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Symbiotic nitrogen fixation is an essential ecological attribute for sustained amelioration of severely eroded, low fertility soils. The long-lived perennial, Sericea (Lespedeza cuneata (Dument) G. Don.), is highly tolerant of depleted soil conditions and has exceptional nitrogen fixation capabilities.Objectives of this study were to determine nodulation characteristics, with adjunctive governing factors, that influence 20 year-age Sericea growth, effectual nitrogen fixation and subsequent improved soil productivity of eroded Dougherty loam (Loamy, mixed, thermic, Arenic Haplustalf). A first-year lime application resulted in significant favorable Sericea growth and nitrogen fixation throughout the 20-year period. Sericea growth and nodulation declined approximately onethird during the second decade of plant age. However, annual nodule regeneration remained at nearly the same level. Peak nitrogenase activity levels occurred with favorable mycorrhizal colonization. Distinctive nonmature and mature nodule morphology contributed to well defined histology for cellular cytology that is associated with ureide transformations unique for Sericea nodule enzyme compartmentation. Soil organic matter increased from 0.35% to 2.65% during the 20-year Sericea growth.

Jack bean (Canavalia ensiformis (L.) D.C.) has been utilized by mankind for over 2,000 years. This high protein, large-seed legume is tolerant of unfavorable soil conditions, drought and adverse climate. However, growth and yield within the neotropical regions are influenced by soil productivity. The objective of this study was to determine effects of soil fertility treatments on growth, seed (bean) yields, nodulation, nitrogenase activity, and distinctive seed and nodule components unique to this legume. Plant growth, seed yields and nodulation were significantly influenced with soil fertility treatments. P was the limiting factor for top growth as no increase was attained from K or Ca without P additions. Mature seed yields were correlated with both top growth, (r = 0.67) and nodulation (r = 0.58). However, nodulation increases with P treatments occurred only when combined with K. Highly significant increased nitrogenase activity 563 .56g top growth + 3.93g nodule + 5.21g seed, R 2 = 0.81 and C.V. = 12.5%. Multiple regression with nodule cytosol composition was nitrogenase activity = 4.40μg P + 8.42μg K + 2.98μg Ca -2.41μg Na, R 2 = 0.78 and C.V. = 13.3%. Ontogenetic metastasis of mature seed content occurred from 104 day-age to 149 day-age after germination with canavanine quadratically increasing from 6.08 mg to 32.8 mg g" 1 seed, Concanavalin A increased from 5.05 mg to 44.0 mg g -1 seed and urease linearly increased from 97.0 IU to 215.8 IU g -1 seed. Nodule histology closely reflected transformations and cytology of lipid components and ureides of nodule cytosol, and the vacuolation of rhizoidal engorged, nitrogenase active cells.

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