If you read the previous article in this series you’ll know the best time to plant Sericea lespedeza, a hardy legume that makes protein-rich hay, is in early summer. But I had something of a wake-up call recently – and it doesn’t just apply to Sericea lespedeza, but to all dryland pasture species on the Highveld. The jolt came while delving into Volume 5 (Calcium) and Volume 6 (Pastures) of the Albrecht Papers.
I invariably advise clients to plant Sericea lespedeza (poor man’s lucerne, now renamed prosperity lucerne) on the worst soils on their farms to start with because it grows better than anything else on such soil. I was told about Sericea in 1982 by Bruce Pennington of Pennington Seeds in Georgia, in the US, while on tour with a few farmers hunting for rainfed legumes. When I described the low-potential soils in the unpredictable rainfall region of the eastern Free State, Bruce said Sericea was the only legume that would do.
The first planting of imported seed was on Willie Nel’s farm Langesnek in Ficksburg. We chose a slope where most of the topsoil had washed away before Willie bought the land adding it to his existing property, Moolmanshoek. We made the all-too-common mistake of planting in autumn and not controlling weeds. It took three years for Sericea to gain the upper hand, but from then on it was a winner.
I can tell you of many more cases where Sericea produced good tonnages of protein-rich hay on seemingly hopeless soils – but that’s not the point of this week’s article. Albrecht points out that it makes little sense to plant a pasture to an eroded land to stabilise it and to return fertility to it without first correcting the mineral balance. Without fertility the land will produce low quality forage.
Many farmers on the Highveld have tried the pasture option to escape the never-ending cost escalation in cash crop production. Invariably the talk has been about the quantity of forage per hectare – quality is hardly mentioned. Yet, as Albrecht puts it, soils low in fertility produce forage not much better than wheat straw. He speaks of the immense value of applying phosphate and lime to Sericea lespedeza. In one trial, hay was made from a land fertilised with phosphate (P) and lime (Ca).
Hay made from an unfertilised section of the same land served as a control. The hay was fed ad lib to young lambs and supplemented with an oat/bran mix at the rate of 230g/lamb/day. The lambs fed hay from the P+Ca plot gave the best results. Lamb liveweight gain was 117% higher than that of lambs who utilised hay from the control plot – 130g/day as opposed to 60g/day. Moreover, the P+Ca plot produced 31% more forage than the control plot.
Transposing this data to Sericea and starting with a hay yield of 4t/ha for the control plot and a hay intake of 1kg hay per lamb per day, I’ve calculated that the total liveweight gain/ha for the control and P+Ca treatments could amount to 240kg and 680kg. That is, an increase of 440kg/ha in favour of the mineralised hay. The additional gross income derived from fertilising Sericea lespedeza with P+Ca works out to about R8 000/ha (R18,20/kg liveweight gain) in this study.
Another very significant fact in Albrecht’s trial is that 42% less concentrate was used per kilogram of liveweight gain when hay made from P+Ca plots was fed as opposed to lambs fed control hay plus the standard concentrate ration.
Quite a wake-up call, don’t you think?
John Fair is a leading expert on pastures and founder and head of the SA Biofarm Institute in Harrismith. Contact John on 058 622 3585 or at [email protected]. Please state ‘Biological farming’ in the subject line of your email.