A discussion of norms for S supply in organic farming based on content in forage and ruminant performance in Norway

The content of sulphur (S) in grassland on 27 Norwegian organic farms with dairy or sheep production was investigated in 2001 and 2002. The forage content of S was below the norms (2 g S kg DM-1) for both plants and animals in a large proportion of the samples. The average S content in forage at dairy farms was 1.4 g S kg DM-1 and at sheep farms 1.5 g. Even on grasslands with low plant S content (<1 g S kg DM-1), S-fertilization did not increase yields and increased the plants’ S content only very slightly. No indications of S deficiency were observed on the dairy farms. For one sheep farm with a forage S content of 1.1 ± 0.1g S kg DM-1, brittle and short winter wool was reported

Vi trenger gode agronomer

God agronomi er en forutsetning for å kunne lykkes med alt landbruk, men en gårdbruker, som ikke er bundet av det økologiske regelverket, kan kompensere noe for dårlig agronomi med ekstra tilskudd av innkjøpt kraftfôr, gjødsel og mer sprøyting mot ugras og skadegjørere. Ved dårlig agronomi blir tilført næring dårligere utnyttet, og det blir et stort næringsoverskudd på gården dersom det gjødsles sterkt. Et slikt næringsoverskudd er dårlig utnytting av verdens ressurser, samtidig som det øker faren for forurensing. For en økobonde vil dårlig agronomi resultere i dårlig avling på grunn av mangel på næring, problemer med ugras osv. Fordi det er mindre næring i jorda på en økologisk gård, er det imidlertid mindre fare for forurensing enn ved kombinasjonen dårlig agronomi og sterk gjødsling

High Nitrogen Costs of Dairy Production in Europe: Worsened by Intensification

Intensification of agriculture has been proposed as one way of minimizing emissions per unit of product, apparently legitimizing the ongoing structural changes in agriculture. We have investigated the relationship between the farming intensity and the nitrogen (N) dissipation by calculating the overall N emission factor (E: total N surplus per unit of N in the produce) from several studies of dairy farms, covering a wide range of environments and production intensities. Fundamental steps were 1) the distinction between trophic levels, mineral, plant and animal N; and 2) the inclusion of N losses related to bought feed. The results show that E increases significantly with the production intensity of the dairy farm. The tradition for separate optimization of the animal and crop sectors may be a reason. We suggest that the N pollution can be mitigated by more extensive farming, both by re-coupling crop and animal production side by side, and by keeping land under cultivation when production is reduced

Long-term effects of cropping systems on the earthworm population in a loam soil

Six cropping systems, ranging from conventional arable without livestock to organic livestock farming dominated by ley, have been compared in 1990 and 2004 in SE Norway. Ley in the crop rotation increased density and biomass of earthworms and channels in both organic and conventional systems. A ley proportion higher than 25 % only increased the density of channels. Among the arable systems, the organic system had a higher density and biomass of earthworms as compared to the conventional systems. Among the fodder systems, the optimised system had the highest density of earthworms in 2004, but there were no differences between these systems in earthworm biomass or density of earthworm channels

Contribution of N from frequently chopped green manure to a succeeding crop of barley

The aim of the present work was to study to what extent N in mulched green manure herbage contributes to spring barley grain yield the subsequent year. The green manure herbage was either chopped and left on stubble (GML) or removed (GMR). On silty clay loam with spring incorporated green manure the subsequent barley grain yield was 10% higher with GML than with GMR. The additional grain N yield of 4 kg ha-1 with GML corresponded to only 3 % of N in above-ground green manure biomass. On loamy soil with late autumn incorporated green manure the treatments did not affect the grain yield the subsequent year. How large part of the N that was lost through leaching or gaseous emissions and how large part that was built into soil organic matter was not measured. However, this investigation confirms that potential N losses from mowed green manure might be large. Alternative ways of using the herbage should be found

Klimagassutslipp ‐ planteproduksjon Innspill til norsk klimagassmodell på gårdsnivå

Denne rapporten er utarbeidet som del av utrednings-prosjektet til Bondelaget: Utvikling av beregningsmodell for klimagasser i norsk landbruk» finansiert av Landbruks-direktoratet. Rapporten omhandler klimagasser fra planteproduksjon og gir omtale av nødvendige data for klimagassberegning. Den gir oversikt over ulike typer modeller for beregning av klimagassutslipp,fra nasjonalt rapporteringsnivå til modeller for rådgivning på gårdsnivå. Det er også gjort vurdering av forsknings og kunnskapsbehov. Se sammendrag i rapport

Examining root nodule activity on legumes

The symbiotic partnership between bacteria and legumes is vital for the supply of biologically fixed nitrogen to soil and plants in organic cropping systems. Perennial clovers in a dense grass clover ley may contribute more than 200 kg nitrogen (N) per ha and year to the cropping system from the second year after sowing. This technical note aims at encouraging farmers to take a closer look at the roots of legumes and become more familiar with the process of nitrogen fixation and its relevance for organic farming. The note provides some key information on biological nitrogen fixation and describes a simple method for examining nitrogen‐fixing root nodules

Examen de la actividad de los nódulos en raíces de leguminosas

La asociación simbiótica entre bacterias y leguminosas es crucial para el aporte de nitrógeno (N) por fijación biológica, tanto al suelo como a las plantas, en los sistemas de cultivo ecológicos. El trébol plurianual pueden llegar a aportar a los sistemas de cultivo más de 200 kg de N por ha/año a partir del segundo año posterior a la siembra. Este documento técnico tiene como objetivo invitar a los agricultores a observar detenidamente las raíces de las leguminosas y a familiarizarse con el proceso de fijación de nitrógeno y su relevancia en la agricultura orgánica. En estas hojas se proporciona información relevante sobre la fijación del nitrógeno bio‐lógico y se describe un método encillo para examinar los nódulos de las raíces fijadoras de nitrógeno. English translation available at https://orgprints.org/31344

Sjekk belgvekstenes egen nitrogenproduksjon

The symbiotic partnership between bacteria and legumes is vital for the supply of biologically fixed nitrogen to soil and plants in organic cropping systems. Perennial clovers in a dense grass clover ley may contribute more than 200 kg nitrogen (N) per ha and year to the cropping system from the second year after sowing. This technical note aims at encouraging farmers to take a closer look at the roots of legumes and become more familiar with the process of nitrogen fixation and its relevance for organic farming. The note provides some key information on biological nitrogen fixation and describes a simple method for examining nitrogen‐fixing root nodules

Effects of ploughing depth on decomposition of barley straw in organically managed soil

Litterbag were used to study the effects of different ploughing depths on decomposition rate of barley straw with different ploughing depths. The burying depth of the litter (13 vs 25 cm) affected the decomposition rate of barely straw more than the different ploughing depths (13 vs 25 cm). From our results we suggest that slowly decomposable organic matter, such as leached barley straw, may be incorporated deeply by ploughing in organic cereal production systems, in order to regulate perennial weeds. In soils with good structure and porosity, the decomposition rate of straw can even be larger with deep ploughing. In dense, clayey soils it is important to be very accurate in ploughing time in order to secure that the ploughing is in fact loosening the soil. Otherwise, lack of oxygen and low decomposition of straw is likely to be the results