Differential Phosphorus Uptake and Use Efficiency Among Selected Nitrogen‐Fixing Tree Legumes over Time

Abstract

A study was carried out on three nitrogen (N₂)‐fixing tree legumes, i.e., Gliricidia sepium cv. ILG50, Leucaena leucocephala cv. K28, and Albizia lebbeck to assess their differential phosphorus (P) nutrition capability over time. Dry‐matter (DM) yields, P concentration, P uptake and partitioning in plants, and P use efficiency were estimated at 4, 8, 12, and 16 months after planting (MAP). The trees showed a large interspecific variation both in DM yields and P uptake. Concentration of P ranged from 0.042 to 0.275% and varied both among parts in each tree and among tree species over time. Leaves P concentrations showed a greater reduction with tree age than either stems or roots. Phosphorus uptake correlated significantly with plant DM (r = 0.893–0.946) across tree species, and had a steady increasing pattern up to at least 12 MAP. Over ages, Gliricidia outperformed the other species in P uptake. However, Leucaena was the most efficient user of P followed by Albizia and Gliricidia, in that order. Further, Leucaena revealed an attractive feature for alley cropping in that it stored up to 37% of the P accumulated in its leaves in contrast to only 24.1% for Gliricidia and 19.2% for Albizia. Therefore, the low P supply by trees into alley cropping is in part due to its unbalanced partitioning into stems to the expenses of leaves. The study shows also that P concentration in perennials is lower than it is reported in annual crops.

Keywords:

• Phosphorus uptake
• P use efficiency
• Albizia
• Leucaena
• Gliricidia

Acknowledgments

The IITA, Ibadan, Nigeria, funded this study through a Research Fellowship grant to the senior author. We thank Drs. Rahmattulah, O. A. Osiname, and K. Mulongoy, for their contribution in various ways.