Incorporation of (15)N from spiked cattle dung pats into soil under two moorland plant communities

Restoration management of cattle resting place in mountain grassland

This study investigated the effect of restoration management of a weed-infested area, previously used as cattle resting place, on herbage production and nutrient concentrations in the soil and herbage. The experiment was undertaken from 2004 to 2011 at the National Park of Nízké Tatry, Slovakia. Three treatments were applied: (i) cutting twice per year, (ii) herbicide application, followed after three weeks by reseeding with a mixture of vascular plant species and then cut twice per year, and (iii) unmanaged. Treatments had significant effect on biomass production and concentration of nutrients in the soil and in herbage. Nutrient concentrations in herbage and in soil declined progressively under the cutting treatments and reached optimum ranges for dairy cattle at the end of the experiment when herbage N was less than 15 g kg-1 and herbage P was 3.4 g kg-1. There was also a strong positive relationship under the cutting treatments between soil nutrient concentrations and herbage nutrient concentrations for N, P, K, Mg and Ca. Although the cutting management as well as the combination of herbicide application with cutting management reduced nutrient concentrations in the soil and in herbage, the nutrient concentrations remained relatively high. We can conclude that restoration of grassland covered with weedy species like Urtica dioica and Rumex obtusifolius, with excessive levels of soil nutrients, cannot be achieved just by cutting and herbicide application.

Quantification of dung carbon incorporation in a temperate grassland soil following spring application using bulk stable carbon isotope determinations

Herbivore dung constitutes a substantial input of C to temperate grassland soils, and its fate must be determined in order to fully understand nutrient cycling in this ecosystem. This experiment used changes in bulk delta13C values of the 0-1 cm and 1-5 cm soil horizons of a dung-treated temperate grassland soil to approximate percentage applied dung C incorporation over 372 days. Natural abundance 13C-labelled C4 dung (delta13C - 12.6%) and C3 dung (delta13C - 31.3% were produced in a monitored diet switch from ryegrass silage (delta13C - 30.1%) to maize silage (delta13C - 11.6%). The dung was applied to a C3 grassland (delta13C 0-1 cm - 29.9%, 1-5 cm - 30.6%), and dung remains and soil cores from beneath the treatments were sampled at intervals. delta13C values were used to estimate a maximum of 12% applied dung C incorporation in the top 5 cm of the soil after 112 days, which declined to around 8% at the end of the experiment. A significant increase in percentage applied dung C was observed in the top 1 cm of soil, compared with the 1-5 cm horizon, after a substantial rain event after 30 days. However, results of forage fibre analyses of the two dung types revealed significant differences in composition which may affect subsequent calculations of percentage dung incorporation based on bulk delta13C values.