Location: Southern Horticultural ResearchTitle: Monthly levels and criteria considerations of nutrient, pH, slkalinity and ionic Variables in runoff containment basins in ornamental plant nurseries
|ZHANG, HAIBO - Virginia Polytechnic Institution & State University|
|RICHARDSON, PATRICIA - Virginia Polytechnic Institution & State University|
|BELAYNEH, BRUK - University Of Maryland|
|RISTVEY, ANDREW - University Of Maryland|
|LEA-COX, JOHN - University Of Maryland|
|HONG, CHUANXUE - Virginia Polytechnic Institution & State University|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2018
Publication Date: 3/1/2018
Citation: Copes, W.E., Zhang, H., Richardson, P.A., Belayneh, B.E., Ristvey, A., Lea-Cox, J., Hong, C. 2018. Monthly levels and criteria considerations of nutrient, pH, slkalinity and ionic Variables in runoff containment basins in ornamental plant nurseries. HortScience. 53(3):360–372.
Interpretive Summary: The water quality of ponds that capture irrigation run-off on ornamental plant nurseries may be affected by fertilizer leachates draining from container-grown plants. Water samples were collected monthly from ponds during the spring and summer months and analyzed for 18 water quality variables from a total of 9 recycling ponds and 1 stream in Maryland, Mississippi and Virginia. The monthly changes of increasing and decreasing nutrient and other water quality levels varied between ponds. Generally, macronutrients, such as nitrogen (N) and phosphorus (P), and electrical conductivity increased one to two months after fertilizer application. N and P forms exceeded preferred levels for irrigation water by June and July in three ponds. Micronutrients fluctuated to a lesser degree. Water pH differed widely between nurseries, but fluctuated less within individual ponds. Although levels of N- and P-forms were mostly suitable by irrigation water criteria, levels were frequently above the U.S. Environmental Protection Agency nutrient criteria for promoting healthy water environments of lakes and reservoirs, which would explain the excessive algal growth present in these nursery ponds. Despite diverse differences between nurseries, no obvious detrimental impact on plant quality was reported due to irrigation water quality. Existing water quality criteria do not adequately help diagnosis the suitability of recycled water for irrigating plants.
Technical Abstract: Triplicate water samples were collected monthly from 9 waterways (8 recycling containment basins (RCBs) and 1 stream) on 4 commercial ornamental plant nurseries from February to July, and from 1 RCB and nursery from April to October. Four RCBs, one per nursery, were actively utilized as an irrigation water source. Analysis was done for 18 water quality variables including ammonium-nitrogen (NH4+ -N), nitrate-nitrogen (NO3- -N), ortho phosphate-phosphorus (PO4-P), Total-phosphorus (T-P), potassium, calcium, magnesium, sulfur, aluminum, boron, copper, iron, manganese, zinc, pH, total alkalinity (T-Alk), electrical conductivity and sodium. The degree and rate of monthly change varied considerably between RCBs. Macronutrients generally increased at most nurseries in one to two months after fertilizer application particularly in 3 RCBs (MD21, VA11 and VA12), with levels of N and P forms exceeding preferred criteria for irrigation water by June and July in VA11 and VA12. Micronutrients fluctuated less, and also varied per RCB with the most monthly change occurring in MD21. Even though pH fluctuated, pH tended to remain alkaline or neutral to acidic respective of the RCB during the entire sample period. T-Alk tended to increase over the summer. EC primarily fluctuated in RCBs with high macronutrient levels. No obvious detrimental impact on plant quality was reported at the commercial nurseries. Although levels of N- and P-forms were mostly suitable by irrigation water criteria, they were frequently above U.S. Environmental Protection Agency nutrient criteria for promoting healthy water environments of lakes and reservoirs, and are discussed.