Effect of Leachate Fraction on Nitrate Loading to the Soil Profile Underlying a Greenhouse Crop

Abstract

Poinsettia stock plants were grown in a greenhouse and irrigated with a 20 mM (280 ppm) N solution to produce a low (10%) or high (50%) leaching fraction (LF). At two week intervals, core samples were removed from the soil underlying the crop at 15 cm (6 in) increments to a depth of 90 cm (36 in). Leachate was collected from pots following each irrigation, and plant tissue and potting medium samples were collected. All samples (soil, leachate, plant tissue and potting medium) were analyzed for nitrate-N (NO3−N) content. The rate of NO3−N accumulation and the depth to which nitrate accumulated in the soil profile were significantly affected by leaching fraction. Under high LF treated plants, nitrate moved deeper into the soil profile and accumulated at higher concentrations than under low LF treated plants. Each irrigation event in the high LF treatment resulted in an average deposition of 243 ml (8.2 fl. ounces) of effluent containing 100 mg (3.53 × 10−3 oz) of NO3−N. The average low LF irrigation event deposited an average of 65.7 ml (2.2 fl. ounces) of effluent containing 33.5 mg (1.18 × 10−3 oz) NO3−N. Poinsettia cutting production and tissue nitrogen levels did not significantly differ between treatment groups.

Modeling Daily Water Use of Hydrangea macrophylla and Gardenia jasminoides as Affected by Environmental Conditions

“…Recommended BMPs do not account for DWU differences among species or for daily fluctuations in DWU resulting from changing environmental conditions. The result is often overirrigation of nursery crops and a resultant increase in fertilizer and pesticide leaching and runoff that is capable of causing eutrophication of surface water bodies (Majsztrik et al, 2011) or contamination of groundwater (Brand et al, 1993;Mangiafico et al, 2009;McAvoy et al, 1992). Leaching of nutrients out of the container substrate also has been shown to reduce plant growth rates as a result of a long-term reduction in fertility (Million et al, 2007).…”

Nutrients and Pesticides in Stormwater Runoff and Soil Water in Production Nurseries and Citrus and Avocado Groves in California

“…of 7.2 and 12.7 mgÁL -1 , depending on irrigation practices (Colangelo and Brand, 2001). Other studies have reported an accumulation of NO 3 -N in soil under woody and herbaceous container-grown crops (Brand et al, 1993;McAvoy, 1994;McAvoy et al, 1992). This increase in soil NO 3 -N occurred particularly in the top 30 cm of the soil profile, although increases in soil NO 3 -N were found to a depth of 90 cm.…”