra seed for seed-bed losses, but not too much, especially if you’re using certified seed.

“If you’re using home-saved spring bean seed, make sure it’s tested for stem nematode first. It costs only £25.50 a sample.”

The pest is unlikely to have much impact in the year of sowing, he says. “But once it’s introduced it can cause big problems later, you can get 50-60% yield loss.”

Significant seed cost savings can be made by choosing pea varieties with good downy mildew resistance, he adds. Most of those on the latest PGRO Recommended List are rated above 5, the level at which Wakil (cymoxanil + fludioxonil + metalaxyl-M) seed treatment, costing £90-100/t, is advisable.

But three listed marrowfats, Falstaff, Kahuna and Samson, all rated 5, should always be so treated, he suggests.

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