Influences of leguminous tree species, Albizia julibrissin Durazz. on growth and feed component characteristics of cool‐season grass, Dactylis glomerata L. beneath the canopy in Japan's temperate zone

To evaluate the capacity of the deciduous leguminous tree, Albizia julibrissin Durazz. as a fertilizing or shading tree for cool‐season grasses, I investigated its effects on the quantitative and qualitative growth performance of Dactylis glomerata L. from germinated seedlings to adult plants, and on the changes in vegetation under no fertilization conditions in Japan's temperate zone. Height, yield and nutritional contents of D. glomerata beneath and beyond the canopies were compared over 4 years. The plant height and dry matter yield were higher beneath the canopy than beyond the canopy for both the first and the second crops. The nutrient differences between the two locations were larger for the second crop than the first crop. Total digestible nutrients ( TDN ) and crude protein ( CP ) were higher beneath the canopy and fibrous components were conversely higher beyond the canopy for the second crop. The TDN yield and CP yield were higher beneath the canopy for both the crops. Weed invasion was suppressed beneath the canopy. These results suggest that the growth of D. glomerata was promoted beneath the canopy of A. julibrissin and that the environment beneath the canopy was more suitable for the cool‐season grass D. glomerata in Japan's hot summers. This is the first demonstration showing the possibility of sustainable grassland production using the deciduous leguminous tree, A. julibrissin and D. glomerata in the cool temperate zone.