Late frost is a major challenge to stone and pome fruit production in northern New Mexico. In this study, we planted three cultivars of peach (Prunus persica L.)-Challenger, China Pearl, and Contender-on three rootstocks-Nemaguard (P. persica), GF677 (P. persica 3 P. dulcis), and RootpacVR R (P. cerasifera 3 P. dulcis)-in a high tunnel outfitted with thermostat-controlled propane heaters and fans to assess the feasibility of frost protection during bloom and fruitlet stage. In 2017, we planted the trees on Nemaguard rootstocks at 4 3 10 ft spacing and trained them in an open vase system. Due to severe leaf chlorosis, two rows of trees were removed and tissue cultured GF677 and RootpacVR R were planted in May 2018 and budded onsite in Aug 2018. In 2021, we began securing the sidewalls and the doors of the high tunnel and setting up heaters, which we continued until 2023. In 2021, it appeared that buds were damaged by extreme cold sometime in February, before the high tunnel was closed. In 2022 and 2023, the high tunnel system was sufficient to protect blooms and fruitlets from frost and yielded an average of 15.8 kg/tree in 2022 and 12.3 kg/tree in 2023. There was no significant difference between the cultivars in either year. There were, however, significant differences between rootstocks in 2022, with Nemaguard averaging 24.3 kg/tree across cultivars, whereas GF677 and RootpacVR R averaged 11.2 and 11.8 kg/tree, respectively, across cultivars because trees on Nemaguard rootstock were planted almost 2 years earlier than the rest. Comparing peach rootstocks, GF677 and RootpacVR R were more suitable for high pH soil in New Mexico than Nemaguard. Cherry had limited fruit set during this study. In 2022 and 2023, we observed blackened pistils and deformed flowers without petals, stamens, and pistils. More research is needed for cherry high tunnel production in northern New Mexico.

Sprinkler irrigation is an effective method for protecting economic crops from frost damage; however, current research on its impacts is insufficient and lacks comprehensive evaluation. This research investigated the effects of sprinkler irrigation for frost protection on the air, soil, and tea plants in the tea garden. Sprinkler frost protection experiments were conducted in the tea garden, where temperature sensors measured the air and soil temperatures, and Monitoring-PAM was used to measure the chlorophyll fluorescence parameters (Fv/Fm) of the tea plants. The results indicated that lower initial ambient temperatures or smaller droplet sizes accelerate the rate of air temperature increase and slow the cooling rate. Under conditions of heavy frost, ice formation from irrigation water acts as an insulating layer, protecting the inter-row soil. Additionally, the Fv/Fm values of tea leaves protected by sprinkler irrigation ranged from 0.6 to 0.7, and were significantly higher than those of leaves exposed to frost damage. The results also showed that air and soil temperature and tea Fv/Fm can be used to perform a comprehensive assessment of sprinkler frost protection effectiveness.