Fig. 5. Total plant dry weight and N content for green manure crops as functions of time (A and B, respectively) and as functions of cumulative intercepted photosynthetically active radiation (PAR; C and D, respectively). Green manure crops shown are: sunn hemp during 2001 () and 2002 (), lupin during 2001–2002 (), and vetch () during 2002–2003. Error bars reflect standard error values.