Compost is an acceptable amendment for blueberry plants, but it's important to test it before you apply it. Pay attention to pH and nutrient levels, and watch out for weeds.
In most years, vineyards in Oregon start the season with a full soil water profile. As the season progresses, the soil dries out. Here's how to gauge a vineyard's water needs and methods for meeting them.
This article describes how to determine vineyard nutrient needs through grapevine tissue and soil sampling. It also provides tissue testing guidelines.