Tillage practice and sowing time affect yield, nitrogen uptake and profitability of catch crops sown after winter forage grazing in New Zealand

ABSTRACT

Eight oats catch crop trials were conducted over two years on winter forage paddocks on commercial dairy farms in Canterbury and Southland measuring the effect of tillage and timing-by-tillage, respectively, on dry-matter (DM) yields, N uptake and profitability (gross profit margin). The main objective was to successfully integrate catch crops into winter forage rotations over a critical period when the soil is normally bare and the potential for N drainage loss from urinary-N deposition is high. Oat harvest yields at green-chop silage maturity (∼50% panicle emergence) ranged from 8 to 10 t DM/ha when sown by the end of winter (4–5 months after drilling). Nitrogen uptakes ranged from 52 to 363 kg N/ha. Net gross profit typically ranged from NZ$1000 to NZ$1600/ha (assuming revenue of NZ$0.20/kg DM for standing feed). Minimum-till cultivation produced higher DM yields than direct-drill treatments in both years of the Canterbury trials (∼30% higher overall) but where N availability and good soil-seed contact were maintained, differences in yield were small (∼5%). Earlier sowing in Southland using a spader-drill combination increased DM yields and N uptake overall by 123% and 48%, respectively, over later sown conventional tillage options.

KEYWORDS:

• Spader-drill
• oats
• Italian ryegrass
• green chop
• minimum till
• direct drill

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Correction

Acknowledgements

The authors wish to thank the following farmers for their contribution to the project: Dairy Holdings Ltd (Hororata/Mt Somers), Craigmore Farming (Te Pirita), Kiwi Dutch Dairies Ltd (Lumsden), Bruce and Sonya Taylor (Mossburn), and Chris Giles (Gore).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.

Correction Statement

This article was originally published with errors, which have now been corrected in the online version. Please see Correction (https://doi.org/10.1080/00288233.2022.2118008)

Additional information

Funding

This study was principally funded by the New Zealand Ministry for Primary Industries (Sustainable Farming Fund Project 405492) and co-funded by Agricom NZ, Ballance Agri-Nutrients, Ravensdown, Beef+Lamb New Zealand and Luisetti Seeds.