CAJ | 학술논문

Leaves of multipurpose tree species (those providing more than one function or product of human use) can serve as sources of fer-tilizer for nutrient supply, especially nitrogen (N). In this study chopped leaves of tropical tree species (5 N-fixing species, 5 non-N-fixing species and combinations of 5 N-fixing with a non-N-fixing species) were in-corporated in soil to evaluate its effects on wheat biological productivity (including grain yield, GYIELD) under dryland conditions. High quality leaves of N-fixing tree species (e.g. Dalbergia sissoo, Cassia fistula and Prosopis cineraria) had lower carbon/nitrogen (C/N), lignin/nitrogen (LIG/N), polyphenol/nitrogen (PPL/N) and lignin+polyphenol /nitrogen (LIG+PPL/N) ratios than low quality leaves of non-N-fixing species. Com-bination treatments had intermediate values of different parameters. Application of high quality leaves caused greater increases in wheat productivity and yield than other species. By the application of leaves of N-fixing trees, on average, wheat yield increased 160% relative to the control (no addition of leaves), and when combined with non-N-fixing Terminalia chebula leaves the yield increased 108%. Mean total net productivity (TNP) with N-fixing species treatments, exceeded mean TNP with non-N-fixing species and combination treatments by 50%and 28%, respectively. Multivariate regressions indicated that nitrogen (N) concen-tration in leaves (main nutrient), interacting with lignin (LIG) and poly-phenol (PPL) concentrations, explained 79%?86% of variability in pro-ductivity parameters and yield. Strong correlation between LIG+PPL/N ratio of leaves with GYIELD of wheat crop suggests that the ratio can be used as a reliable index for mass screening of multipurpose tree species for use as soil amendments especially in dryland agriculture. Direct ap-plication of high quality N-fixing tree species leaves (especially D. sissoo, C fistula and P. cineraria), an uncommon practice in dry tropics in India, may serve as a short-term option for rapid enhancement of wheat produc-tivity and soil fertility.