Straw decisions: To chop or not to chop?

Straw as we all know is a valuable commodity – the full value of which is difficult to estimate. Tillage farmers are becoming more and more conscious of soil health and fertility and so chopping straw is becoming a common option in a year when price is not working out to what it was expected to be.

As many straw buyers wait in the long grass to make a move on price, more and more tillage farmers are considering turning on the chopper.

Why chop straw?

Chopping straw results in some of the nutrients which were taken away by the plant being incorporated back into the soil. Phosphorus (P) and potassium (K) are the main value, while straw incorporation will also lead to an increase in soil organic matter levels over time.

Mark Plunkett – soil specialist with Teagasc – estimated the value of that straw for the 2019 season. This estimate is based on a price of €2.25/kg for P and €0.85/kg for K.

According to Teagasc, the straw from a 10t/ha crop of winter barley will give back 4kg/ha of P and 51kg/ha of K. Bringing the value in Ps and Ks from that hectare of straw to €52.

It’s no surprise that straw from winter oat crops is being chopped lately as oat straw has the highest value in Ps and Ks with a value of €82/ha.

A full list of P and K values is available in the table below.

Data source: Teagasc

Soil organic matter

Quantifying the value of this straw to soil organic matter build up and the effect it can have on soil structure is a harder task. Soil organic matter build up is a slow process and will only happen by adding back to the soil with things such as farmyard manure, straw or cover crops.

When a crop is harvested it takes away nutrients which must be replaced to maintain healthy soils. Soils becomes depleted over time when organic matter levels decline. The soil’s biology and biodiversity will also reduce.

Straw prices

Earlier this week, AgriLand released straw prices from across the country. In plentiful areas for straw, such as counties Wexford, Carlow and Laois, prices are ranging between €15/bale and €20/bale out of the field – with an odd exception below this level.

Also Read: Straw prices: Chopping common where prices dropping

In Co. Tipperary, winter barley straw is moving at between €15/bale and €16/bale in some areas.

Prices are somewhat higher in Co. Cork. €18/bale looks to be the low of the market so far in this area; however, there are some exceptions to this price.