Strawberry plant fruiting efficiency and its correlation with solar irradiance, temperature and reflectance water index variation

Uneven light distribution and low water holding capacity are two constraints limiting strawberry (Fragaria×ananassa Duch.) production in coastal northern Atlantic areas. A study was conducted in a commercial strawberry production field characterized by rapid internal soil drainage and undulating land features in Nova Scotia. The objectives were to examine the uneven distribution patterns of solar irradiance (IRR), temperature and soil water content (SWC) and quantify correlations of these physical variables with strawberry fruit yield, plant reflectance water index (WI) and leaf chlorophyll. Strawberry row orientation was along the field aspect in the north-south (N-S) direction for maximizing plant sunlight exposure and spring rainfall drainage. The measurement design consisted of a nested grid with five transects. Results showed that solar radiation incident upon the canopy was significantly higher (mean IRR 779-820Wm⁻²) in the shoulder and slope areas compared to the mean IRR of 709Wm⁻² in downslope area (P <0.001), where higher SWC and lower temperature stimulated strawberry fruit bearing. Significantly higher reflectance WI was related to low strawberry yield (R ² =0.55, P <0.05). Strawberry fruit yield was positively correlated to normalized difference vegetation index, ratio nitrogen vegetative index and leaf chlorophyll (0.46< R ² <0.61, P <0.05). Distribution patterns and correlations between strawberry fruit yield and physical variables suggested that IRR and water stress occurring with the influence of high topographic features resulted in reduced strawberry fruit bearing ability. It was suggested that the N-S row orientation along the aspect would help sunlight capture but not water holding for strawberry plant fruit bearing needs. A new planting design for alternative orientation of rows (NE-SW or W-E) and drip irrigation should be tested for light and water management in soils with natural constraints.