Finding guidelines for cabbage intercropping systems design as a first step in a meta-analysis relay for vegetables

Modern agriculture has been focused on optimizing production, neglecting supporting and regulating ecosystem services. Meta-analyses have demonstrated the potential of intercropping to deliver multiple ecosystem services. However, guidelines for the design and management of such systems remain unclear, especially for the understudied vegetable-based intercropping systems. Given the diversity of vegetable crops, we propose a ‘relay’ of classical crop-specific meta-analyses to capitalize on vegetable intercropping research. Each ‘leg’ in the relay analyzes the effects of companion crops on a focal crop, and over the course of subsequent legs, the network of interactions among the different crops is built. In this study we start what we aspire to be the meta-analysis relay, focusing on cabbage (Brassica oleracea ssp.) and the delivery of the provisioning services Productivity, Product Quality (grade and pest injury in cabbage products), and Yield Stability across different companion species, spatio-temporal configurations, and management practices. We identified 76 studies from all inhabited continents across 81 field sites, comprising 892 data records, of which 689 remained after cleaning. We show that intercropping reduced cabbage productivity (−7% on average, P < 0.05) but also pest injury (−48%, P < 0.001) relative to sole cabbage systems. Cabbage grade on the contrary was not significantly improved by intercropping (+1%, P = 0.71). Effects on yield stability varied widely as only few data records were available from trials conducted over more than two years, pointing to the need for longer-term experimentation. Greater productivity was associated with companion species with a low growth habit or types sown at or after planting of the cabbage crop thus limiting competition with cabbage at early development stages. The decrease in pest injuries was associated with intercropping patterns involving strong inter-plant interactions (i.e., mixed, row, and additive) and companion species that supported biodiversity such as living mulches. Overall, beneficial effects of intercropping tended to be more evident in organic production systems, possibly because synthetic inputs may have hidden regulating effects. Cabbage growers and agricultural advisors can use these guidelines when designing intercrop systems specific to their needs. Applying the approach to other crops and agro-ecosystem services as part of the proposed meta-analysis relay will foster comprehensive understanding of vegetable intercropping systems interactions

Si-O-Si Angle Distribution in Amorphous Silica Characterized by EXAFS Multiple Scattering Calculations

EXAFS-Multiple Scattering (MS) calculations has been performed to characterize the second shell of neighbours around silicon in amorphous silica. To render the large Si-O-Si angle distribution, a combination of three regular [(Si(OSi)4] structural models covering the 130 to 160° angle range is used in the calculations

Zooplankton community structure in a highly turbid environment (Charente estuary, France): Spatio-temporal patterns and environmental control

Zooplankton assemblages were studied from January 2007 to January 2008 along the salinity gradient of the Charente estuary (France). A Lagrangian survey was performed monthly at five sampling stations defined by salinity (freshwater, 0.5, 5, 15 and 25) in order to collect zooplankton and measure the main environmental parameters (concentrations of suspended particulate matter, particulate organic carbon, chlorophyll a and phaeopigments). A combination of multivariate cluster analysis, species indicator index and canonical correspondence analysis was used to relate the spatio-temporal patterns of the zooplankton assemblages with environmental drivers. The estuary was divided into three different zones by means of environmental parameters while four zooplankton assemblages were identified along the salinity gradient. The Charente estuary appeared as one of the most turbid systems in Europe, with suspended particulate matter (SPM) concentration reaching 3.5 g l-1 in the Maximum Turbidity Zone (MTZ). Algal heterotrophy and microphytobenthos resuspension from the wide mudflats could be responsible for the relatively high chlorophyll a concentrations measured within this MTZ. Salinity and SPM affected significantly the spatial distribution of zooplankton species while temperature and river flow seemed to control their temporal variations. From a zooplanktonic viewpoint, the highly turbid Charente estuary seemed to match an "ecotone-ecocline" model: the succession of species assemblages along the salinity gradient matched the concept of ecocline while the MTZ, which is a stressful narrow area, could be considered as an ecotone. Although such ecoclinal characteristics seemed to be a general feature of estuarine biocenoses, the ecotone could be more system-specific and biological compartment-specific. © 2010 Elsevier Ltd. All rights reserved

Finding guidelines for vegetable-based intercropping design through a relay of meta-analyses. Framework and application to cabbages

Modern agriculture has been focused on improving and optimizing production, neglicting supporting and regulating ecosystem services. Meta-analysis has been a useful tool to demonstrate the potential of cereal-legume intercropping to deliver multiple ecosystem services and providing guidelines for their intercrop design. However, detailed guidelines for the design and management of such systems remain unclear, especially for the understudied vegetable-based intercropping systems. whether such premises apply to vegetable-based intercropping systems remains unknown. Given the diversity of vegetable crops, we propose a ‘relay’ of crop-specific meta-analyses to capitalize on vegetable intercropping research. Each ‘leg’ in the relay analyzes relevant performance criteria from the perspective of one focal crop, and over the course of subsequent legs the network of interactions among the different crops is built. We argue that this approach provides crop-specific guidelines and identify designing principles that are applicable under a range of different environmental conditions. We started the ‘relay’ meta-analysis focusing on cabbage (Brassica oleracea ssp.) and the delivery of the provisioning services productivity, product quality (grade and pest injury in cabbage products), and yield stability across different companion species, spatio-temporal configurations, and management inputs. We identified 72 studies across 62 field sites, comprising 564 data records. We show that intercropping did not significantly compromise cabbage productivity (-6 % on average) or grade (1%) and significantly reduced pest injury (53 %) relative to sole cabbage systems. Effects on yield stability remained unknown as trials were rarely conducted for more than two years, pointing to the need for long-term experimentation. Greater productivity was associated with short companion species with a low growing habit or types sown at or after planting of the cabbage crop thus limiting competition with cabbage at early development stages. The decrease in pest injuries was associated with intercropping patterns involving strong inter-plant interactions (i.e. mixed, row and additive) and companion species that supported biodiversity such as living mulches. Overall, beneficial effects of intercropping tended to be more evident in organic or no input production systems, possibly due to synthetic inputs overriding potential regulating effects and/or promote imbalance between the intercropped species. Cabbage growers and agricultural advisors can use these guidelines for designing intercrop systems specific to their local conditions. A more holistic understanding vegetable intercroping systems interactions can be achieved by implementing the database structure developed here with other crops and agro-ecosystem service