Tree row spacing affected agronomic and economic performance of Eucalyptus-based agroforestry in Andhra Pradesh, Southern India

Abstract

The 3 9 2 m spacing currently used for eucalyptus plantations in the state of Andhra Pradesh, southern India does not permit intercropping from the second year. This discourages small landholders who need regular income from taking up eucalyptus plantations and benefiting from the expanding market for pulpwood. Therefore, on-farm experiments were conducted near Bhadrachalam, Khammam district (Andhra Pradesh) for over 4 years from August 2001 to November 2005 to examine whether wide-row planting and grouping of certain tree rows will facilitate extended intercropping without sacrificing wood yield. Eucalyptus planted in five-spatial arrangements in agroforestry [3 9 2 m (farmers' practice), 6 9 1 m, 7 9 1.5 m paired rows (7 9 1.5 PR), 11 9 1 m paired rows (11 9 1 PR) and 10 9 1.5 m triple rows (10 9 1.5 TR)] was compared with sole tree stands at a constant density of 1,666 trees ha -1 . Cowpea (Vigna unguiculata) was intercropped during the post-rainy seasons from 2001 to 2004, and fodder grasses (Panicum maximum and Brachiaria ruziziensis) were intercropped during both the seasons of 2005. At 51 months after planting, different spatial arrangements did not significantly affect height and diameter at breast height (dbh). Total dry biomass of eucalyptus in different spatial arrangements ranged between 59.5 and 52.9 Mg ha -1 , the highest being with 6 9 1 m and the lowest with 10 9 1.5 TR, but treatment differences were not significant. The widely spaced paired row (11 9 1 PR) and triple row (10 9 1.5 TR) arrangements produced 62-73% of sole cowpea yield in 2003, 59-66% of sole cowpea yield in 2004, and 79-94% of sole fodder in 2005. In contrast, the 3 9 2 m spacing allowed only 17-45% of sole crop yields in these years. The better performance of intercrops in widely spaced eucalyptus was likely because of limited competition from trees for light and water. Intercropping of eucalyptus in these wider rows gave 14% greater net returns compared with intercropping M. R. Rao-Former staff of ICRAF (World Agroforestry Centre), Nairobi, Kenya. in eucalyptus spaced at 3 9 2 m, 19% greater returns compared with that from sole tree woodlot and 263% greater returns compared with that from sole crops. Therefore, in regions where annual rainfall is around 1,000 mm and soils are fairly good, eucalyptus at a density of 1,666 plants per ha can be planted in uniformly spaced wide-rows (6 m) or paired rows at an inter-pair spacing of 7-11 m for improving intercrop performance without sacrificing wood production.

Effect of Eucalyptus Based Agri-Silvi-Horticultural System on Growth and Yield of Wheat in North-Western Region of Haryana, India

“…In agrihorti (kinnow + wheat) and agri-silvi-horti (kinnow + eucalypts + wheat) system, RDF + additional dose of N (10, 20 and 30%) significantly increased the plant height over recommended dose of fertilizer at different time intervals of growth in wheat. Prasad et al, (2010) predicted a loss of 45 percent for various yield attributing characters of cowpea under Eucalyptus tereticornis based agroforestry system as compared to sole cropping in southern India. However, the differences between RDF + 10% additional dose of N, RDF + 20% additional dose of N and RDF + 30% additional dose of N were non-significant.…”

Estimativas da produção e propriedades da madeira de eucalipto em Sistemas Agroflorestais

“…Os espaçamentos amplos do componente arbóreo em Sistemas Agrissilvipastoris e Silvipastoris favorecem o crescimento em diâmetro e volume individual das árvores (LEITE et al 2006) e são fundamentais para a satisfatória produção das espécies forrageiras PAIVA, 2010;PRASAD et al, 2010). Quando espaçamentos menores, entre plantas, nas linhas de plantios, ou fileiras múltiplas adensadas, são adotados visando elevar o número de árvores por área, desbastes tornam-se necessários quando se planeja a produção de madeira de qualidade para serraria (FRANKE;FURTADO 2001;PAIVA, 2010).…”

Comparison of wheat yield and soil properties under open and poplar based agroforestry system

“…Significant yield reduction by tree species could be due to their shading effect and below ground competition for resources. Allelopathic effect is important cause of crop yield reduction in agroforestry systems (Prasad et al, 2010). The loss of yield, however, was not only due to the growth of trees but also due to the loss of land area to trees.…”