Grasslands are generally established in late summer or late winter. Three types of climatic events are increasingly disrupting grassland establishment and growth: i) long summer droughts, ii) excessive winter precipitation, and iii) early onset of drought in the late spring. Overseeding grasslands into grain crops or grain-protein crop associations seems to be a promising way to limit the negative impacts of such events and to provide a supplemental food resource (forage or seeds). We performed experimental trials and gathered observations at various sites in northwestern France. We present a preliminary summary of our results here. To circumvent the effects of summer droughts, it can be helpful to overseed grasslands into spring grain crops grown in deep and healthy soils in late winter. For soils that experience extremes in moisture levels (both hydromorphic and prone to drying), an innovative approach is currently being tested: carrying out the simultaneous establishment in mid-October of perennial grasslands overseeded into grain/protein crops (in the form of late forage or seeds). It is thus possible to (i) avoid the negative impacts of late summer droughts, (ii) optimise the use of the cover crop, and (iii) ensure grassland establishment. A regime in which this technique of autumn establishment is combined with earlier harvesting of the cover crop is also under study. In the conclusion, we discuss several promising strategies based on soil type and cover crop usage (forage or seeds).
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