Optimisation of N fertilisation is a central issue and goal of applied research in agricultural systems. Site-specific management techniques are needed in order to closely match availability with require- ment throughout crop cycle and to reduce as much as possible environmental dispersion of N. Lysimeter experiments were conducted in central Italy in two subsequent seasons to investigate the response of two commercial durum wheat cultivars to different N fertilisers applied before seeding and at topdressing, and to split applications of N. Grain yield and yield components, N uptake and N leaching were deter- mined. Ammonium sulphate (AS) and urea containing the nitrification inhibitor 3,4-dimetihyl pyrazole phosphate (Entice® 46) were applied before seeding; AS, ammonium nitrate sulphate containing the nitrification inhibitor 3,4-dimetihyl pyrazole phosphate (Entec® 26), and urea were applied at 5th leaf unfolded stage. Six N-fertiliser treatments with a total N amount of 180 kg N ha−1 were tested, consisting of splitting application before seeding, at GS15 and GS30 respectively of 0-180-0, 0-90-90, 30-150-0, 30-75-75, 60-120-0 and 60-60-60 kg N ha−1 . In both years, fertiliser splitting affected durum wheat grain yield and N concentration; variations due to splitting reached 1 t in grain yield and 7 g kg−1 in N concentra- tion of grain, corresponding to 4% increase in protein content. Highest grain yield, protein concentration, nitrogen use efficiency (NUE), and nitrogen uptake efficiency (NUpE) were obtained with the application of 30 kg N ha−1 before seeding. The yield advantage was related to higher number of kernels per spike, resulting from higher number of fertile spikelets per spike. Grain yield was not affected by nitrogen source applied before seeding, but was modified by topdressing N fertiliser. Yield increased by 0.4 t ha−1 with urea, compared to AS and Entec® 26, owing to a greater number of kernels per spike. Nitrogen leaching was closely related to rainfall: total amount of N lost during wheat cycle was almost entirely accounted for N leaching in winter, before topdressing N application. As a consequence, the quantity of N lost by leaching increased with the increase of N rate applied before seeding, while topdressing fertiliser did not affect losses

Waterlogging stress is one of the limiting factors influencing wheat (Triticum aestivum L.) production. Wheat tolerance to waterlogging is related to the duration of the waterlogging event, the crop development stage in which waterlogging occurs, and the sensitivity of genotype. In this paper we investigated the impact of eight waterlogging durations (from 0 to 60 days) imposed at 3-leaf and 4-leaf growth stages (~30 and 40 days after sowing) on grain yield, grain yield components, straw and root dry weight and nitrogen concentration of grain, straw, and roots of two cultivars of wheat. The results showed that of the two cultivars, one (cv. Blasco) was tolerant to waterlogging and the other (cv. Aquilante) was sensitive, thus confirming that there are high genotypic differences in terms of tolerance to waterlogging in wheat. The sensitive cultivar showed a significant reduction in grain yield and straw and root dry weight only when waterlogging was prolonged for more than 20 days. Waterlogging depressed the grain yield of the sensitive cultivar, slowing tiller formation and consequently preventing many culms from producing spikes. It slowed down spikelet formation, consequently reducing the number of spikelets per spike, and reduced floret formation per spikelet, thus reducing the number of kernels per spike.

Waterlogging is one of the limiting factors influencing durum wheat (Triticum durum L.) production. In this paper we investigated the impact of seven waterlogging durations of 4, 8, 12, 16, 20, 40, and 60 days, imposed at 3-leaf and 4-leaf growth stages, on grain yield, grain yield components, straw and root dry weight and nitrogen concentration of grain, straw, and roots of two varieties of durum wheat. Grain yield of both varieties showed a significant reduction only when waterlogging was prolonged to more than 20 days, and 40-d and 60-d waterlogging reduced grain yield by 19% and 30%. Waterlogging depressed grain yield preventing many culms from producing spikes. It slowed down spikelet formation, consequently reducing the number of spikelets per spike, and reduced floret formation per spikelet, thus reducing the number of kernels per spike.

Waterlogging can reduce barley grain yield depending on the sensitivity of the cultivar, the duration, and the stage of development in which waterlogging occurs. This study was conducted to determine whether waterlogging during the tillering stage reduces the grain yield of barley by reducing the spikelet formation and, consequently, the number of kernels per spike, and whether this reduction is related to the length of waterlogging. The impacts of seven waterlogging durations of 4, 8, 12, 16, 20, 40, and 60 d, imposed at 3‐leaf and 4‐leaf stages were investigated for 2 yr at University of Pisa, Italy, on grain yield, grain yield components, straw, and root dry weight and nitrogen concentration of grain, straw, and roots of two cultivars (‘Amorosa’ and ‘Mattina’) of six‐row barley (Hordeum vulgare L.). Cultivar Mattina was tolerant to waterlogging and none of the measured parameters were different from the controls. Cultivar Amorosa was sensitive to waterlogging prolonged for more than 16 d. The highest waterlogging duration (60 d) decreased grain yield (−23%), straw (−29%) and root dry weight (−24%), culm number per plant (−36%), and number of spikelets per spike (−21%) and kernels per spike (−23%) of the sensitive cultivar. The stage at which waterlogging was imposed did not affect the measured parameters. High genotypic differences for tolerance to waterlogging exist in barley. In conclusion, the grain loss of the sensitive cultivar Amorosa resulted from the slowing down of spikelet initiation and consequently the reduced number of kernels per spike.

Wheat grain products are the primary source of dietary Cd-intake for humans. Since varieties differ markedly in grain-Cd accumulation, efforts are needed to find traits associated with low, or high, accumulation. Two durum wheat varieties, selected in a field screening as low (Creso) and high (Svevo) grain-Cd accumulating, were grown on soil spiked with 1.5, 3 and 4.5 mg Cd/kg. Growth patterns, Cd uptake and translocation were investigated at heading and maturity. Cadmium did not affect plant growth and grain yield, but grain-Cd concentration always exceeded the permissible limit of 0.2 mg Cd/kg, and was approximately double in Svevo than in Creso. At maturity, total Cduptake increased linearly with supply in Creso, from 13 to 23 µg/plant, and was approximately 18 µg/plant, irrespective of Cd level, in Svevo. Partitioning to shoot was higher in Svevo than in Creso, both at heading and maturity. We suggest that reduced plant height, high root to shoot biomass ratio during vegetative growth and elevated postheading dry matter accumulation promoted Cd accumulation into grain. Since these traits are common to modern wheat varieties, risks of grain Cd-contamination can increase in the future.