Species Interactions and Nitrogen Use during Early Intercropping of Intermediate Wheatgrass with a White Clover Service Crop

Perennial grain crops intercropped with legumes are expected to use nitrogen (N) resources efficiently. A pot experiment using the 15N isotope dilution method demonstrated interspecific competition and of N from soil N2 fixation in intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey, IWG) white clover (Trifolium repens L., WC) intercrops at five species-relative frequencies four levels inorganic fertilizer a replacement series design. The proportion WC derived atmosphere increased 39.7% sole crop 70.9% when IWG, 10.1% IWG transferred WC. Intermediate showed high fitness maintained total dry matter production low relative frequencies. Decreasing IWG-relative frequency only accumulation WC, resulting amounts fixed. Increased fertilization acquired but decreased fixed by absorbed soil. Our study indicates that supply sufficient for intercrop biomass yields under appropriate fertility