Nitrogen Fertiliser Affects Fresh Weight and Dry Matter Concentration in 'Hayward' Kiwifruit

New Zealand is geographically isolated from many of its key markets where kiwifruit are sold. To retain a competitive edge, the New Zealand kiwifruit industry needs to produce high-quality fruit whilst minimising production costs. In the market, high quality means uniform size, acceptable taste and good storage potential. Consumer acceptability has been linked to fruit dry matter concentration (DMC; dry weight as a proportion of fresh weight (FW)). Nitrogen (N) fertiliser application can affect canopy vigour, fruit size, DMC and storage potential. Therefore applying the right amount of N at the right time could have financial benefits to growers. We discuss some of the factors that need to be considered when managing N fertiliser application and give preliminary results from a long-term N-input experiment we have set up on a numbers of 'Hayward' orchards in the North Island of New Zealand. The main findings were that increasing N application could increase fruit FW, meaning that less fruit needed to be thinned off during the season, giving the potential for higher crop loads to be produced. Conversely increased N input reduced fruit DMC. The future challenge is to maintain a balance between fruit FW, crop load and DMC, and to determine which attributes are the best predictors of how much N to apply to individual orchards.