Abstract
Recycling irrigation return flow is a viable option to achieve sustainability in horticultural production systems, but residual herbicides present in recycled water may be phytotoxic. The sensitivity of plants to residual herbicides may vary depending on the growth stage of the plant. If sensitive growth stages are avoided, the risk associated with using recycled water can be reduced. Here, we quantified the effect of residual oryzalin and oxyfluorfen exposure at various growth stages of Hydrangea paniculata. Exposure to both herbicides reduced plant growth, leaf visual rating, soil plant analysis development (SPAD) chlorophyll index, net photosynthesis, and light-adapted fluorescence of H. paniculata. Herbicide injury was greater for plants exposed to herbicides at early growth stages, however, the recovery rate of those plants was also rapid. For oxyfluorfen, plants produced healthy new growth immediately after the end of exposure, but for oryzalin, even newly formed leaves developed herbicide injury after the end of exposure, therefore leaf damage continued to progress before recovering. However, damage caused by residual herbicide exposure at all growth stages recovered over time. Physiological measurements such as the SPAD index, net photosynthesis, and light-adapted fluorescence responded quickly to herbicides exposure hence provided an early indicator of herbicide damage and recovery.
Highlights
Production of container-grown ornamental nursery plants is an intensive horticultural system that requires frequent inputs of water and agrochemicals to produce visually appealing plants
This study focused on: (1) quantifying the physiological and morphological effects of residual oryzalin and oxyfluorfen in simulated recycled water at various growth stages of Hydrangea paniculata Siebold‘Limelight’; (2) identifying variation in sensitivity among growth stages of plants to residual herbicide exposure; and (3) determining the time required to recover from herbicide damage
We found that the sensitivity of plants to residual herbicide in recycled irrigation water was dependent on the growth stage of the plants at the time of exposure
Summary
Production of container-grown ornamental nursery plants is an intensive horticultural system that requires frequent inputs of water and agrochemicals to produce visually appealing plants. Irrigation in nurseries often generates substantial amounts of return flow, as 70–80% of applied water may be lost from nursery production areas [1,2,3]. Irrigation return flow generated from nurseries often contains various agrochemicals, which, if released without remediation, may degrade neighboring ecosystems. Public awareness of non-point source pollution is growing, and so are the regulations to reduce irrigation return flow. Several states, including California, Florida, Texas, Oregon, and Maryland restrict return flow from nurseries and other states will likely follow [4,5]. Nursery growers in states with and without mandatory return flow capture are starting to recycle water for irrigating ornamental crops
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
