Auteur: Kykkänen S., Virkajärvi P., Hyrkäs M., Järvenranta K., Kurki P. and Suomela R.
Jaar van uitgifte: 2015
In Finland, grass yield response to potassium (K) fertilization varies with soil acid-extractable potassium (KHCl) availability, rather than the traditionally used measure of soil acid ammonium acetate-extractable potassium (KAAc). However, in previous experiments, no animal manure was used and grass nutritive value was only partially taken into account. The objective of this experiment was to measure the effects of cattle slurry, mineral K-fertilization (0, 50, 100, 150, 200 kg ha‑1 year‑1) and their interaction on grass (Phleum pratense – Festuca pratensis) dry matter (DM) production and nutritional value (organic matter digestibility, K concentration, Diet Cation Anion Difference = DCAD, grass tetany index) under three different levels of soil KHCl. Three-year field experiments were established at three locations: site 1, 2 and 3. The study was carried out as a split plot experiment. KHCl concentration of soil did not entirely explain the utilization of potassium by grass. Mineral K fertilization, given as KCl, decreased nutritional value of forage except for DCAD, on which Cl has a strong positive effect. K uptake was more effective without slurry application especially on soils with low and medium levels of KHCl.