Review of History and Recent Development of Organic Farming Worldwide

The history of the organic farming worldwide was reviewed in this paper. The development of the organic farming worldwide had gone through three stages, emergence, expansion, and growth. The contributors and their thoughts during the different development stages of the organic farming were briefly introduced. And the development status of the organic farming worldwide was reviewed from the aspects of land area under organic management, land area under organic management in percentage of total agricultural area, and world markets for organic products. Besides, the main existing problems for the further development of the world＇s organic farming, as well as the development status, problems and strategies of the Chinese organic farming were discussed.     

The structure of a pH-sensing mycobacterial adenylyl cyclase holoenzyme

Class III adenylyl cyclases contain catalytic and regulatory domains, yet structural insight into their interactions is missing. We show that the mycobacterial adenylyl cyclase Rv1264 is rendered a pH sensor by its N-terminal domain. In the structure of the inhibited state, catalytic and regulatory domains share a large interface involving catalytic residues. In the structure of the active state, the two catalytic domains rotate by 55 degrees to form two catalytic sites at their interface. Two alpha helices serve as molecular switches. Mutagenesis is consistent with a regulatory role of the structural transition, and we suggest that the transition is regulated by pH.     

HIV-1 proviral DNA excision using an evolved recombinase

HIV-1 integrates into the host chromosome and persists as a provirus flanked by long terminal repeats (LTRs). To date, treatment regimens primarily target the virus enzymes or virus-cell fusion, but not the integrated provirus. We report here the substrate-linked protein evolution of a tailored recombinase that recognizes an asymmetric sequence within an HIV-1 LTR. This evolved recombinase efficiently excised integrated HIV proviral DNA from the genome of infected cells. Although a long way from use in the clinic, we speculate that this type of technology might be adapted in future antiretroviral therapies, among other possible uses.     

Electron transfer-induced dynamics of oxygen molecules on the TiO2(110) surface

Diffusion of oxygen molecules on transition metal oxide surfaces plays a vital role for the understanding of catalysis and photocatalysis on these materials. By means of time-resolved scanning tunneling microscopy, we provide evidence for a charge transfer-induced diffusion mechanism for O2 molecules adsorbed on a rutile TiO2(110) surface. The O2 hopping rate depended on the number of surface donors (oxygen vacancies), which determines the density of conduction band electrons. These results may have implications for the understanding of oxidation processes on metal oxides in general.     

Effects of nitrogen supply on growth and nitrogen uptake by Miscanthus sinensis during establishment

The effect of nitrogen (N) supply on growth and N uptake of Miscanthus sinensis during the establishment was determined. Seven different N addition regimes were compared in a nutrient solution experiment. In the treatments N111 (severe deficient), N222 (moderate deficient), N333 and N444 (optimal for maximum growth) different N concentration ranges were held constant during the entire growing season. In the treatments N144, N414 and N441 plants were subjected to low (1) N concentration in one of three experimental periods, whereas the N concentration was high (4) in the other two periods. Depending on the N demand of the plants, N concentrations were adjusted to 250–500 μM (N1), 500–1000 μM (N2), 1250–2500 μM (N3) and 2500–5000 μM (N4) when the N concentration in the N222 treatment had dropped below 100 μM. The other elements in the solution were replenished according to the estimated element ratios in the plants. As a reference the potassium concentration in the solution was measured regularly. During the first year plants with a non-limited N supply (N444) produced new tillers and increased the length of individual tillers until the end of the growing season. This resulted in a 48% shoot dry matter increase late in the growing season between August and October and a linear increase of cumulative N uptake between July and October. Limited N supply during the entire growing season (N111, N222) caused lower shoot yields but rhizome and particularly root dry weights were less affected. Significant final yield losses were also observed when the N supply was limited only during the first 7 weeks of growth (N144). By contrast, final shoot yield was hardly affected when the plants were exposed to limited N supply over a period of 9 weeks at the end of the growing season (N441). In the second year regrowth of shoots in spring was affected by the previous year's N supply, since five weeks after the beginning of regrowth, shoot dry matter was significantly positively correlated with N contents in rhizomes and shoots in the previous October. Our results show, that N supply at the beginning of the growing season has a major effect on final yield in the first establishment year of M. sinensis. However, from the second year on, the capacity of N reserves in rhizomes and roots affects spring growth much more than current N supply.     

Water and Element Fluxes of Red Oak Ecosystems during Stand Development on Post-Mining Sites (Lusatian Lignite District)

Most spoils in the Lusatian lignite district have been afforested successfully. However, since soil chemical status remains very different compared to unmined locations even after decades it is still unclear if forest ecosystems develop to a self-sustainable status or if restoration will fail in the long term. To clarify this question water and element fluxes of different-aged red oak(Q. rubra L.) stands on both Quaternary pure sands and Tertiary, pyritic loamy sands were investigated and compared to a nearby, unmined location. Due to increasing interception and evapotranspiration, the deep percolation rates of red oak forests decline drastically within30 yr. Annual groundwater recharge is about 300 mm yr^-1(41–46% of precipitation) initially. Deep percolation of the older stands decrease to less than 15% of precipitation, independent of substrate type. Tertiary substrates are characterized by intensive leaching of H, Fe, Al, Mg, Ca, NH₄-N and SO₄-S due to pyrite oxidation and therefore enhanced silicate weathering. Despite of drastically declining output rates with progressing ecosystem development, they remain remarkably higher as compared to Quaternary sands. However, despite differences in soil chemistry, the aged stands act as an almost complete sink for N, P and K. Compared to adjacent oak forests on undisturbed soils the stands on reclamation sites show very similar patterns with regard to N, P, K, Ca and Mg turnover.     

Monographs on underutilized and neglected crops

An initiative is presented which is intended to promote the conservation and use of underutilized and neglected crops. The aim of this project is to identify key information sources and to systematically compile, analyze and disseminate information on a selected set of neglected crop species/gene pools with a view to facilitate the development of a well-targeted global plan of action to improve their conservation and use. The resulting information base will support continued research on these neglected crops. So far, 24 monographs have been published.     

Geo‐Pedogenese mariner Rohmarschen Spiekeroogs

Geo‐pedogenesis of Salic Fluvisols on the North Sea island of Spiekeroog Although the mainland's Salic Fluvisols of the southern North Sea coast are rich in carbonate, those of the adjacent island Spiekeroog are not. Thus, the aim of this study was to investigate the Salic Fluvisols of Spiekeroog in comparison to those of the mainland and to find out the reasons for the lack of carbonate, which was supposed to be an interaction between sedimentation and sulfur dynamics. The vegetation, many physical and chemical properties (e.g. pH, C_org, salinity, Fe_od, exchangeable cations, CEC) of the Spiekeroog Fluvisols are similar to those of the mainland. However, the Spiekeroog soil profiles extended over the marsh sediments, and the sand sediments below and they contained more silt and less clay and carbonate (0.3 – 34.5 g kg^–1) than the soils of the mainland. A survey proved carbonate‐free areas. The relatively moderate S dynamics showed a spatial and temporal stabile SO₄‐S‐fraction (0.3 – 0.6 mg g^–1), a fairly stabile HNO₃‐HCl‐S fraction (1.5 – 2.9 mg g^–1), but a variable HCl‐S fraction. The vertical Cs‐137 distribution showed peaks at 3 – 4 and 7 – 8 cm soil depth, indicating sedimentation rates of 0.2 – 0.5 cm a^–1. The results showed that moderate S dynamics lead to carbonate losses which are not compensated because of low sedimentation rates. Consequently, the Spiekeroog Salic Fluvisols will enter the terrestrial phase of soil development without carbonate. Thus, besides the usual pedogenesis of Eutric Fluvisols via Salic and Calcaric Fluvisols, the investigation proved a direct development from Salic to Eutric Fluvisols.