Fig. 5.

Foliar nutrients in Hyeronima. Shown are nitrogen (A) and phosphorus (B) (both on mass basis), where filled circles are analyses of bulk leaf samples (n = 3) from monocultures and other symbols are disks punched from lamina free of large veins. Values are means ± SE. Squares are samples from monoculture; diamonds are from polyculture. Nitrogen regressions for disks are not different between monoculture and polycultures; bulk samples differ in intercept from the disk samples, as expected (P = 0.007), but not slope (b_mono = −0.091 disks and −0.106 bulk samples; b_poly = −0.097; difference test P = 0.776). N values from disks for age 8 yr were not included in calculation of regressions because of uncertainty of their validity. (C) Ratio of nitrogen to phosphorus, molar basis, where dotted line indicates level below which N may be limiting (9, 10).