Precision in Irrigation Water and Nitrogen Application for Optimizing Yield, Fruit Quality, and Mineral Nutrients in Apples

Precision in application of irrigation water and nutrients plays an important role in fruit yield and quality attributes of apples. Using fruit analysis alone or in combination with leaf analysis often permits more precise prediction of fruit quality. Leaf mineral analysis is a useful tool to diagnose apple tree deficiencies but often is poorly related to fruit quality.  In a long-term study, the impact of different irrigation systems and nitrogen levels on water use, tree growth, yield, biennial bearing, and mineral nutrients of ‘Fuji’ apples were studied. A single drip had similar fruit charectersitics as those with a double drip as long as the same volume of water was used. However, application of water at 50% crop evapotranspiration level (50% ETc) reduced fruit size. Fruit yield and quality attributes, particularly size and color were drastically impacted by varying levels of nitrogen applications.  In this study, the influence of minimum levels of water and nitrogen on apple trees will be discussed in detail.