Orchard recycling improves climate change adaptation and mitigation potential of almond production systems

additions and potential alteration of pore-size distribution of amended soil [60]. These signifi- cant gains in soil water conservation could help better retain precipitation and water inputs, allowing growers to delay the onset or decrease the frequency of irrigation. Biomass recycling improves crop yield, productivity and water stress resistance Trees following biomass recycling out-yielded those grown in the burn treatment under both irrigation scenarios. Yield benefits were significantly associated with differences in SOC between treatments, attributed to improvements in soil nutrition and moisture retention as well as increased soil biological activity [61,62]. Presumably, long term N supply from mineral- ization of SOM also contributed to higher yields in the grind plots. This was supported by greater accumulation of N in the leaves of grind trees compared to that of burn. Biomass recycling decreased tree water stress as shown by a significantly less negative SWP throughout the course of the trial. The difference in SWP between the treatments was more pronounced when trees were at their most water stressed at hull split. Trees also showed greater recovery post stress after WOR. Stomatal conductance of WOR orchard trees was also significantly higher under the deficit irrigation treatment, and trended higher under regular irrigation. It has been shown that changes in SWP play a major role in short-term stomatal regulation of woody plants [63]. This was confirmed in our study, where a negative correlation

was found between stomatal conductance and SWP. Trees under deficit irrigation conditions Fig 6. Average of neutron probe readings at different soil depths during the deficit irrigation period (6/5-7/3) as affected by soil (grind and burn) and irrigation treatments. https://doi.org/10.1371/journal.pone.0229588.g006 PLOS ONE Whole orchard recycling PLOS ONE | https://doi.org/10.1371/journal.pone.0229588 March 27, 2020 16 / 22