Nutrient loading from initial watering of container plants

T. Yeager, T. Gardner, K. Nyhuis
Nursery plants are often placed in the container substrate and immediately watered intensively. The watering or irrigation is sometimes accomplished with a ‟shower-like” structure that has multiple high-volume nozzles positioned to distribute water over a wagon load of container plants as the wagon passes underneath. The objective of this research was to document nitrogen (N) and phosphorus (P) loading from initial watering of containers using this type of watering station. To accomplish this objective, a concrete pad with collection channel was constructed. Each month for six months, 84 containers (8-L) were filled with a 60% pine bark 40% organic compost (v/v) amended with 11 kg m-3 of a 17N-2.2P-8K controlled-release fertilizer, planted with one of several woody plant species, and loaded onto a wagon that passed under the watering station. Irrigation water applied was metered and runoff volume collected in the channel was measured by weighing. Nitrate N (NO3-N), total Kjeldahl N (TKN), and total P (TP) concentrations in irrigation water and runoff were determined and respective loads from container leaching were calculated considering contributions from irrigation water. An average of 160 L was applied per watering resulting in an average of 93 L of runoff that contained 3.7 and 5.3 g of NO3-N and TKN, respectively, and 372 mg of TP. That equates to potential nutrient loads of 1.3-1.7 kg ha-1 of NO3-N, 1.9-2.5 kg ha-1 of TKN, and 131-175 g ha-1 of TP if container plant densities ranged from 29,640-39,520 on 1 ha of production area. Efficient application of irrigation to minimize leaching and runoff should be an important practice in container plant production.
Yeager, T., Gardner, T. and Nyhuis, K. (2018). Nutrient loading from initial watering of container plants. Acta Hortic. 1191, 183-186
DOI: 10.17660/ActaHortic.2018.1191.25
irrigation, leaching, nursery, runoff, substrate

Acta Horticulturae