The impact that future climatic conditions will have on agricultural productivity depends on the sensitivity to each environmental factor and relative changes in temperature, precipitation and UV-B radiation. The strawberry (Fragaria x ananassa) is a microclimatic crop cultivated almost worldwide and Spain is the world's second-largest strawberry producer after the USA. Strawberry production in Huelva has been affected by climate change in recent decades. Temperature and solar radiation are primary environmental factors controlling short-day strawberry plant growth and development. Temperature is a limiting factor in crop productivity. We assessed the effect of variations in temperature and solar radiation on strawberry production and crop cycle duration. The study was carried out in commercial strawberry fruit production fields in the province of Huelva (Spain's southwestern coast). Fresh plants of cv. Camarosa were cultivated from October to June. The resulting crop was recorded weekly in the production field: early and total strawberry productions (g/plant), were recorded from January to March and from January to May, respectively. Data revealed that between early production and temperature (R²= 0.86) and between early production and solar radiation (R²= 0.73) there was a linear relationship. However, total production and temperature (R²= 0.69) and total production and solar radiation (R²= 0.69) were related by a quadratic relationship. Our estimates suggest that strawberry production could be affected by climate change. Due to the relationship between yield and temperature, and between yield and solar radiation, climate change scenarios were found to result in reductions in crop cycle duration.

Crop load can influence fruit quality in several horticultural species. The aim of the present study was to determine the effect of different concentrations of calcium on crop quality traits in three short-day strawberry (Fragaria x ananassa Duch.) cultivars ('Ventana','Camarosa' and 'Candonga') and to assess the relationships between crop load and quality parameters. The studies were conducted using a hydroponic system in a greenhouse. Calcium was added as Ca(NO3)(2) at 2 mM, 3 mM, 4 mM and 5 mM. A completely randomized block design (4 Ca concentrations x 3 cultivars) with three replicates was used. Each replicate consisted of 12 plants grown in polyethylene bags (100 cm x 18 cm x 3 cm) filled with coconut peat. Titratable acidity, total soluble solids and firmness were measured throughout the experimental period. Calcium application had no effect on fruit quality attributes but the genotype effect was clear. At the end of the experiment (28th May, 2008), titratable acidity was positively related to the fresh weight of above-ground biomass and number of leaves respectively in the 'Ventana' and 'Camarosa' cultivars. Higher values of total soluble solids were found at low crop load in 'Ventana' but in 'Camarosa' this relation was not found. In 'Candonga', higher total soluble solids were linked to crop load. In 'Ventana', titratable acidity significantly decreased as crop load increased, and in 'Camarosa' high values of titratable acidity were found at different values of crop load. 'Ventana' seemed to be more sensitive to the effects of crop load patterns. Genotype was an important factor in determining fruit quality parameters. (C) 2011 Elsevier B.V. All rights reserved

Core Ideas: Miscanthus and switchgrass are often touted as biomass crop choices, but have rarely been compared side‐by‐side. Miscanthus was slower to establish than switchgrass cultivars, but out‐yielded switchgrass in the latter 3 yr of the trial. Phosphorus was the soil nutrient most likely to be drawn down to levels requiring fertilization, after N. Comparative performance tests of perennial grasses for biomass yield, quality, and soil nutrient removal are needed to guide decisions toward meeting European Union targets for renewable energy production. We compared hybrid miscanthus (Miscanthus × giganteus Greef and Deuter ex Hodkinson and Renvoize) and switchgrass (Panicum virgatum L.) cultivars Cave‐in‐Rock, (upland type), Alamo, and Kanlow (lowland types) for biomass yield and changes in soil macronutrient levels and removal rates in a humid Spanish environment. Soil and plant nutrient and C levels were measured after each annual biomass harvest for 4 yr. Plant nutrient concentrations were multiplied by biomass yield to express nutrient removal. Yield ranking (4‐yr mean) was miscanthus (17.6 Mg ha⁻¹) > Kanlow (13.3 Mg ha⁻¹) = Alamo (13.0 Mg ha⁻¹) > Cave‐in‐Rock (7.7 Mg ha⁻¹). Miscanthus biomass yield peaked in the third year at 27.0 Mg ha⁻¹. The high yield of miscanthus together with its relatively low macronutrient concentrations and intermediate removal rates, indicate its advantages over switchgrass as a biomass crop choice. Alamo and Kanlow usually removed more macronutrients than Cave‐in‐Rock, suggesting a greater long‐term fertilizer requirement for the lowland types. Soil C stocks increased by a mean of 2850 kg ha⁻¹ over 4 yr at 0‐ to 20‐cm depth. Phosphorus was the macronutrient most likely to become deficient after repeated harvests. Miscanthus and lowland switchgrass cultivars performed well in the Atlantic maritime region of Spain, therefore the choice of crop would rely on economics of establishment and long‐term stand maintenance.