How Cover Crop Sowing Date Impacts upon Their Growth, Nutrient Assimilation and the Yield of the Subsequent Commercial Crop

Paul Cottney,Ethel White,Paul Williams,Lisa Black

doi:10.3390/agronomy12020369

Paul Cottney, Ethel White + Show 2 more

Open Access

https://doi.org/10.3390/agronomy12020369

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Abstract

Cover crops are typically sown post-harvest of commercial crops, prior to winter, which means that as sowing date is delayed, so will biomass production potential. The wide range of benefits associated with cover crops relies on them to produce sufficient biomass. Therefore, it must be identified how late certain species of cover crops can be sown. In the climatic conditions of Northern Ireland, not only has no research been conducted on how cover crops perform at various sowing dates but also their effect on the subsequent commercial crop yield has not been investigated. Addressing these issue will in turn help provide recommendations to maximise and encourage later sowing of cover crops. Consequently, five species of cover crops were chosen, from a range of families, then sown on 14 August, 7 September and 27 September. This is to mimic when land becomes fallow post-harvest of typical crops/rotations to this region. It was found that tillage radish (Raphanus sativus L.), when sown on the earliest date, could accumulate a maximum of 261 kg/ha of nitrogen (N), whereas, when sown on the last date, phacelia (Phacelia tanacetifolia L.) significantly outperformed all other species and assimilated 70 kg/ha of N. The cover crops were then incorporated into the soil and over-sown with spring barley (Hordeum vulgare L.). However, the spring barley yield was unaffected by any treatments. This trial shows that the non-leguminous species chosen are highly effective in assimilating nutrients when sown mid-August until early-September.

Highlights

When the sowing of cover crops is delayed later into autumn, their exposure to conditions critical for growth is reduced
To maximise the area of land sown with cover crops, they must be planted after crops with harvests that are later than winter barley, such as winter wheat (Triticum aestivum L.), spring barley (Hordeum vulgare L.) and vegetables
This raises the need for investigation of how late in the autumn, in the climatic conditions of Northern Ireland (NI), can cover crops be sown and grow successfully, and which species are better suited to later sowing dates

Summary

Introduction

When the sowing of cover crops is delayed later into autumn, their exposure to conditions critical for growth is reduced. To maximise the area of land sown with cover crops, they must be planted after crops with harvests that are later than winter barley, such as winter wheat (Triticum aestivum L.), spring barley (Hordeum vulgare L.) and vegetables. This raises the need for investigation of how late in the autumn, in the climatic conditions of Northern Ireland (NI), can cover crops be sown and grow successfully, and which species are better suited to later sowing dates

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