Figure 4
Nitrogen accumulation of maize with (a) N0, (b) N1 and (c) N2 in three cropping systems. S, sole cropping; Int-1, intercropping with strip width ratio of 80:80 cm for maize:pea; Int-2, intercropping with strip width ratio of 120:80 cm for maize:pea. N0, N1 and N2 represent the N fertilizer applied at 0, 300 and 450 kg N ha−1 for the maize. 15, 30, 45, 60, 75, 105, 135 and 165 day after sowing are respectively at the VE, V3, V8, V12, V16, R1, R4 and R6 stage of maize. The error bars are standard errors of the means (n = 9).
