Crop Performance Indexes Applied to Legume Used as Summer Cover Crops under Water Deficit Conditions

Summer legume cover crops (CC) such as Crotalaria juncea, spectabilis, ochroleuca, and Cajanus cajan could offer diverse advantages for the environment productive cropping systems. A low transpiration efficiency (TE) of CC can induce soil water content to levels that present a challenge subsequent crop. In 75-day growth chamber experiment, using natural abundance 13C, 18O, 15N we evaluated TE BNF under two conditions. Our results showed four species tested are good candidates their use because they in terms productivity parameters, TE, BFN. had highest high shoot dry matter production, accumulated more N from BFN than C. ochroleuca. ?18O increased moderate deficit an inversely proportional relationship with amount transpired water, supporting this isotopic indicator proxy stomatal conductance. For parameters no interaction between factors regimen were found. We propose mass ratio nitrogen fixed by volume discrimination 13C useful indicators drought fixing legumes tolerance.