Seminar, Oct. 19: Evaluating grafting and integrated fertilizers for improved high tunnel tomato production in northwestern Washington

Student speaker Fairuz Buajaila presents a seminar on “Evaluating grafting and integrated fertilizers for improved high tunnel tomato production in northwestern Washington.”

This seminar is offered by the Dept. of Horticulture on Thursday, Oct. 19, at 2:50 p.m. in 204 Johnson Hall.

Abstract

Growing tomato is a challenge in the short, cool growing season of northwestern Washington. This study investigated two fertilizer sources, conventional and integrated poultry-manure fertilizer, and grafting for effects on growth, N content, yield and fruit quality of tomato grown in a high tunnel in northwestern Washington. Conventional fertilizer was applied at 112N-74P-47K and 356 Ca kg.ha-1 in 2015, and 112N-62P-43K and 288 Ca kg.ha-1 in 2016. Integrated fertilizer was composted poultry manure applied at 2.4 t.ha-1 in both growing seasons (application rates were 12N-58P-26K and 344 Ca kg.ha-1 in 2015, and 17N-61P-43K and 295 Ca kg.ha-1 in 2016), plus urea fertilizer at 90 kg.ha-1 N. Grafting treatments consisted of ‘Panzer’ tomato grafted on rootstocks ‘Estamino’, Maxifort’, ‘DRO138TX’, or non-grafted (control). Conventional fertilizer and grafting increased growth of tomato plants compared to the integrated fertilizer, and non-grafted plants. Grafted plants showed higher nitrate-N than non-grafted plants. Total and marketable fruit weight was higher for grafted plants than for non-grafted plants in the second growing season. Total soluble solids (TSS) and lycopene content were higher with integrated fertilizer, and for fruit from grafted plants. The healing process after grafting is a key factor impacting grafted seedling survival. A greenhouse study investigated the effect of different light (0%, 25%, 50%) and relative humidity (RH) (50%, 100%) levels in the healing chamber environment on the grafting success and plant growth of solanaceous vegetable crops. Survival and growth of grafted plants was greatest when the healing chamber environment was 50% light and 100% RH. Tomato and pepper had 14% greater survival rate on average than eggplant. It is not as critical to control light level in a healing chamber, but RH level can have a significant impact on graft survival, and different solanaceous vegetable crops may have different optimal environments for graft healing.