Outcome of Developing integrated Irrigation Management Strategies to Improve Water and Nutrient Use Efficiency of Organic Processing Tomato Production

This project aimed to develop integrated irrigation practices that capitalize on soil health to improve efficiency of irrigation water and decrease pest pressure and potential N losses of California organic processing tomato production. The current drought has dramatically decreased irrigation water allocated to organic tomato growers and there is an urgent need to test new irrigation strategies that reduce water inputs while maintaining product quality, nutrient supply and high productivity levels. In collaboration with Scott Park, an organic grower located in the Sacramento Valley, we measured how soil health building management strategies can help decrease irrigation water inputs and improve tomato quality in organic system. We found that in fields under long-term organic management, eliminating the final irrigation before harvest saved 0.2-0.5 ac/feet of irrigation water and increased water use efficiency (T harvested fruit/acre feet) by approximately 20% without significantly affecting yield. We observed no impact on diseases and canning quality and there was a trend toward higher nutritional quality (higher phenols). Our findings indicate that terminating irrigation slightly earlier in the growing season is a viable strategy to help organic tomato growers dynamically cope with irrigation water shortages without hampering the quality of their harvested product.