Rainfed orchards have huge social importance in territories of low agro ecological potential. Research on almond is limited for dry-farmed orchards in particular for crop nutrition and fertilization. This makes difficult to implement a cropping practice adjusted to the ecological constraints of these agrosystems. It is known that nitrogen (N) and boron (B) are determining nutrients for dicot tree crops such as olive and vineyards grown under these environmental conditions. Thus, this study aims to test at what level the crop responds to soil-applied N and B, and whether the foliar sprays can supplement or replace the application of the nutrients to the soil. It is also important to check if the sufficiency ranges set for the almond, which have been based on irrigated orchards, are adjusted for rainfed farming. The N rates applied to the soil were 0 (N0), 25 (N25), 50 (N50) and 100 (N100) kg hm −2 and those of B 0 (B0), 1 (B1), 2 (B2) and 3 (B3) kg hm −2. The foliar sprays consisted of three annual applications of N (two in 2017) and two applications of B (one in 2017), the last ones of 2015 and 2016 applied at post-harvest. Foliar N and B sprays were respectively applied at the concentrations of 0.5% N and 0.036% B. The experiment was arranged as a split-plot design with soil applied N or B assigned to the main plots and foliar N or B as subplots. Kernel yield showed a marked alternate-fruiting, with two years of good crops (2015 and 2017) and a year of practically no production (2016), likely due to adverse ecological conditions for almond growth and cropping practices incorrectly performed. Soil-applied N significantly increased kernel yield in comparison to the control but the differences were not significant in N rates higher than 25 kg N hm −2. The application of B to the soil improved tissue B concentrations but did not increase productivity. In general, foliar applications of N or B failed to improve plant nutritional status and kernel yield. The current sufficiency ranges for almond seem to be unnecessarily narrow for several nutrients such as N, potassium (K), calcium (Ca), manganese (Mn) and iron (Fe), since several results were found to be out of the sufficiency range with no apparent negative consequences for the trees. The laboratories carrying out soil testing and plant analysis should take this into account in diagnosing the nutritional status of almond orchards.

In this work, bioclimatic parameters and indices relevant to the grapevine are estimated for the years 2000 (recent-pat), 2049 (medium-term future) and 2097 (long-term future), based on very high resolution (1 km × 1 km) MPI-WRF RCP8.5 climate simulations. The selected parameters and indices are the mean temperature during the grapevine growing season period (April to October, Tgs), the cumulative rainfall during the grapevine growing season period (Pgs), the Winkler index (WI), the Huglin heliothermic index (HI), the night cold index (CI) and the dryness index (DI). In general, a significant increase in mean temperature during the grapevine growing season period is observed, together with a significant decrease in precipitation. The recent-past WI is associated with the production of high-quality wines; the higher values predicted for the future represent intensive production of wines of intermediate quality. The HI shows the passage of a grapevine growing region considered as temperate-warm to a warm category of higher helio-thermicity. The recent-past CI indicates very cool conditions (associated with quality wines), while in the future there is a tendency for temperate or warmer nights. Finally, DI indicates an increase in water stress considered already high under the recent-past climate conditions. These results point to an increased climatic stress on the Douro region wine production and increased vulnerability of its vine varieties, providing evidence to support strategies aimed to preserve the high-quality wines in the region and their typicality in a sustainable way.

Climate change is of major relevance to wine production as most of the wine‐growing regions of the world are located within relatively narrow latitudinal bands with average growing‐season temperatures (GSTs) limited to 13–21°C. This study focuses on the incidence of climate variables and indices that are relevant both for climate change assessment and for grape production, with emphasis on grapevine bioclimatic indices and extreme events (e.g., cold waves, storms, heatwaves). Dynamical downscaling of European Reanalysis‐Interim and Max Planck Institute Earth System low‐resolution global simulations forced with a Representative Concentration Pathway 8.5 (RCP8.5) greenhouse gas emission scenario was performed with the Weather Research and Forecast (WRF) model to a regional scale including the Douro Valley of Portugal for recent‐past (1986–2005) and future periods (2046–2065, 2081–2100). The number, duration and intensity of events were superimposed over critical phenological phases estimated by using a specific local grapevine varietal phenological model in order to assess their positive or negative implications for wine production in the region. An assessment of the relevance of climate parameters and indices and their progression in recent‐past and future climate scenarios with regard to the potential impact on wine production was performed. Results indicate a positive relation between higher growing‐season heat accumulations and greater vintage yields. A moderate incidence of very hot days (daily maximum temperature above 35°C) and drought from pre‐véraison phenological conditions have a positive association with vintage ratings. However, the mid‐ and long‐term WRF‐MPI RCP8.5 future climate scenarios reveal shifts to warmer and drier conditions, with the mean GST not remaining within range for quality wine production in the long‐term future climate scenario. These results indicate potential impacts that suggest a range of strategies to maintain wine production and quality in the region.

The almond tree is generally recognized as drought-tolerant, though it depends on water resources to achieve high yields. During the summer months of two consecutive years, several physiological and biochemical parameters were observed, to understand the almond tree's seasonal sensitivity and behavior under different irrigation strategies based on crop evapotranspiration (ETc): T100 optimal water requirement regime (applying 100% ETc); T70 and T35 sustained deficit irrigation regimes (applying 70% and 35% ETc); T100-35 regulated deficit irrigation regime (reducing the application to 35% ETc during fruit filling stage); and T0 (rainfed). The total leaf chlorophyll and carotenoid reduction in T0 and T35 treatments was significant compared to T100-35. Leaf soluble proteins and total soluble sugar contents were significantly higher in non-irrigated trees compared to other treatments, while the starch content showed the opposite trend. Rainfed trees were under obvious water stress, displaying the lowest values for relative water content (RWC), stomatal conductance (gs), photosynthetic rate (A), and transpiration rate (E), and the highest for intrinsic water use efficiency (A/gs). Plant hormones (ABA and IAA) generally accumulated more in non-irrigated trees. The almond tree has been confirmed as a drought-tolerant species, and when water is scarce, reducing the water application to 35% ETc during fruit filling stage, results in no yield losses, and the plant status remains unstressed. However, to get the maximum crop potential, in years and areas where water is not restricted, full irrigation requirements have been shown to boost almond tree performance.