ASHS 2024 Conference

Micronutrients like boron, similar to essential macronutrients (nitrogen, phosphorus, and potassium), play a crucial role in plant growth and productivity, even though they are required in smaller quantities. In California’s pistachio production, boron deficiency was initially identified as a concern. However, more recently, the issue has shifted to excess boron in soils and water, potentially affecting the plants as boron toxicity. The current study is investigating the relationship between soil and leaf boron levels, leaf surface area damage and yield in pistachio drip irrigated orchard. Soil, leaf and yield data were collected from a second year running salinity management trial on an eight-year-old pistachio orchard (established in 2015) on the west side of the San Joaquin Valley. Our preliminary findings indicate that while soil boron levels significantly reduced pistachio yield, no significant correlation was found between leaf boron level or percentage of leaf damage (indicative of boron toxicity) and yield. This indicates that the decrease in yield with increasing soil boron is not caused by a reduction in active photosynthetic area. Based on these findings, focusing on monitoring and maintaining optimal soil boron levels might be the most effective strategy for minimizing potential yield losses associated with boron issues in pistachio orchards.