Ishita Ahuja
Post Doctor
(+47) 458 37 316
ishita.ahuja@nibio.no
Place
Steinkjer
Visiting address
Innocamp Steinkjer, Skolegata 22, 7713 Steinkjer
Authors
Jaime Puértolas Pedro Villar-Salvador Enrique Andivia Ishita Ahuja Claudia Cocozza Branislav Cvjetković Jovana Devetaković Julio J. Diez Inger Sundheim Fløistad Petros Ganatsas Barbara Mariotti Marianthi Tsakaldimi Alberto Vilagrosa Johanna Witzell Vladan IvetićAbstract
Drought hardening is a nursery technique aimed to enhance early forest plantation establishment under dry conditions, which is a main limiting factors for plantation success. However, the quantitative effectiveness of drought hardening remains unclear. We conducted a meta-analysis to evaluate the influence of different factors in the effectiveness of drought hardening on seedling post-planting survival and growth. Overall, drought hardening did not significantly affect survival or growth, as several factors induced great heterogeneity, but analyses of those factors explained its effectiveness, especially on survival. A longer time between hardening and transplanting strongly reduced survival. Indoor-grown seedlings did not benefit more from hardening than outdoor-grown seedlings. Evaluations of drought hardening effectiveness in pots showed positive effects on survival but negative effects on growth, while no effects were found in large bed experiments. In field experiments, hardening significantly increased survival and growth with site aridity. Survival benefits were independent of species drought tolerance, measured by osmotic potential at the turgor loss point (πtlp), in moderate to high aridity sites. However, in low aridity sites, hardening increased survival in drought-tolerant species but decreased it in drought-intolerant species. Field results showed that hardening benefited shrubs more than trees in angiosperms. In conclusion, drought hardening at the end of nursery cultivation tend to increase post-planting seedling performance particularly in scenarios limiting post-planting root growth such as in arid climates and pot experiments. Our findings highlight the importance of future research on modelling the interaction between these technical features and species water use strategies..
Authors
Jørgen E. Olesen Robert M. Rees Sylvie Recous Marina Azzaroli Bleken Diego Abalos Ishita Ahuja Klaus Butterbach-Bahl Marco Carozzi Chiara De Notaris Maria Ernfors Edwin Haas Sissel Hansen Baldur Janz Gwenaëlle Lashermes Raia S. Massad Søren O. Petersen Tatiana Francischinelli Rittl Clemens Scheer Kate E. Smith Pascal Thiébeau Arezoo Taghizadeh-Toosi Rachel E. Thorman Cairistiona F. E. ToppAbstract
Crop residues are important inputs of carbon (C) and nitrogen (N) to soils and thus directly and indirectly affect nitrous oxide (N2O) emissions. As the current inventory methodology considers N inputs by crop residues as the sole determining factor for N2O emissions, it fails to consider other underlying factors and processes. There is compelling evidence that emissions vary greatly between residues with different biochemical and physical characteristics, with the concentrations of mineralizable N and decomposable C in the residue biomass both enhancing the soil N2O production potential. High concentrations of these components are associated with immature residues (e.g., cover crops, grass, legumes, and vegetables) as opposed to mature residues (e.g., straw). A more accurate estimation of the short-term (months) effects of the crop residues on N2O could involve distinguishing mature and immature crop residues with distinctly different emission factors. The medium-term (years) and long-term (decades) effects relate to the effects of residue management on soil N fertility and soil physical and chemical properties, considering that these are affected by local climatic and soil conditions as well as land use and management. More targeted mitigation efforts for N2O emissions, after addition of crop residues to the soil, are urgently needed and require an improved methodology for emission accounting. This work needs to be underpinned by research to (1) develop and validate N2O emission factors for mature and immature crop residues, (2) assess emissions from belowground residues of terminated crops, (3) improve activity data on management of different residue types, in particular immature residues, and (4) evaluate long-term effects of residue addition on N2O emissions.
Authors
Ishita Ahuja Inger Sundheim Fløistad Per Grande Øyvind Meland Edvardsen Adam O’Toole Arne SteffenremAbstract
No abstract has been registered