Biomass yield and N uptake in tall fescue and reed canary grass depending on N and PK fertilization on two marginal sites in Denmark

Abstract

Perennial grass species may ensure a productive use of marginal land with limited potential for production of annual crops. We investigated the biomass yield and N uptake of tall fescue (TF) and reed canary grass (RCG) grown on two sites with coarse, sandy mineral soil, i.e., marginal wetter land areas with limited suitability for cereal production. Plots with TF and RCG were sown in April 2011, and fertilization trials were established in spring 2012 with three factors: (a) grass species, (b) PK fertilization (either no P and K or 24 and 250 kg ha-1 y-1 of P and K, respectively), and (c) N fertilization (0, 150, 300, or 450 kg ha-1 y-1 N). Three cuts were taken annually from 2012 to 2014. Both species responded strongly to N fertilization. In TF, 450 kg ha-1 y-1 N combined with PK fertilization gave DM yields of 19.3, 12.1, and 14.2 t ha-1 y-1 in the 3 years, respectively, and corresponding yields for RCG were 17.3, 14.4, and 14.3 t ha-1 y-1. Without PK fertilization yields were significantly lower: 15.2, 7.5, and 7.3 t ha-1 y-1 in TF and 16.3, 8.7, and 4.8 ha-1 y-1 in RCG. When fertilized with PK, N uptake in harvested biomass balanced with N fertilization at rates of 244, 187, and 172 kg ha-1 y-1 N in TF in the 3 years and at 332, 256, and 198 kg ha-1 y-1 N in RCG. In conclusion, high yields can be obtained by both species on moist, sandy soils, provided a sufficient and balanced nutrient supply. The results indicate that it is possible to apply 150–200 kg ha-1 y-1 N to these species with very limited risk of N leaching.