Effect of Subsurface Drip Fertigation with Nitrogen on the Yield of Asparagus Grown for the Green Spears on a Light Soil in Central Poland

During the growing period of many agricultural and horticultural plants, the use of fertigation usually increases the yield; however, the response to this treatment may depend on the cultivar. The effect of subsurface drip fertigation with nitrogen on the yield of three asparagus (Asparagus officinalis) cultivars grown for green spears in light soil was studied. The multi-year (2011-2017) field experiment was carried out on sandy soil and was arranged in a split-plot design with four replications. The first factor was the method of fertilization with nitrogen: (1) control-spreading nitrogen fertilization without irrigation and (2) subsurface drip fertigation with nitrogen. The second factor was the genotype (a cultivar) of asparagus-the following cultivars were tested: Ramada, Rapsody and Ravel. Generally, subsurface drip fertigation with nitrogen increases the marketable yield of green spears and the number of spears produced by a single plant, as well single-spear weight. 'Ramada' achieved the best results with all yield parameters. A significant correlation coefficient between the sum of rainfall and irrigation rates and yield parameters of tested cultivars was also found. The studies showed a varied response of the tested asparagus cultivars to the fertigation treatment.