Improving Jatropha curcas L. photosynthesis-related parameters using poultry litter and its biochar

Abstract

Poultry litter and biochar contribute to improved plant growth due to their high nutrient content. However, to the best of our knowledge, how incorporating poultry litter and its biochar in soil affects photosynthesis-related parameters of Jatropha curcas L. has not been reported. Therefore, a greenhouse pot experiment was conducted using a complete randomised design with three replicates per treatment to determine the effects of poultry litter, biochar pyrolysed at 350 °C and 750 °C at different application rates (0, 0.5, 1, 2, 3 gkg-1) on Jatropha curcas L. photosynthesis parameters. The control plants recorded the lowest values of photosynthesis-related parameters compared to the treated plants except for water use efficiency. The study observed a significant (P < 0.05) increase in leaf surface area (1807 m2, PL), dark-adapted Fv/Fm ratio, carbon dioxide uptake, and transpiration rate for PL and BC350 with increased application rates, compared to BC750 treatments. BC350 treated plants exhibited higher values (0.79) of Light-adapted Fv’/Fm’. The quantum yield of PSII electron transport displayed an increase with an application rate of 3 gkg-1in PL (0.75) treated soils. Comparing organic amendments used, BC350 exhibited a significantly higher value of carbon dioxide uptake rate (2.67 μmol m-2 s-1) and transpiration rate (2.20 mmol m-2 s-1); however, WUE increased at an application rate of 3 gkg-1 in BC750 (3.8 µmol (CO2) mol-1(H2O)) treated plants. The study results indicate that poultry litter and biochar produced at a lower temperature significantly improved photosynthesis parameters than biochar produced at a higher temperature.

Keywords

• biochar
• chlorophyll fluorescence
• Jatropha curcas L.
• photosynthesis parameters
• poultry litter