How strawberry plants cope with limited phosphorus supply: Nursery-crop formation and phosphorus and nitrogen uptake dynamics

Healthy, well-rooted planting stocks are important for profitable fruit production of strawberry (Fragaria x ananassa Duch.). Adequate nutrient inputs and crop-rotation practices are among the most important measures to insure a successful, rapid development of strawberry nursery plants. However, relationships between macronutrient use and strawberry-nursery-plant formation in different rotation environments are not well understood. Our objectives were to assess strawberry plant P : N nutrition and nursery development under various limited and unlimited P inputs applied at different growth stages and to examine how nursery plants cope with limited P inputs. The field studies were conducted in a wheat-ryegrass-ryegrass-strawberry (WRRS) system in 2008 and in another corn-ryegrass-ryegrass-strawberry (CRRS) system in 2009 in Nova Scotia, Canada. The nursery crop was cv. Strawberry Festival and the experimental treatments consisted of three mother-stock P (MSP) rates (0, 6.6, and13.2 Pkg ha(-1)) and five daughter-plant P (DPP) rates (0, 13.2, 26.4, 39.6, and 52.8kg P ha(-1)), representing 0%-125% of the regional recommendations for strawberry nursery. The P treatments were arranged with three blocks in a split-plot design in each field. The results showed that the effects and interactions of the MSP and DPP treatments were significant (P < 5%) on whole-plant P and N acquisition and nursery productivity. Two-year whole-plant total P and N acquisition varied between (13.2 +/- 2.0)kg P ha(-1) and (46 +/- 7.3)kg N ha(-1) (n = 270) in both nursery systems. There was a quadratic regression relationship between nursery runners and daughter plants with plant P and N acquisition (0.33 < R-2 < 0.42, P < 5%). Soil pH levels declined with time and were positively correlated with nursery-plant formation. Too many runners (18-22 per mother stock) might reduce nursery-plant formation. Limited P inputs (37.5%-62.5% of regular recommendation) might result in a suitable plant P:N ratio (0.12-0.13) and adequate daughter plant-to-runner ratios (1.4-1.7) for optimum nursery formation (14-16 daughter plants per mother stock). Nutrient P was the single controlled factor influencing the N acquisition of nursery plants. High P inputs (> 39.6 P ha(-1) or > 75% of regular recommendation) may harm the crops. Therefore, this study implies that low-input horticulture can improve the nutrition management of strawberry nursery.