In white clover/ryegrass mixtures grazing in one year significantly increases the yield in the next, compared to cutting. Red clover is a good supplement to the mixture as it performs well under cutting regime, while white clover takes over during grazing. Overall, inclusion of red clover in the mixture contributes to a more robust sward and

increased flexibility in utilizatio

Askegaard, M.

Eriksen, J.

Søegaard, K.

English

Organic Eprints

1/2011 6ArticleThe production of grass-clover is affected by grazing. Dung and urine excreted during grazing increases the growth of both grass and clover. At the same time the nitrogen fixation by clover decreases. This is something always occurring with the addition of nitrogen. In ad-dition, growth is affected by the animals with their fre-quent defoliation. The grass becomes denser, ie. there are more shoots per unit area. White clover has a good ability to adapt, its lea-ves become much smaller by grazing and it has the ability to cover bare spots by stolon development. This happens, for instance where animals thread, below ma-nure or urine affected spots. Red clover does not pos-sess this ability to spread. The number of plants is limited to those established, but grazing means that its growth becomes low and flat to the ground, and the leaves become small. We have studied the impact of grazing on grass-clover pro-duction, composition and fertilizer response in mix-tures of ryegrass and white clover with and without red clover.Positive effect of grazing in white clover/grass mixturesYield under cutting regime was affected by whether the field was previously cut or grazed. Yield was higher when the grass-clover was grazed up until the cutting period (grazing for at least a year before the time of cut-ting), compared to cutting (Table 1).This was especially so where slurry was injected, which may be due to denser grass population and thus greater growth potential. Also, the clover content was strongly reduced by previous grazing when cut-ting in spring, while there was no effect on the sum-mer cut. This may be due to the fact that white clover growth is faster in summer Table 1. Dry matter (DM) yield and clover proportion in spring and summer growth following different management in the previous and the year of harvest. Different letters indicate significant differences. Yield effects of grazing and red clover in white clover/grass mixturesBy: Jørgen Eriksen and Karen Søegaard, Aarhus University, Department of Agroecology and Environ-ment, Tjele, Denmark and Margrethe Askegaard, Knowledge Centre for Agriculture, Skejby, DenmarkIn white clover/ryegrass mixtures grazing in one year significantly increases the yield in the next, compared to cutting. Red clover is a good supplement to the mixture as it performs well under cutting regime, while white clover takes over during grazing.   Overall, inclusion of red clover in the mix-ture contributes to a more robust sward and increased flexibility in utilization.Spring growth  Summer growthYield t DM/ha Clover % Yield t DM/ha Clover %Ryegrass/white clover - slurry Cutting 3,8 c 21 a 2,4 ab 58 aGrazing 3,9 c 11 b 2,4 ab 54 a+ slurry Cutting 4,8 b 13 b 2,2 b 34 bGrazing 5,4 a 4 c 2,7 a 34 bRyegrass/white and red clover- slurry Cutting 5,0 b 52 a  2,3 b 76 aGrazing 4,9 b 23 c  2,9 a 57 b+ slurry Cutting 5,6 a 31 b 2,5 b 70 aGrazing 5,9 a 16 d 3,0 a 51 bSward with white- and red clover1/2011 7Articlethan in spring. Similarly, the yield response of fertilizer was significantly increased by grazing. The reason may be the recycling of urine and manure by grazing, con-tributing to a higher level of fertilization as well as a higher plant density, which both affect the potential for production.Red clover in the mixtureThe corresponding residual effect was studied where the seed mixture contained 1 kg red clover per hectares (4%). This caused the significant yield effect of grazing found in the white clover mixture to disappear (Table 1). The explanation lies in the dyna-mics of white and red clover in the sward. Red clover is influenced significantly by grazing and contributes mainly in cut grassland, and vice versa for white clover, whose share increased dramatically du-ring grazing (Figure 1). The amount of red clover seeds was approx. half the volume in the recommended seed mixtures. Without slurry application and cutting only, the proportion of red clover was less than 50% of total dry matter, which is a satisfactory level without the grass being outcom-peted. In this way red and white clover complements each other more than they compete and an overall higher clover proportion is achieved. Overall, inclusion of red clover in the mixture con-tributes to a more robust sward and increased flexi-bility in utilization.Figure 1. Proportion of red and white clover in a mixture of perennial ryegrass, white and red clover subject to previous grazing and cutting, with and without slurry. Different letters indicate significant differences.Harvest in parcelsMore informationRead more about the DARCOF III project Orggrass on the webpage: http://www.icrofs.org/Pages/Research/darcofIII_org-grass.html The project is funded by the Da-nish Ministry of Food, Agricul-ture and Fisheries.

Yield effects of grazing and red clover in white clover/grass mixtures

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