Biomass yield stability of interspecific Jatropha hybrids through multiple harvest rotations with varying harvest ages

Abstract

Importance of the work:The consistency of biomass production is crucial for Jatropha cultivation as a short rotation woody crop for use as a biomass source. Objectives: To investigate the effect of harvest age on Jatropha hybrid growth, assess the relationship between growth traits and biomass yield and evaluate the biomass yield stability of interspecific hybrids between Jatropha curcas and J. integerrima. Materials & Methods: For 5 yr, 14 genotypes of Jatropha hybrids, were evaluated in the field, using three different harvest age rotations. Plant height, canopy width, stem and branch diameter and biomass yield were measured. Results: Harvest ages and genotypes affected Jatropha hybrid growth traits. Jatropha hybrids grew larger with age. Plant height, canopy width and stem and branch diameter were all highly correlated with biomass yield (correlation coefficient range = 0.59 [p < 0.05] to 0.94 [p < 0.01]). At the first, second, third, fourth and fifth harvests at 12 mth intervals, the Jatropha hybrids had average biomass yields of 45.91 t/ha, 40.63 t/ha, 36.46 t/ha, 42.77 t/ha and 37.29 t/ha, respectively. Although harvest frequency affected biomass yield, the yield did not substantially decrease, suggesting pruning tolerance of the Jatropha hybrids. The optimal harvest age rotations for Jatropha hybrids were intervals of 12 mth and 18 mth, due to the highest five-yearly total biomass yields of 202.79 t/ha and 221.29 t/ha, respectively. Furthermore, the KUBJL 14 genotype had the highest growth and biomass production. Main finding: The growth traits of the Jatropha hybrids could be used to assess biomass production. Jatropha hybrids have a high biomass potential and good biomass yield stability, even after multiple harvests.

Genotype performance and relationship between leaf traits, biomass yield and wood quality on interspecific hybrids of Jatropha

“…In the cultivation of Jatropha hybrids, the stems and branches must be pruned each year to harvest biomass and then allowing the rootstock to regrow in the following year (Arunyanark et al, 2022). Thus, concern has been raised that pruning might affect the growth and biomass yield of Jatropha hybrids.…”

“…The cultivation of Jatropha hybrids as a source of raw materials for sufficient and sustainable energy production requires relevant management information. While a fastgrowing tree may be suitable for planting as a source of biomass energy, it should have a high biomass per area as well as the ability to regrow quickly after pruning (Pleguezuelo et al, 2015;Arunyanark et al, 2022) as this allows harvesting multiple biomass yields without having to replant. Many fastgrowing trees, such as willow and Populus, require years of maturation before being pruned to harvest their biomass, with some cultivars not recovering and producing new growth or there may be several unproductive years until sufficient regrowth has developed to warrant harvesting (Pleguezuelo et al, 2015;Griffiths et al, 2019).…”

Biomass productivity and wood chemical composition at different pruning ages of interspecific hybrid Jatrophas

“…Although the hybrids showed an increase in biomass yield with increasing age, the optimum age for biomass harvesting was 18 MAP, based on the highest rate of biomass increase per period and the proportion of biomass of the hybrids with a large amount of wood. Furthermore, post-pruning regrowth ability is an important characteristic for raising fast-growing trees for biomass energy crops, as it is related to the ability to harvest multiple biomass yields without requiring any replanting investment (Pleguezuelo et al, 2015;Arunyanark et al, 2022). Therefore, jatropha hybrid plantations as a biomass energy crop should be evaluated for biomass yield recovery and stability after pruning.…”

“…However, the optimal pruning age for hybrids utilized for biomass has never been determined. Pruning age is an important factor in determining biomass production capacity and the harvesting cycle in the Jatropha hybrids cultivation system (Arunyanark et al, 2022). Furthermore, a consistent and sufficient supply of raw materials for industry and power plants might necessitate the use of biomass from multiple harvesting cycles.…”