FORAGE HERBS IN GRASS MIXTURES FOR DAIRY PRODUCTION

The forage herbs chicory (Cichorium intybus) and plantain (Plantago lanceolata) have become regular components of south-eastern seaboard dairy pastures. They are mostly planted in a mixture with grasses and often clover species are added as a minor component. How they do and what benefits they bring to the pasture mix and the cow have not been well researched in these areas. This was then the purpose of the trials cited below. 

The trials were conducted at Outeniqua Research Farm on mixtures of the herbs with grass, and compared with pure stands planted in spring and autumn using a 4x4 balanced lattice design. Biomass dry matter (DM) yield and botanical composition were determined. The spring-planted trial had a substantial weed component of 37% to 65% at the first harvest, depending on the treatment. By January 2017 the weeds decreased to a mean of 28% for the herb treatments and 84% for the grass only treatments. The autumn-planted trial had a mean of 13% weeds at the first harvest, decreasing from there onwards. 

During the first summer the grass component was outcompeted by the forage herbs, while the forage herb pure stands had the highest yields (p < 0.05), with chicory yielding best with 8.0 tons DM per hectare (ha). From autumn 2017 onwards, all treatments with plantain, pure and mixed, out yielded (p < 0.05) the chicory treatments and pure grass treatments, including the second summer. The chicory treatments were higher yielding (p < 0.05) than the grass treatments. For the grass/herb mixtures the herb component dominated with 71% to 97%, depending on the mixture. At 38.7 ton DM per ha, plantain had the highest DM yield over the 17-month period. The highest chicory yield was 32.1 ton DM per ha and was lower (p < 0.05) than the plantain. The pure grass treatments were lower (p < 0.05) than all other treatments with a mean of 20.6 ton DM per ha. In the autumn-planted trial the perennial ryegrass component dominated and out-yielded in both the pure stands and in a mixture with forage herbs until the end of winter. During spring the forage herb treatments were higher yielding (p < 0.05) than perennial ryegrass, while during summer the pure plantain treatments yielded a mean of 8.4 tons DM per ha, which was higher than all other treatments. The same was true for the total DM yield, with plantain sown at 10 kg per ha producing 22.0 ton DM per ha during a 12-month period and perennial ryegrass at 15.3 ton DM per ha. In the autumn-planted mixtures the grass-component was smallest at the end of January with 5%. 

In conclusion: The pure stands of the forage herbs yielded significantly better than the mixtures. In terms of pasture systems and how forage herbs can best be used, these results indicate that there could be merit in rather planting a pure forage herb sward and a grass pasture separately, where both are grazed alternatively during the same day to ensure sufficient fibre from the grass pasture to counter the low DM content and high carbohydrate content of the forage herbs.  

Reference: 

Sigrun Ammann, 2018.THE EFFECT OF PLANTING DATE ON YIELD AND BOTANICAL COMPOSITION OF FORAGE HERB AND GRASS MIXTURES. In Proc. of the 53rd Annual Congr.

Grassland Society of Southern Africa, ARC – Training Centre, Roodeplaat, Pretoria, 22-27 July 2018.