Modelling competition of paired columns of Eucalyptus on interplanted grass

摘要

Adequate evaluation of competition interfaces of tree growth on intercrops is an important consideration in the assessment of agroforestry systems. Spatial methods wherein positional effect of an observation with respect to trees or columns of trees can be accounted for were examined. Yield ofbhabbargrass (Eulaliopsis binataRitz) planted under paired and staggered columns of Eucalyptus (Eucalyptus tereticornisSmith) was analysed for four years. Grass production at 7 positions recorded across staggered and paired tree columns was significantly different. Spatial correlations among contiguous observations across paired tree columns were significant. Cyclicity corresponding to seven columns of grass of 3.5 m distance between paired tree columns explained variation in grass production significantly during the first observation year. Additional competition interfaces at 1.75 m and 1.17 m appeared in the subsequent years. These competition interfaces were attributed to pairing of trees and staggering. Error distributions of fitting of cyclic patterns were more acceptable as compared to ANOVA. Possibilities of the use of this methodology in many other agroforestry situations are discussed.