The importance of root interactions in field bean/triticale intercrops

To highlight the contribution of belowground interactions to biomass and N and P yields, field bean and triticale were grown in a P-poor soil as sole crops and as replacement intercrops at two N levels. The shoots were always in contact, while the roots of adjacent rows were free to interact or were completely separated. This allowed simultaneous testing the intraspecific and interspecific competition between rows, which to our knowledge has not been studied before. Root biomass, distribution in soil, morphometry, and functional traits were determined, together with the nodule number and biomass. The Land Equivalent Ratio for shoot biomass and N and P yield were higher than 1 when roots were in contact, and markedly lower when they were separated. This demonstrates the positive contribution of root interactions, which in field bean, consisted of increased root elongation without changes in biomass and nutrient status; in triticale, of increased N and P uptake eciency and reduced biomass partitioning to roots. The soil-plant processes underlying intercrop advantage led to complementarity in N sources with low N inputs and facilitated N and P uptake with high N inputs, which demonstrates that intercropping could be profitable in both low and high input agriculture

Optics Measurements and Matching of TT2-TT10 Line for Injection of the LHC Beam in the SPS

A well matched injection in the SPS is very important for preserving the emittance of the LHC beam. The paper presents the algorithms used for the analysis and the results of the optics measurements done in the transfer line TT2-TT10 and in the SPS. The dispersion is computed by varying the beam momentum and recording the offsets at the BPMs, while the Twiss parameters and emittance measurements in TT2-TT10 are performed with beam profile monitors equipped with OTR screens. These results are completed by those obtained with a matching monitor installed in the SPS as a prototype for the LHC. This device makes use of an OTR screen and a fast acquisition system, to get the turn by turn beam profiles right at injection in the ring, from which the beam mismatch is computed and compared with the results obtained in the line. Finally, on the basis of such measurements, a betatron and dispersion matching of TT2-TT10 for injection in the SPS has been performed and successfully put in operation

Root dynamics and soil-enzyme activities in field bean/barley intercrops

The study and design of cropping systems that better exploit ecological processes is a priority of the scientific community and intercrops, involving two or more crop species growing simultaneously on the same field, are considered valuable to increase the productivity of traditional family farming and for the sustainable intensification of industrial agriculture. Advantages of intercrops are based on ecological principles such as diversity, complementarity, facilitation and replacement, which are enhanced in cereal/legume associations because of the differences in the morphology and distribution of the root systems and in the use of different N sources. Understanding the complexity of plant-plant and plant-soil interactions is crucial because beneficial complementarity and facilitation relationships can rapidly turn into negative competition. The field experiment consisted of a barley (Hordeum vulgare L. subsp. polystichum, var. Jallon) field bean (Vicia faba minor Beck, var. Vesuvio) intercrop (IC) and the respective sole crops (SC) grown at low (0 kg ha-1) and high (120 kg N ha-1 and 100 kg P ha-1) fertilizer inputs. Seed density was100 seeds m-2 for Fb, 250 seeds m-2 for B, and 100:125 seeds m-2 in the Fb:B IC, where plants were arranged in a 1:1 row ratio spaced 15 cm. At barley heading, soil and root samples were collected from the 0-20 cm soil profile and roots were cleaned from the soil with a water flow and then separated by species. Root morphological traits such as length, diameter, surface area and volume were analysed with WinRhizo, then samples were oven dried. On soil samples dehydrogenase, ß-glucosidase, alkaline phosphatase and arylsulphatase activities were determined, and the geometric mean (GMea) of the assayed soil enzyme activities was calculated. Root density of IC was intermediate between Fb and B SC, the former displaying the highest density on dw basis, the latter on length basis. In both SCs root density was higher without fertilizer input, demonstrating a higher investment in roots in response to NP limitation. In contrast, fertiliser input increased root density in the IC, which we interpreted as a competitive root growth stimulated by the higher nutrient availability in soil. The specific root length (SRL, m/g) increased in Fb SC in response to NP supply, demonstrating an energy investment in root elongation instead in feeding N2-fixing bacteria when mineral N was available, which is confirmed by the lower nodule density. The opposite occurred in the B SC, where SRL was reduced by mineral supply. In the IC, NP input increased the SRL of both species, demonstrating strong interspecific competition for nutrient acquisition and not complementarity, as it is generally supposed for cereal/legume intercrops. As a result of the higher investment of resources in root elongation, in Fb, nodule density decreased dramatically. In the fertilized IC soil also the GMea was higher, suggesting a major production of exudates from roots

Controlled Transverse Emittance Blow-up in the CERN SPS

For several years, a large variety of beams have been prepared in the LHC injectors, such as single-bunch and multi-bunch beams, with 25 ns, 50 ns and 75 ns bunch spacings, nominal and intermediate intensities per bunch. As compared to the nominal LHC beam (i.e. with nominal bunch intensity and 25 ns spacing) the other beams can be produced with lower transverse emittances. Beams of low transverse emittances are of interest during the commissioning phase for aperture considerations and because of the reduced long-range beam-beam effects. On the other hand machine protection considerations might lead to prefer nominal transverse emittances for safe machine operations. The purpose of this paper is to present the results of controlled transverse emittance blow-ups using the transverse feedback and octupoles. The procedures tested in the SPS in 2008 allow to tune the transverse emittances up to nominal values at SPS extraction

FIRE Cirrus on October 28, 1986: LANDSAT; ER-2; King Air; theory

A simultaneous examination was conducted of cirrus clouds in the FIRE Cirrus IFO-I on 10/28/86 using a multitude of remote sensing and in-situ measurements. The focus is cirrus cloud radiative properties and their relationship to cloud microphysics. A key element is the comparison of radiative transfer model calculations and varying measured cirrus radiative properties (emissivity, reflectance vs. wavelength, reflectance vs. viewing angle). As the number of simultaneously measured cloud radiative properties and physical properties increases, more sharply focused tests of theoretical models are possible