Farm Ireland
Independent.ie

Wednesday 29 March 2017

Measured nutrition central to excellent yield returns

tillage

Gerry Bird

Harvesting is in full swing in the midlands and northeast regions, and growers are generally happy with the results to date.

Winter oats was the crop which was 'nursed' during the season, due to the ravages of the frost and snow earlier in the year, and it yielded satisfactorily. Yields in the region of 7.5-9.1t/ha were achieved, which fully justified the decision not to plough them out.

Plant counts at the time were 120-200/m2 and the aim was to encourage root development to stabilise the plant and also to increase root area to maximise nutrient uptake. The low plant populations performed well with good grain fill and quality.

The question of plant counts has been raised by some growers in relation to winter wheat. Pre-harvest inspection, when all the leaves are dead, presents a different crop view relative to the full canopy present earlier in the season. Heads/m2 are a combination of seed rate, fertiliser, growth regulation programmes, weather factors and management.

Seed rate is generally around 350-450/m2. Germination and emergence rates reduces this to 325-410/m2, and after you add in the impact of winter and pests, the springtime plant count could be 230-330.

Tillering adds to the basic head count, resulting in about two viable tillers per plant, which in turn leads to around 840 heads/m2 on average. This is a theorectical figure and the reality shows a greater range.

However, the importance of tiller management and survival is the essence of yield potential.

I recently looked at crops with low plant counts but which subsequently yielded very well at more than 11.4t/ha.


The grain number and quality have compensated for the lower plant numbers, with the grain sites at the top and bottom of the head filled. Smaller tillers have also had good grain fill with grains bursting out of the glumes. The effect of the early frosts on grain set was not obviously a major factor. First wheats and crops following organic manure applications have returned excellent yields, due to the good root development and continuous nutrition -- something to bear in mind when planning next year's cropping programme.

Good

Combining of spring barley crops is also under way, with initial yield reports good at 6.5-7.6t/ha and excellent quality. Straw yields are good and balers are busy.

Ploughs have been in action, working on winter barley stubbles, preparing for winter oilseed rape. It is good practice to roll the ground after ploughing to breakdown the clods and conserve moisture.

I favour the application of fertiliser to the rolled ground prior to drilling to allow for good early plant growth. Oilseed rape is a great crop to use high nitrogen organic manures such as poultry manure and pig slurry, due to the quick emergence and green leaf production. Ploughing also releases stored nitrogen stocks.

Early oilseed rape establishment is vital, with the last week of this month generally the target date. While the traditional method of establishment has been ploughing and one-pass drilling, minimum tillage establishment is now becoming popular.

Oilseed rape requires a fine, firm seedbed, and most importantly the soil has to be aerated and not compacted. Soil aeration prior to drilling is essential to allow maximum root penetration and good establishment. It also improves nutrient uptake. There is a lot of interest in oilseed rape this season as a result of the good yields and it is an excellent breakcrop.

Harvesting conditions have been ideal and machinery is not leaving marks in fields. Minimum tillage operators are aware that the soil surface at harvest time is also the seedbed a couple of weeks later, and that rough treatment at harvest results in compromised growth in the subsequent crop. The conventional tillage farmers also benefit from undamaged stubbles, in fuel consumption, water percolation and seedbed quality.

This season began on a high note; lets hope it continues on song for the remainder of it.

Gerry Bird is a crop consultant and member of the ITCA. Email: gjbird@eircom.net

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