Red clover can contribute 150 to 200 kg of nitrogen/ha or more, according to speakers at a recent British Grassland Society forage legume day in Shropshire.
Popular up to the 1960’s, red clover fell out of favour when artificial fertiliser offered an easy option for supplying nutrients for crop growth. Now, rising fertiliser prices, (1kg N/ha is worth £1), are reviving interest in this useful plant said Dr George Fisher.
However, to derive all the benefit, farmers have to nurture the nitrogen fixing bacteria which live in lumpy nodes on the roots.
- soil pH 6
- decent soil structure
- no water-logging
- P index 2
- K index 2-
Jewel is the crown
The engine of the red clover plant is the crown – explained Dr Athole Marshall of IBERS, a little white area at the base of the stems the size of a thumb nail. It is vital that this is protected – once physically destroyed or damaged by disease, the plant will die.
Breeders at IBERS (at Aberystwyth University) have revived their red clover breeding programme, and are looking to develop traits such as greater disease resistance and persistency – as short life span is one of its downsides.
New varieties Aberclaret and Aberchianti (like the wine-related names!) show promise, with Aberclaret still yielding 14t DM/ha in year 3 when older varieties have fallen away to 6-7t DM/ha.
But beware even with newer varieties it is vital to protect the crown – don’t cut too low (below 5-7cm) and never overgraze.