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Manure is a common source of nitrogen (N) in organic farming. However, manure is not always easily available, while the maximum N amount added as animal manure in organic agriculture is restricted by EU regulations. The present study was designed to test whether green manuring with a warm-season legume and intercropping with a cold-season legume can substitute farm-yard manure or compost as N sources in organic greenhouse tomato crops. To test this hypothesis, a winter-spring (WS) tomato crop was installed in February following the incorporation of crop residues of an autumn-winter (AW) tomato crop intercropped with faba bean, which had been fertilized with cowpea residues as green manure. This treatment, henceforth termed legume treatment (LT), was compared with the use of compost or manure as an N fertilization source in both tomato crops. In addition, a combination of compost and LT was also used as a fourth treatment. The results showed that green manuring with legumes and particularly cowpea can contribute a significant amount of N to the following organic tomato crop, through the biological fixation process. Nevertheless, legumes as green manure, or compost, or their combination cannot efficiently replace farmyard manure as an N fertilization source. Compost exhibited a slow mineralization course.

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For Mediterranean countries irrigation is by far the major water consumer. In this framework the development of operational tools that are able to generate recommendations aiming to improved irrigation management is of great importance. Such a system is IRMA_SYS (the system hereafter) that covers the plain of Arta in Greece. Data from 6 agro-meteorological stations are used by the system to apply spatial interpolation techniques and produce maps of all the basic agrometeorological variables plus evapotranspiration and rain. Among other crops, the system's performance was tested on turfgrass during the irrigation season of 2015. In the present study, a treatment where irrigation frequency was based on the integral of solar energy at the site, as provided by the system (IRS) was compared to a reference one (REF) where irrigation was managed by a controller that used water budget periods and which was equipped with a rain sensor. The latest is considered "best practice" for for Greece. Irrigation water volume, soil moisture, vegetation growth (weight of cuttings) and canopy reflectance were monitored. Canopy reflectance provided data to calculate indices of NDVI and PRI formats which were used as quality indicators. Results revealed similar water consumption, while no statistically significant differences were found in turf growth or quality among treatments. These results are promising as they document the application possibilities of a system that does not use sensors installed on site and yet can automatically compensate for the effects of weather changes on crop water needs.