Nitrogen (N) is an essential nutrient required to support citrus yield and fruit quality. Its bioavailability to the tree must be continuous to support adequate biomass production, especially at key phenological stages such as vegetative flush and fruit setting. However, most commercial nutrition programs in southern Texas deliver synthetic fertilizer on average twice per year when not drip-irrigated. Although adoption of fertigation strategies continues to gain ground, the rate of transition is of low velocity, and a percentage of orchards is still flood-irrigated. In these systems, trees rely on the soil storage capacity to meet permanent nutrient demand. This field study investigated the effects of traditional N management practices on two orchards with different rootstock * scion combinations. We evaluated the effects of different N fertilization rates on fruit growth and postharvest traits such as brix, and size-class distribution. Our preliminary data indicates that despite trees growing in similar soil properties, they exhibited differences in fruit growth rate, and size-class distribution of fruits. Moreover, certain rootstocks * scion combinations exhibited superior fruit yield and quality. Continue refinement of nutrient management practices, especially N application is imperative to support tree long-term productivity under the constant pressure of pathogens in commercial settings.
