Photosynthetic and Growth Responses of Two Broad‐Leaf Tree Species to Irrigation with Municipal Landfill Leachate

Abstract

A study was undertaken to investigate leaf photosynthesis and stem growth responses of saplings of two broad‐leaf tree species to irrigation with municipal solid waste (MSW) leachate in a northern temperate climate at Ontario, Canada. The objective was to quantify plant stresses or changes in plant productivity that could be attributed to this low technology option for the treatment and disposal of groundwater contaminated by municipal refuse. Red maple (Acer rubrum L.) and hybrid poplar [Populus spp. nigra × maximowiczii (NM6)] were subjected to two consecutive seasons of leachate irrigation in a three factor, RCBD split‐plot field experiment. The three factors were irrigant type (MSW leachate, water), mode of application (spray, surface trickle, subsurface irrigation), and rate of application (3.5, 7.0, and 14.0 mm d−1). The main treatment plots in each of three blocks were split into subplots planted to different tree species. In the second irrigation season, the mean seasonal photosynthesis rates increased for irrigated saplings of both species relative to rain‐fed control saplings, irrespective of irrigant type. Mean seasonal photosynthesis rates for red maple increased with irrigant application rate, but were unaffected by irrigant type. Incremental stem diameter and height growth for this species were largely unaffected by the experimental treatments. Mean seasonal photosynthesis rates for hybrid poplar were unaffected by either irrigant type or application rate, but stem growth did increase significantly with leachate irrigation. The mode of irrigant application was not a significant factor in explaining plant response for either species. Direct exposure of leaves to potentially phytotoxic compounds in MSW leachate (volatile organics, and inorganics including metals) by spraying did not induce phytotoxic symptoms in the saplings. Irrigation of a MSW leachate of relatively high ionic strength can be carried out successfully on clay soils under Ontario climatic conditions without causing significant adverse effects on saplings of these tree species. Treatment and disposal of MSW leachates in tree plantations may offer a low technology, low cost option to municipalities.

Growth and biomass of Populus irrigated with landfill leachate

“…This information is useful for increasing yield when applying an alternative irrigation and fertilizer source such as landfill leachate. Shrive et al (1994) irrigated NM6 for two seasons with 3.5 mm d À1 of leachate, a volume similar to the current study, and found height to be significantly greater than with the water treatment. In contrast, fertilization effects from the leachate were not present in the current study.…”

“…Several phytoremediation projects utilized wastewater in the form of landfill leachate as an irrigation and fertilization source www.elsevier.com/locate/foreco Forest Ecology and Management 248 (2007) [143][144][145][146][147][148][149][150][151][152] for poplar trees (Shrive et al, 1994;Erdman and Christenson, 2000;Zalesny and Bauer, in press). Proper clonal selection practices must be utilized given the genetic variability within the genus Populus (Rajora and Zsuffa, 1990;Eckenwalder, 1996) and the variable concentrations of inorganic and organic components in the leachate (Gettinby et al, 1996).…”

“…Leachate production occurs through natural degradation processes aided by the movement of water through the landfill profile (Christensen and Kjeldsen, 1989). Due to the variation associated with residential, commercial, and industrial waste material, the leachate is highly variable and compositional changes occur seasonally and annually (Shrive et al, 1994;Kjeldsen et al, 2002).…”

Remediation of fly ash landfills through plantation

“…and no alarming content of toxic trace metals (Pb, Ni, Co, Cd, Cr, As, and Hg), which conforms with observations by others (Kamble & Patil, 1998;Khan et al, 2000;Lal & Sharma, 2003;Ram et al, 1999Ram et al, , 2000Ram et al, , 2007aSingh & Vibha, 1999). Other studies have shown landfill leachate as a good fertilizer (Hasselgren, 1992); Salix aquatica irrigated with landfill leachate on a restored landfill showed a better yield as compared with unirrigated controls (Ettala, 1988); significant increase in biomass yields of trees when compared with wateror rain-irrigated controls (Brierley et al, 2001;Shrive et al, 1994); and parity with conventionally fertilized trees when irrigated with landfill leachate (Hasselgren, 1992). …”

Effect of landfill leachate on cell cycle, micronucleus, and sister chromatid exchange in Triticum aestivum

“…Many plants are known to be affected by landfill leachate under natural and experimental exposure conditions, including their growth, biomass production, physiological changes and genetic stability [3,[14][15][16][17][18]. Therefore, it is possible to use the sensitive and tolerant plants for monitoring landfill leachate toxicity.…”