Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Plants, Soils, and Climate

Committee Chair(s)

Grant E. Cardon


Grant E. Cardon


Brent L. Black


Paul R. Grossl


Suitable orchard land in regions of the Intermountain West is becoming more limited due to urban sprawl. With the loss of suitable farmland, increasing production costs, and the lack of sound fertility information for these regions, fruit growers face challenges to produce high quality fruit for market demand. Current standard management practices are not sufficient to optimize yield and fruit quality in the marginal farm land that is currently be used for fruit production. Fertility management of orchard trees is vital to tree health, yield, and fruit quality.

Three different approaches were used to investigate the effects of Phosphorus (P) and Potassium (K) nutrient additions on tart cherry yield and fruit quality, including: the correlation between fertilizer application rate and yield and fruit quality, the influence of different P and K nutrient sources on tree performance, and the relative importance of P or K on tree performance measures

The rate that optimized yield was accomplished with rates between 0.45 and 0.91 kg/tree of 16-16-16 fertilizer. These rates produced optimum yields at sites with histories of moderate or not very aggressive nutrient management programs. For sites with a history of aggressive nutrient management there was no effect of rate on yield or fruit quality. The addition of K had larger effects on yield then the addition of P. No advantage of higher cost nutrient sources over standard low-cost sources was found. Furthermore, no advantage was observed from splitting fertilizer applications over time during the season.

Commercial orchard managers in the Intermountain West need information on optimum fertility management for their unique environment. Results from these studies were integrated in a series of grower recommendations contained in Chapter 4. Fertility management strategies in high elevation, arid climates, and alkaline soil conditions will provide benefits to fruit producers as well as fruit consumers. With fertility management strategies specific to the conditions of the Intermountain West, fruit growers will produce enough fruit that is high quality to take full advantage of local and global demand.



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Horticulture Commons