Nitrogen fertilization strategies suitable to achieve the quality requirements of wheat for biscuit production

A low grain protein content (GPC) and flour strength (W) are desirable traits for wheat for biscuit production. Nitrogen (N) fertilization is the main factor that affects storage proteins as well as technological quality. The aim of this study was to compare the effect of different commonly applied N fertilization strategies on the quality requirements of common wheat intended for biscuits production. Field experiments were set up over 3 growing seasons at 3 sites in NW Italy on 2 wheat cultivars. Three N rates (100, 130 and 170 kg N ha-1), applied split as ammonium nitrate, have been compared to a slow release fertilizer, applied only at tillering (130 kg N ha-1). The leaf greenness, grain yield, grain and flour protein content and W were affected directly by the rate of N distributed as ammonium nitrate in several of compared agro-environments. Taking in account the same N rate, the application of a slow release fertilizer resulted in a significantly lower GPC (­4%), W (­6%) and flour stability measured through the Brabender farinograph (­10%) compared to the split fertilization with ammonium nitrate, while no difference were observed for ear density and grain yield. Suitable rheological parameters of wheat for biscuits could be achieved through the split application of ammonium nitrate only at low N rate, but this could limit their productive performances. Conversely, the fertilization strategy of applying a slow release fertilizer at tillering is able to better satisfy the qualitative requirements for biscuit production, without causing any grain yield loss.