Rows of tightly packed olive trees stretch across California’s Central Valley. These super-high-density orchards, where trees are planted close together for faster, mechanized harvesting, can grow strong with less fertilizer than expected, according to new research from the University of California, Davis.
The study, published in the journal Agronomy for Sustainable Development, tested how different levels of nitrogen fertilizer and compost affected tree growth, yield and olive oil quality. The two-year field experiment, conducted with local growers in Woodland and near Stockton, found that olive trees produced the same yields and high-quality oil even when using 25% to 50% less nitrogen fertilizer than recommended amounts for traditional orchards.
Andrew Curtright, lead author of the study and postdoctoral scholar with the Department of Land, Air and Water Resources, said this key finding suggests olive growers can use less fertilizer without compromising productivity…