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THIS PROMOTIONAL FEATURE WAS PROVIDED BY BALLANCE AGRI-NUTRIENTS

Look back and plan ahead to get the most from your autumn sown cereal crop.

Cereal crops are demanding on soil, and nutrient levels should be in the right ranges for optimum production. But on some South Island soils this may not be practical or economic, so to avoid mining nutrient reserves, the nutrients removed by the previous crop should at least be replaced.

When looking at fertiliser requirements for your cereal crop, consider the nutrients removed and retained by the previous crop, current soil test status and yield potential of the planned crop. With a high yielding crop, more nutrients will potentially be removed.

Also take into account the previous crop type and how its residue was managed. Different types of cereal crop residues contain varying amounts of nutrients, and this coupled with how it’s managed impacts the amount of nutrients returned to the soil. Sowing cereal crops in autumn also needs a bit of planning ahead for winter conditions, as Sulphate Sulphur (S), Nitrogen (N), and to a far lesser degree, Potassium (K) can leach in cold, wet soils when plant uptake is low.

Phosphorus (P) is important for crop establishment. Where the Olsen P level is less than 15 for wheat, phosphate fertiliser should be ideally drilled next to the seed at sowing. At higher Olsen P levels, phosphate fertiliser can be broadcast and incorporated prior to sowing.

Sulphur is required for crop growth and protein development. It is usually applied at sowing, and 15-25 kg S/ha/year generally satisfies requirements. However, sulphur may be leached over a wet winter. When this occurs, plant available sulphate-S (sulphate of ammonia or SustaiN Ammo) needs to be applied in the spring as part of the first nitrogen side dressing.

Applying K in autumn means one less thing to do in spring. Potassium (K) is essential for plant structure, straw strength, and flower quality. Optimum soil Quick Test ranges of 6-10 are suggested; however, increasing levels may not be economically viable. To ensure sufficient K is provided, depending on soil test status 25-70kg k/ha will typically be required.

In the South Island, relatively little growth occurs between an autumn sowing and late winter. Even with wheat, there is usually enough N in the soil to support growth until the first spring side dressing is required at GS (growth stage) 30-31. But if spring soil mineral N levels are very low or the crop has had a poor establishment, some N application may be brought forward.

Products such as Super 10K is an ideal base/starter fertiliser for autumn sown cereals not requiring N, providing P, K and S, which can be broadcast and incorporated, helping achieve successful establishment.

If Magnesium is needed then a product such as Serpentine Super 7K, also containing K, is useful. Granulated Calmag is another option, or for extremely low magnesium levels requiring an immediately plant available form, Kieserite Granular.

Soil acidity for cereal crops should be between pH 5.8 and 6.2. Wheat can cope with a slightly lower pH but barley is more sensitive. Lime needs at least 12 months to take full effect, and 1 tonne of lime per hectare will shift pH by 0.1.

For more information talk to your Ballance Agri-Nutrients Nutrient Specialist or to your local Ruralco Representative.