Farm Ireland
Independent.ie

Saturday 24 June 2017

Crops can overcome poor plant numbers

Gerry Bird

The change in the weather has brought field activities to an end, with some crops sitting in water-saturated soil. A lot of organic manure was spread over the past few weeks and ploughed down under good, dry conditions ideal for maximising nutrient retention.

The winter oat saga continues, with crops which appeared in reasonable condition earlier showing further signs of disintegration after some recent nights of frosts. I had hoped that we might get to roll and feed these crops with liquid phosphorous as soon as soil conditions allowed, but this could prove futile as plants disappear.

Wheat and barley crops look very good, with tillering encouraged by the mild conditions.

Winter oilseed rape is under constant pigeon attack, which will impact on the yield potential of the later-sown crops.

Crops sown at the end of August had very good leaf canopies going into the winter and had put down excellent roots, which will respond quickly to applied fertiliser. Viable crops would need to have 20-25 plants/m sq. Crops sown later had reduced leaf canopy and poorer root development and, as a result of grazing, will have lower plant numbers surviving.

Compensate

Oilseed rape is very vigorous and will compensate with lower plant stands allowing light to penetrate and promote pods down the plant. High yields are produced with deep and dense root systems that maximise water and nutrient utilisation and intercept maximum light. Yield is determined by the number and weight of rapeseed per square metre. Rape crops will be the first to get nitrogen as soon as ground conditions allow and the crop response will confirm the root status.

Crop observations at this time of year are mainly confined to plant and weed counts, and a little knowledge can help to make the right financial and management decisions.

Winter wheat and barley crops have great tillering capacity, and wheat especially can compensate for low spring plant counts. Plant numbers in the order of 225-250 plants/m sq for wheat and barley are the target, but wheat numbers as low as 80-100 plants/m sq can produce top yields.

Crops with low plant populations coming out of the winter, as a result of slug attack, winter damage or reduced seeding rate, will have high tiller numbers if the roots are good and will get more light and fertiliser and less disease than high plant populations.

Direct

Shoot numbers in the region of 800-1,000/m sq for wheat and slightly higher for barley (1,000-1,200/m sq) should be the aim. There is a direct relationship between the number of plants and heads per square metre, the number of grains per head and the weight of the grains, so crop management is about finding the correct balance.

Weed growth on untreated crops has not been excessive, with grass mainly at the three-leaf stage and most broadleaf species at cotyledon or first true leaves. However, cleavers are quite vigorous with plenty of true leaves. The winter herbicide programmes are still adequate in most cases but cleavers, volunteer bean and rape will need more robust treatment later on.

I spotted a few drills working last week, planting winter wheat after potatoes and drilling beans. Beans are a great break crop, but in order to get high yields they need to be sown early. Between now and the early part of next month, you would need 25-30 seeds/m sq. I have a piece of equipment for estimating the Thousand Grain Weight of cereal seed -- contact me by email for details.

Grain has been forward sold for next harvest, at prices in the region of €185/t green for wheat and €175/t green for barley at harvest, with €210/t for wheat and €195/t for barley in November this year.

The price stability removes a major variable and offers a degree of confidence to growers. Let's hope the weather is as stable.

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

Indo Farming