Spring barley yield and nitrogen recovery after application of peat manure and pig slurry

The effectiveness of peat manure, manufactured of pig slurry and moderately humified Sphagnum peat (slurry:peat ca. 1:1.5 v/v), as nitrogen (N) source for spring barley was investigated in a four.year field experiment on a clay loam soil in south-western Finland. Pig slurry, NPK fertilizer and plain peat were used as references. Manures were incorporated before sowing or surface-applied after sowing in spring at an ammoniacal N rate of.54.106 kg.ha-1 with or without supplementary NPK fertilizer (40.kg N.ha-1). Soil moisture conditions were varied by different irrigation treatments. Peat manure produced 5.15% higher grain yields than pig slurry, with the largest difference after surface application. Incorporation was more important for slurry than for peat manure in increasing N uptake and yield. Soil moisture deficit in spring and early summer limited the availability of manure N. Part of the manure N that was not available in the early growing period was apparently taken up by the crop later. Consequently, N concentration tended to be higher with lower yields, and differences in the recovery of manure N were smaller than the differences in grain yield. Supplementation of manures with inorganic fertilizer N increased yield by 37%, on average, and improved the N recovery

Ammonia volatilization, nitrogen in soil, and growth of barley after application of peat manure and pig slurry

Peat is added to manure, because its low pH and capacity to adsorb ammonia (NH3) give it potential to reduce nitrogen (N) loss. Peat manure was prepared by mixing pig slurry with moderately humified Sphagnum peat. Less than 1% of applied ammoniacal N was volatilized as NH3 from peat manure and pig slurry within 8 h of surface application on clay loam soil according to JTI method. Incorporated manures showed even smaller N loss. The low volatilization was due to the adsorption of manure ammoniacal N by peat, and the infiltration of slurry into harrowed, moist clay soil. In another experiment, peat manure was applied on polypropylene fabric without soil contact. Within the first 3 days there was only 9% reduction in the ammoniacal N of peat manure, but the major part of it was lost during several weeks of dry and warm weather. Peat manure did not cause any major improvements on the growth and N uptake of spring barley in spring and early summer as compared with slurry. Moisture deficit limited the availability of ammoniacal N of manures. As compared with surface application, incorporation of manures increased nitrification of ammonium in the soil, and dry matter mass (19–73%) and N uptake of barley. Supplementing manures with inorganic NPK fertilizer increased both dry matter mass (40–98%) and N concentration of barley stand

A Latent Class Application to the Measurement of Poverty

This paper investigates whether and in what sense the west German wage structure has been 'rigid' in the 1990s. To test the hypothesis that a rigid wage structure has been responsible for rising low-skilled unemployment, I propose a methodology which makes less restrictive identifying assumptions than some previous related work. I find that the relative stability of educational wage premia was justified by market forces. However, relative wages did not respond to negative net demand shocks for young workers, as well as white-collar workers.

XMM-Newton observations of OY Car III: OM light curve modelling, X-ray timing and spectral studies

We revisit the XMM-Newton observations of the dwarf nova OY Car taken in July 2000 which occured shortly after an outburst. Ramsay et al (2001a) found a prominent energy dependent modulation at a period of 2240 sec: this modulation was only seen for app. 1/3 of the observation duration. In our new analysis, we examine this time interval in greater detail. In addition to the 2240 sec period we find evidence for other periods, the most prominent being near 3500 sec. Both these modulations are most likely due to changes in photoelectric absorption over this period: this is supported by phase-resolved spectroscopy. This may indicate the presence of matter above the accretion disc or a presence of a magnetic accretion curtain. In this case the 2240 sec period could represent a spin period of the white dwarf and the 3500 sec period a beat period between the spin and orbital periods. We also model the B band and UV eclipse profiles and light curves using a new technique to map the spatial extent of the accretion disc. As a result we find that whilst the optical emission is dominated by both the emission close to the accretion disc boundary layer and the hot spot where the accretion stream hits the disc, the UV emission is mainly dominated by the inner disc/boundary layer only.Comment: 10 pages, 12 figures, accepted for publication in A&

An approach to graph-based analysis of textual documents

In this paper a new graph-based model is proposed for the representation of textual documents. Graph-structures are obtained from textual documents by making use of the well-known Part-Of-Speech (POS) tagging technique. More specifically, a simple rule-based (re) classifier is used to map each tag onto graph vertices and edges. As a result, a decomposition of textual documents is obtained where tokens are automatically parsed and attached to either a vertex or an edge. It is shown how textual documents can be aggregated through their graph-structures and finally, it is shown how vertex-ranking methods can be used to find relevant tokens.(1)