Friday, 18 June 2021 07:55

Catch crops a valuable tool

Written by 
Catch crops are a good way to capture and use nitrogen left in the wake of winter forage crops. Catch crops are a good way to capture and use nitrogen left in the wake of winter forage crops.

Along with several other organisations, Beef+Lamb NZ helped fund the catch crops for reduced nitrate leaching project. Sown as soon as possible after grazing has finished, catch crops have been the subject of a Sustainable Farming Fund project led by Peter Carey from Lincoln Agritech, with support from Brendon Malcolm and Shane Maley from Plant and Food Research and AgResearch.

The project highlighted the value of catch crops as a tool to capture and use nitrogen left in the wake of winter forage crops, provided the correct management principles were followed.

The researchers carried out trials at both plot and farm scale to determine how to make the most effective use of catch crops to reduce nutrient losses while generating dry-matter.

Speaking a recent workshop, Brendon Malcolm says catch crops mop up N and reduce drainage by taking up water. However, timely sowing with the appropriate winter-active species was important to make the most effective use of these crops.

July-sown oats had the greatest impact on reducing nitrogen losses. At paddock scale, oat crops were capturing up to 100kg N/ha by the end of the leaching period, N that would be otherwise be lost to the environment.

Yields in catch crops grown for green-chop silage were typically between 8-10t/ha with a maximum of 12t DM/ha.

Malcolm says while the oats sown in July were very slow to come away, they were still capturing significant amounts of N through the root system, despite the lack of above-ground foliage.

Growing a crop at a time of year when the paddock would normally be bare, does add to bottom line and an onfarm trial looking at an ex-kale crop showed that it only took a crop of 2-3t/ha to break even.

Returns per hectare were greater in the direct drilled crop versus the crop established with tillage – $1,620 versus $1,520/ha. However, Malcolm acknowledged that tillage was sometimes necessary to provide good seed-to-soil contact if the field surface was too pugged from the previous forage crop – like fodder beet.

Peter Carey says early sowing is one of the most important factors with catch crops.

“The key point is sowing as early as you practically can.”

Modelling carried out in Canterbury on freedraining soils showed the earlier the sowing, the greater the amount of N captured.

A sowing date trial comparing crops sown on 11 July, 3 August and 31 August highlighted the importance of early sowing. By harvest in November, there remained a big difference in the crops despite the three-week difference in sowing dates.

“Some years you just cannot get on the paddock – maybe one in every five years – and you just can’t do anything about that,” Carey explains.

He adds that they focused on oats because they are robust, will germinate at lower temperatures and produce quality green-chop silage.

A trial comparing Italian ryegrass, with Triticale and oats showed oats (Intimidator) to be the stand-out performers in terms of both dry-matter yield and nitrogen captured.

For more information about catch crops go to B+LNZ’s Knowledge.

More like this

Oh dear!

OPINION: This old mutt suggests that farmers' growing discontent with Beef+Lamb NZ's performance is going to reach fever peak after its latest stunt.

More youth funded into sheep and beef careers

Beef + Lamb New Zealand (B+LNZ) have signed a funding agreement with the Growing Future Farmers (GFF) Essential Farm Skills Programme, helping attract and train more young people in the red meat sector.

We are fighting - Morrison

Beef+Lamb NZ is committed to arguing for a fair and appropriate framework for tackling climate change, claims chairman Andrew Morrison.

B+LNZ remains unconvinced by low-slope map

The Government’s new proposed low-slope map for stock exclusion is better than the original, however the map still won’t practically work on the ground, says Beef+Lamb New Zealand (B+LNZ).

National

Tatua smashes $10 barrier

Waikato milk processor Tatua says keeping products moving to overseas customers during the pandemic was one of the highlights of…

New regs boost Massey Ag course enrolments

Demand for expertise in sustainable nutrient management, environmental planning and improved freshwater outcomes has seen Massey University's range of agricultural…

Machinery & Products

Keeping everyone safe

As tractors get larger and front linkage kits become more common, many have started fitting underrun or collision protection systems.

Keeping stock and drivers safe

Livestock haulers are a crucial link in the New Zealand agriculture supply chain, transporting stock onto or between farms, to…

Making lamb marking easy

Designed by a sheep and beef farmer, Vetmarkers are made in New Zealand and sold around the world.

» The RNG Weather Report

» Latest Print Issues Online

The Hound

Flag it!

OPINION: Agriculture and Trade Minister Damien O'Connor tried to keep his latest overseas jaunt secret squirrel.

Oh dear!

OPINION: This old mutt suggests that farmers' growing discontent with Beef+Lamb NZ's performance is going to reach fever peak after…

» Connect with Rural News

» eNewsletter

Subscribe to our weekly newsletter