Grassland utilisation in autumn and yield in spring

The consequences of a late closing date in autumn on pasture in spring are mostly unknown. An experiment comparing the effect of three different closing dates in autumn (early October, late October, late November) was therefore carried out over a three-year period on two sites in the Swiss lowlands. The aim was to determine, how much herbage mass has to be left over before winter, in order to guarantee a vigorous growth in spring. The effect of the three treatments on grass yield in the following spring was highly significant. Each kilogram dry matter used between early October and late November reduced spring yield by 0.34 kg DM in mid-March and 0.45 kg DM in early April. In Mai this reduction of spring yield was particularly high (2.64 kg DM) if the residual herbage mass before winter was below 300 to 500 kg DM/ha. Grass-height measurements were closely related to DM-yield measurements, and can thus be used as a simple but useful estimation of yield. No significant differences were found between the two types of utilisation analysed (cutting or grazing). The utilisation of pasture in late autumn is recommended, if conditions are favourable and the residual herbage height before winter is not lower than 5 to 6 cm (plate pasture meter) corresponding to 300 to 500 kg DM/ha residual herbage mass. Major losses in spring must be expected if this limit is not respected.