Optimising Subsidiary Crop Applications in Rotations (OSCAR): A Perspective for the North Africa Region

Background: For sustainable improvement of wheat-based farming systems in the North Africa, there is a need to improve plant health, soil health and fertility. One approach to achieve this is by integrating subsidiary crops (SC) as living or dead mulches or cover crops with the main crops in rotations, which will increase plant species and microbial diversity and reducing water demand in dry climates. Methods: A collaborative research project funded by EU FP 7 (Project No. 289277) was initiated in April 2012, in partnership with European Union (public research organizations and private sector small and medium enterprises of Germany, Norway, Sweden, Denmark, the Netherland, UK, Poland, Switzerland and Italy), Brazil and Morocco (INRA-Morocco and ICARDA), in order to enhance understanding and use of SC systems, develop suitable farm technologies, increase the range of SC species, and enhance understanding of impact of SC on soil ecology, biology and microbial diversity and crop pests and diseases. Results: Based on two field experiments in Morocco (Sidi AI-Aidi and Sidi Allal-Tazi), the project will assess the economic and ecological impact including legume root health and soil health, fertility and microbial diversity and compare the results with other sites in Europe. Screening of new species and genotypes will result in identification of range of potentially useful plant species for SC for the North Africa and Europe. The identified SC species will be tested for their potential as forage and for extraction of useful biochemicals. Conclusion: The results of the project as a whole will be of use for and improve sustainability in low-input, organic, and conventional farming systems in the North Africa, Latin America and Europe

Towards identification of novel legume species of potential interest as cover crops and living mulches for the North Africa region.

Subsidiary crops (SC) grown either as cover crops (CC) preceding or following the main crops, or as living mulches (LM) together with the main crops can deliver multiple ecological services within farming systems. These include increasing the duration of soil cover in the rotation, increasing plant and microbial diversity, improving plant health, soil health and fertility, minimizing the use of tillage and agrochemicals, enhancing biological N fixation and soil C content, and reducing water demand in dry climates. However, species available for growing as SC for dry areas are limited. To identify species of potential interest to CC and LM, we screened 197 accessions from the ICARDA genebank, belonging to 142 species/sub-species at Rabat, Morocco in one square meter plots. The preliminary assessments based on visual observations enabled us to identify: (1) 21 accessions belonging to Medicago and Trifolium species with prostrate growth habit, early maturity and senescence, determinate growth cycle and good potential for seed production, as potentially suitable for LM; and (2) 28 accessions belonging to Vicia, Lathyrus, Medicago and Trifolium species with high biomass and competitive ability, and also good potential for seed production, as potentially suitable for CC or green manure crops. Further evaluations in replicated trials are in progress. The selected accessions have been planted in the field during autumn 2013 at Sidi El Aidi

Field homogeneity in OSCAR-MEE

Soil properties at the beginning of the MEE (Multi Environment Experiments) were statistically analyzed in order to verify the field homogeneity. The initial soil properties represent the starting point to interpret the effect of CC and LM on soil fertility during crop cycle.Soil properties of the fields were quite homogeneous at the beginning of crop cycles (first and second). The soil properties of the experimental fields in the selected areas showed a wide variety of pedons to be used for the comparison of CC and LM effect in different climate zones. Soils from the Northern European sites are more acid and richer of nutrients and organic matter with respect to the soils in Southern sites

Variability in natural populations of Sinorhizobium meliloti in Morocco Options Méditerranéennes, A no. 92, 2010 -The contributions of grasslands to the conservation of Mediterranean biodiversity Variability in natural populations of Sinorhizobium melilot

----------------------------------------------------------------------------------------------------------- To cite th is article / Pou r citer cet article Abstract. In Morocco, alfalfa (Medicago sativa L.) is being grown in harsh environments (such as mountains and oasis) and is frequently subjected to abiotic stresses such as salinity, drought and high temperature. Both alfalfa and its nitrogen fixing symbiotic bacteria Sinorhizobium meliloti are affected by these abiotic stresses. Improvements in biological nitrogen fixation could be achieved through selection of tolerant strains of S. meliloti to these abiotic stresses and inoculating them to the crop and also growing tolerant cultivars. This study examines phenotypic diversity for tolerance to drought, extremes of temperature and soil pH, soil salinity and heavy metals and genotypic diversity at Repetitive Extragenic Pallindromic DNA regions of 157 Sinorhizobium isolates, sampled from marginal soils of arid and semi-arid regions of Morocco. The results revealed high degree of phenotypic and genotypic diversity in Sinorhizobium populations. Further more, the isolates which showed tolerance to salinity stress also showed tolerance to water stress, indicating direct relationships between these two physiological pathways. High salt and water stress tolerant strains were isolated and tested for their ability to biological nitrogen fixation. Some of the isolated tolerant strains were also efficient nitrogen fixers, under water and salt stress conditions. The Analysis of Molecular Variance revealed that largest proportion of significant genetic variation was distributed within regions than among regions. Keywords. Sinorhizobium meliloti -Phenotypic diversity -Genotypic diversity -Abiotic stresses. La variabilité des populations naturelles de Sinorhizobium meliloti au Maroc Résumé. Au Maroc, les populations locales de luzerne (Medicago sativa L.) sont cultivées dans des montagnes et des oasis présahariennes. Dans ces environnements, la luzerne et son microsymbion

Genotypic characterization of indigenous Sinorhizobium meliloti and Rhizobium sullae by rep- PCR, RAPD and ARDRA analyses

The rhizobia, Sinorhizobium meliloti and Rhizobium sullae, which fix nitrogen in root nodules of alfalfa (Medicago sativa L.) and sulla (Hedysarum sp.) forage legumes, respectively, were isolated from rootnodules and soils from Morocco. We used three PCR-based techniques namely, rep-PCR, RAPD and ARDRA techniques for genotypic characterization of 10 isolates of S. meliloti and R. sullae, in order toidentify rapid and reliable techniques for applications in population genetic analysis of these species. The analysis revealed characteristic banding patterns for S. meliloti and R. sullae isolates by all the three techniques, even though the isolates are from a narrow geographic region in Morocco. Furthermore, the results showed that the rep-PCR with REP and ERIC primers was more efficient than RAPD and ARDRA technique for genotyping S. meliloti isolates; and rep-PCR with REP primers and the ARDRA technique with restriction enzyme HinfI, were more efficient than the other rep-PCR and RAPD-PCR techniques for genotyping R. sullae isolates

Composting parameters and compost quality: a literature review

International audienc

Soil quality grouping variables in OSCAR-MEE

Soil chemical properties were correlated with microbial biomass and its activity. Different correlations were found at the beginning of the first and second cycles, respectively. Soil samples were grouped with respect to the different climate zones. The main variables that separated the countries were organic Carbon, total Nitrogen, pH and clay content

Water use efficiency, transpiration and net CO2 exchange of four alfalfa genotypes submitted to progressive drought and subsequent recovery.

The predicted worldwide increase in arid areas and water stress episodes will strongly affect crop production. Plants have developed a wide diversity of physiological mechanisms for drought tolerance. A decline in photosynthesis and thus yield production is a common response to drought, as are increases in the water use efficiency of photosynthesis (WUEph) and productivity (WUEp). The aim of our study was to determine the physiological effects (especially WUEph and WUEp) of progressivedrought and subsequent recovery in three cultivars adapted to a Mediterranean climate [Tafilalet (TA), Tierra de Campos (TC), and Moapa (MO)], and another representative from an oceanic climate (Europe (EU)). The accuracy of the relationships between WUEph or WUEp and carbon isotope discrimination (Δ 13C) in shoots was also investigated as a function of water stress intensity. Mild drought (7 days of water withholding) decreased the net CO2exchange (A), leaf conductance to water (g) and transpiration in EU leading to an increased WUEph. Δ 13C was correlated with WUEp but not with WUEph, probably due to a late decrease in g. After moderate drought (14 days), A and g decreased in all cultivars, increasing WUEph. In this period WUEp also increased. Both WUE parameters were correlated with Δ 13C, which may indicate that the g value at the end of moderate water stress was representative of the growing period. After 21 days, TA was the most productive cultivar but under severe drought conditions there was no difference in DM accumulation among cultivars. After the recovery period, leaf area was increased but not total DM, showing that leaves were the most responsive organs to rewatering. Severe water stress did not decrease WUEph or WUEp, and Δ 13C did not increase after recovery. This absence of a response to severe drought may indicate significant effects on the photosynthetic apparatus after 21 days of withholding water. As for mild drought, WUEp but not WUEph was correlated with Δ 13C, supporting the view that WUEp is a more integrative parameter than WUEph

Water use efficiency, transpiration and net CO2 exchange of four alfalfa genotypes submitted to progressive drought and subsequent recovery.

The predicted worldwide increase in arid areas and water stress episodes will strongly affect crop production. Plants have developed a wide diversity of physiological mechanisms for drought tolerance. A decline in photosynthesis and thus yield production is a common response to drought, as are increases in the water use efficiency of photosynthesis (WUEph) and productivity (WUEp). The aim of our study was to determine the physiological effects (especially WUEph and WUEp) of progressivedrought and subsequent recovery in three cultivars adapted to a Mediterranean climate [Tafilalet (TA), Tierra de Campos (TC), and Moapa (MO)], and another representative from an oceanic climate (Europe (EU)). The accuracy of the relationships between WUEph or WUEp and carbon isotope discrimination (Δ 13C) in shoots was also investigated as a function of water stress intensity. Mild drought (7 days of water withholding) decreased the net CO2exchange (A), leaf conductance to water (g) and transpiration in EU leading to an increased WUEph. Δ 13C was correlated with WUEp but not with WUEph, probably due to a late decrease in g. After moderate drought (14 days), A and g decreased in all cultivars, increasing WUEph. In this period WUEp also increased. Both WUE parameters were correlated with Δ 13C, which may indicate that the g value at the end of moderate water stress was representative of the growing period. After 21 days, TA was the most productive cultivar but under severe drought conditions there was no difference in DM accumulation among cultivars. After the recovery period, leaf area was increased but not total DM, showing that leaves were the most responsive organs to rewatering. Severe water stress did not decrease WUEph or WUEp, and Δ 13C did not increase after recovery. This absence of a response to severe drought may indicate significant effects on the photosynthetic apparatus after 21 days of withholding water. As for mild drought, WUEp but not WUEph was correlated with Δ 13C, supporting the view that WUEp is a more integrative parameter than WUEph