Developing Energy Plants for Biofuels Production may Comply to Organic Principles

Biofuels are the only source of renewable environmentally friendly fuel currently suitable for road transport without any negative traits associated with traditional biodiesel or other green energy alternatives. The combustion of petrol and diesel produces many different types of local air pollutants, but the use of biofuels may result in the reductions in emissions of greenhouse gas carbon dioxide up to 70%. Impacts on land use require careful planning to maximise the gains and minimise the losses. The role of biofuels in organic farming will solve three significant problems: 1) waste will become valuable resources; 2) low quality forage products can be utilized for biofuels and thus get value-added; and 3) the trafficable damage on soil fertilities will be reduced by the minimized recirculation rate of bulky watery waste products

DOC and DON from grass-clover - results from a field experiment

The C and N dynamics in perennial grass-clover mixtures are not fully understood although such mixtures dominate temperate grassland. The co-existence of clover and grass involves both competition for and transfer of nutrients between the species. The nutrients that are competed for and transferred may originate from leaky root systems, from a rapid turnover of the fine root systems, or from degradation of more stabile organic material. The aim of the present study was to investigate the origin of dissolved organic C and N in perennial grass-clover mixtures. In an existing grass-clover ley, field mezotrons (cylinders with a diameter 30 cm) were installed in the spring of 2003 to depths of 20, 40 and 60 cm. Suction cups was installed beneath the mezotrons in order to sample the soil solution during the growth season. In late June 2004 cross-labelling of clover and grass populations in the mezotrons was done by leaf labelling (5 days) of either grass or clover using 15N- and 14C-labelled urea. During the following 3 months the percolating soil solution was sampled either after heavy rain or after irrigation of the mezotrons and the content 15N- and 14C-labelled compounds were determined. Leaf material was harvested at tree times during the growth season and at the end of the growth season the mezotrons was excavated and the distribution of 15N and 14C in the plants and soil determined. 14C was detected in the percolating soil solution imediately after leaf-labelling was initiated, with the highest amounts occuring from labelled grass. The peak of 14C reached the depths of 20 and 40 cm between 3-10 and 5-15 days respectively after labelling was initiated while no 14C was detected beneath the 60 cm mezotrons. The majority of 14C in soil solution was identified to be 14CO2 originating either from root respiration or from biomass respiration of 14C-labelled root parts or root exudates. The transfer of 14C was higher from grass to clover than vice versa. This transfer of 14C properly occurs as 14CO2 exchange between the leaves or in the root zone. Transfer of 15N was highest from clover to grass, while the transfer from grass to clover was negligible. These observations confirm previous investigations of 15N transfer between grass and clover. No clear connection was found between the transfer of 14C and 15N. After excavation of the mezotrons 14C was found in higher amounts and at larger depths in the soil for grass compared to clover. The results from this experiment point to that in a grass-clover ley carbon would primarily originate from grass and nitrogen would come from clover. The depths at which 14CO2 is found in the soil solution seem to be somewhat related to the depth of 14C-labelled root material meaning that the rooting profile of a crop influence the deposition of carbon and nitrogen in the soil matrix. These findings add significant new dimensions to our current understanding of processes governing the build up of soil fertility under grass-clover leys

To meet future food demands we need to change from annual grain legumes to multipurpose semi-perennial legumes

The last meal of an Iron Age man buried in a Danish bog included at least 60 plant species, including barley, linseed and species we now consider weeds. A modern man relies in contrast on a remarkable small number of crop plants, mostly cereal stables like wheat, rice and maize (Evans, 1998). Both land and people in Sub-Saharan Africa are suffering. Natural resource management is in distress and most rural Africans remain poor and food insecure despite widespread macroeconomic, political and sectorial reforms. Most predictions are that these Africans will remain food insecure in the foreseeable future (Pinstrup-Andersen & Pandya-Lorch, 2001). Innovations are, however, changing this landscape much faster than we could expect. A market-oriented agriculture has been promoted by many agents of change. And change is happening. The last 10 years a renewed optimism has taking root in the fact that a number of African countries are demonstrating high economic growth rates (Radelet, 2010). We do not know the winners and the losers yet – just that they are there. Not all farmers will have the capacity to join the market orientations by high-value commodities. They are simply not able to innovate. Nitrogen is a major limiting nutrient for food production but the growing demand for food is met in two ways. One through fossil fuel driven fixation of nitrogen, Haber-Bosch nitrogen (Erisman et al., 2008), is one way and symbiotic fixation of nitrogen, leguminous nitrogen (Giller, 2001) is the other. Feeding approximately half of humanity is made possible by Haber-Bosch nitrogen, the other half by leguminous nitrogen. With the current focus on reducing emissions of greenhouse gasses while simultaneously increasing the biomass production for food, fibre, feed and fuel, the use efficiency of the leguminous nitrogen must be improved. Annual grain legumes basically satisfy their own need for nitrogen via their capability for fixing atmospheric nitrogen (see e.g. Unkovich et al., 2010). However, they seldom contribute much to soil fertility or to subsequent crops. Further, due to their annual structure they must be reseeded every season with consequences for investing resources and potential sensibility for unfavourable growth conditions during the renewed crop establishment phase. Legume seeds hold a carbon-nitrogen ratio of approximately 10 compared to values up to 30 for cereals. Thus from a diet point of view, grain legumes are very valuable protein sources. This importance has been recognized since ancient history (Cohen, 1977). In addition to the nitrogen located in the grain, some nitrogen pools are located in the residues, which can be utilized for fodder or returned to the soil. Another important leguminous nitrogen pool is in the roots and rhizodeposits (Wichern et al., 2008)

Ti ubekvemme om biobrændsler

Diskussionen om fremtiden for bioenergi raser disse dage i medierne under brug af simple slagord og forenklede billeder som taler til læserens følelser gennem billeder men ikke til intellektet. Det er en kamp om den politiske og forskningsmæssige dagsorden som kæmpes her. Kronikøren er landbrugs- og udviklingsforsker og stiller her 10 ubekvemme spørgsmål – ubekvemme fordi der ikke findes lette svar

New Challenges in Underprivileged Regions Call for People-Centered Research for Development

The need for enhancing food production and availability in underprivileged regions of the world requires the attention of scientists. This article explores the possibilities for rethinking agricultural research for development (R4D) in the light of new challenges characterized by a high degree of scientific uncertainty along with associated intense political differences of interest. New challenges that particularly influence food production in underprivileged regions include global climate change, globalization of food chains, and emerging low-carbon energy systems. We argue that by applying the people-centered sustainable livelihoods approach as a research paradigm in R4D, researchers may be more successful in producing knowledge that is useful to entrepreneurial smallholder farmers. Without such rethinking, traditional scientific approaches and logic may limit the contribution that agricultural R4D can make toward the achievement of the Millennium Development Goals of halving extreme hunger by 2015 and improving the livelihoods of all

In field N transfer, build-up, and leaching in ryegrass-clover mixtures

Two field experiments investigating dynamics in grass-clover mixtures were conducted, using 15N- and 14C-labelling to trace carbon (C) and nitrogen (N) from grass (Lolium perenne L.) and clover (Trifolium repens L. and Trifolium pratense L.). The leaching of dissolved inorganic nitrogen (DIN), as measured in pore water sampled by suction cups, increased during the autumn and winter, whereas the leaching of dissolved organic nitrogen (DON) was fairly constant during this period. Leaching of 15N from the sward indicated that ryegrass was the direct source of less than 1-2 percent of the total N leaching measured, whereas N dynamics pointed to clover as an important contributor to N leaching. Sampling of roots indicates that the dynamics in smaller roots were responsible for N and C build-up in the sward, and that N became available for transfer among species and leaching from the root zone. The bi-directional transfer of N between ryegrass and clover could however not be explained only by root turnover. Other processes like direct uptake of organic N compounds, may have contributed

Research in sub-saharan African food systems must address post-sustainability challenges and increase developmental returns

The article argue that the livelihood approach is relevant for Research in sub-saharan African food systems, which must address post-sustainability challenges and increase developmental return

Illusionen om kunstgødning i Afrika

Der er grund til at aflive illusionen om at landbrugerne i Afrika bare skal lære at bruge noget mere kunstgødning for at afhjælpe sultproblemerne. Det er nemlig en illusion for imod taler priserne, distributionsnettet, og landbrugernes (mangel på) kapital. Mere brug af kunstgødning vil således ikke afhjælpe fattigdomsproblemerne

Productivity and quality, competition and facilitation of chicory in ryegrass/legume-based pastures under various nitrogen supply levels

Traditional perennial ryegrass-white clover mixtures have limitations in combined productivity and quality that herbs like chicory may alleviate. This study examined the consequences on productivity and quality of as well as competition and facilitation after introducing chicory into varies ryegrass-legume-based pastures in a field study over 3 consecutive growing seasons. A cultivar of chicory, suitable for grazing, in pure stand was found to out-yield a pure stand ryegrass in terms of dry matter and nitrogen (N) accumulation but was found to yield similar to mixture of chicory and ryegrass. The inclusion of chicory, increased N accumulation per area unit irrespective of associated leguminous species but had no effect (P>0.05) on the combined dry matter yield of these mixtures as compared to the chicory-ryegrass mixture. Chicory was not found to co-exist well with associated fodder legumes but it co-existed well with perennial ryegrass. Determined by a direct 15N plant labelling technique, chicory transferred little N to associated legumes and under moderate soil N conditions it almost out-competed the white clover whereas lucerne was able to withstand the competition with birdsfoot trefoil as intermediate. Chicory and ryegrass did exchange N amounting to less than 5% of the receiver plants’ N economy whereas the N transfer from the N-rich lucerne constituted 15% of the associated ryegrass’ N economy but less (P<0.05) of the chicory’s N economy. These differences are ascribed to the species’ root morphology and root zonation. Chicory accumulated large amounts of calcium, potassium, sodium and zinc but significant less of magnesium and manganese, irrespective of the N supply. In the case of sodium it was a short-term effect whereas calcium and possibly also sulphur, copper and zinc accumulation increased over time. It is concluded that chicory may improve the management of intensive dairy farms with a large N surplus because of the increase in productivity per unit area and N uptake efficiency and add significant improvements of the quality of the forage

Organic Agriculture: A New Field of International Development Policy

This paper reviews strategically selected global policy documents and development literature and analyse perspectives on the role of organic agriculture (OA) as a possible vehicle for sustainable development in developing countries. It shows that not only has compliance assessed organics made entry in terms of projects and programmes in many LICs. OA is also gaining position in formal policies and strategies of international donor agencies and organisations. If agriculture is generally “back” in development business, organic farming has certainly “arrived”