Ciaran Collins, Crops Specialist at Teagasc, reminds tillage growers of the importance of planning for the season ahead, focusing on crop choices, pre-emergence herbicides and cereal crop phosphorus and potassium requirements.

Rotations

Keeping a good rotation on farm is central to profitability. Research from Teagasc Oak Park showed that wheat grown after a break crop yielded 11-19% more than continuous wheat. The margin from any break crop should not be considered in isolation, but across the entire rotation.

Oilseed rape

Oilseed rape can be sown until mid-September in the south and a week earlier further north. The key to successful establishment at this time of year is a good seedbed. It is also an ideal opportunity to apply organic manure, and this will aid establishment. Choose a variety with good autumn vigour and increase seed rate by 10% if sowing late.

Rye

Before considering rye, consult your local agricultural merchant, as not all are equipped to handle it. There is growing interest in rye because it can be sown from mid-September, taking advantage of favourable seedbed conditions

Rye has high yield potential, comparable to wheat, and good tolerance of take-all. While straw yields are high, lodging requires careful management. Modern hybrid varieties carry a low risk of ergot, but it is important to watch out for slug damage.

Rye is best suited for planting at the end of the rotation due to its take-all tolerance, and this allows volunteers to be controlled in the succeeding crop, e.g., beans/oilseed rape. The seed rate is 200 seeds/m², but be careful not to sow too deep – max. 2-3cm.

Wheat

Sowing wheat after break crops reduces the risk of take-all and provides the best opportunity for high yields. However, while take-all risk is reduced, early sowing still leaves it vulnerable to barley yellow dwarf virus (BYDV) and grass weeds. Additionally, a growing concern with the current wheat varieties is their poor resistance to septoria – a problem that is worsened by early sowing.

Barley

Over 60% of the seed available this autumn is likely to be a BYDV-tolerant variety. Results from Department of Agriculture, Food and the Marine (DAFM) variety trials indicate that in the presence of BYDV, there is a benefit to using a BYDV-tolerant variety. However, the risk from take-all remains, so delay sowing in a take-all risky slot. Seed dressings for take-all were of limited benefit in Teagasc winter barley trials.

Pre-emergence herbicides

Pre-emergence herbicides provide the most effective control of grass weeds. Grass weeds are becoming an increasing problem on tillage farms, and using pre-emergence herbicides helps reduce the need for post-emergence applications. This approach also plays an important role in managing herbicide resistance.

Cereal crop P and K requirements

Winter cereals demand phosphorus (P) and potassium (K) to ensure crops are well established in terms of rooting and tiller development entering the winter period. Index 3 soils will have a good supply of P and K for crop establishment; therefore, omit P and K applications until spring. For Index 1 or 2 soils, apply nutrients as shown in Table 1. A fertiliser product such as 0-10-20 or 0-7-30 will supply the correct balance of P and K at this stage. Apply at sowing and incorporate into the seedbed. Complete fertiliser P applications by October 31.

Table 1: Autumn P and K requirements for winter cereals (build-up)

The above first appeared in the September Teagasc Crops Advisory Newsletter, view it here.

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