Despite being necessary for effective water management, the assessment of an irrigation system requires a large amount of input data for the estimation of related parameters and indicators, which are seldom measured in a regular and reliable manner. In this work, spatially distributed surface energy balance fluxes and geographical information systems analysis of multiple groundwater parameters were used to estimate water availability, supply, and demand, in order to calculate water-accounting indicators. This methodology was used to evaluate the performance of an irrigation system in the Pinios river basin (Greece) at two selected years of high and low water availability. Time series of archived satellite images and groundwater measurements have been used for past years to support comparative analyses, due to the limited availability of actual water measurements. The resulting maps from the proposed methodology show that the performance of the irrigation system varied across space and time due to differences in its characteristics and changes in its operation, driven by fluctuation of water availability and the response of stakeholders to water depletion. Irrigation districts with unsustainable water management were identified and, together with those with slow and/or limited groundwater recharge, were brought to the attention of water managers. The observed differences in the system operation between the wet and dry years were attributed not only to the hydrological conditions of each year, but also to the changing behaviour of farmers and the improvement actions of the water managers

During the cultivation periods of 2001 (a dry year) and 2002 (a wet one), an experimental cotton field was irrigated using a subsurface and a surface drip system. Both systems included drip-lines 17-mm in diameter, with emitters discharging 3.8 l/h and spacing 1 m. The treatments included four irrigation levels. These were equal to 120%, 100%, 80% and 60% of the net crop water requirements during each irrigation interval. For their calculation the FAO56-Penman-Monteith methodology that estimates crop evapotranspiration was utilised. From the statistical analysis of the harvested cotton plantations it has been found that during the dry year (2001) the seed cotton yields were significantly higher where the subsurface irrigation system was used and the irrigation applications met the 80% and 60% of the crop water needs. During the two experimental years the higher irrigation applications, 120% and 100% of the crop water needs, gave seed cotton yields that did not differ significantly for both systems (subsurface and surface).

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2 Field experiments were conducted for two years to compare and identify bread spring wheat (Triticum aestivum L.) genotypes which make the most efficient use of nitrogen (N). Such information is required for breeding strategies to reverse the negative relationship between yield and protein content. Three Swiss spring wheat cultivars ('Albis', 'Toronit', 'Pizol') and an experimental line ('L94491') were grown without (N0; 0 kg N ha −1 ) and with high fertilizer N [(NH 4 NO 3 ); (N1; 250 kg N ha −1 ) supply on a clay loam soil with low organic matter content. Biomass and nitrogen accumulation in biomass as well as the leaf growth and senescence patterns (SPAD) were investigated in an attempt to explain the physiology of growth and N translocation of these genotypes. The pre-anthesis accumulation of biomass and N in the biomass depended on genotype only at N1 in 2000. In this year, conditions were less favorable for the pre-anthesis accumulation of biomass and N, which was, on average, 10 and 20% lower, respectively, of the total than in 1999. The contribution of pre-anthesis assimilates to the grain yield (CPAY) was higher in 1999 for all genotypes (36.9%) compared to 2000 (13.5%) except 'Toronit'. Between anthesis and maturity the climate influenced the genetic variability of some N use efficiency components: N translocation efficiency (NTE) and dry matter translocation efficiency (DMTE). NTE was higher in 1999NTE was higher in (68.1%) compared to 2000; 1999 was a year in which the post-anthesis period was drier and warmer than usual. 'Toronit' produced the highest biomass by maturity due mainly to greater and longer lasting green leaf area after anthesis. 'Albis' performed relatively well under low input conditions, with considerable amounts of N being re-translocated to the seeds at maturity (NHI), whereas 'Pizol' accumulated in grains N as high as for 'L94491'. In a humid temperate climate breeding for greater N uptake and partitioning efficiency may be a promising way to minimize N losses and produce high phytomass and grain yields. Using high protein lines as selection material and combining them with high biomass genotypes may lead to high protein contents without decreasing yield.

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